Primers "falling out"...

Bluejay · Mar 29, 2007

Got some strange results from my last 7x64 test and have no idea why.

On some loads (and not the maximum ones), I got the primers "emerging" from the primer socket.
Is this a sign for high pressure?
What else could it be?

I am using RWS brass, Vihtavuori N140 powder and Sierra Gameking BT 150 grs. and NOSLER AB 140, keeping the O.A.L. as indicated in the manual and shooting from a Blaser R93 straight pull rifle.

Thanks for your reply.

Cheers

rigpig78 · Mar 29, 2007

I'm not familiar with the RWS brass, but it sounds like overpressure or possibly just a bad batch of brass. Personally I'd go and get another lot of brass of a well known brand and see if the problem still occurs. How are you seating the primers. If you are doing it by feel it might pay to check your primer seating depth. I have had brass where the odd few in the batch the primer feels like it just falls in. In this case I have discarded the brass from that particular lot number. Hope this helps a bit!

Savage99 · Mar 29, 2007

The brass might be too short headspace wise for that chamber, the brass might be FL sized too much or the rifle might have excessive headspace.

Make your own case gage. Get a 30-06, 35 Whelan etc. seating die and remove the seating stem. Now drop a new unfired, unloaded case into the die and measure the distance from the top of the die to the base of the case with a caliper. Then do the same with a fired case where the primer did not back out.

If its in the .015" range between the two your brass is too small for that chamber.

At that point you can get a no go gage or just make brass to fit from 280 Rem brass.

clearwater · Mar 29, 2007

Low pressure loads and or a rough chamber can cause this too. The brass
doesn't stretch back so the primer backs out.

R Flowers · Mar 29, 2007

Primers backing out is often a sign of excess headspace.

However, light loads can cause it as well.

I own an XP-100 chambered in a wildcat 6 X 47 and it does it all the time. I have learned to ignore it. I shoot IHSMA competition with it and it is very accurate, but the primers back out most of the time.

fredj338 · Apr 2, 2007

Backing out or falling out. If the primers are falling out, the load is too hot for that brass. If they are backing out, I suspect a headspace issue as well. Try partial sizing & see what happens.

Brian · Apr 2, 2007

I'm assuming that your 7X64 is a 7X64 Brenneke. If so, have you shot commercial loads, and did you see this problem in them?

In your handloads, were the primers flattened on your maximum loads? If yes, the backing out with less than maximum loads is probably a head space problem.

If the primers were only pushed out on less than maximum loads, it could be either head space or too weak a powder charge. I'd bet too weak a charge, but you should have the head space checked (you could have excessive and too weak a charge).

flashhole · Apr 2, 2007

Did you uniform your primer pockets? If you did it is possible you may have been too aggressive with the cutting tool and opened the diameter slightly more than needed. I've found the uniforming tool is not very forgiving if you are slightly off axis during use.

SOTN · Apr 2, 2007

Bluejay":3jzekhui said:
Got some strange results from my last 7x64 test and have no idea why.

On some loads (and not the maximum ones), I got the primers "emerging" from the primer socket.
Is this a sign for high pressure?
What else could it be?

I am using RWS brass, Vihtavuori N140 powder and Sierra Gameking BT 150 grs. and NOSLER AB 140, keeping the O.A.L. as indicated in the manual and shooting from a Blaser R93 straight pull rifle.

Thanks for your reply.

Cheers

The classic cause of protruding primers after firing is LOW pressure.

On firing the case normally is knocked forward by the firing pin, and when the powder ignites the sides of the case stick to the sides of the chamber. The case then stretches backwards and flattens the primer.

If the primer ain't flattened, that ain't happenin.

Once, with a friends rifle, I kept LOWERING the powder charge to solve a problem/indication like that, and later learned I was goin the RONG direction. I live and learn. So far, anyways.
Smitty of the North

Bluejay · Apr 5, 2007

Thank you ALL for the load of info.

Based on all the possibilities you have "lined up", I believe the one that fits my "case" would definitely be the "too low of a charge" issue.

I have tried heavier loads and had not noticed this problem anymore.

Will proceed on this direction.

Appreciate your help.

Cheers
:wink: