Loading 308 for an m1a. The load is 42.5gr of 4064, Winchester primers and 168smk, prvi brass, col is 2.800, no crimp. I checked the primers and don't see any flattening but looks like an extractor mark on the brass. I had been getting failures to pick up rounds at 42gr, since it was at the lower end of the charge I thought I was getting short bolt cycle so I increased the load to 42.5. The last round I fired was not extracted, I could not pull the op rod back. I came home and took the rifle apart to see if the op rod was bent but it looked ok. Once I got it in a vise I was able to pull the op rod back and the case extracted. I don't see anything that looks abnormal, case and primer look ok. I dble checked my charge and col, I also went back to imr site, no where near max load. I might have has 75rounds through it so I don't think it was a dirty chamber. One more comment, after the round was fired the bolt was not completely home. I could not push it home or pull it back until I put it in a vise.
Is this a sign of pressure?
- Thread starter 1stmar
- Start date
More info please
How many times has the PRVI brass been fired? Depending on the original neck thickness, after a couple of firings, enough brass flows to the necks so that it makes bullet release difficult and you get pressure spikes. Stuck case is one of the symptoms.
If you have a ball micrometer you can measure the thickness of the stuck case at several points.
I know nothing about M1s chamber sizes etc.. but maybe Bart will come along and give you some help.
How many times has the PRVI brass been fired? Depending on the original neck thickness, after a couple of firings, enough brass flows to the necks so that it makes bullet release difficult and you get pressure spikes. Stuck case is one of the symptoms.
If you have a ball micrometer you can measure the thickness of the stuck case at several points.
I know nothing about M1s chamber sizes etc.. but maybe Bart will come along and give you some help.
You're lucky you got that many firings. Without a micrometer yo're flying blind. It's time to tool up. You need to measure the neck thickness, than you will add .308+ (wall thickness x 2) and discover that your running out of space in your chamber and the brass can't release the bullet without overpressure.
Decision time!! Get new brass, learn about neck turning.
Thanks I won't be neck turning. Sounds like time to switch brass. I just bought 500 lc once fired. Would annealing have helped? Neck turning is to tedious for me. I just assume buy new brass. Micrometer is a good recommendation. Been looking at them but up to now, i really didn't have a need. How would I know the diameter of my chamber, Even if i had a micrometer?
)If a fired case goes into and out of the chamber easily and a bullet drops into the fired case neck easily, your case necks are OK for the rifle and the way they are sized.
How much are you bumping fired case necks back?
With .308" bullets and even .014" neck walls, the round's neck is .336" diameter. Your rifle's chamber neck is probably at least .344" which allows .003" clearance all the way around it. Plenty of room.
What's the shape of that extractor mark on the case?
How much are you bumping fired case necks back?
With .308" bullets and even .014" neck walls, the round's neck is .336" diameter. Your rifle's chamber neck is probably at least .344" which allows .003" clearance all the way around it. Plenty of room.
What's the shape of that extractor mark on the case?
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