Gunsmithing Threading and clambering a barrel with out the action

[GaryinCC]

I have heard the a surgeon action can be have a barrel made with out having the action on hand at the barrel company.

Can the same be done with a defiance action?

And who can do it?

I have heard that Rock and a couple of others have the pattern saved in their CNC to chamber and thread the barrel without needing the action because they are so precision made.

Is any of that true?


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[bohem]

It can be done. There are a couple of makers that I'd attempt it with under special conditions. Trying to skimp on a gunsmithing bill is not a good reason to do it. Defiance are not actions that I'd attempt such a thing with. I've done it with a Bighorn just to see if I could, it worked without a hiccup and I did it on a manual toolroom lathe without a DRO. It's not hard if you know what to track while you're cutting chips.

The biggest issue is the consistency of the actions, like I said, I wouldn't try it out side of experimentation with anything other than a Bighorn or one of ARC's Mausingfields whenever they finally hit the market.

I'm really surprised that more builders out there are not tracking the thread dimensions on each receiver that they fit a barrel to. Seems silly not to considering the very low cost of thread micrometers or a set of 3-wire gauges. It also makes subsequent barrel fittings that much easier. I have a tracking sheet with all the dimensions necessary on file for it already.

 

[Killswitch Engage]

i tried it on a stiller tac30aw and it was fine. there dimensions were spot on to print on that one... cant say on others.

 

[bohem]

The outliers are what I worry about, without for metrology and process tracking that isn't really present in most shops the ability to do this and not constantly worry over liability stop me from accepting such a job without serious extenuating circumstances.

 

[GaryinCC]

But what about guys like
Brux
Hart
Rock
Surgeon
Broughton

Can any of them. I'm not worried about cost just down time. I don't want to have to ship my action to guys that are months back logged on work.


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[bohem]

Do you have the barrel in hand or do you need the barrel?

 

[jonaddis84]

Well Gary, to test this out I tried screwing your barrel on 3 other actions I have on hand and none of them headspaced perfectly (all closed on go, but also closed on no-go). This is strange considering the thread lead starts in the exact same location on all Defiance's. I would be able to chamber a new barrel for the same action/bolt combo without having them in hand based off measurements. But throwing a new bolt into the mix it would require new measurements. I think its always best to just have it on hand to confirm headspace, since its not something to really screw around with.

Whats this talk about long lead times haha? Its only been a few days! Ill go ahead and guarantee with the bolt/barrel in hand, less than 3 day turnaround for ya.

 

[GaryinCC]

Na man....you rock!!!!!! That thing is the shit.
But your test dose tell the story. I guess it's more rumor than truth.
Like I said it's just one of those things I've heard but couldn't confirm.

I guess when I want to so another caliber ill just have to send it.

But the thing I wondered what about surgeon or one of those? Surgeon is the one that I heard the story about. My previous GAP rifle was property of a sponsored shooter and he said that they would send him a new barrel when he needed it or of he wanted to try a different caliber.


And again Jon is the shit.....that's my new rig in the pics I can't freaking wait.


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[bohem]

Gap had the Action and the dimensions, they could track the measurements in the first run and repeat them afterward.

This would be one of those special circumstances I mentioned, it's going to someone I know and can trait to thread it onto the action without screwin something up. You wouldn't think that is too difficult if a task but I've been surprised about it myself.

 

[jonaddis84]

I wouldnt necessarily call this a downfall, at least not for me. I wouldnt be entirely comfortable chambering a barrel without the action in hand for liability purposes anyway (not just this case, in general). If one number was written down wrong, or whatever, we're talking about 0.002" that can throw it out of headspace. For me at least, I would just always prefer to have that confirmation of checking with gauges. We are all only human.

 

[gewehr]

I have heard it can be done on a bat


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[LawnMM]

3 days turn around ain't bad at all. So I'll toss a curve ball in for discussion's sake...

Obviously the concern is whether a barrel chambered without the action will headspace properly, seemingly because the end user either doesn't have the gauges, or if they do and it doesn't headspace, they don't have the ability to adjust the headspace without sending it back.

What about a blank cut up like a rem/age with a barrel nut the end user can adjust the headspace on? Seems like a neat option but I haven't seen any smiths cutting up match grade blanks in that manner.

 

[bohem]

There is a way to do it, I even asked around with guys that I shot with about making a run of something like that but the best response was lukewarm and most didn't like the idea overall for one reason or another. Things like "how close can the headspace really be" to "then I have an ugly barrel nut"

Functionally I think you're on the right path, I even contemplated setting one of my bighorn actions up like that, but haven't found a driving need to go for it on that gun yet.


I have/know the right folks with the right equipment necessary to provide exactly what you're asking; it's just too much overhead to entertain with the mediocre support I hear for the idea.

 

[LRI]

If I may:

Lets look at what's being suggested. Measure an action from the ring face to the lug abutments. That's your first dimension to worry about. Now measure a lug thickness. There's a 2nd concern. Move onto the bolt lug-to-bolt face height. That's the 3rd. Bolt nose projection is #4.

A great many recoil lugs are always all over the place. +/- .003" seems to be the norm. In 99.9% of applications this matters little as they are fitted individually. So the numbers are taken individually when compiling the worksheet.

Someone above mentioned the start point of the thread. That doesn't influence anything. The distances I just mentioned do. I can cut 90% of the threads out of brand X action and still have an unaltered barrel tennon.


Last, your playing with someone's life everytime you fit a barrel. Last year I displayed photos of a guy who crammed 93 grains of Varget into his 338 Lapua. He split his Defiance action in half in two places. These pressures are real and they can kill you. I had an action blow apart on me last winter that we still have no rational explanation for. Orbital fracture and torn iris was the result of that fiasco. I still have a hole in my ceiling from the bolt body.


Point is; One can measure, double check, document, and run with it on the assumption that everyone did their job before you. (meaning fitting barrels with no receiver in hand) Then one day that phone is going to change your life. Your cinnamon ring is going to pucker as your career dissipation lamp goes into melt down. Is it really worth it? Is it really that inconvenient? How do you test fire the gun to ensure things will function as advertised.


We test fire every single barreled action/rifle that leaves here. We STILL get the occassional issue because I shot the gun with brand X brass (usually domestic) and the owner is using Lapua/Norma. It's the only time we have a conversation about chambers that don't want to let go of stuff. So, I have to go buy Lapua brass now because something isn't working.

You can't ever know any of this if your not evaluating your work prior to it leaving.. My ignorance in using only domestic brass instead of thinking ahead of time just demonstrated this fact.


Understand this is an effort to help someone out and not meant to beat anyone up or make us look "good" and you "bad".


Guns are dangerous devices. Never forget that. AJ Goddard and Ted (Bighorn/American Arms) are two guys cut from different cloth than the vast majority of gun parts makers. They are super sharp dudes with decades of experience in the design/manufacturing aerospace community.

I have total confidence with either products. That said I'd still never dream of fitting one up without the parts being here in my shop. They would both be the first ones to tell you the same thing. The three of us talk on a daily/weekly basis.

It's just not worth it.


Hope this helps.


C.

 

[GaryinCC]

Good info guys.

Also
3 days is awesome. Jon built my whole rifle in a week. We only started talking two weeks ago and the only hold up was me shipping parts.

So ya the guy is awesome!



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[jonaddis84]

Well said Chad, exactly my thoughts on it. I also wont let a rifle leave the shop without putting a few through it, nice having 100yds in the side yard to also confirm accuracy when possible.

 

[bohem]

Same here. I keep a piece if fired brass attached to a hard copy of the spec sheet for every barrel that leaves the shop.

I've given a ration of shit to builders that send guns out without firing a single round. It may be extra work or having no convenient place to shoot bullets before shipment but think about the liability that can be avoided by firing a round first.

Shop-based bullet taps aren't cheap but they are a shit ton cheaper than a lawsuit, even if you carry liability insurance which many guys don't. Another thing I take issue with but that's another topic.

 

[jsthntn247]

You can do it with a Kelby's action. Give them the serial number and they'll chamber a barrel and send it to you. I've heard of someones barrel crapping out in a match and somebody giving them an extra barrel, just screw on and go. The caliber markings lined up perfectly also. These actions do have integral lugs also though.

 

[LRI]

Same here. I keep a piece if fired brass attached to a hard copy of the spec sheet for every barrel that leaves the shop.

I've given a ration of shit to builders that send guns out without firing a single round. It may be extra work or having no convenient place to shoot bullets before shipment but think about the liability that can be avoided by firing a round first.

Shop-based bullet taps aren't cheap but they are a shit ton cheaper than a lawsuit, even if you carry liability insurance which many guys don't. Another thing I take issue with but that's another topic.

15" well casing 40" long filled with play sand a little prestone to keep the dust down has worked flawlessly for us for 3.5 years now. Tested with the full gamut of cartridges up to the big 50's. Cost me maybe a day of my time and $300 to build/weld up.

$ well spent.

 

[bohem]

That's a good idea, I've been using test firing as an excuse for a kitchen pass to go to the range. It would be nice to have handy though, I don't want to derail for pics but if you have them handy I'd be interested in taking a look.

 

[LRI]

Big tube O'h death:

 

[xringaccuracy]

Only a fool would garauntee head space without the barrel present

 

[matt2143]

Buy an AI and be done with it haha. But seriously there are several barrel makers that have barrels in stock or can cut a custom barrel for you and ship it out.

One of the benefits of an Accuracy International rifle.

 

[Terry Cross]

Only a fool would garauntee head space without the barrel present

Do you mean "without the action present"?

 

[DAVETOOLEY]

Only a fool would garauntee head space without the barrel present

If you mean having the action in the shop then I guess I'm a fool. Leave out Accuracy International barrels I do. Leave out barrels I do for another manufacture with no action in hand. Since 1982 I have records for every action that's been through the shop. Some are incomplete but most provide all the information I need to thread, chamber and also index the engraving regardless of manufacturer. It's nothing more than working to a set of specifications.

 

[Terry Cross]

If you mean having the action in the shop then I guess I'm a fool. Leave out Accuracy International barrels I do. Leave out barrels I do for another manufacture with no action in hand. Since 1982 I have records for every action that's been through the shop. Some are incomplete but most provide all the information I need to thread, chamber and also index the engraving regardless of manufacturer. It's nothing more than working to a set of specifications.

Then that makes two of us Dave. Only my records have been since 1987.

When I build a rifle, everything is marked with the last 4 of the SN and indexed. That includes the recoil lug and bolts that are not already marked so that if that rifle ever comes back into the shop, I can quickly tell if it's been altered. Every spec is recorded and like you Dave, I can easily time the markings so that they clock correctly when the barrel is installed. I deal only with my own known chamber reamers and only with actions that I have previously built or rebarreled. Lots of barrels sent out including out of country where it would be a bit cumbersome to return the rifle for a rework. Stand alone replacement barrels are verified for true bore size and chamber dimensions. They are then marked per usual and serial numbered to match the host rifle action.

I have pictures of a .300RUM that I built a few years ago. It is in many pieces where it detonated with a reload that contained a fast (pistol?) powder and the shooter was very seriously injured. We just have to trust that the user is going to use precautions, etc.

Being in this business is risky and litigious to begin with. I do not think I am outside of my lane but also believe that this should be decision made by each shop and also on a case by case customer basis.

Best,
Terry

 

[wfjames22]

Only a fool would garauntee head space without the barrel present

Let he who is without sin cast the first stone....

 

[xringaccuracy]

I apparently spoke out of line. What I mean is when I close a bolt on a go gauge and its nice and comfy but close, then insert the no-go gauge and it says "no way mf'er" I get the warm fuzzies

 

[GaryinCC]

Through all this I was referring also to doing all this on a CNC not by hand.

Not sure if that matters.


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[bohem]

It doesn't matter, the record of the action details are what matter.

As Terry and Dave have explained they keep records on the actions that go through their Shops, as I mentioned doing myself. In fact, I simply took the idea from Dave after having spoken with him a few times.

To the original question, as I read it, can you do a barrel without ever seeing the receiver?

There is one action maker that I have seen repeatable enough to attempt it: Bighorn

I suspect that American Rifle Mausingfield actions will be capable of it as well; knowing the folks making the actions. In fact this very topic has been something that Ted and I discussed recently.

The vast majority of riddle receivers need to be in my hands the first time for proper documentation and after that I can repeat them from the measurements.

I can also do it on a manual machine that does not have a DRO. It takes longer than a CNC lathe for the threading and profiling but it is still possible without much trouble.

The CNC isn't magic and it doesn't make poorly documented processes work just because they're done on CNC.

A great example if that is in this thread already: Jon Addis took your barrel that was already headspaced to your Acton and tried to screw it into 3 other "identical" receivers and none of them fit properly.

Now, I have done otherwise with several bighorn actions, the two I run regularly as personal guns are so close that they not only share headspace but the barrels time identically from action to action. These are both older bighorns without integrated lugs.

The new actions with integrated lugs are even better across the board.

I have delivered barrels to guys without having seen the action a second time, I have also taken requests to match headspace across several barrels so that the guy can determine which is the tightest shooter and use that for matches with the other barrels as practice barrels.

I have not previously recorded the thread lead-in location to track the engraving location as Terry Cross mentions but I don't doubt it's possible, I just need to add the option into my tracking spreadsheet.

 

[mcfred]

The biggest issue is the consistency of the actions....

Next would be timing of the threads. Even if two actions have identical headspace dimensions, a fitted barrel might not clock the same way between the two. So brakes, barrel markings, etc. may not be clocked the way you want.

Receivers that are thread milled are probably consistent, but then the later operator would still need to know how to clock the barrel.

 

[bohem]

Next would be timing of the threads. Even if two actions have identical headspace dimensions, a fitted barrel might not clock the same way between the two. So brakes, barrel markings, etc. may not be clocked the way you want.

Receivers that are thread milled are probably consistent, but then the later operator would still need to know how to clock the barrel.

there is no influence of thread lead in to the headspace dimension. If the threads all start in the same spot there is no requirement for the headspace to be the same. Jon Addis demonstrated this on the first page.

It depends on the maker, bighorn thread mills their tenon threads and so does defiance. None of the defiance actions Jon tested had the same headspace but the thread lead is all in the same spot.

 

[Terry Cross]

It doesn't matter, the record of the action details are what matter.

As Terry and Dave have explained they keep records on the actions that go through their Shops, as I mentioned doing myself. In fact, I simply took the idea from Dave after having spoken with him a few times.

To the original question, as I read it, can you do a barrel without ever seeing the receiver?

There is one action maker that I have seen repeatable enough to attempt it: Bighorn

I suspect that American Rifle Mausingfield actions will be capable of it as well; knowing the folks making the actions. In fact this very topic has been something that Ted and I discussed recently.

The vast majority of riddle receivers need to be in my hands the first time for proper documentation and after that I can repeat them from the measurements.

I can also do it on a manual machine that does not have a DRO. It takes longer than a CNC lathe for the threading and profiling but it is still possible without much trouble.

The CNC isn't magic and it doesn't make poorly documented processes work just because they're done on CNC.

A great example if that is in this thread already: Jon Addis took your barrel that was already headspaced to your Acton and tried to screw it into 3 other "identical" receivers and none of them fit properly.

Now, I have done otherwise with several bighorn actions, the two I run regularly as personal guns are so close that they not only share headspace but the barrels time identically from action to action. These are both older bighorns without integrated lugs.

The new actions with integrated lugs are even better across the board.

I have delivered barrels to guys without having seen the action a second time, I have also taken requests to match headspace across several barrels so that the guy can determine which is the tightest shooter and use that for matches with the other barrels as practice barrels.

I have not previously recorded the thread lead-in location to track the engraving location as Terry Cross mentions but I don't doubt it's possible, I just need to add the option into my tracking spreadsheet.

^ ^ ^ ^ ^ This. ^ ^ ^

Bohem, the desired results for documenting and clocking future barrels is very easy to get.
If you want to call my shop, I will be glad to share with you if you're interested. If I swing my hands around a lot when I'm explaining over the phone, it will prolly only take a couple of minutes.
My approach is likely very "caveman" compared to Dave's but it works very well.

 

[DAVETOOLEY]

Terry

Caveman style has always worked well around here.

 

[flatland1]

Good to hear confirmation on my experience with only two (so far) Bighorn TL2-SA actions. These two had identical recorded ring face/bolt nose depths as measured with a Mitutoyo depth mic. Still waiting on another of these actions for my own use - built a 6x47 Lapua for myself on the 1st one, then did a 6XC build for my shooting partner on the 2nd one, and will be using the 3rd TL2-SA for a 260 Imp 30* of my own.

I was just a tad skeptical after reading some of the posts on these actions here, but after building & seeing the results on target with the first two, then talking with AJ on the phone, it didn't take long to get another action coming for myself.

 

[bohem]

[MENTION=5624]flatland1[/MENTION]

I think you're going to be a convert shortly, you're well on the way. If/when I decide to build another rifle the build starts like this:

Pick Caliber
Get the bighorn necessary for that caliber

other details....





[MENTION=2944]Terry[/MENTION]Cross - Thank you for the offer, I'll try to give you a call this coming week. It's busy with some work travel but I can probably squeeze a few minutes for a conversation. I'm looking forward to it. JeffVN consistently has highly positive things to say, it's about time I called to introduce myself.
[MENTION=26671]DAVETOOLEY[/MENTION] - It is probably shameless but I admire the work I've seen you produce, I've got to bug you on a few questions about your Haas anyway, perhaps it's time to call and touch base again.

 

[SamLS]

Nice bullet trap Chad. What do you do to keep the sand from flying everywhere. Any trouble with sand in the barrel. etc. Thanks

 

[skeetlee]

we chamber ppc barrels for BAT actions all the time from a print. Very simple stuff!! Lee