I need a little advice from a Smith who knows M1's .

Simply and short ; New brass Rem or Win. full length resize load fire in my chamber . Now neck size load fire all is well for say 7-10 times , then primer backs out of the pocket say .010-15". Load isn't hot nor is there any indication of pressure problem , chrony says it's 200-250 FPS under a normal load and velocity .

.006" headspace and every once in awhile a round lacks full battery say 1/16" for full lock up ?.

Opt rod disconnected for single fire .

This Old Dane is putting #5 into 7/16- 3/4" on a regular basis with a VAR barrel .

I used range pickup brass I used every brand and finally bought new stuff and it got a LOT better. 8 loads as opposed to other brass it happened 2 reloads !?.

The primer pockets aren't loose !. They're just backing out at random ??.

Shoot Straight Know Your Target . ...

Are you annealing the necks of the brass after every 5-6 loads? I would do that after every 5 loads. Try it and see what happens. You might try full length size them afterwards also.

Westpac ; Do you think gas is bypassing the neck ?.I'm assuming you want the neck softer to form a tighter seal ?. I'll try to full length resize and see if that makes a difference . thanks

Shoot Straight Know Your Target . ...

does it fire when out of battery? the safety bridge is supposed to prevent that. put in a new firing pin and see what happens.

Presuming this is a CMP-sourced rifle or receiver? not a weld job?

Yes it's a CMP M1 .It's a Danish reissue with a VAR barrel . I've never allowed it to fire out of battery ,as I'm firing single shot at the present so I ensure it's locked up . Opt rod is disconnected .

This has me stumped as to why the primers are backing out . Before I would use what and whom ever's brass reloading for it . Primers backed out after 2-3 reloadings . I used the same cases over and over . This load isn't even close to being max .Primers showed no damage , just backed out .

So then I bought some new brass Rem & Win and it got a lot better now 7-8 times on the average before a primer backs out .I full length resized loaded fired then neck sized from then on .
Why doesn't it do it all the time ?.


I didn't anneal the necks as I didn't see any need to at the time . I'll be trying that right after this Heat wave passes in a few days .

Firing pin looks OK and is hitting what I believe is correctly not overly deep but not dinging the surface either . Have had NO misfires and accuracy is out standing for a service grade rifle . When a beater will drop 5 into less than 1" consistently ,I've learned to leave well enough alone . This one does an honest 7/16-3/4" if I do my part .

Shoot Straight Know Your Target . ...

I think a couple of grains more powder with fix the primer thing. JMO