test fired new 6br

[realhunt]

HEY GUYS TESTED MY NEW 6BR AND HAD 3 MISSFIRES NEW LAPUA BRASS PRIMERS APPEARED TO BE SEATED TOO DEEP.IS THIS POSSIBLE? {HAND SEATED WITH A RCBS TOOL} HAD 5 OF 25 REMMINGTON 7.5 BENCH REST PRIMERS PIERCED.ACCURACY LOOKED GOOD BUT HAVE TO FIX THE MISS FIRES COULD IT HAVE BEEN FROM SHRAPNEL FROM THE PIERCED PRIMERS? NO SIGN OF EJECTOR MARKS BUT I PROBABLY WILL BACK DOWN FROM THE 30 GRAINS OF VARGET.I WAS USING 107 SMK SEATED .010 OFF THE LANDS .ANY ADVICE WILL BE APPRECIATED THANKS G.HAMILTON

 

[kitsap]

First advice is to get off of the CAPS LOCK KEY. In forums it is considered shouting.........

Yes, it is possible to seat the primers too deep. Experience and touch to determine when the primer is deep enough only comes with time with your primer seating tool.

Yes, debris from the pierced primers could have blown back into your bolt and caused problems leading to more miss fires. You need to disassemble the bolt and clean it out and re-lube. You may have damaged the firing pin tip.

Did you work up to the load of 30 grains of Varget in your gun or pick it out of a book? If you are piercing Rem 7 1/2 primers there is a good chance your load is too hot for your specific gun. What action does your rifle use?

DougF

 

[Mark Walker in TX]

Doug is correct on all points.

In addition, you could have some debris in the trigger now causing the misfires as well...

 

[Hammerhead]

I have a friend up in the Northwest who has had several misfires with the Rem 7 1/2 primers. A few different guns and different loads. We think he got into a bad batch of primers.

Tim

 

[NorCalMikie]

Could also be the "New" Lapua brass hasn't been fireformed to the chamber yet, is too short and the case is being pushed forward by the firing pin and the primer is not getting hit hard enough to go bang?? Never had a primer seated too deep in "New" Lapua brass. ??? Check the case length between "fired" and new. Shoulder pushed back too far?

 

[fdshuster]

Yes, yes, and yes to the : "Dump the caps". And the debris from the pierced primers getting into the trigger/ been there, done that, and wiped out a Neil Jones Rem. 700 tuned trigger to the tune of $70+. Rem 7 1/2 primers normally have a cup thickness of .025", one of the thickest available, and that's one of the reasons I like them, especially when working up a new load. You may also try backing off on the seating depth a little more: I usually start, again with a "new" load, at .020" off the lands. If all is ok, then may go forward to .010", and then to touch. My standard procedure when having a new chamber cut is to take the first case fired from that chamber (usually the 'smiths test firing), hand pnch out the primer, clean the case (hand polish), take all relevant dimensions, and set-up the die(s), using new, unfired brass (Lapua) to exactly duplicate those measurements. Works for me.

 

[Mikem]

NC Mikie took the words right out of my mouth, and I agree with fdshousters post as well.
I don't think you can seat a primer to deep in new Lapua brass. The primer is supposed to bottom out in the primer pocket.
To me, it sound like you have something in the bolt effecting the firing pin, or the chambers headspace is a little to deep for New never fired Lapua brass.
Now that you have several fire formed cases, you should compare the fire formed case's headspace with a new unfired Lapua case.