Pre fit barrels question

RTH1800

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Minuteman
  • Sep 16, 2009
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    I’ve been on this site since ‘09 iirc. Shooting since too long ago.

    Lot of changes taking place. One that I notice is pre fit barrels. Seems no action is acceptable unless it accepts pre fits.
    Has anyone compared accuracy of pre fits vs top notch custom work?
    Are they equal or just “good enough”?
    Would Tony Boyer compete with a pre fit or would @Terry Cross build a rifle that way? Would @Frank Green prefer a custom barreled rifle to one built as a pre fit?

    Not looking for one off one group antidotes but real scientific testing.
     
    The same precision machining applies. The actions are held to a tight enough tolerance to where the gunsmith doesn't need to measure each one. The only real difference I'm aware of is they can time the natural curvature of the bore to the action if they have it in hand. Don't think that matters too much.
     
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    The same precision machining applies. The actions are held to a tight enough tolerance to where the gunsmith doesn't need to measure each one. The only real difference I'm aware of is they can time the natural curvature of the bore to the action if they have it in hand. Don't think that matters too much.
    And to dovetail onto that, prefits can have the bore curvature timed as well.
     
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    As has been said before prefit does not mean sitting on a shelf at some mom and pop barrel shop. It only means the tolerances on the action are tight enough that they do not need the action to fit the barrels. In reality top shooters have been using prefits for years. Years ago I shot Centerfire Bench Rest and we would call up our friendly Barrel smith and they had had our tenon specs in their files and we would order a bunch of barrels (between 3 and 12 depending on activity and bank account). These were prefit, cut by spectacular smiths, and we installed them ourselves. I am sure other disciplines did the same. Nothing really new, it is just that the action makers just hold the actions to tighter specs so that the barrel smith don't need the action to deliver a great pre-head spaced barrel.
     
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    I’ve been on this site since ‘09 iirc. Shooting since too long ago.

    Lot of changes taking place. One that I notice is pre fit barrels. Seems no action is acceptable unless it accepts pre fits.
    Has anyone compared accuracy of pre fits vs top notch custom work?
    Are they equal or just “good enough”?
    Would Tony Boyer compete with a pre fit or would @Terry Cross build a rifle that way? Would @Frank Green prefer a custom barreled rifle to one built as a pre fit?

    Not looking for one off one group antidotes but real scientific testing.


    So I have both pre-fits and custom screwed-on barrels from the same gunsmith. Two pre-fit rifles and three screwed-on to be exact.

    I notice no difference in accuracy. All of the rifles are capable of accuracy that is beyond what I'm capable of.

    A lot of benchrest or F-Class guys will get multiple barrels done up at once and then change them themselves...so I would say that the level of precision is more determined by the gunsmith than whether or not the barrel is screwed on by the individual or not.
     
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    You might want to define what the difference is between a prefit and a "top notch custom work" barrel. In a lot of cases, whether you send an action into a smith or not, the barrelwork is exactly the same.
    This.
    The consistency of actions these days means a cut to spec part and a cut to fit part should be the same thing.
     
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    Anyone have data?
    You keep asking if you need a TacOps to shoot PRS, and the answer is...NO

    Howver, top shooters in every serious discipline from PRS centerfire, 22LR rimfire, and Fclass, ELR etc all use gunsmiths.
    In pro-level PRS is approx 70/30 custom /pro fitment barrels vs pure DIY lego builds, with about 30% of the guys have pro-fittment (bedding) done on their chassis.
     
    Anyone have data?
    Don't take this the wrong way, but data about what? What do you see as the difference?

    If I send a smith my action, smith measures said action, cuts a barrel, then sends me the action & barrel separately, is that a prefit or a "custom" barrel?
    If the action mfg sends tenon print, smith cuts barrel based on tenon print, and then smith torques the barrel to the action, is that a prefit or a "custom"?
    If smith has action in hand, measures action, and the measurements match the mfg print, is the barrel that gets subsequently cut a prefit or a "custom"?

    Is the difference whether or not bore curvature is timed? Is the difference whether or not the smith torques the action to the barrel themselves? Does the engraving need to be timed? Is there something else that you are thinking of that differentiates the two?
     
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    I have “data”. I’ve done barrels for a custom action with it in hand. I recorded the specs in a notebook so I no longer needed the action in hand. From that point on I span the customer “prefits”. The prefits shot just as well as the “custom fit barrel”. There is no difference.
    Actions that accept Prefits are simply actions which should have better QC/QA than actions which don’t accept Prefits from a production standpoint.
     
    @Shanerbanner, correct me if I'm wrong. The difference when your threading to fit a barrel on an action or cutting a prefit is you take several passes on the tenon threads and as you get close to the thread spec you test with the action by screwing it on. On a Prefit you just cut the threads to a predetermined spec. So on a thread to fit barrel vs a prefit you may get a slightly tighter thread fit. That is the only difference, ya?

    My own interpretation: Barrel torque erases the difference.
    Rem 700 threads are still the standard 1.0625” x 16 tpi. The thread tolerance or “class” determines how “tight” a thread fits. Most smiths will cut class 3 threads for prefits unless the print says otherwise (Bighorn origin which if memory serves calls out for a class 2 thread).

    In the case above, I would determine if a standard class 3 thread fits as it should and make a note of it. I would use the thread mic to note the pitch diameter. If it was a trued action the threads specs would likely be different than standard. You are kind of correct that a smith would typically cut the thread to fit, but that does not dictate accuracy of a rifle. The squareness of the shoulder/receiver surfaces are a major factor there along with how the barrel is indicated.
     
    Threads, for the most part, just align an action and barrel. They do not determine how square and concentric things are (unless they are horrible threads). Accuracy is more reliant on how straight the bullet starts in the rifling which is determined by indicating the barrel at setup and how square the shoulder is to the receiver.
     
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    Here is my beef with the prefits and why for the most part we don't offer it as a standard.

    Argue all you want about cnc this or that and how much better the actions are held to spec. wise... the reality is... the receivers and bolts still have a tolerance. Not naming one but I'll pick one and say the receiver and bolt are supposed to be held to +/-.002".

    Even when we've done a prefit for close customers/guys and I personally delivered the barrel and we put it on the action together and we held the barrels breech length and head space right to the middle of the tolerance spec... we put the barrel on and the headspace ended up right at .000". If we would've been only .001" on the short side... the bolt wouldn't have closed on the go gauge.

    Bolt, barrel, and the receiver... you start stacking the tolerances and it can turn into a quicksand pit.

    One custom gun/receiver manufacturer that we have made a lot of bolt gun barrels for they supplied us with a master receiver and a master bolt to be used as a master gauge for inspection on the barrel fit etc..... we threaded and chambered the barrels to a given spec and we checked fit with they're master gauges but they had us hold the headspace to the short side... so when we would ship a 100pcs at a time... if a bolt or receiver tolerance was stacked and things where tight headspace wise... they would go in with they're chamber reamer and bump the chamber to set the headspace.

    So if you get a prefit and it doesn't shoot... doesn't mean the barrel is necessarily bad etc... you need to check fit/clearances/headspace etc...who's doing it for the customer? The barrel should first go back to the shop and they should double check everything.

    Also we use to offer prefits for CZ actions for example. Based on what we seen.... one out of every 10 barrels we shipped there was a issue. Every time it happen we had the customer send us the barrel along with his bolt and receiver. I can't recall a single time that the barrel breech details was out of spec... tolerances smack dab in the middle of the factory CZ barrel specs... every time it was either the receiver was slightly different or the bolt was slightly different spec wise or the tolerances stacked. Then we have to do the rework which cost time and money. We seen receivers where the barrel wouldn't go on at all or it went on but the bolt wouldn't close or if it did the headspace was off. That's one of the reasons we no longer offer prefits for CZ stuff (besides being to busy). I hated getting the phone call and at times the customer was bent sideways and it was automatically our fault they assumed. Then on top of that we get them to send the stuff in and you can see where they were forcing things to make it fit/work and even more of a mess to deal with. Like I said... a quick sand pit!

    Later, Frank
    Bartlein Barrels
     
    Here is my beef with the prefits and why for the most part we don't offer it as a standard.

    Argue all you want about cnc this or that and how much better the actions are held to spec. wise... the reality is... the receivers and bolts still have a tolerance. Not naming one but I'll pick one and say the receiver and bolt are supposed to be held to +/-.002".

    Even when we've done a prefit for close customers/guys and I personally delivered the barrel and we put it on the action together and we held the barrels breech length and head space right to the middle of the tolerance spec... we put the barrel on and the headspace ended up right at .000". If we would've been only .001" on the short side... the bolt wouldn't have closed on the go gauge.

    Bolt, barrel, and the receiver... you start stacking the tolerances and it can turn into a quicksand pit.

    One custom gun/receiver manufacturer that we have made a lot of bolt gun barrels for they supplied us with a master receiver and a master bolt to be used as a master gauge for inspection on the barrel fit etc..... we threaded and chambered the barrels to a given spec and we checked fit with they're master gauges but they had us hold the headspace to the short side... so when we would ship a 100pcs at a time... if a bolt or receiver tolerance was stacked and things where tight headspace wise... they would go in with they're chamber reamer and bump the chamber to set the headspace.

    So if you get a prefit and it doesn't shoot... doesn't mean the barrel is necessarily bad etc... you need to check fit/clearances/headspace etc...who's doing it for the customer? The barrel should first go back to the shop and they should double check everything.

    Also we use to offer prefits for CZ actions for example. Based on what we seen.... one out of every 10 barrels we shipped there was a issue. Every time it happen we had the customer send us the barrel along with his bolt and receiver. I can't recall a single time that the barrel breech details was out of spec... tolerances smack dab in the middle of the factory CZ barrel specs... every time it was either the receiver was slightly different or the bolt was slightly different spec wise or the tolerances stacked. Then we have to do the rework which cost time and money. We seen receivers where the barrel wouldn't go on at all or it went on but the bolt wouldn't close or if it did the headspace was off. That's one of the reasons we no longer offer prefits for CZ stuff (besides being to busy). I hated getting the phone call and at times the customer was bent sideways and it was automatically our fault they assumed. Then on top of that we get them to send the stuff in and you can see where they were forcing things to make it fit/work and even more of a mess to deal with. Like I said... a quick sand pit!

    Later, Frank
    Bartlein Barrels
    As manufacturing processes improve the QC should as well… keyword there- should.

    I’ve been out of the game for a couple years now, but I know your exact reasoning was a huge problem for us when making Prefits for certain receivers. Are there specific companies which are still the problem children? (Not asking you to name any names).
     
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    Frank,

    Thank you for the detailed, fact based reply.
    This is exactly what logic implies would happen.

    Basically hit or miss with a gimmicky sales pitch.

    Accuracy International, Barrett MRAD, Desert Tech, etc...

    I'm not out here to start a flame war with you man, just showing that there are quite a few big companies out there with a decent track record of accuracy and reliability that take pre-fit barrels.
     
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    Frank,

    Thank you for the detailed, fact based reply.
    This is exactly what logic implies would happen.

    Basically hit or miss with a gimmicky sales pitch.
    I would not say they are a gimmick at all.
    All the major gunsmiths offer prefits for a reason. They work and shoot well, you don’t need a receiver in hand and I firmly believe prefits are the future of “gunsmithing” for precision rifles.

    The manufacturing world is finally being introduced to the precision rifle world. Spinning up a barrel was thought to be this Vudoo magic for so long and the “secrets” were being kept but turns out all you need is a basic engine lathe, some decent tooling and a little bit of know how. There is nothing magical about it. It’s basic turning, threading and reaming, I wouldn’t even call it “advanced” machining.

    There used to be some issues with a specific company or two where their tolerances did not match their prints which caused issues as Frank stated.
     
    As manufacturing processes improve the QC should as well… keyword there- should.

    I’ve been out of the game for a couple years now, but I know your exact reasoning was a huge problem for us when making Prefits for certain receivers. Are there specific companies which are still the problem children? (Not asking you to name any names).
    No I can't pick if there is a specific company that might be an issue etc... even if I could I wouldn't say. I have an action from a custom high end maker/gun manufacturer that the receiver not the bolt is .005" out of spec. length wise. I know that and fit the barrels accordingly.... the rifle pounds stupid small groups with no issues. If stuff like this gets out though and inspection doesn't catch it.... issues happen.

    To me the issue is tolerances and the stacking of tolerances. A .0001" let alone a .001" can make all the difference in the world.

    I look back on a issue we had some years back with a half a dozen ammunition pressure test barrels we made. It wasn't a fit issue or a headspace issue but a dimension issue on the chamber. Some ammo chambered and some ammo wouldn't chamber all the way. The reamer even though brand new cut undersize in the throat. The rocket scientist that wrote the spec's spec'd the bullet could be as big as .3090" diameter and the throat was spec'd at being .3090" diameter also. Sorry Charlie but that can lead to a situation where your size on size and guess what issues will happen. Got two of the barrels back... I inspected them. Pulled all the prints.... that's when I found that spec... so I measured the throat diameter with our bore gauges... reamer cut .0001" to .0002" undersize. That .0001"/.0002" under drove up pressures on average 6k psi on the reference ammo. We took the reamer to a local shop that has a CMM machine and that $120k machine measured to within a .0001" of what I was getting with our $5k bore gauge. So got a new reamer sent in overnight... hand cut the chambers and presto... even the reference ammo that wouldn't chamber before now chambered all the way. Barrels went back for testing and presto... all pressures and velocities came right into spec. Called the other two places up we made barrels for at the same time... they seen the same thing... touched up the chambers and everything for them also fell right into place.
     
    I once bought a factory AI barrel in 6CM, the blank was a Bartlein from a large distributor. They shipped it to me (and thousands of others) without ever seeing my individual action. ;)

    It shoots lights out. Brass looks as perfect as any custom re-barreling job I've ever had after being fired.
     
    Frank, are you saying headspace will affect accuracy to the point that a barrel won't shoot well?
    No headspace as long as it's in spec... I don't see it affecting accuracy...

    but if the headspace is too short.... bolt won't close on a live round... will have function issues to say the least. Don't forget the brass even virgin/brand new brass is held to a tolerance. About 10 years ago you couldn't find any 284 brass. I found brand new in the package like 200pcs of Winchester brass. Heck I still had some 284win brass from the 80's and the stuff ran like a watch so I didn't give it a second thought about using it. I rand all the brass thru my dies to clean them up and prep them for loading. Even checked a half a dozen rounds to make sure they went thru the gun like a hot knife thru butter. I was good to go... so I thought! Went to a F class match and as soon as I made the switch to the new ammo/brass after one relay... go figure... about 80% of my rounds wouldn't chamber and if I did get them to chamber I almost couldn't open the bolt to get the dam round out. Got back home after not being able to finish the match. Nothing changed on my gun etc... so went to checking all of the brass and most of it to the shoulder dimension was too long. I pulled almost 200 bullets, dumped the powder and adjusted my sizing die like 3 times to get the brass to work in my gun. After all of that I still thru out like 20pcs that there was no way I was going to try and push the shoulder back any further. Said I was done with it. Again goes back to stacking tolerances.

    If the headspace is too long... and I'll say that with a grain of salt... but way to long you could run into case failure issues.
     
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    Most ammunition pressure test barrels we set the headspace to +.001" off the breech face. The ammo makers don't want the headspace at .000". That will cause issues.

    The only time we hold it short (.000" or less... let's say a -.0005") and it's per request... is where the ammo maker needs to verify headspace when they put that particular barrel onto a specific test receiver and if need be they will bump the chamber to set the headspace.

    Again guys... back to tolerances.
     
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    Frank, is it fair to say that your contention with prefits isn't in accuracy then? Just basic function?
    Function and accuracy bud.

    You could have a function issue along with a accuracy issue. For example if there isn't enough clearance between the bolt and the breech face of the barrel.... it could cause accuracy issues. Gun can chamber, cycle and go bang etc... but it can affect accuracy as well.

    I can't even count how many guns I/we've seen over the years where the bolt was touching the breech face of the barrel.... give it .005" more clearance and presto... groups come right in and no more flyers.
     
    IMO coming from the machining QC world the best way forward is the prefit setups that use a barrel nut. Two reasons: the first is that it allows an easy remedy to situation such as Frank described where actions on the short side of acceptable tolerance can still be used with barrels on the long side of tolerance. The second is that it allows for very slightly more flatness variance in the mating faces of the action and the ‘shoulder’ (now the nut instead of the barrel) when torquing to spec. The why for the second one is more a topic for a Mech Eng classroom, but shouldn’t be overlooked.

    I will say however on the topic that a gunsmith is more likely to know how to torque to proper spec and have the tools to do so than your average customer who is just as likely to use german torque: gudntight
     
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    I’ve been on this site since ‘09 iirc. Shooting since too long ago.

    Lot of changes taking place. One that I notice is pre fit barrels. Seems no action is acceptable unless it accepts pre fits.
    Has anyone compared accuracy of pre fits vs top notch custom work?
    Are they equal or just “good enough”?
    Would Tony Boyer compete with a pre fit or would @Terry Cross build a rifle that way? Would @Frank Green prefer a custom barreled rifle to one built as a pre fit?

    Not looking for one off one group antidotes but real scientific testing.
    My Proof prefit I had Eric @ Blue Mountain Precision build for one of my Solus actions shoots 1/3 MOA 5-shot groups average. That's just as good as any of my custom built 700's do. The weak-link, like most all of these builds, is going to be the shooter (me) moving slightly on the bags, and I'd be willing to bet that without any shooter error (clamping/bolting the rifle down into a 100 lbs. free-recoiling hydraulic sled like the BR rail gun guys use), it would shoot same hole.

    A GOOD (precision machined) action, and a good barrel builder making your prefit, you should have no problems.
     
    I’ve been on this site since ‘09 iirc. Shooting since too long ago.

    Lot of changes taking place. One that I notice is pre fit barrels. Seems no action is acceptable unless it accepts pre fits.
    Has anyone compared accuracy of pre fits vs top notch custom work?
    Are they equal or just “good enough”?
    Would Tony Boyer compete with a pre fit or would @Terry Cross build a rifle that way? Would @Frank Green prefer a custom barreled rifle to one built as a pre fit?

    Not looking for one off one group antidotes but real scientific testing.

    Equal. I have had plenty of both.
     
    WRT the question asked, there is a point where you need to define the question, or explain what answer you desire. Asking for speculation about Tony Boyer might/would do is pointless. Asking for quantified answers means you need to define the quanta, and the desired variances.

    WRT dimensional exactness or precision of the two questioned options, you are in the area of statical variations. There is not a bimodal answer. Both options share similar precision.

    ETA: As Rob says; "Equal"
     
    IMO coming from the machining QC world the best way forward is the prefit setups that use a barrel nut. Two reasons: the first is that it allows an easy remedy to situation such as Frank described where actions on the short side of acceptable tolerance can still be used with barrels on the long side of tolerance. The second is that it allows for very slightly more flatness variance in the mating faces of the action and the ‘shoulder’ (now the nut instead of the barrel) when torquing to spec. The why for the second one is more a topic for a Mech Eng classroom, but shouldn’t be overlooked.

    I will say however on the topic that a gunsmith is more likely to know how to torque to proper spec and have the tools to do so than your average customer who is just as likely to use german torque: gudntight

    Agree 100%. The barrel nut options get a lot of hate on this site, but I don't give a flying F. I'll use them as long as I can get them. I sleep well at night knowing that when I screw a new barrel on my action, I will have no headspace issues due to the tolerance stackup issues Frank mentions. The barrel nut allows me the ability to do that. Most of the people on here pissing and moaning about how it's SOOO much easier with a shouldered barrel are just lazy and whiners. As a mechanical engineer I deal with tolerance stackup issues every single day and the delays/headaches it can cause, so I choose to eliminate that in my personal rifles as much as possible. Using a barrel nut is the easy button. I laugh out loud every time I read a new thread on here where someone is describing headspace issues with their shouldered prefit.
     
    Let's flip the script. Barring any scary imagined dragons, when a prefit is properly executed......

    ....is there any accuracy (precision) difference?
    I'll say no... I see no difference.

    Also to your other question... if you like prefits and the smith etc... is all working out... run them.

    I look at it this way and you can call it prefits.....

    If Sierra Bullets for example and this has been done... calls me up and says we are using this Barnard PL action.... they give me a headspace dimension and tolerance, breech length dimension etc.... we've done all the threading, chambering etc.... and every barrel worked like a million bucks. We've made barrels for they're action in 300 and 338 Norma with no issues.

    As long as we have the dimensions and tolerances.... or if you will a print... it works.

    The unknown for us.... is when you have X amount of actions being produced and I'll put it this way... the vast majority of the time all should work... your just back to tolerances from the barrel to the receiver and bolt... if any are off.... that's when the issue pops up. We don't make or control the actions and bolts... so that's our variable and the reason I don't want to offer a prefit barrel.
     
    Last edited:
    Agree 100%. The barrel nut options get a lot of hate on this site, but I don't give a flying F. I'll use them as long as I can get them. I sleep well at night knowing that when I screw a new barrel on my action, I will have no headspace issues due to the tolerance stackup issues Frank mentions. The barrel nut allows me the ability to do that. Most of the people on here pissing and moaning about how it's SOOO much easier with a shouldered barrel are just lazy and whiners. As a mechanical engineer I deal with tolerance stackup issues every single day and the delays/headaches it can cause, so I choose to eliminate that in my personal rifles as much as possible. Using a barrel nut is the easy button. I laugh out loud every time I read a new thread on here where someone is describing headspace issues with their shouldered prefit.
    You can have the same exact issue of the bolt face running into the breech with a barrel nut as you do with a shouldered. Mcgowen has proved that to me, counter bore .020 less than it should be meaning it screwed in to an hard stop and the go gauge just rattled around freely in the chamber until it was .007 over go via tape.
    IMG_1183.jpeg


    If the smith cuts it correct it’s the same.

    If the smith fucks it up then he fucked it up.
     
    Last edited:
    You can have the same exact issue of the bolt face running into the breech with a barrel nut as you do with a shouldered. Mcgowen has proved that to me, counter bore .020 less than it should be meaning it screwed in to an hard stop and the go gauge just rattled around freely in the chamber until it was .007 over go via tape.
    View attachment 8549446

    If the smith cuts it correct it’s the same.

    If the smith fucks it up then he fucked it up.

    Exactly. Barrel nuts are not some fix all. They can have issues and you also have more parts. If you have an action that takes shouldered prefits and you use a nut well I don’t know what to tell you but it tells me you like making your life harder. Lol

    Bottom line is the smith makes the difference.
     
    I'll say no... I see no difference.

    Also to your other question... if you like prefits and the smith etc... is all working out... run them.

    I look at it this way and you can call it prefits.....

    If Sierra Bullets for example and this has been done... calls me up and says we are using this Barnard PL action.... they give me a headspace dimension and tolerance, breech length dimension etc.... we've done all the threading, chambering etc.... and every barrel worked like a million bucks. We've made barrels for they're action in 300 and 338 Norma with no issues.

    As long as we have the dimensions and tolerances.... or if you will a print... it works.
    But but but but.... hand fit... better quality... etc etc etc.

    (y)(y)(y)
     
    But but but but.... hand fit... better quality... etc etc etc.

    (y)(y)(y)
    Yes I'll say hand fit because then there should be no guess work as to what was done then.

    The other thing not really mentioned and we run into quite a bit.... not really on new actions but a guy buys a used rifle and then someone monkeyed around with the action and did truing or repair work etc... again throws the dimensions right out the window.

    I will also say this and we see it and it's happened to myself as well... a receiver gets damaged ( I had a thread gall and lock the barrel onto the receiver and had to cut the barrel off and bore out the breech area to get the rest of it out... never touched the threads) and the receiver goes back to the maker and they repair the threads but now the threads are bigger. I had to do that to one of my BAT actions years ago. It all works fine... but you need to use the actual receiver to check the thread fit.
     
    Agree 100%. The barrel nut options get a lot of hate on this site, but I don't give a flying F. I'll use them as long as I can get them. I sleep well at night knowing that when I screw a new barrel on my action, I will have no headspace issues due to the tolerance stackup issues Frank mentions. The barrel nut allows me the ability to do that. Most of the people on here pissing and moaning about how it's SOOO much easier with a shouldered barrel are just lazy and whiners. As a mechanical engineer I deal with tolerance stackup issues every single day and the delays/headaches it can cause, so I choose to eliminate that in my personal rifles as much as possible. Using a barrel nut is the easy button. I laugh out loud every time I read a new thread on here where someone is describing headspace issues with their shouldered prefit.
    Barrel nuts fix only 1 of the potential issues. Chamber shape is not detected when you throw a headspace gauge in the barrel and run it down on the locked bolt.
    The latest recurring problem we see coming into the shop these days is conic runout in the chamber and runout in the throat. The worst offender is the conic runout as it's harder to pin down and it's insidious in that the problems it creates are down the road.

    They shoot fine typically, sometimes not, but when the barrel inevitably wears out and the guy buys another one he finds out there's no way to size the brass web back to fit the new chamber that has less/no conic runout in the body. Now the guy is stuck: the new gunsmith didn't do anything wrong but he's going to get an earful about how his chamber is undersize and the old gunsmith is going to say "but it shot fine for x,xxx rounds why are you calling me now". The prevalence of cheap barrels being made with minimal QA checks puts these onto the market and as of late we've seen a lot of them coming from the places that make inexpensive barrel nut drop ins.

    Being an engineer you're probably pretty mechanically inclined like I am. I look at it thinking "how is this hard to put that together or take it apart." Unfortunately many people are not so fortunate as we are. When you deal with the general public that thinks it can assemble a rifle because they read about it online or watched a youtube video you'll get a better appreciation as to why some of us strongly encourage the use of shouldered prefits due to the reduced complexity. Even with shouldered prefits we still get an email or phone call at least once a month that is some form of "you guys did this wrong, the headspace is off by like 1/4"!!!

    We get the photo of the assembly and tell them to put the recoil lug in the joint and the problem disappears.

    Headspace issues are really not the unsafe problem that the internet makes it out to be. If they were then the entire fireforming concept wouldn't work as well as it does. Even from an accuracy perspective something that squeaks shut on a NoGo gauge is not going to cause accuracy problems; I've tried it and ended up with some outrageously deep chambers that still shoot very well and doesn't rip apart brass. Anyone that has fireformed 6BR into Dasher has done exactly this. It's common to hear about someone fireforming that's getting insane repeatability while they're forming brass. It really isn't the issue that the internet has turned it into.

    Yes I'll say hand fit because then there should be no guess work as to what was done then.

    The other thing not really mentioned and we run into quite a bit.... not really on new actions but a guy buys a used rifle and then someone monkeyed around with the action and did truing or repair work etc... again throws the dimensions right out the window.

    I will also say this and we see it and it's happened to myself as well... a receiver gets damaged ( I had a thread gall and lock the barrel onto the receiver and had to cut the barrel off and bore out the breech area to get the rest of it out... never touched the threads) and the receiver goes back to the maker and they repair the threads but now the threads are bigger. I had to do that to one of my BAT actions years ago. It all works fine... but you need to use the actual receiver to check the thread fit.
    We've dealt with that too and on the numbers of barrels we chamber every year the situation we're talking about happens about 1 time per year. It's easy to handle with the customer on a case by case basis and for the very rare occasions when it happens it's a straightforward solution.

    The solution that we've advertised for years with "hand fit" actions or receivers that don't hold a stackup tight enough to do them all sight unseen is to install the barrel with the action here. Engrave the dimensions onto a tag and send it back with the action. We do additional barrels off the tag dimensions regularly, it takes about 3 mins to provide the tag.

    Far be it from me to tell you to branch out the business and I know you guys are swamped. We have ways to deal with a lot of the commonly raised concerns to make the idea work.
     
    Exactly. Barrel nuts are not some fix all. They can have issues and you also have more parts. If you have an action that takes shouldered prefits and you use a nut well I don’t know what to tell you but it tells me you like making your life harder. Lol

    Bottom line is the smith makes the difference.
    I have some great actions that are older and not "pre fit" ready - barrel nut remage barrels work great and keep those older actions viable.
     
    I have some great actions that are older and not "pre fit" ready - barrel nut remage barrels work great and keep those older actions viable.
    If you let me see that action once I can solve the barrel nut problem for you. And the tags aren't something that only we can use. I tell folks all the time that if you want to give it to another gunsmith in the future have at it. If they say they can't work with the information that's on the tag though, be very careful about giving them the work...
     
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    If you let me see that action once I can solve the barrel nut problem for you. And the tags aren't something that only we can use. I tell folks all the time that if you want to give it to another gunsmith in the future have at it. If they say they can't work with the information that's on the tag though, be very careful about giving them the work...

    100%! I did this with Josh with a Surgeon action I had. Sent the action once and after that could just order shouldered prefits.
     
    If you let me see that action once I can solve the barrel nut problem for you. And the tags aren't something that only we can use. I tell folks all the time that if you want to give it to another gunsmith in the future have at it. If they say they can't work with the information that's on the tag though, be very careful about giving them the work...
    Bought the Remage barrel nut prefits from you - happy with the solution - the Rock Creek deal
     
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    I’ve been on this site since ‘09 iirc. Shooting since too long ago.

    Lot of changes taking place. One that I notice is pre fit barrels. Seems no action is acceptable unless it accepts pre fits.
    Has anyone compared accuracy of pre fits vs top notch custom work?
    Are they equal or just “good enough”?
    Would Tony Boyer compete with a pre fit or would @Terry Cross build a rifle that way? Would @Frank Green prefer a custom barreled rifle to one built as a pre fit?

    Not looking for one off one group antidotes but real scientific testing.
    Back to the original topic here:


    Yes, I've done it. I did it a over decade ago and then proceeded to win a bunch of matches with them. Would Tony Boyer do it? Maybe, maybe not. The difference in me sitting down with a rifle to shoot against Tony has way more to do with the people sitting on the stool than the quality of the machine work. One of the things that folks at Tony's level do is get a bunch of barrels made "identical" and then test them to see which one shoots the tightest and that's the national match barrel. Everything else falls into various categories like fireforming, practice, local match, and "The One"... I'm pretty confident in saying that if Tony in his prime sat down and we shot head to head, then switched guns and did it again, he's still almost assuredly going to beat me.

    The variability of the machine work and the blank itself factors into that. And the variability of the machine work for a "hand fit" or "custom fit" barrel will struggle to match the consistency that comes from my process using CNC's. Those OG bench rest gunsmiths can hand fit a barrel just great. Now I want to see them make 10 identical barrels within 2 tenths on every dimension and do it in less than a week. I'll start at 9am and be done by lunchtime.

    On the comparison of the actions: Let's take this scenario

    Take a TL3-SA that the action headspace is 0.9248 and the print says 0.9250 +/-0.0005" with a Class 3B tenon thread.
    I cut a tenon for it that headspaces to 0.9240 +/-0.0005"

    Against the prints the worst case is 0.9235 barrel headspace and 0.9255 action headspace.

    That's 0.002" apart.
    Tightest they get is 0.001" apart.
    Thread fit: I cut to a Class 3 ring set. The fit is guaranteed to be Class 3 by both parties.

    By all data driven metrics this barrel is just as tight as a standard BR install comes from any of the OG guys. Is it less somehow because it was done in a machine in 20 mins instead of 2+ hours? Hardly. The data says the fit is there and it's backed by the inspection process.


    Let's talk about thread fit

    When I started offering gunsmithing services to customers I was already building my own rifles and had rebarreled a number of them for local friends. Fun story: one time I'm threading a tennon and my buddy Josh is sitting in the garage talking to me and drinking beer. I screw up and take 5 thousandths off on a spring pass instead of a spring pass. That thread fit goes from a squeaky tight Class 3 to a middle of the road Class 2.

    The look of horror on my face says it all to him and once I took a couple of deep breaths he goes "screw it, let's put it on and see how it shoots"

    It was to that date, the best shooting rifle I'd seen out of the gate. So I decided to try it again with my own barrel on the next one.

    I cut it tight so it barely threaded on without lapping (lapping threads is dumb but that's another discussion).

    Take it to the range, all the bells and whistles work up and it shoots in the 0.2's consistently with a 6.5 creedmoor. Definitely a good rifle.

    I bring it back, disassemble, put it back in the machine and proceed to wipe 5 thou off the pitch diameter. Put it back together and shoot the same ammo the same day. After 5 shots of settling in I get a group that's in the high 0.1's; then two more. It's a marked improvement on an already good gun.

    Then I take it home, take another 5 off, so now it's 10 thou under the squeaky "thread to fit" it originally was. It shoots in the high teens again the next day.

    Was the internet wrong? Is thread fit that important?

    So I call AJ Goddard, the founder of Bighorn, and the guy who made the action I was using as a base. He goes "oh yeah, so I did the same thing by accident. I thought the barrel was gonna be junk but it turned out to be one of the best shooting guns I ever put together." So I call Mark Channlynn and tell him what I did and what AJ said and ask him if I was nuts. He tells me that he's been fitting threads somewhat loose on his own rifles for years.

    Apparently this is the best kept secret on the internet because EVERY forum swears upside down and sideways that thread fit has to be tight.

    So now what? I decide to quietly start experimenting with barrels for some of my close friends who will forgive me if I make a mistake. Turns out that a little thread "slop" AKA the natural space designed into the Class 3 fit, works well. It also shows that properly lubricating the threads and the mating shoulders has a lot to do with how a gun shoots, not so much if it's a squeaky tight thread or a standard Class 3 fit.

    A little while goes by and I start offering gunsmithing work and call the business Patriot Valley Arms. When the doors open I offer a previously un-heard of option for folks. "We don't need your Bighorn to make you a sub 1/2 MOA barrel, no gunsmithing required when it shows up".

    The Establishment predicts that I'll be under litigation within a year, someone will be maimed or worse, and this is a horrendous idea. Since then we now offer the broadest range of prefit options of anyone on the market that I'm aware of. I launched the Tikka barrels and it took 3 days before a big competitor decided they could advertise it too. Then I fixed problem barrels sent in from their customers for 6-8 months while they figured out where that window actually sat so they weren't making boomerangs and stuff that fails a headspace check. Guys still argue that the Tikka shouldered prefit shouldn't be available. With a 99.3% FTQ rate I continue to argue otherwise.

    Now, over a decade later there are F class, BR and PRS matches being won with the unthinkable prefit barrel. The first BR match I'm aware of happened with a Zermatt Origin, PVA Prefit in 6BR on a Rock Creek blank in 2018.

    Now, where I think the disconnect happens on "where's the data" comes from the fact that high ranking folks like Tony Boyer, Dave Tooley, Speedy Gonzalez, etc. made their BR Hall of Fame points with the old method. The guys currently winning the top of things came up under the old method. The old method works fine, why change it? Shooters are more superstitious than baseball players sometimes.

    The Old Guard isn't inclined to change and so there will be a years-long lag time from guys that do it the old way and guys that do it the new way trading places at the top of the finish sheets. It will take time for the new guard to get established and gain the shooting skills to compete with the guys who've been doing it the old way since time immemorial.

    It's the same reason why I knew there would be an uphill battle when I started my own barrel brand in 2021. Guys will point to the established brands and say "those guys won more than you, so they must be better". Being around before and for longer doesn't mean better, it means more chances to win. In 3 years we've delivered almost 10,000 barrels and the "dud" pile is still less than 30 deep. But each week I still have that conversation... Don't misconstrue that to be that I'm somehow talking down on the competition. They make great stuff. They stay busy and have long lead times because they make great stuff. Anyone that decides they're going to take stainless steel, drill a 100:1 hole down it with a super tight tolerance, then rifle it and turn it into something that places lead gumdrops on top of each other from hundreds of yards away has my respect.

    If you don't want to use a prefit, you don't have to. That's the beauty of an open market.