tight cases

[jaybray]

I fired 20 new lapua cases today in my .272 no turn 6br using 27.8 grains of n135 so as not to stress the new cases much and used the 80 grain berger varmint bullets. My fired cases measured 1.158 using the hornady head space Gauge. I tried to re chamber a fired case and they are so tight I can't even think of closing the bolt. Using a redding full length bushing die I had to bump the shoulders back to 1.154 before I could close the bolt and at 1.154 it does so as it should. Anyone have an idea what would be causing this? Should you not be able to rechamber a fired case several times before needing to bump the shoulders back?? One thing I read is it could possibly be case lube residue in the chamber allowing the brass to slide back. Any ideas??

 

[Chuckhunter]

Jay, it could be the lube, causing excessive pressure, also you are severely undercharged, which causes several powders to create extreme pressures. Did you notice a click when you opened the bolt on a fired case, if so you could be way over pressure. Personally I would pull those bullets and put 30Gr's of your N-135 in the case, re-seat your bullets, then spray your loaded rounds with Non- chlorinated brake cleaner to remove all lube, also clean chamber with brake cleaner on a clean cotton patch over you chamber swab I think you'll find every thing will work fine assuming your chamber is right.

 

[jaybray]

Jay, it could be the lube, causing excessive pressure, also you are severely undercharged, which causes several powders to create extreme pressures. Did you notice a click when you opened the bolt on a fired case, if so you could be way over pressure. Personally I would pull those bullets and put 30Gr's of your N-135 in the case, re-seat your bullets, then spray your loaded rounds with Non- chlorinated brake cleaner to remove all lube, also clean chamber with brake cleaner on a clean cotton patch over you chamber swab I think you'll find every thing will work fine assuming your chamber is right.

Hey thanks. In this particular rifle 29.4 is hard bolt lift and at 30 grains of n135 the primers fall out with huge pressure signs. Maybe it's because of the short free bore. I will clean the chamber with brake cleaner and see what happens. My accuracy node is 28.8 of n 135.

 

[stansrifles]

What is your lead an what barrel are you shooting

 

[jaybray]

What is your lead an what barrel are you shooting

It is a .104 free bore and a 8 twist Krieger barrel.