What increases/decreases pressure more, seating depth or jamming?

[Mega]

I really think you should look at your firing pin clearance in the bolt face and maybe firing pin contour. Are you using soft or hard cup primers.

 

[cavedweller29]

They are hard primers...wolf. I was using Rem 7 1/2 but like my powder, I ran out. I had a bunch of wolf that I use in my service rifle so I used them. I believe that wolf primers are harder than the 7 1/2 but I could be wrong.

 

[Mega]

Best I can find is that Wolf have at least a couple of different SR Primers with different cup hardness / thickness but cannot find a stated value and the Remington 7 1/2, CCI 450 & CCI BR4 are the thickest I know of at 0.025".

Wolf Primers are not available to me so I have not measured a cup but in any of the "high pressure" cartridge calibres I use I ony use one of the primers above and have never had a pierced primer even at the top end of the load testing with bullets jammed.

When I first came across the Savage Primer problem I did quite a bit of searching for info and kept coming across the Savage Bolt Firing Pin Clearance issue and as I said the two I had experience with solved their problems with false pressure signs by fixing the firing pin issue.

I feel for you and hope you resolve the issue.

 

[WyleWD]

I normally load Berger 108's ahead of 30.4 grains of Varget and get great accuracy there. I am out of Varget and I am working up a load using RL15. I did some ladder testing and found that a load of 29.8 grains just touching the lands showed the most promise. I thought I could squeeze out some more accuracy so I was playing with seating depth today. As soon as I moved into a slight jam, I started piercing primers. I had only loaded test rounds in lengths that would jam to various degrees so I stopped shooting and went home.

A few questions for clarification.

1) Did the 29.8grains of R15 pierce the primers BEFORE you increased to a slight jam?

2) How were the groups on that R15 load compared to the 30.4grains of Varget? Same, nearly the same, equal?

3)Have you disassembled and cleaned the bolt and firing pin since you started piercing primers.?

I have a 7 twist 6br and 29.5gr of R15 is about all I can comfortably load and have no pressure or piercing issues with 105-108gr bullets NOT jammed. Of course yours is a different rifle than mine, but just threw that in there as a point of reference. WD

 

[Patch700]

Two things that I have done when faced with a situation such as yours.. First i reduced pin protrusion to .035" and secondly i had my smith bush the bolt head as there was a good amount of play between the pin and the bore of the bolt head.. These two modifications allowed me to get a better look at what the primers were really showing me and also dropped my es numbers into the single digits .

Good luck.

 

[BoydAllen]

Are your Wolf primers standard or magnum?

 

[cavedweller29]

Thanks again for all the replies.

Wylie, They didn't pierce before jamming with loads up to 30.5 of RL15. What has me scratching my head the most is that when today, I backed off to my starting point of just short of the lands. it continued piercing. The groups are probably not quite as good as with Varget but close. I am shooting about .35 with Rl15 compared to about .25-.3 with Varget. I did clean out the bolt after it started piercing and I checked the firing pin under fairly high magnification and I don't see any damage to it. I do think the accuracy "window" is bigger with Varget though. I had really good accuracy though almost a whole grain while testing. With RL15, I went from about 3/4 inch from 29 gr to 29.6. 29.6 and 29.8 both made 1 ragged hole. After that it fell off rapidly to approx 3/4 inch again all the way to to 30.5. I shot them all through a chrono and my ES was pretty big on all of the loads except 29.8. There my ES was just about 30.

Patch- I'm going to send it to Gre-Tan for a bushing but, because this started so abruptly, I would like to figure out what is causing it/caused it for future reference.

Boyd-they are the standard wolf primers.

 

[BoydAllen]

Standard Wolf primers are your problem, they are too soft for your application, you need magnum, that have the same pellet and a tougher cup. I am pretty sure on this, unless they have made a change. You changed three things, seating depth, powder and primers. It was the primers, they have less wiggle room, because they are near their limit, and above.

 

[cavedweller29]

Thanks for the suggestion Boyd. I have 15-20 7 1/2's left that I am going to load up right now. I will try them tomorrow and report back. If that is the problem I am going to have to find some more and keep the wolf for my 223 loads. Thanks again to all who have made suggestions.

 

[BoydAllen]

If you have an action that has an .072 (nominal) firing pin tip, having the bolt bushed and the pin tip diameter to a nominal .062 as it is on my Viper, my make the use of the softer primers feasible. Greg Tannel does this work very well, for a great price, with quick turn around. Also, make sure that your firing pin spring is up to snuff on poundage, when fully cocked. Other factors, that can be involved are a radius at the edge of the hole, and clearance.

 

[cavedweller29]

Well everyone, I think Boyd was right. I had a few Rem 7 1/2 stragglers kicking around so I loaded up 10 rounds with no change other than the primers. I didn't have any pierced primers with those loads. I then tried a few of the cartridges that were primed with the wolf standard srp and it pierced everyone I tried.

I was under the impression that Wolf primers were quite hard but apparently that is their magnum primer.

I did notice a lot of cratering with the 7 1/2's so I am gonna ship my bolt out to Gre-Tan tomorrow and get it bushed.

Thanks everyone for getting me steered in the right direction.

 

[Old Navy]

Just ask Greg to install a new spring after bushing the bolt. Later! Frank

 

[cavedweller29]

Just an update. I spent a couple more days messing with seating depth, different primers, firing spring tension, etc with no reliable fix to the problem. Last Thursday I mailed the bolt to Gre-Tan to get bushed and I got it back today. Nice looking job with really fast turn around. I will get to the range tomorrow and report back if it fixed the problem. Thanks again for the tips and recommendations.

 

[jsthntn247]

Just an update. I spent a couple more days messing with seating depth, different primers, firing spring tension, etc with no reliable fix to the problem. Last Thursday I mailed the bolt to Gre-Tan to get bushed and I got it back today. Nice looking job with really fast turn around. I will get to the range tomorrow and report back if it fixed the problem. Thanks again for the tips and recommendations.

That's serious fast turn around right there.

 

[cavedweller29]

Just wanted to give one final update. Went to the range today and, shooting the loads that were previously piercing, I had no pierced primers, no cratering, no signs of excessive pressure and seemingly better consistency. The bushing of the bolt face solved every problem I was experiencing. If anyone out there is contemplating having it done I can highly recommend it and Gre-Tan Rifles to do it. Once again, thanks everybody.

 

[BoydAllen]

Part of the bushing job, as done by Greg, is a reduction of firing pin tip diameter to a nominal .062. I can tell you from experience with my Viper action, that came with that feature, that it gives more latitude as far as blanking or piercing primers is concerned. As far as accuracy enhancement goes, the bushing is long enough so that the pins tip never comes out of the hole. This makes for less vibration because the tip does not have to ramp into the hole.