260 lrp Lapua brass pressures

I've been lurking for awhile and need advice/help. New (factory) model 12 .260, virgin Lapua brass 39 gr. of H4350 cci br2 and a 139 Lapua, .020 off and it almost blows the case head off. Headspace is good with a ptg and Forster go gauge. Same components with 34.5 Varget and it shoots about 1/2 moa, but really slow and leaves a ring near the case head.
Kinda reluctant to buy another batch of Lapua. I did buy some Federal fusion 140g at it shot a 6" at 100. Yeah, 6" at 100. I tried that brass with the 4350 load and neck sizing between the brass stayed together.
So, is the Lapua brass generally an issue with saami reamed chambers? I had this rig over 2 years and I'm beginning to become frustrated. Any help is greatly appreciated.

edit: my goal here is to find a combination of components that work, not to place blame on a component company or the rifle maker.

I don't think it is pressure causing your problem. The problem is more than likely your brass expanding excessively lengthwise. It is possible that you don't have your sizing die set up correctly. I would bet that you are bumping your shoulder back too far..... or maybe you need to recheck your head space. You did not mention the use of a no-go, It might be long.


How are you checking your case head space?

It's virgin Lapua brass. I'm neck sizing with a Redding comp bushing die on the Federal and Lapua/varget load. My Forster no-go won't chamber. Headspace is checked with the bolt head stripped and the firing pin removed.

Need to know the velocities being run at those charges. Assuming that you don't have a fat chamber, Lapua brass is typically a smaller volume than others. So that can speed-up the burning rates and you will have higher pressures.

39 g of h4350 is not anywhere close to a max load and if lapua put out a bad lot of brass, there would be more than one person having problems. Have you taken measurements before and after sizing? Before and after firing? All the data is in front of you, we just need to find out what is changing.

As an aside, I fully prep virgin lapua brass before loading. Full length size, trim and neck turn.

Have you measured the base of a new case and a fired case to see if the chamber is oversized?

Are the primers backed out?

If you have the tools, check fired Case head space against you go/no-go gauges.

Have you called Savage?

Just throwing things out there to get more data.

I have not called Savage, yet. I'm away for the weekend but I'll have the data Sunday afternoon. Bear with me, and thanks.

I would also want to know the loaded and fired neck diameter of cases. You may have a tight neck or short throats chamber. Savage has had a number of chamber issues in the last few years


Sent from my iPhone using Tapatalk

Ok here it goes...
new brass mouth .291, mouth loaded .2935, mouth fired .298
new brass shoulder 1.5565, shoulder fired 1.5625
new brass base o.d. .464, fired .471
new brass length 2.022, fired 2.032
primer is flattened and backed out of case ~.002
Separation occurs about .280 up from base of case and .o.d is .4705 at that point.
Go gauge measures 1.549 No-go measures 1.554 (in my comparator)
Tools used: RCBS digital caliper, Sinclair comparator body and Sinclair "bump" insert #20A and Forster go (1.630) and no-go (1.634).

Dang.. IM anxious to hear what is causing it... Could it have a super tight bore?

It looks like a very loose chamber. Your brass is growing a lot, especially length and necks. Mine grow less than .003 in length each firing. I would change bushing size so your loaded necks are .295 to work the brass less. Aside from that, I don't see anything off unless maybe there is a bulge in your chamber. My base-shoulder measurement on fired brass is 1.626, but that is probably just different comparators.

Are you using imr 4350 instead of h4350? The varget load seems very low too but I never messed with it shooting heavies. I used 36.5g in a .220 swift to push 55 gr bullets.

maybe change powders? Rl17 or h4831sc are both pretty easy to get and great options in .260.

Measure the brass in question with the headspace comparator, and compare this measurement with the go-gauge measurement. This will tell you everything you need to know.

If the brass is indeed sized to far (shoulders bumped too much causing excessive working headspace) there is a way to salvage the brass. But it requires a fireforming technique with the bullets jammed hard in the lands. And preferably a faster burning powder like Varget or Benchmark and a load near the middle between the starting and max load, maybe more like 1/3rd of the way from minimum book recommendation just to be unquestionably safe.
This will form the brass with out thinning the brass above the case head.
Sometimes it requires fireforming more than once to get the shoulders as far as the chamber if the load is too mild.

Also a picture or link to one would be helpful for us to judge the brass in question.

I think at this point I would either have the chamber inspected by a competent Gunsmith or contact Savage and see if they will inspect it. The other option would be to rebarrel with an after market barrel and start fresh. Also are you measuring distance from the lands to a specific jump or jam for seating depth?

https://instagram.com/p/BVhxvNig19y/

https://instagram.com/p/BVhx3ftgnWT/

I used a Hornady oal tool, modified case, and comparator to "find" the lands.

Very well. Same method I use. I believe this may be beyond an internet diagnosis at this point.

Why was the tread "260 lrp Lapua brass pressures" locked out?

I collect milsurp rifles and had many .303 British Enfield rifles that have "LONGER" military headspace. And there are many reasons for case head separations, defective brass, thin case wall thickness and excessive head clearance.

Below is a animated image of firing a thin commercial .303 British case in a Enfield military chamber.

http://i.imgur.com/sHgqVJR.gif

This factory loaded Winchester .303 case started to seperate after being reloaded just once.

http://i.imgur.com/DVy4C4T.jpg

Please do not take this question the wrong way, and I'm not claiming a expert but after discussing reloading methods in Enfield reloading forums my .303 case life improved greatly.

My wild ass guess is the new Lupua brass had excessive head clearance on the first firing and stretch and thinned.

I bought a RCBS case mastering gauge below as my $100.00 bent paper clip to check for stretching and thinning in the base web area. And with moderate loads have gotten over 30 reloads from thicker Prvi Partizan .303 brass with case walls .010 thicker than Winchester .303 British cases.

http://i.imgur.com/jDCS39v.jpg

The Winchester case below stretched .009 on the first firing and had .009 head clearance.

http://i.imgur.com/YoV80b4.jpg

A .303 British Enfield Rifle at max military headspace of .074 and a case with a rim thickness of .058 will have .016 head clearance. And these cases must be properly fire formed to prevent them from stretching when first fired.

Below the properly fire formed .303 case below is now headspacing on its shoulder with "zero" head clearance and will not stretch and thin when fired.

http://i.imgur.com/AQEQ9Vw.jpg

The .308 cases below were fired in a Savage rifle and full length resized over and over until they failed. These cases were sized per the dies instructions with the die making hard contact with the shell holder, meaning not adjusted for minimum shoulder bump.

http://i.imgur.com/TDwPD1Q.jpg

http://i.imgur.com/XEuny9C.jpg

Again no offense but I have had brand new Winchester .243 cases over .012 shorter than chamber headspace. And if not fire formed properly they will separate after very few reloadings.

A reloading forum is where experience and knowledge can be shared, and with modern rifle with a good venting system a case head separation is not the end of the world.

The Enfield rifle below has had the headspace adjusted from .004 "under" minimum headspace and .010 "over" maximum headspace. And any escaping gas from case head separations excaped from the vent hole in the receiver.

http://i.imgur.com/v1GFvaK.jpg

On the Enfield rifle below paper was wrapped around the receiver with a cartridge chambered that was going to separate on its next firing.

http://i40.tinypic.com/29fw5ft.jpg

After firing and a full case head separation "NO" rips or holes were in the paper.

http://i42.tinypic.com/11ayg6q.jpg

And Savage rifles have two vent holes on both sides of the receiver, and a Remington 700 only has one vent hole on the right side.

http://www.shootingtimes.com/files/2...00_041106b.jpg

If I may..I was just curious if European brass didn't work well with Saami chambers. SAAMI vs CIP. The indication (that I got) from the other thread is Lapua should work fine in my chamber. My original plan was to buy a reamer from Dave Kiff to accommodate the Lapua brass if the opposite was true.
I've been hand loading for almost 10 years for a variety of other rifles (Savage included) and never had an issue. I do understand speculation, especially when it comes to diagnosing a potential problem with a firearm, can be extremely dangerous when ones experience is questionable. I am not a smith, but I am more mechanical than most. You have offered some great information here that may help me when I call Savage. I haven't called yet only because I wanted to understand better what might be causing my problem so I can better communicate it to them. I also understand my first post questioning the manufacturers (Savage and Lapua), probably the two most highly regarded companies on the site, could draw the conclusion I was trolling. This could not be farther from the truth. I'm here to contribute and learn when I can. No offense and none taken.
Moving forward I'm going to cut a few cases apart and take a look. Ultimately, as LoneWolf indicated, either a smith or Savage needs to inspect things.
Thanks

tizzy

If it was my rifle I would measure a fired case with a Hornady cartridge case headspace gauge or RCBS precision mic. Then measure new unfired cases and see how much shorter they are than the fired case and chamber.

Case head separations are cause by the case stretching to meet the bolt face when fired. Head clearance is the air space between the bolt face and the rear of the case and the distance the case can stretch and thin. A case with .002 shoulder bump will have approximately .002 head clearance which is well within the elastic limits of the brass.

http://i.imgur.com/HK76WCp.jpg

Below I'm measuring a fired Lake City 5.56 case fired in my AR15 carbine, after taking this measurement I set up the sizing die for .003 shoulder bump.

http://i.imgur.com/OJqNmQH.jpg

And again my WAG is the new Lupua cases had excessive head clearance when fired and caused the case head separation. Meaning the new cases were far shorter than the chamber and stretched excessively and separated. Another clue is the primer backed out .002, meaning the base of the case never made contact with the bolt face when fired. And this normally happens at "lower" chamber pressures well below max pressure.

Bottom line, you either had excessive head clearance with the new Lapua brass or the cases were defective. And this WAG is only if you only neck sized the cases, if these cases were ever full length resized then the case head separation could have been caused by excessive shoulder setback.

I may know a little more today when I cut some open. Thanks

Since you already established the chamber with go and no-go gauges that it's withing spec...
This should be very easy to diagnose with a headspace comparator by checking the unfired Lapua brass and comparing it to a go-gauge.

Or with Masking tape on the head of the unfired brass.

I only know of one way this can happen. If the brass has excessive working headspace. If there is another way this can happen I would like to know.
I'm just going of off the pictures tizzy provided. Looks like a typical excessive working headspace issue. In this case due to the brass and not the chamber, since it's been checked to be good.

I would also cut a unfired case lengthwise with a dremel to see if the brass above the head is thin to begin with, causing this problem.

The thread you reference has not been locked. Not sure what gave you that idea. I do not see the post as trolling either. Just an issue that is believed to require someone with the proper knowledge to inspect the rifle. If this is happening with new Lapua brass not once fired ect. like stated in the other post I would also check any other brass I've fired in the rifle by taking a paper clip straightening it out leaving a hook on the bottom and run it inside the case scraping against the side wall near the case head to see if it catches on the wall. This would tell you that the case is getting ready to fail near the head due to excessive case stretch.

Old antique rifles like the 303 British you've posted can show what may be occurring, but the Savage should not be having this issue plain and simple. It needs to be inspected for safety of the shooter/OP and anyone who may be around him. Not because he does not know what he is doing at the bench, but because there appears to be a true issue with the chambering of the rifle in question.

The comparator I am using (Sinclair body and insert 20A) locates on the shoulder where it meets the case body, not on a datum line partially up the shoulder. Those measurements I listed earlier in this post don't seem to add up. My fired brass is longer than the no-go gauge. I'm not sure how that's possible unless it has to do with the design of the insert I'm using. I have a #26 insert that would locate farther up the shoulder and for all intents and purposes for this specific comparison, might work better. Otherwise I'll have to get the Hornady body and insert this weekend. I'll cut a few cases and try to get them posted today.

After a quick google check it appears as both comparators are equally fine. Here, though, is a new case and a once fired virgin cross-sectioned.

https://instagram.com/p/BVkAnRRAD6-/

You've got a lot of brass moving there!

Velocity averages were measured using a ProChrono 5 shots
34.5 Varget 139 Scenar virgin=2450/1 fired=2584
39.5 H4350 same bullet virgin=2767

Remove the barrel from the action. and drop an unfired case in the chamber. See how much is hanging out. I'm wondering if you have a properly headspaced barrel to action with a short chamber that wasn't reamed to the proper depth.

Lonewolf yesterday after your noon hour post the thread was locked. Now it isn't.

Quote:

---

Originally Posted by rjtfroggy

Lonewolf yesterday after your noon hour post the thread was locked. Now it isn't.

---

:confused: Wasn't me...... If I had locked it I would have noted a reason why!

The OP stated he checked the rifle with a GO and NO-GO gauges, and the bolt would not close on the NO-GO gauge. This eliminates rifle headspace issues and leaves the new Lapua brass. The OP also shot some Federal Fusion ammunition and that brass did not have a case head separation.

If you look at the SAAMI cartridge and chamber drawings it lists headspace as min and max with .010 in between. The GO and NO-GO gauges have .003 between them and are for setting up new or re-barreled rifles. And a Field gauge represents the maximum of .010 more than the GO gauge and max allowable headspace.

Bottom line, according to the OP only one brand of case had a case head separation and that was his Lapua cases. And from all the posts by the OP this tells me its not a rifle problem and points to a Lapua case problem.

And my "antique" Enfield rifles have a removable bolt head to adjust the headspace. And to study the effects of headspace on the cases I set the headspace to different amounts.

And I then checked the cases for stretching and thinning.

http://www.larrywillis.com/RCBS%20casemaster3.jpg

So forgive me LoneWolf for having "antique" rifles with adjustable headspace that allowed me to play with my bolt heads until I nearly went blind.

P.S. And LoneWolf Savage made more No.4 Enfield rifles during WWII than any other country. (antiques my gluteus maximus)

And the "antique" Enfield rifle below was made in 1950 and then was custom bedded by the military for competitive shooting.

http://i.imgur.com/v1GFvaK.jpg

tizzy

You stated you had no problem with the Federal fusion factory ammunition the first firing and after reloading the Federal cases once. So do not start working on your rifle and taking it apart and do some more checking of the fired cases.

1. Section a few of the Federal cases and see if you had any stretching and thinning. If you have no problems with the Federal cases then the new Lapua brass was defective or extremely short in cartridge headspace length.

2. Always measure new cases, fired cases and resized cases for shoulder location. This way with your measuring your cases you will have a good idea of your chambers actual headspace.

3. Below the cheap bastards headspace/head clearance gauge

Measure the length of the new case before firing and write down this measurement.

http://i.imgur.com/SgwqgaU.jpg

Next take a fired spent primer and start it into the primer pocket just using your fingers.

http://i.imgur.com/oNIvIiX.jpg

http://i.imgur.com/zQxlYGp.jpg

Now chamber this test case and slowly close the bolt and let the bolt face seat the primer. Then extract the case and measure the case from the base of the primer to the case mouth and write it down.

Now subtract the first case measurement from the second and this is your head clearance and how far the case has to stretch to meet the bolt face. You can do this same test with a Hornady cartridge case headspace gauge using the primer method.

So again if the Lapua brass was too short in cartridge case headspace length or if the case was too "soft" in the base you can have a case head separation.

I buy bulk once fired Lake City 5.56 and 7.62 cases because this military brass is harder in the base than commercial brass. These cases are then checked with my RCBS case mastering gauge for stretching and thinning. And I have yet to find one of these military cases that have stretched and thinned.

Just one of the early jamming problems with the M16 rifle was soft brass which was brought to light in the 1968 Congressional Hearings.

http://i.imgur.com/OujD1z7.jpg

Below my buddy CatShooter did a Rockwell hardness test of various .223/5.56 cases and the Lake City brass had the hardest brass in the base.

How Hard is Your Brass? 5.56 and .223 Rem Base Hardness Tests
http://bulletin.accurateshooter.com/...ardness-tests/

https://instagram.com/p/BVk76VTAOm5/

https://instagram.com/p/BVk78Frgq0V/

https://instagram.com/p/BVk7_tTgR7b/

https://instagram.com/p/BVk8DpagMAp/

This is the Federal Fusion case shot initially with the factory load, then necksized 4 times and fired with the 39gr. H4350 load. The difference in length is .002 between no primer and seating the primer with the bolt. The bolt head currently only has the extractor claw installed.
The virgin Lapua brass base to shoulder is .006 shorter than a new Federal. Case length of the Federal is .005 longer than a new Lapua.

I have merged this and the second thread Ed started together so all the posts and info are in this one. Next time you have a question about something a moderator does Ed, ask in PM so as to avoid duplication such as this.

I am curious if the case protrusion is correct. I realize that failure to extract might/should be an issue, however if the firing pin is hitting hard enough it may be growing enough to facilitate extraction.

Are there any circular marks on the face of the bolt? If you can see the breech are there any rub marks on the face?

Being a new rifle and if that is in fact the problem, Savage is the only one that should touch it. I can think of a couple of Savage smith ways to verify...... naw. Call Savage



EDIT: I just noticed and I think this is the same or similar to what LW was saying in post 27.

No unusual marks on the bolt face.
I really appreciate everyones patience and help.

Tizzy

Your Federal brass did not stretch and thin and has nothing wrong with it, and the Lapua brass stretched, thinned and separated.

If you had a problem with your rifle both cases would have separated, and the actual problem is bad Lapua brass.

Should Lapua brass work fine in a SAAMI chamber, or is it more suited for "match" custom reamed chambers? The million $ question is, will another box of Lapua net the same results or did I just get a bad batch?
Thanks again.

I have 300 pieces of .260 lapua brass from different lots and I can't tell a measurable difference worth a bother. I turn the necks for a match chamber but I haven't ever heard of a problem with SAAMI chambers. The one picture of fired vs unfired lapua brass looks off. LoneWolf already said, that is a lot of brass to move just above the web. It looks like the case is not chambered fully and unsupported where it is failing.

Gonna have to agree with the above and refer it to a gunsmith. With a full separation like that you may have scarred the chamber and it's just getting worse.

I think the same thing as Bigedp51.

The Lapua brass is the problem. It's very obvious after farther evidence provided by tizzy.

A very good example tizzy posted is the big gap in velocity from virgin to once fired.

The reason why the Virgin brass made so much less velocity than the once fired is because when the brass stretches this much during firing it delays the pressure buildup / peak pressure.

You can still save the Virgin brass by either making a false shoulder on the neck or jamming bullets hard in the rifling. The false shoulder on the neck is the best solution, but you'll need a bigger expender or bushing in the sizing die. Research "false shoulder reloading brass" on google and you'll save the rest of the good virgin brass.

On the other hand... I would first call Lapua and let them know what's happening. I'm sure they would want to know.

I'm on it. Thanks again!

bigedp51: Well done. That is some great work and outstanding analysis!.