Gunsmithing Why do you need to true the bolt face?

[MarineMD]

I have looked at several videos on action truing and most of it makes sense (at least intuitively). For example, I can see why the action, bolt lugs, recoil lug and barrel have to all be perfectly level to each other and perpendicular to the bore. I can see why you need to cut new threads if the original threads are not holding the barrel perfectly straight.

But why does the bolt face have to be any better than how it comes from the factory?

(1). When the firing pin strike the primer doesn't it move the whole cartridge slightly forward in the chamber to the point where the shoulders touch the chamber.

(2) As the primer ignites the overall charge the brass expands first in the shoulders. This holds the shoulders in place in the chamber. The whole brass case then stretches out towards the rear to the bolt face. Isn't this why you can rupture a case if you have excess head space that allows the case to stretch to the point of failure and rupture?

(3) My point is that by the time the bullet begins to move into the bore it is centered by the expanded case shoulders. Which means that it is meaningless where the case head ends up. Even if the boltface is slightly off the bullet is already centered by the expanded case shoulder that have already expended in the chamber.

 

[DocB]

MarineMD,

So you don't bend the brass. If you bend the brass at the expansion area ahead of the web, it will chamber when correctly oriented, but not when reversed 180. You have to have a tight neck chamber or really bad bolt face for this to occur.

HTH,
DocB

 

[MarineMD]

I understand if the bolt face is out of spec it will bend the brass. Presumably the factory bolt face should be within a specification to not allow this. So, DocB would you say that truing the bolt face should have no effect on accuracy and precision of the rifle?

 

[Turd in the Pool]

I can't speak for DocB but everything you read is a cumulation of thousands of guys meter metering and experimenting. Recent threads here discuss truing actions and case head separation. The hill of beans it amounts to is not very tall.

What makes a rifle "precision" is largely credited to the barrel. Sure you can take a great bbl and hack into one that one that won't shoot.

Addressing truing the bolt face. Do you true it on the bolt's axis or the axis of the action/bore when it's in the cocked position and kicked up in the back.

Back to the hill of beans, if you don't shoot fire formed cases, the extractor pushes the rear of the case to one side of the chamber. (fire formed cases also to a lesser degree) Even with the most perfectly aligned chamber to the bore's axis, your projectile is not in line with the bore axis.

 

[djarecke]

Good explanation! I've been considering a true job on my 5R but it shoots so well I'm afraid to mess with it!

 

[pinsandpitons]

Back to the hill of beans, if you don't shoot fire formed cases, the extractor pushes the rear of the case to one side of the chamber. (fire formed cases also to a lesser degree) Even with the most perfectly aligned chamber to the bore's axis, your projectile is not in line with the bore axis.

Ok, I follow the logic but.... then why do we care so much about concentric ammo? Or is that only truly relevant to fire formed cases in tight benchrest chambers?

 

[Turd in the Pool]

The idea is to eliminate any bad influence on the projectile. Be it case, powder charge variance, alignment or such. Most chambers are cut large enough to accept any factory crap that you can shove in the hole. (for good reason) Most shooters are not willing to go to the trouble of turning necks and the like. Next time you are bored, measure some case necks for wall thickness. Lapua is pretty good about making them uniform but unless it's a match case, there is likely .oo3"+ variance. Between that and the extractor pressure, it almost seems like a waste of time to cut a perfect chamber.

Robbed this from Ebbs on another thread.

The Over-Rated Crown

Page 3 goes into some interesting perspective on bullet alignment/tilt. Interesting crown info also. Well worth the read. Thx Ebbs

 

[MarineMD]

The idea is to eliminate any bad influence on the projectile. Be it case, powder charge variance, alignment or such. Most chambers are cut large enough to accept any factory crap that you can shove in the hole. (for good reason) Most shooters are not willing to go to the trouble of turning necks and the like. Next time you are bored, measure some case necks for wall thickness. Lapua is pretty good about making them uniform but unless it's a match case, there is likely .oo3"+ variance. Between that and the extractor pressure, it almost seems like a waste of time to cut a perfect chamber.

Robbed this from Ebbs on another thread.

The Over-Rated Crown

Page 3 goes into some interesting perspective on bullet alignment/tilt. Interesting crown info also. Well worth the read. Thx Ebbs

This crown link is awesome.

With regard to action truing, I think of it like the performance of a Philharmonic Orchestra. Eliminate a violin or 2 and it will make no detectable difference. Even if you eliminate a whole section, the other sections can compensate to give you a nice concert.


RJBGuns00 makes a point about the ejector I didn't even consider, i.e., that it is pushing the whole case to the side. That means the case is crooked in the chamber no matter how true the bolt face is.

I would love to deconstruct the entire process of "truing." I will gladly defer to the experts on this but I think that truing a bolt face beyond factory specs is useless.

 

[Killswitch Engage]

i think about 20% of action truing is for a significant purpose. that would be a true square action face for the recoil lug and shoulder joint to mate to. a good thread is helpful for that. evertything after that is simply for brass life in my opinion. if a great barrel is installed you can almost be rest assured it will shoot lights out. my point would be made by having a conversation with a many time benchrest champion who does his own barrel work. he told me he believes most of the action truing is bullshit and even feels the rediculous amounts of .0000000001 guys chase is unecessary. he said he purposely chambered a barrel off axis at the rear of the chamber .020 to prove the point. took that barrel to win the canada f-class national(i believe it was called). he said yeah, my brass was all junk but the barrel shot great. its an easy sell for truing and screwing a rifle together but when you see stock remington 700p time after time shoot .5 moa or better with factory fgmm are you chasing the ghost?

 

[E. Bryant]

Presumably the factory bolt face should be within a specification to not allow this.

Why not extend that same presumption to every other dimension and tolerance in the action, and just skip the truing process altogether? That's a bit of a rhetorical question, BTW

Frankly, on the hierarchy of important steps in truing a factory action, this is probably low on the list for many of the reasons listed here. I don't know if I can resize my brass "square" (base perpendicularity to the cartridge centerline) to the level required to observe any negative effects from an untrue bolt face, and RJB's point about the ejector effects might just make this a moot point when employing practical brass/chamber clearances. Plus, there are those little flecks of brass that sometimes accumulate on the bolt face - I doubt that they bear evenly on the cartridge head, and yet they don't seem to have any significant effect on accuracy.

 

[pinsandpitons]

ok, the natural arc of this thread (in my eyes) now brings us to;
The truing operations or features of a bolt action that have an influence on accuracy or brass life listed in descending order of importance. (might have to be two separate lists)

Edit;
I didn't list them 'cause that would be speculation. I'm willing to do that but thought I'd give the experts a chance to do it first.

 

[DocB]

MarineMD,

Factory spec or shoots well all the time spec? These are different specs. Manufacturers spec is shoot the cartridge once and toss it, having a 2-3 MOA or higher accuracy realm as acceptable vs. reloaded where variances are reduced to a minimum and a 1/2 MOA accuracy realm is considered acceptable.

HTH,
DocB

 

[Turd in the Pool]

ok, the natural arc of this thread (in my eyes) now brings us to;
The truing operations or features of a bolt action that have an influence on accuracy or brass life listed in descending order of importance. (might have to be two separate lists)

Edit;
I didn't list them 'cause that would be speculation. I'm willing to do that but thought I'd give the experts a chance to do it first.

Why don't you start the list? Did you read the "over rated crown" article? Volumes of info there, not just some blowhard spouting off.

 

[pinsandpitons]

I did read it. Hard to believe, but his data and methods looked solid. As he said, I'm not about to go to town on mine, but it makes me think that all the concerns folks have about dragging a cleaning rod or brush across the muzzle are misplaced.

I'll give it a go. (only attributes of the action itself)

1-strong, stiff design
2-barrel threads true to centerline
3-receiver face square to centerline
4-bolt lug mate surfaces lapped/polished (even lug contact)
5-above surfaces square to the centerline
6-bolt face centered in action
7-bolt face square to centerline


Let the flaming begin...

 

[Turd in the Pool]

I'm sure you've seen a Garand or 2 that have been muzzle reamed with a cleaning rod. I believe they might be the source of cleaning rod fears.

Not a bad list but there are countless factory Rem's that strongly disagree.

I will admit that most Rem's that shoot extremely well don't get inspected/scrutinized. Every Rem I've rebarreled (with the exception of a couple of custom shop models) fail 2-7.

 

[pinsandpitons]

To be clear I'm not saying that 1-7 are conditions for accuracy, merely that the farther down the list you go the less critical the item is for an accurate action/receiver.

 

[MarineMD]

I did read it. Hard to believe, but his data and methods looked solid. As he said, I'm not about to go to town on mine, but it makes me think that all the concerns folks have about dragging a cleaning rod or brush across the muzzle are misplaced.

I'll give it a go. (only attributes of the action itself)

1-strong, stiff design
2-barrel threads true to centerline
3-receiver face square to centerline
4-bolt lug mate surfaces lapped/polished (even lug contact)
5-above surfaces square to the centerline
6-bolt face centered in action
7-bolt face square to centerline


Let the flaming begin...

I think I agree with your list for both precision, accuracy and for brass life. Of course, since I started this thread questioning the use of 7, I will stipulate that 7 does not have to be altered from the way it comes from the factory.

2 things:

I don't reload (I'm still chicken but I will try soon). For you reloaders, the question would be if you have 2 different rifles but with the same barrel twist, length and chambered for the same cartridge, that is, identical rifles but one rifle is factory, say Winchester, the other is a Surgeon action based rifle built by the greatest gunsmith in the world, will the factory rifle give you a lower brass life on average? One possible way to study this would be to take one hundred rounds of ammo, shoot and reload say 5 times and have expert reloaders, blinded to which rifle shot which brass, inspect the brass at the end of 5 rounds. The rifle with the most viable brass after 5 rounds, wins. I would bet anyone lunch at Le Cirque that the brass life would be essentially the same.

 

[pinsandpitons]

 

[Turd in the Pool]

The only thing that truly extends brass life is neck sizing. It's not likely that a factory chamber and a custom could swap neck sized cases.

Full length sizing both, I'd put my money on the factory chambered fired cases failing first. They tend to be sloppy.

 

[timjoebobbradley]

i think about 20% of action truing is for a significant purpose. that would be a true square action face for the recoil lug and shoulder joint to mate to. a good thread is helpful for that. evertything after that is simply for brass life in my opinion. if a great barrel is installed you can almost be rest assured it will shoot lights out. my point would be made by having a conversation with a many time benchrest champion who does his own barrel work. he told me he believes most of the action truing is bullshit and even feels the rediculous amounts of .0000000001 guys chase is unecessary. he said he purposely chambered a barrel off axis at the rear of the chamber .020 to prove the point. took that barrel to win the canada f-class national(i believe it was called). he said yeah, my brass was all junk but the barrel shot great. its an easy sell for truing and screwing a rifle together but when you see stock remington 700p time after time shoot .5 moa or better with factory fgmm are you chasing the ghost?

I think the statement of "stock remington 700p time after time shoot .5 moa or better with factory fgmm" is total BS. Especially in comparison to benchrest. most benchrest is 5, 5 shot groups averaged. No called flyers bs no throwing out the worst group, no self measuring groups. F class is at distance, what distance is this .5 moa M700p shooting at?

Face it, if truing certain things didn't make a difference they wouldn't be done by most gunsmiths or they would be recommended as cosmetic.

 

[Killswitch Engage]

Well Timbob, I've seen too many remington 700p's do it for it to be a fluke. I don't much care how benchrest or f class does it because we are rreferring to tactical precision rifles here at snipers hide I believe?

I did not say there was no action truing that was beneficial to the accuracy of a rifle but I believe it is very little overall. I've seen many trued rems with match barrels installed shoot exactly the same as untrued rems with match barrels installed. These guns printed in the .2-.3 area. That's more then sufficient for a tactical fielded weapon.

You welcome to believe what you want to make yourself feel better about truing and by all means do what makes you feel good. As for me I will continue to approach it like reloading ffor precision weapons, I will do the steps that yield me the most results for my efforts and pass over the ones that don't.

 

[timjoebobbradley]

Ok, maybe you could describe what method is used to determine these M700p's are capable of .5 moa, and at what distance?

What is the name of your benchrest friend?

would having reusable brass be part of rifle accuracy in your story? If so, then it is pretty obvious truing the bolt face is helpful.

 

[Killswitch Engage]

well im not a group shooter much but when i do check its 5rds off of a bipod and rear bag prone. i measure groups center to center if i'm really worried about doing it. i slap a caliper on the paper but i always figure if its basically one hole-ish looking thats good enough for me. i shoot for groups at 100yd, 300yd, 600yd or whatever the mood strikes me. i'm not a benchrest shooter and have no need to be. if i was trying to achieve benchrest results i would probably add in the extra steps you seem to feel necessary to achieve the results you want. my rifles need to do a couple things....they must function 100% in as many shitty environments as i can take them to and they need to be accurate/repeatable. for them to do that i need to be in a happy medium of tolerances. i promise you your benchrest rifle wouldn't survive 5 minutes where i take my rifles before you had galled lugs and shit locked up.

i don't have any benchrest friends....i said i talked to a benchrest competitor/gunsmith and he had told me what i repeated. his name is bob pastor.

 

[bodywerks]

So what if a factory rifle will shoot just as well as a custom. And heck, i won't even argue it. Some factory rifles shoot lights out.
But if you say your factory action lifts, cycles, ejects brass, chambers, and locks into battery with the smoothness and precision of a custom or trued action then I call BS. That, or you just got lucky.
Its not just about how well the rifle shoots when the trigger is pulled - what happens between then and chambering the next round is just as important. A trued action will cycle noticeably smoother, and that's just as important to me as how well the rifle shoots.
And to keep this on topic for the OP, yes, truing the bolt face matters. I may not affect accuracy, but will affect how smooth the bolt cycles.

 

[Killswitch Engage]

my rifles have trued actions. i never said they didnt and i do not think factory guns always perform well but these days most do. this discussion wasn't really about how smooth the bolt cycles, it was about accuracy. i don't think the bolt face really does shit for that unless it was grossly untrue.

yes, it's all about how well the rifle shoots when you pull the trigger....function is a requirement.

i have shot untold numbers of rifles, trued-untrued, factory action-custom action, blah blah. i have a new action that was trued and lapped including the bolt face it is no where near as smooth and glassy feeling as my well worn multiple barreled 700 action on my creedmoor. that tells me time, lube, break-in and wear are what makes a 700 butter smooth. i have not seen the drastic improvements from a custom action over a worn rem to justify the need for what i do. good barrels are where its at with my argument and i stand by it.

trued and untrued rem actions seemed to have been very suffiecient for our military for the last 40yrs...

 

[MarineMD]

Face it, if truing certain things didn't make a difference they wouldn't be done by most gunsmiths or they would be recommended as cosmetic.

Threads take on lives of their own. But at the heart of my original intention is get just what is important and what isn't.

I'll give you an example, one gunsmith tells me it is unnecessary to re-thread a Remington action and yet I will see others swear by it. It seems to me that of all the things that are done in a typical truing job that truing a bolt face beyond factory spec is unnecessary.

Finally, I am not putting any gunsmith down so please don't take it that way, but to me it's just not good enough to say, "well the gunsmiths recommend it therefore that's the best thing:" buyer beware. In general, in life and in medicine, when there is a profit motive, people will offer services that cost more money either consciously or subconsciously. This has been borne out in multiple studies in surgical practice. This is not an "ugly" secret. It is a reality in a capitalist society. It is up to us to become educated consumers. That is why forums such as these are invaluable to us.

I have nothing inherently against truing the bolt face beyond factory specs. In fact, I have had it done. I just don't think it would affect accuracy. Since I don't reload (yet), brass life is irrelevant to, but safety is paramount when you have a several 10s of thousands PSI explosion going off inches from your face.

With respect to the smoothness of the action. I have a beautiful Stiller Tac 30 action that is unbelievably smooth to me. When you cycle the bolt it's hard to believe it's not on ball bearings. I have a Jamie Dodson trued 700 action with a PTG bolt that is almost as smooth.

 

[MarineMD]

One last thing on little things that matter. When I was with 3/6 in the early 80s, I underwent the 2nd Marine Div school sniper adventure training course. I believe it was call the Kopfenjaeger course. Don't quote me. I was NOT a sniper, it was for infantrymen who were thinking about becoming Snipers. The big course back then was in Quantico. I am giving this info not portray myself into some kind of badass dude, but just to establish that I have done a little bit of shooting in my time and I have been taught by the best.

Anyway, I played with my battalion's M40A1s since my good bud at STA invited me to shoot with them many times. What comes to mind is an M40 that shot excellent groups, but when you got out to the 300 yard line, it started to pull shots wide of the point of aim. By the time you got out to 600 yards, it started to miss consistently if you didn't dial in some windage. It turns out that this particular rifles scope base holes did not line up to the centerline of the action. This was a small thing, hardly noticeable that became apparent only at long distance. We sent it back to Quantico, they welded over the holes and re drilled them. After this, the rifle shot fine.

Therefore, to me, in the truing process, I would say that insuring that the scope base holes are true to the centerline of the action (and then the bore) is an example of an important thing to be done when truing an action.

 

[pinsandpitons]

Therefore, to me, in the truing process, I would say that insuring that the scope base holes are true to the centerline of the action (and then the bore) is an example of an important thing to be done when truing an action.

Excellent point! I thought about scope base issues when I took a stab at the list above, but did not consider the holes (which are a part of the action). I have a .22 that shoots great, but the barrel does not share the same centerline axis as the action, same issues as that M40A1. That may even be number 3 on the list.

 

[300sniper]

a question for those who feel truing the bolt face will increase brass life, what is the maximum measured deviation you have found across an oem bolt face? next question, what is the max measured deviation across your case head after it comes out of your press? something tells me your loading press is creating a case further out of whack than a typical oem bolt face.

 

[MajorHeadTrauma]

Tag for later

 

[pinsandpitons]

a question for those who feel truing the bolt face will increase brass life, what is the maximum measured deviation you have found across an oem bolt face? next question, what is the max measured deviation across your case head after it comes out of your press? something tells me your loading press is creating a case further out of whack than a typical oem bolt face.

No sense truing the bolt face unless you also true the shell-holder, press etc. Hard to argue with that.

 

[Turd in the Pool]

The amount of force it takes to bend a case at the web is much greater than what a press and die exert on it. If the decapper was replaced by a ram that forced the head to seat on the shell holder, I might buy into the theory.

300sniper, I'll measure the next one before I cut it. It will be a while since I'm still in checkering hell.

 

[DocB]

300,

The gunsmiths I've used tell me 0.006" is not uncommon, 0.002" is pretty good.

The test is to line up a case in the chamber with a known orientation and shoot it. Then chamber the case after turning 180 degrees. If it doesn't chamber easily, you definitely need to at least check the bolt face.

HTH,
DocB

 

[Killswitch Engage]

300,

The gunsmiths I've used tell me 0.006" is not uncommon, 0.002" is pretty good.

The test is to line up a case in the chamber with a known orientation and shoot it. Then chamber the case after turning 180 degrees. If it doesn't chamber easily, you definitely need to at least check the bolt face.

HTH,
DocB

That could very well be chamber run out at the back of the chamber as well and not necessarily the bolt face.

 

[timjoebobbradley]

Threads take on lives of their own. But at the heart of my original intention is get just what is important and what isn't.


....
I have nothing inherently against truing the bolt face beyond factory specs. In fact, I have had it done. I just don't think it would affect accuracy. Since I don't reload (yet), brass life is irrelevant to, but safety is paramount when you have a several 10s of thousands PSI explosion going off inches from your face.
.....

I do not understand your point- are you suggesting that truing a bolt face will somehow make it weaker?

 

[wnroscoe]

I have looked at several videos on action truing and most of it makes sense (at least intuitively). For example, I can see why the action, bolt lugs, recoil lug and barrel have to all be perfectly level to each other and perpendicular to the bore. I can see why you need to cut new threads if the original threads are not holding the barrel perfectly straight.

(1) But why does the bolt face have to be any better than how it comes from the factory?

(2) When the firing pin strike the primer doesn't it move the whole cartridge slightly forward in the chamber to the point where the shoulders touch the chamber.

(3) As the primer ignites the overall charge the brass expands first in the shoulders. This holds the shoulders in place in the chamber. The whole brass case then stretches out towards the rear to the bolt face. Isn't this why you can rupture a case if you have excess head space that allows the case to stretch to the point of failure and rupture?

(4) My point is that by the time the bullet begins to move into the bore it is centered by the expanded case shoulders. Which means that it is meaningless where the case head ends up. Even if the boltface is slightly off the bullet is already centered by the expanded case shoulder that have already expended in the chamber.

Marine,

I'll offer you my take on the whole "Truing" aspect and try to answer your questions/concerns.

#1. When truing a clients receiver, a Rem700 in your case, part of the process is to make sure the bolt lugs are perpendicular to the bolt body. The only way I know to check this is to dial the bolt body into the late and check it. My way to check it is just touch off on the bolt lugs with a carbide tool while all is static, set the travel dial to .000", turn the lathe on, return the tool to .000" and make a cut. Most of the time, the bolt lugs are square/perpendicular to the bolt body and the ensuing cut confirms it. Sometimes, the lugs are not perpendicular to the bolt body.

At this point, the bolt body is dialed in and the client has paid for results, why not make slight clean up cuts in key areas like bolt nose, bolt face and bolt lug fronts to make sure all contact and non-contact surfaces are on the same setup. Again, for me, 99.9% of the time, the bolt face is perpendicular to the bolt body and the cut confirms it. The bolt face is also checked in the same manner as the bolt lugs.

The client has to receive something for his hard earned money and we as precision rifle smiths need to provide a level of accuracy expectations to that client. Nothing says it square nor confirms it like fresh cut metal.

#2. Correct, the case will move forward on FP strike approx .0005"+ depending on how the sizing dies was/is set. I set mine for a .0015" bump.

#3. Most but not all case head separations are due to improper FL sizing operations coupled with repeated sizing’s. Excessive HS issues can also cause separation but the excess HS would have to be fairly long for this to happen. I know guys that run +.003" on a go with zero issues but not me. I try to run where I can feel a slight drag on the gauge on closure.

#4. True to an extent. The amount of deviation / run out at the bolt face / case head juncture point, if any, will be such a microscopic, non-measurable amount that in the chamber and throat area it'll matter none. We'll never get it to a lab environment, scientific level of square, parallel or perpendicular.

We do the best we can with what we have and deliver our best work to the client. The simple answer is this, if a client has paid $200+ for a trued receiver, you damn well better cut metal if but only a slight clean up cut. From my experience in truing Remington 700's, and I've done a couple, the receiver bolt lug recess is where the issue lies. Like the receiver face and threads, they're never perpendicular to the raceway, the bolt is usually golden and GTG as is but, like I said, the client deserves something for his money and clean up cuts are cheap insurance..................we damn well better deliver the goods.

 

[pawprint2]

When you "true" the lugs, you are removing material, then the bolt face you are removing material, isn't the firing pin going to protrude the exact amount as the total of the amount's that were removed? If so, does the average smith remove the same amount from the firing pin to preclude primer piercing?
An awful lot has been talked about in this string, much of it very informative and thought provoking, of course not all factory actions are in need of "truing" or polishing, they are very "true" and smoooooth running right from the mfg. There was a very interesting thread regarding the SPR FN's, they are factory trued, another example, as I understand it, the TRG's from Sako are very good actions and run quite smoothly, I believe it is wrong to "condemn" all factory actions because Rem 700's seem to be in need of trueing.

 

[pawprint2]

For the experts: When converting a 30-06 to a 6.5x55, Rem long action, as the rim diameter and rim thickness and base diameters are all different, would this effect brass life and or accuracy? I'm going with Lapua brass, and not counting on US mfg to make out of spec brass. How about in reverse? How much "slop" is too much? How much is right on, no problem?

 

[Greg Langelius *]

When you make assumptions, they will usually turn on you and bite you in the ass.

There's nothing wrong with American (Rem.Win./Etc.) brass that reasonable case prep can't handle. Additionally, American 6.5x55 brass is usually identical to .30-'06 in the rim area; Sako, etc., foreign brass may not be.

I shoot factory rifles, and do my case processing accordingly. When a case is fired, it ends up as big as it's ever supposed to get. Whatever we do then simply amounts to work hardening, and I bank on doing as little as possible. My F/L dies are backed off so only about 20% percent of the neck length, out at the very mouth end, gets narrowed down. This leaves the lower neck (and lower case wall) fully expanded. Two potential benefits accrue. First, most of the neck and lower case wall remain unworked (by the resizing process anyway), maybe somewhat better preserving flexibility in those areas. Second, the still expanded lower case wall and neck area centers the case better in the chamber. There may be other benefits I'm missing, I seldom see any chambering resistance, and my cases don't seem to grow much, if any at all; but that may also be due to staying away from hotter loads.

Bolt face bending brass? Maybe, probably even; but with factory guns I'm not seeing any consequences.

In theory, all this trueing activity makes excellent sense. In practice, I strongly suspect a proportion of such customers can't shoot well enough to gain significant benefit from the process.

First, tune the shooter; then, tune the gun. Me, I'm still tuning the shooter; got some ways to go, yet. Only been at it two, three decades now...

Greg

 

[pawprint2]

Making assumptions do bite people in the ass! For example, when one assumes that foreign brass, lapua and Fin surplus "may not be", that is a strange assumption to be sure. In fact they are not, in fact the Fins have a spec for their 6.5 x55 that is in fact different than that of a 30-06(base diameter, rim diameter,rim thickness)! My enquiry is in regards to how much slop is okay, not that some slop is okay, but an actual-factual number. Because someone is running a "good shooter" with a certain amount of slop in it, is not really a quality investigation. A lot of real expertise has been posted on this string regarding the importance of bolt face trueing, action trueing etc., I would like to hear from those doing this for a living on how much slop they consider okay. And how that slop effects the brass-for those intending to reload.
Is it that some gun smiths think x amount is fine, while others believe Y is the maximum? I'd love to hear how they came up with that figure(s). Does x amount of slop effect accuracy, and/ or is it manifested in the brass when reloading? I realize Greg Langelius suspects, "a proportion of such customers can't shoot well enough to gain significant benefit from the process.", but that doesn't address the question, and he may very well be 100% correct. If we take it to the logical conclusion, most of the trueing done by smiths is just an exercise in money making, and is of no value to a proportion of their customers. I would rather believe trueing does deliver a better more accurate shooting weapon, trued actions are easier on brass, and the customers see a true gain from an expertly trued weapon. But just like Greg, we both have opinions. In my experience, and I too have been shooting for a few decades, most gun smiths do what they do to make their customers guns better, not just because...., but rather because they know what they are doing makes a better gun. The gun smiths I know, have all the work they can handle-waiting time is longer than ever. They [gunsmiths] do not need to "make work" to run their charges up, the work they do, for the most part, is better than it has ever been-accuracy wise, and as a lot, most gun smiths are honest hard working people, the insinuation that gun smiths are doing all this trueing, for a proportion of their customers just to make money, and their is no significant benefit is hard for me to believe.

 

[Greg Langelius *]

Good points, and no aspersions toward gunsmiths intentions (or yours, either). Gunsmiths do as requested by their customers, and only some (the best among them, I believe) will contend with those requests. The problems lie less with the gunsmiths, but rather with the customers, who assume (there's that word again...) that the gunsmiths probably couldn't get it right without detailed directions from the customers. Must be frustrating sometimes, those gunsmiths listening to those obviously better minded customers (none of whom inhabit this site, of course...).

If I deal with a gunsmith (rarely, but I do), I ask them to do something generic (i.e., please mount this barrel for me...), and leave the details to them. As such, the results have always far exceeded my expectations. If you like such pleasant surprises, I recommend Darkeagle Custom, always and forever my only gunsmith.

If my post comes across as any sort of indictment of gunsmiths, then I apologize, no such was intended. I agree, more truing makes for a more accurate weapon. I just suggest that in some cases the improvement may be as ultimately effective as placing a GAP into the hands of a chimp. Again, glad there aren't any of them around here...

Oh, and sorry American made brass can't stand up to your discerning scrutiny. Never had a problem with it making ammo for the '96 Mauser 6.5x55.

Sometimes I simply amaze myself, never saying all those things some folks get out of my posts. As it happens, since I am no expert, nearly none of what I said was directed at you, Mr. p. You need a number? OK; 42
Greg

 

[pawprint2]

Load for my 96 also, I use Lapua brass-mostly because I was able to purchase a large load several years ago. I use/and have used untold thousands of pieces of American made brass, in many different calibers! Love it, dollar for dollar American made brass is the best in the world (remember-dollar for dollar). Thank you for your very thoughtful post! I'll take full responsibility for not being clearer in my original question. How Much Slop is OKAY? Would be the question I'm bring forward. Hopefully those that have trued/tested rifles over the years, are in a position to answer it. I know many of the "custom" actions actually offer different bolt faces, 222/6ppc/308 etc., they are offered at the same price, do you think this is marketing hype, or is there a point where slop can and does effect the brass? If so, what is that point. In other words, how much slop is okay? I take issue with your- very wrong statement," Gunsmiths do as requested by their customers, and only some (the best among them, I believe) will contend with those requests", many gunsmiths, and small rifle building shops, build rifles all the time- for sale, without a customer telling them what to do or how to do it, the good ones often true the actions-to include the bolt face. As you omitted this, it leaves the impression that without a customer "telling them what to do" they wouldn't true the action and bolt face on a rifle they were building, as a spec rifle. Nonetheless, the crux of my question, "how much slop is okay" never seems to get addressed.

 

[Greg Langelius *]

I'll address it this way. I can't answer the question directly. I'm not sure anyone can give a conclusive "this much and no more, and why" answer to it.

I would rephrase it to ask "who has had problems loading for the 6.5x55 that trace directly back to the source and specs of the 6.5x55 brass they are using, and what form did those problems take?" It's more to the point and leaves out opinions about what is and isn't OK.

As for my assessment of how gunsmiths receive their instructions, not being one, again, I can't answer conclusively. I think I gave a reasonable characterization of how I think it should be done.

If there are any other points in dispute, I concede them without further debate. I.e. you win. Now what? For me, now nothing. TTFN.

Greg

 

[insight3b]

I just don't see the point. Get the bolt face all trued up then chamber a round with the ejector and spring installed in the bolt...everything was squared up and now a round is chambered with a lot of spring pressure exerted on one side of the case head...all the truing and straightness in the world has just been thrown out the window. When an action is all trued up and square it remains that way but the chambered ammunition is canted by spring pressure to one side the chamber. In theory everything is straight to the bore...except the ammunition

 

[Turd in the Pool]

For the experts: When converting a 30-06 to a 6.5x55, Rem long action, as the rim diameter and rim thickness and base diameters are all different, would this effect brass life and or accuracy? I'm going with Lapua brass, and not counting on US mfg to make out of spec brass. How about in reverse? How much "slop" is too much? How much is right on, no problem?

I'm not an expert but I've seen them on TV.

Sloppy diameter is much more detrimental to case life than an out of square face or long headspace as long as it's not in the field range.

If you size like Greg or just plain neck size. The issue is eliminated. I'm partial to Lee collet sizers.

It also eliminates the issue cited by insight3b.

 

[300sniper]

I just don't see the point. Get the bolt face all trued up then chamber a round with the ejector and spring installed in the bolt...everything was squared up and now a round is chambered with a lot of spring pressure exerted on one side of the case head...all the truing and straightness in the world has just been thrown out the window. When an action is all trued up and square it remains that way but the chambered ammunition is canted by spring pressure to one side the chamber. In theory everything is straight to the bore...except the ammunition

the ejector spring force is far greater pushing the case shoulder into the chamber than it is trying to cant the round. the round can't cant very far, if at all anyways.

 

[300sniper]

300,

The gunsmiths I've used tell me 0.006" is not uncommon, 0.002" is pretty good.

The test is to line up a case in the chamber with a known orientation and shoot it. Then chamber the case after turning 180 degrees. If it doesn't chamber easily, you definitely need to at least check the bolt face.

HTH,
DocB

.006" over .473"? really? when i used to face the bolt face, i never removed anywhere near that much to clean it up.

i'd lke to know how they were measuring it.

 

[pawprint2]

With a tight chamber-neck turned round the "cant" put on a round via spring pressure is very small, but on a standard chamber where there is more slop than is Best for accuracy (not function, just accuracy)the spring pressure does have a measureable effect on accuracy. PS magazine had an article about this years ago. BenchRest shooters-shooting same gun, same load, same day etc, with and without were able to Measure the effect on the target. I'm sure they didn't go into the longevity of the brass-full length sizing after every firing, vs neck sizing only (that has been tested and written about at nauseam). In fact most BR shooters are running very weak springs for this very reason-and the fact they don't want their brass flying over to another bench. Of course you have to take into consideration the rim diameter of the brass your loading. Is there constant contact or not, if you go to thicker rims than you've been set up for, then the likelihood of contact, i.e. constant pressure, is greater. Arguing over will it or won't it, is easy, but the proof is on the target, in your own gun, try running your rifle with a weaker spring, and see if you in fact get a better group. At the very least, you may end up finding all your brass in a much small pile!

 

[insight3b]

the ejector spring force is far greater pushing the case shoulder into the chamber than it is trying to cant the round. the round can't cant very far, if at all anyways.

Well we know it will cant at least two thousandths. Ammunition needs at a minimum two thou clearance all the way around in order to chamber. Before someone adds that they only neck size yadda yadda let's remember that brass expands to chamber dimensions only briefly then contracts several thou when cooled. If brass was the same size as a chamber then we couldn't chamber or extract a round of ammunition

 

[pawprint2]

You are exactly right. Some seem to forget that actions flex-the more they are out of "square" or out of "true" the more (the worse) the effect of the flex is, as relating to accuracy. This is a well know principle of accurate rifle making. This is why squaring the action, lugs threads etc. to the center line results in very accurate rifles, this Fact has been demonstrated 10,000s of times. Less square-less accuracy. How much off, how much slop is okay, is the question, but there is no doubt when things are less square brass suffers, as the forces (expanding and contracting) are not happening in a straight line. I know there are a lot of really good gun smiths on this board, I would find it hard to believe that none of them have a "spec" regarding bolt facing being square or over sized, spring tension etc. Some of these guys consistently produce very accurate rifles, this can't be by pure luck, but rather by sticking to time proven principles, and keeping a constant vigilance toward quality. The "spring back" brass demonstrates when being fired, of course differs based on the actual mix of bass and the construction by the mfg (even among lots of brass by the mfg), but as insight3b very correctly points out, it always happens when we fire a round. Bench rest shooters spend countless hours, and $$$ trying to squeeze the last drop of accuracy from their rifles, along with the gun smiths the body of knowledge concerning the consequences of out of square, and/or over sized bolt faces is well known, the closer the bolt face is to square, the less slop in the bolt face, the less tension on the brass by the ejector-all these things add to accuracy, and are only trivial to those willing to accept a lesser degree of accuracy than otherwise could be achieved-not to mention brass life.