Help: Gap 338 Lapua tight chamber. Small Base die??????????

M

mosquitoshooter

Sergeant
Full Member
Minuteman
Jun 2, 2010
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#1
Hello all,
So i got my GAP 338 Lapua a few weeks ago. Accurate as hell. 2" at 600 yards it will do very consistently. My problem is, after shooting virgin lapua brass once, thus "fireforming" to my chamber it seems i need to body size it back down because my chamber is so damned tight. I get a sticky primary extraction at the top of the bolt lift. Plus, chambering on the next cycle is even a little "stiff". If I try necksizing (redding bushing die) only, it is especially tight when i chamber a round after fireforming and of course tight when i extract a spent round. I basically have to pop the bolt at the top of the bolt lift somewhat firmly with my palm. Virgin lapua brass chambers just fine.

I assure you, it is not a high pressure round blowing the brass out of wack. With 90 grains of h 1000 under a 300 gr. sierra hpbt seated at 3.720", it is not a hot round.

The kicker is, even the redding body die doesnt do much good. When I push the shoulder back 2 - 4 thousandths, the case is still "sticky" when chambering and also on extraction. The "stickiness" is coming from the base. I marked it with a sharpie and the base is where the friction is coming from.

So, it would be nice to be able to use my lapua brass more than once!!!!! Any thoughts? Again, i am using lapua brass and the high dollar $300 redding bushing die, body, seater die set (Type S? Dont remember the type).

My hypothesis is that the Bartlein barrel chambered by Gap is just tighter than a nun's Vag and thus I need a "Small Base Die". However, nobody makes these???? Any thoughts on who can custom make me one? Ive looked on line and I see Redding supposedly will make a custom die for you but I have no experience with doing this. Any 338 Lovers out there that have had the same issue? Feel free to let me know if my thinking is wrong. I am a longtime reloader but this is new to me. Usually, you body size it and you are good to go for a few firings with just "Necksizing" thereafter. I do know the 338 is high pressure but I have a feeling something is not right.
 
#4
poison123 said:
Just curious but does this do it with factory ammo that doesn't use lapua brass?
Click to expand...

Good question. I havent tried it with other factory ammo. I have used the lapua loaded factory ammo and it did the same thing. I shot the factory ammo in which chambering and extraction was smooth. Then neck sized the "fireformed" brass and loaded 90 grains of h1000. Took it out to the range and it chambered kind of "snug". However, extraction was not a 2 finger bolt operation process. Again, had to kind of whack it with my palm. Not hard but the bolt certainly didnt "slide" up and back like with the factory stuff.
 
#5
DAVETOOLEY said:
If that is indeed your problem it's very simple to polish out the chamber a few thousands to allow room for the expansion, sizing and spring back movement of the brass. Call GAP tomorrow and discuss this with them.
Click to expand...

I appreciate it. last question. I have it shooting pretty damned accurate. If i decide to continue to shoot it this way (tight extraction, etc), I assume it will create premature wear or even breakage? Extractor? Bolt? Camming surface on action? Etc?
 
#7
machtig said:
I'm having a very similar similar issue with my tight chambered TAC 308. See some of the responses in a thread I started http://www.snipershide.com/shooting...-bolt-lift-hand-loads-mcmillan-tac-308-a.html
Click to expand...


Wow, very similar issue. I bet if you tumble the shit out of your already fired brass that was hard to extract so it has a mirror finish then chamber that brass then extract it, i bet you will find "friction marks" around the base of the brass. Or you can use a non permanent sharpie. I can almost guarantee its not a headspace issue. I say that because i thought that was my issue too. Then I measured and measured and measured. I even bumped the shoulder way the fuck back with a body die and it still was "stiff". I even "trimmed" the shoulder and neck completely off the brass with my LE Wilson trimmer and the bastard still was stiff while chambering!!!! All that was left was basically the base!!!!!! I "eliminated" all possibilities except for the base.
 
#14
are you measuring the shoulder bump with a gauge or the "till the shell holder touches minus a quarter turn" method? Bot knocking you just running down the list of possibilities
 
#15
I had the same issue with my gap .338 when I tried using once fired brass from another rifle. Gap chamber was just much tighter at the base and even fl sizing didn't help. Switched to new brass and its working fine
 
#18
LawnMM said:
are you measuring the shoulder bump with a gauge or the "till the shell holder touches minus a quarter turn" method? Bot knocking you just running down the list of possibilities
Click to expand...

I appreciate you helping. I measure with my hornady headspace guage (bump gauge?). I also measured with the LE wilson headspace cylinder gauge. I have even bumped the shoulder back by having the die touch the shell holder PLUS a quarter turn, per Redding's advise. It was a big camover and it bumped the shoulder back so far i wouldn't use it now but it certainly proved the point that it wasnt the headspace. It was still tight!!! Again, i even chopped the shoulder off and chambered the back half of the case. It was tight!!!
 
#22
I just did a google search on custom dies and it seems like Warner Machining is a high quality maker of custom dies. I sent them an email to see if they can hook me up. I will let you know what they say. Looks like they get rave reviews for quality. They look nice.
 
#23
In theory if you have brass with at least .001" of clearance it ahould spring back to that dimension after firing allowing you to extract. If you have a "snug" fit when chambering already and then fire the brass can only spring back to a dimension where you already have a somewhat interference fit only this time the brass is likely larger....

New brass dimensions at the base vs fired.. Report back.
 
#24
I've had two 338 LM's that were chambered with PT&G reamers and they both do this with low pressure loads. I've just learned to live with it. In my case the first 2-4 firings aren't so bad, but firings 5+ it gets more noticeable. I primarily use Forster FL dies where I am bumping the shoulder .001/2" using Redding Comp. Shellholders. At one point I used a Redding Type S die and the problem persisted. I have also done a lot of experimentation and isolated it to the base of the brass. I am using solely Lapua brass; never tried any other brands.
 
#27
mosquitoshooter said:
I just did a google search on custom dies and it seems like Warner Machining is a high quality maker of custom dies. I sent them an email to see if they can hook me up. I will let you know what they say. Looks like they get rave reviews for quality. They look nice.
Click to expand...

I did a write up on they're dies a while back. I have a custom .30cal. (7.5x58mm) and a .308win. sizer made and use them both in this die body. Here is the write up....

http://www.snipershide.com/shooting...ng/96885-warner-tool-company-custom-dies.html

Don't email Warner. I would call them. Al and Dan do all the phone calls etc....and do all the shop work. They are busy so I wouldn't be surprised if it takes them a while to answer the email.

They will need one or two fired rounds/cases from virgin brass. They will make the sizing die to your sample brass etc...

What are you using for a case lube when you resize the brass.

The .338 Lapua round seems like it's been a headache on and off with the maker of the brass etc....some soft, some not so soft. Firing a round in one gun reloading it and trying it in a different gun seems to be a bigger problem with this round vs. other rounds.

Also the .338 Lapua round was originally made from .416 Rigby. I've seen Hornady brass, Lapua brass, Ruag ammo etc...all have different cuts on the extractor groove for the diameter. I've got two if not three different shell holders for the different brass. Hornady brass if memory serves me correctly is made to the Rigby spec.

I used the redding dies and imperial sizing die wax. My chamber was cut with the Navy spec. reamer. I think the same one GAP uses on they're builds as well. I haven't had any issues.

Using Hornady one shot lube which I love and is my main case lube I get the .338 Lapua cases stuck in the die. So I had to switch to the imperial sizing die wax. No issues.

Later, Frank
Bartlein Barrels
 
#28
If GAP used what we call the Navy reamer vs. a cip spec. reamer the web area of the chamber is about .0014" to .003" tighter. Depends on which spec. cip reamer print you look at and which drawing reamer/maker you look at.

That being said a friend of mine has his own spec. .338 Lapua chamber/reamer. His is .002" tighter than a cip spec. He has no issues with sizing brass/sticking rounds etc....

So off hand I'm going to say nothing to do with the chamber but I'm not looking at it either.

Dave Tooley had a good point. To call GAP and talk to them.

Later, Frank
 
#29
I am somewhat surprised that no one suspects a Redding die out of spec. I have, but very rarely, seen that happen.
I owned and shot the TRG42 in 338LM. My issue was the total opposite of yours. I had once fired brass that had been resized actually stick in the sleeve of the seater die but would easily rechamber in the gun. I had to return the die to Forster for repair. They had to make the sleeve fit one of my fired and resized casings.
Whatever you find the issue to be, a call to GAP is headed in the right direction.
 
#30
I would be interested in there is a solution out there; to add to my prior post I have used two different Forster dies (ordered years apart) as well as a Redding and the issue was there. To be clear it's not an enormous amount of effort required to open the bolt by any means, just slightly more than I'd expect. It progressively gets worse with each firing but never to the point where I am concerned about hurting the action or anything like that.

If the solution is to have Warner make a custom die I would be thrilled. Would love to hear from more shooters with custom 338's.
 
#31
Dave at CH4D has small base dies for the 338. I found out the hard way when someone gave me a bunch of brass fired out of an AI. It would not chamber after sizing in 2 different dies. Small base cured the problem.
As for extraction . Now I still do have to "bump" the last bit . But I blame that on the shitty design of the Surgeon XL action cam setup.

Greg
 
#32
I don't have an up to date RCBS catalog. But my Sinclair's only shows small base for 223, 308 and 30-06. If you call RCBS on their toll free number, they do make custom dies. The cost isn't too awfully much, if I remember right. But they are made from measurements taken from a few of your rifles fired cases.

A rifle chamber can't have a mirror slick finish. The pressures achieved in the chamber will drive the bolt out of the receiver. There has to be a small amount of friction for the brass to grab when it expands. I'm not talking rough as a dried corn cob or a piece of 80 grit sand paper. But it does need a slight bit of friction, for safety reasons.

Good luck.
Victor
 
#33
SPAK said:
In theory if you have brass with at least .001" of clearance it ahould spring back to that dimension after firing allowing you to extract. If you have a "snug" fit when chambering already and then fire the brass can only spring back to a dimension where you already have a somewhat interference fit only this time the brass is likely larger....

New brass dimensions at the base vs fired.. Report back.
Click to expand...

Okay, I am back home from my business trip. I did the measurements. Instead of retyping, below is an email I sent to Dan Warner.

Dan, I'm sending you two fireformed pieces of brass. Also I am sending two body sized pieces of brass where I bumped the shoulder back by 5 thousandths, which is fairly excessive. However, still, the base on the body sized brass is about an identical measurement to the fire formed brass. They are both .582". My brand-new Lapua factory ammo is quite a bit smaller than that (around .577). What are your thoughts? I don't want to size the brass down so much that I lose accuracy. But, at the same time, I want to be able to chamber it and eject. I am sending in the mail. Please advise on what steps you would take if you were in my shoes. Thanks
 
Last edited:
#34
pyrofx said:
Dave at CH4D has small base dies for the 338. I found out the hard way when someone gave me a bunch of brass fired out of an AI. It would not chamber after sizing in 2 different dies. Small base cured the problem.
As for extraction . Now I still do have to "bump" the last bit . But I blame that on the shitty design of the Surgeon XL action cam setup.

Greg
Click to expand...

Exact route I went with my GAP 338. C4HD small base full length die took care of my issue - excellent quality.
 
#35
I have the same thing with my Gap badger 2008 .338 lapua about 85% of them are ok but then about every so often i get a stuck one. I am really getting tired of it. 2 and 3 times fired lapua brass. bought once fired. bump them .002 of a inch and neck size them to .002 spring back. the loads not that hot 87.6 out of a 30in bartlein im estimating because of trajectory 2750 fps which in my opinion is a bit slow.
 
#37
DAVETOOLEY said:
Does anyone else see what's happening. A small number of people are having issues. Instead of curing the disease they're choosing to treat the symptoms.
Click to expand...

Im not sure i understand this comment. Your last message said either fix the chamber or fix the sizing process or do a combination of the two. I chose to fix the sizing process. Your option 2. WHAT AM I MISSING????

It doesnt seem to be too "small" of a group. So far I have seen about 5 people post something somewhere where they had a GAP chambered 338 Lapua with this issue. I talked to George and he said it is not a "CIP" chamber and it is designed that way. The gun is accurate as hell and if a small base die makes it work for the life of the barrel, which will only last me 6 months, what is the issue. Especially if i get a kickass die in the process. Again, i thought i was following your advise.
 
#39
Good luck calling GAP i have a good friend of mine that his BIL just bought a GAP 10 308 and it would take any factory ammo like Federal Gold Match or BHA etc. He called GAP and they told him to shove it. And that their was no way anything was wrong with a gun they sent out. He paid to send it back and they claimed they did nothing to the gun but now it cylces anything. he finally talked to a guy in the shop and they said they had to ream the chamber a quite a bit. That they had messed up. But everyone else at GAP still denies they messed up. Id take it and have the chamber reamed like said above so you dont have to mess with it.
 
#40
DwClifton, What in the hell are you talking about? I guarantee you we have never ReReamed a chamber in a Gap -10. We have re throated a few. I also Guarantee we have never told anyone to "Shove it" either. Tell this friend of a friend of yours to call George. The only persons that talk to customers with issues are myself and Marc Hall. So I'm guessing your getting Something wrong in the translation
 
#41
338 Lapua chambers. The problem lies in the Spec. Initially there was only a CIP "euro spec". And most dies are made to this spec. Now there is a Sami Spec and a Mil Spec and a NavSpec. Our mainstay reamer is the Crane/ Navy reamer. It's a little tighter than The CIP .003-.004. Some dies work well others don't. I'm not sure what the best way for shops to proceed. CIP chambers are huge so I don't see that as the answer either. Dave is correct polishing the chamber a couple thou will help. And may be a fix for guys that are having problems with their dies. Best answer is always to call Me with any issues. Thanks!!
 
#42
A10XRIFLE said:
338 Lapua chambers. The problem lies in the Spec. Initially there was only a CIP "euro spec". And most dies are made to this spec. Now there is a Sami Spec and a Mil Spec and a NavSpec. Our mainstay reamer is the Crane/ Navy reamer. It's a little tighter than The CIP .003-.004. Some dies work well others don't. I'm not sure what the best way for shops to proceed. CIP chambers are huge so I don't see that as the answer either. Dave is correct polishing the chamber a couple thou will help. And may be a fix for guys that are having problems with their dies. Best answer is always to call Me with any issues. Thanks!!
Click to expand...

Thanks George. I sent you an email. I read about every article on the 338 Lapua before i chose it as a new caliber to play with. Of course, i never saw these issues until now. Many people are having these issues with the caliber it seems. Just my luck. It could be raining pussies and i would get hit in the face with a dick.
 
#43
George,
What would be your advice as to figuring out which reamer was used in our rifles and finding a corresponding die that would help fix our problems?
If we called or email serial numbers do you still have records of what would have been used? Mine is an older Eric Reid build.
Thanks for chiming in
B
 
#44
I would contact Widden Gun Works and send them a few of you fired cases. I am having them make a custom die for my 408 Cheytac with a full length sizer and bushing neck sizer in one die.

Here is a link to his die sets.

Whidden Gunworks

I looked at the Warner tool company die also, it looks to be an amazing setup. You have to buy the die and then the inserts for it. It comes out to about 500.00. I just could not justify the funds for one die at this time.


When I contacted Whidden, I explained everything I wanted to do and they said it would be easy to make it happen.
 
Last edited:
#45
mosquitoshooter said:
Thanks George. I sent you an email. I read about every article on the 338 Lapua before i chose it as a new caliber to play with. Of course, i never saw these issues until now. Many people are having these issues with the caliber it seems. Just my luck. It could be raining pussies and i would get hit in the face with a dick.
Click to expand...

Did not get an Email

[email protected]

try that

George
 
#46
BusterB said:
George,
What would be your advice as to figuring out which reamer was used in our rifles and finding a corresponding die that would help fix our problems?
If we called or email serial numbers do you still have records of what would have been used? Mine is an older Eric Reid build.
Thanks for chiming in
B
Click to expand...

If yours is an Eric Build it would be a reamer we had made using new Lapua Brass and a 300 Sierra at AI Mag Length (old AI Mags) I have several rifles build on that reamer and have no problems with my Forester FL Dies Resizing it perfectly.

Pat Sinclair has a 338 with that chamber and he neck sizes ill try to find out from him how often he Body bumps the brass. I know his Dies are Redding.


Most of the problems ive seen come from guys buying once fired brass and guys that have 2 338 rifles and one has a CIP chamber. IE AI, SAKO, ETC these chambers are CIP SPEC
 
#47
A10XRIFLE said:
If yours is an Eric Build it would be a reamer we had made using new Lapua Brass and a 300 Sierra at AI Mag Length (old AI Mags) I have several rifles build on that reamer and have no problems with my Forester FL Dies Resizing it perfectly.

Pat Sinclair has a 338 with that chamber and he neck sizes ill try to find out from him how often he Body bumps the brass. I know his Dies are Redding.


Most of the problems ive seen come from guys buying once fired brass and guys that have 2 338 rifles and one has a CIP chamber. IE AI, SAKO, ETC these chambers are CIP SPEC
Click to expand...



The problem I was having was when I was using brass from another rifle also. I did switch to lapua and all is good at the moment. I have only neck sized so not sure if my redding fl die will work the body enough or not when the time comes. If not I will try the forester.

I know with the brass from another rifle my redding die could not size it enough to fit.
Thanks again
B
 
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