Loosening Primer Pockets

[swampshooter]

I can't make it to Novembers match. But If the creek doesn't rise I'll be there in Dec. I could bring something with me to the match if you desired.

 

[ShootDots]

That would be excellent! There was a book I had of Jack O'Connor that had devoted each chapter to a selected cartridge. I can not remember the name of the book. However, one of the chapters was called "The Good Old Thuddy Thuddy">>> Do you have that book by any chance?

 

[swampshooter]

I remember that chapter name. I think that's in a book called either "The Rifle" or "The Hunting Rifle". I have both. I'll go look and see which one it is as soon as I feed the dogs.

 

[ShootDots]

Well if you could dig that one out Bill, I would L-O-V-E to read it again.. I was about 18yrs old when I first bit into that delicacy!

 

[swampshooter]

That chapter is in "The Hunting Rifle". I have it. Would you like for me to bring it to Decembers long range match for you to read? If you want you could send me your address in a PM and then bring it back in December.

 

[ShootDots]

You have the PM inbound Bill..

 

[swampshooter]

Ben, you have a return PM inbound.

Bill Batson

 

[Erik Cortina]

Wow, I was catching up on this thread and all I could think of was "squirrel!" with some of the comments. Topic was going in and out. ;D

Anyway, back to topic. Mystic brought up a good point, if you have too much clearance between your barrel tenon and your bolt, too much of your case will be unsupported and primer pockets will be more likely to opening up.

I doubt it's the brass because like I said before, I have three firings on my brass and they are still very tight. How many firings on your brass so far?

 

[ShootDots]

Wow, I was catching up on this thread and all I could think of was "squirrel!" with some of the comments. Topic was going in and out. ;D

Anyway, back to topic. Mystic brought up a good point, if you have too much clearance between your barrel tenon and your bolt, too much of your case will be unsupported and primer pockets will be more likely to opening up.

I doubt it's the brass because like I said before, I have three firings on my brass and they are still very tight. How many firings on your brass so far?

Yeah, we got a little off track.. But us "Old Heads" have a tendency to reminisce! LOL!!! I have the initial fireforming firing and 2 "full power" firings on that brass. I still have to use the primer seater to seat the primers and they are "loosening up" but not too loose to be unusable.. I am loading them up as we "speak"..

 

[bigedp51]

ShootDots

You are playing with the wrong cartridge if you truly read about Jack O'Conner and his favorite cartridge..........................

Everyone of that age group should know the .270 Winchester is the worlds best non-belted magnum. ;D

 

[ShootDots]

ShootDots

You are playing with the wrong cartridge if you truly read about Jack O'Conner and his favorite cartridge..........................

Everyone of that age group should know the .270 Winchester is the worlds best non-belted magnum. ;D

I had 2 / .270's.. One when I was a "kid" in New York and 1 (one) here in Texas for many, many years and killed most of my deer with it. Personally, I believe that the .270 and 7mm-08 may very well be the best "Deer cartridges" you can own. Certainly, there are others their equal, however, surpassing them will take some doing.. O'Connor was correct in his assertion...

 

[BradY]

We have found this problem here too in Aus with lapua 6.5x284 cases necked up to 7mm. 6-8 firings above 2900fps is pretty much what you get. Its the reason why people here dont push velocity- so they get good case life. All our world champion shooters are below 2850fps with 284 and 284 shehanes. Ive had 2 barrels in shehane and agree the only way to shoot 2900+ with 180's with good brass life is to use a SAUM- or live to be happy with 6 firings per case.

 

[Elwood]

Ben, I have experienced loose primers pockets once before using a fire forming load for my Shehane, I was using 52 gr RL17 to fire form Lapua 6.5x284. I did manage to get 5 firings out of that brass until they felt to loose. In the I used a Hart case saver to tighten up the loose primer pockets. Despite what people say, the Hart case saver can work, or at least it did for me ( I have since broken it!) I managed to get another 4 firings out of those cases. That's the only time I have ever experienced loose primer pockets in 3 Shehanes.


A typical load in the UK for a Shehane with formed brass using H4831sc is 58gr and that is a very common go to load, we look for fps between 2930-2960 and still get pretty good case life, so you're not over doing it in that compartment.

 

[SmokinJoe]

I don't shoot what you guys shoot, but it is an interesting thread. After reading through it, sounds like shootsdots may have a somewhat unique situation, which would indicate to me that there is a possible problem with the chamber or bolt nose to barrel fit. Those areas are worth a thorough check at least. Checking shootsdots fired brass dimensions against someone else's, who doesn't have a problem & shoots that level load or higher would also be worth the effort. One thing I have found about chambering is that some smiths use techniques that result in the rear of chambers being a little larger than others, so reamer dimensions won't necessarily tell the story. Maybe a chamber cast compared to reamer print would tell you what you need. Loosening primer pockets is a frustrating, perplexing sorta problem, especially when you think you are well within the bounds of a load range. I also think y'all would be wise to contact Kevin Thomas and share your experience with the Lapua brass. Maybe they need to give that brass an extra strike during manufacture to harden the case head a little more. Lapua is a quality oriented company so they should take such commentary constructively.

 

[Erik Cortina]

I don't shoot what you guys shoot, but it is an interesting thread. After reading through it, sounds like shootsdots may have a somewhat unique situation, which would indicate to me that there is a possible problem with the chamber or bolt nose to barrel fit. Those areas are worth a thorough check at least. Checking shootsdots fired brass dimensions against someone else's, who doesn't have a problem & shoots that level load or higher would also be worth the effort. One thing I have found about chambering is that some smiths use techniques that result in the rear of chambers being a little larger than others, so reamer dimensions won't necessarily tell the story. Maybe a chamber cast compared to reamer print would tell you what you need. Loosening primer pockets is a frustrating, perplexing sorta problem, especially when you think you are well within the bounds of a load range. I also think y'all would be wise to contact Kevin Thomas and share your experience with the Lapua brass. Maybe they need to give that brass an extra strike during manufacture to harden the case head a little more. Lapua is a quality oriented company so they should take such commentary constructively.

I agree 100%

 

[nhm16]

See this thread about the .284 case and bolt thrust. It may be endemic to the design of the case (and similar rebated rim cases).

 

[ShootDots]

See this thread about the .284 case and bolt thrust. It may be endemic to the design of the case (and similar rebated rim cases).

If you read on this thread, Page 2, Comment #29, you will see that I am beginning to believe that too.. I think it is inherent in the design of the case.. I have NEVER had primer pocket problems out of ANY "non-rebated" cartridges. In my "old" 270 that we actually discussed on this thread somewhat, I was shooting 61.0grs of H4831 (there was no SC back then) which was 2grs OVER the max (using a 140 Nosler B-tips) in the Hodgdon manual back then, and never had loose primer pockets. I ran 49.5grs of H4350 in one of my 7mm-08's with the Hornady 139gr Interlocks and never had loose primer pockets. The "common denominator" with the "loose primer pocket syndrome" appears to emanate from the rebated rim design, especially when you shoot either the 6.5 x 284 OR the Shehane. This could easily be corrected with a thicker web area..

 

[Erik Cortina]

See this thread about the .284 case and bolt thrust. It may be endemic to the design of the case (and similar rebated rim cases).

If you read on this thread, Page 2, Comment #29, you will see that I am beginning to believe that too.. I think it is inherent in the design of the case.. I have NEVER had primer pocket problems out of ANY "non-rebated" cartridges. In my "old" 270 that we actually discussed on this thread somewhat, I was shooting 61.0grs of H4831 (there was no SC back then) which was 2grs OVER the max (using a 140 Nosler B-tips) in the Hodgdon manual back then, and never had loose primer pockets. I ran 49.5grs of H4350 in one of my 7mm-08's with the Hornady 139gr Interlocks and never had loose primer pockets. The "common denominator" with the "loose primer pocket syndrome" appears to emanate from the rebated rim design, especially when you shoot either the 6.5 x 284 OR the Shehane. This could easily be corrected with a thicker web area..

Ben, how come I'm not having problems with loose primer pockets? I know of a few other guys getting 8+ firings on their brass and they are using H4350 and H4831 at 2,900+ fps.

 

[ShootDots]

I can not explain that Erik... I also noticed on a few various lots of brass (both Lapua and Norma) that some primer pockets are "relatively" loose before firing>>like mine were this time... I had a lot of Norma brass that had TIGHT primer pockets when I had my 6.5 X 284 and they never opened up.. However, I was using H1000 then too. Why was that lot of brass tighter in the primer pocket area than a different lot? I can't explain that either..

Here is another thought... Tom Holbrook used my reamer for his 2 Shehanes, Omar did his barrels at the same time he did mine.. Same reamer, same 'smith and Tom's does not have any primer issues. His load is 0.10gr less than mine. I think it falls in the design and manufacture of the brass itself.. Some lots are better than others.. I have had both..

 

[ShootDots]

I have an observation... I just primed my "load development" brass for about the 12th time. It has just about the same resistance to seating primers as my "match brass" does.. Same reamer, obviously the same 'smith, MAYBE the brass has a "tipping point" for expansion and will not go over that unless you run H-I-G-H pressures?

I have a thought too... When I first started out, I was using H1000 and the Berger Hybrids. They have a CONSIDERABLY shorter bearing surface than the 180 Scenars. The H1000 was just a shade too slow. GREAT accuracy, GREAT velocity BUT because it was not burning quite efficiently enough, the E.S. were running about 40f.p.s. Just possibly, now with the Scenars L-O-N-G bearing surface, it might just allow the H1000 to be back in business. So I decided to load some up>>>that's when I noticed the primers going in about the same as my "match brass"! And these "load development" pieces have been fired at least 10 or 12 times! That may shed some additional light on this situation!