28 Nos Flat Primers

[tomcat818]

Add shims where?

Wasn't very clear there. Add precision shims (.001, .002, .004) to the bolt face until the bolt won't fully close on it own weight using a .003-.005" go gauge and then back off in .001" increments until it does in order to set the headspacing at .001-.002". One other smith makes his own go gauges for .002" headspacing. Both of these smiths are involved in building both bench rest LRH rifles. Several I've seen use a piece of scotch tape which measures .004" thickness to test for too much headspacing without a no go gauge. One piece of tape on bolt face closes easily apply second layer of tape to bolt face should not close.

 

[Rflshootr]

Wasn't very clear there. Add precision shims (.001, .002, .004) to the bolt face until the bolt won't fully close on it own weight using a .003-.005" go gauge and then back off in .001" increments until it does in order to set the headspacing at .001-.002". One other smith makes his own go gauges for .002" headspacing. Both of these smiths are involved in building both bench rest LRH rifles. Several I've seen use a piece of scotch tape which measures .004" thickness to test for too much headspacing without a no go gauge. One piece of tape on bolt face closes easily apply second layer of tape to bolt face should not close.

That is a whole other topic on barrel installation. Maybe we can cover that in another thread at some point. But 1 thing I will say real quick, which is what I think you are referring to, is that when a barrel is final tightened to an action after machining, you loose about .002 head space over what it was after hand tightening because of thread stretch and shoulder seating force.

 

[Hikinghunter]

Wasn't very clear there. Add precision shims (.001, .002, .004) to the bolt face until the bolt won't fully close on it own weight using a .003-.005" go gauge and then back off in .001" increments until it does in order to set the headspacing at .001-.002". One other smith makes his own go gauges for .002" headspacing. Both of these smiths are involved in building both bench rest LRH rifles. Several I've seen use a piece of scotch tape which measures .004" thickness to test for too much headspacing without a no go gauge. One piece of tape on bolt face closes easily apply second layer of tape to bolt face should not close.

sort of what I did with my custom build. I put a piece of tape on the back of virgin brass, screwed the barrel down onto that, then double-checked with both gauges. Super nice to not have more than a a thou or two for the brass to move.

Not so with my 28 nos factory gun. Looks like I have 6 thou or so of room to grow.,Need to get out the brass stretcher

 

[MagnumManiac]

Buy a RCBS precision Mic and you will KNOW what dimensions we are talking about.
Speculation leads to erroneous conclusions…

Cheers.

 

[tomcat818]

sort of what I did with my custom build. I put a piece of tape on the back of virgin brass, screwed the barrel down onto that, then double-checked with both gauges. Super nice to not have more than a a thou or two for the brass to move.

Not so with my 28 nos factory gun. Looks like I have 6 thou or so of room to grow.,Need to get out the brass stretcher

One would think MAP being 65K for the 28 Nosler that brass would be fully fired formed in 2-3x firings. This is why the subject of tighter tolerances on barreled action headspacing was brought up. It would be real interesting to know how much headspacing your rifle was built to. Considering this rifle did this from the first shot I'm thinking there's too much headspacing built into the rifle and/or bad\wrong\defective firing pin spring. This could explain why your brass is taking more firings to fully fire form. My 270 win also has 65K MAP and fully fire formed in 3 firings. I realize in a gunsmith's hands over headspacing a barreled action almost never happens but in a factory you never know. Your first inclination to send it back for QC testing might be the right course of action.

 

[Hikinghunter]

One would think MAP being 65K for the 28 Nosler that brass would be fully fired formed in 2-3x firings. This is why the subject of tighter tolerances on barreled action headspacing was brought up. It would be real interesting to know how much headspacing your rifle was built to. Considering this rifle did this from the first shot I'm thinking there's too much headspacing built into the rifle and/or bad\wrong\defective firing pin spring. This could explain why your brass is taking more firings to fully fire form. My 270 win also has 65K MAP and fully fire formed in 3 firings. I realize in a gunsmith's hands over headspacing a barreled action almost never happens but in a factory you never know. Your first inclination to send it back for QC testing might be the right course of action.

I wouldn't have thought of a firing pin spring issue. Thanks for bringing that up.

 

[tomcat818]

I wouldn't have thought of a firing pin spring issue. Thanks for bringing that up.

By attempting to help others I help myself. Good luck sorting this out and please update the thread when you do.

 

[Mike Matteson]

Ok, so that's a possibility. Still odd that it flattens factory ammo primers.

There has been some problem with factory ammo here for awhile with overloads. There has been some recalls.
Generally I do load over the manual top load as I do a workup. I look what each case and how it's reacted after it's fired. Primers are biggest item I look at. I look at each primers after being fire and their shape. My start up loads are at the low end and work up from there until I see flatten primers, and start to note creating. Sometime I will note ejector marks and I know I am way overload.
Some of my loads are as much as 5.5grs over manual max. Flatten primers for sure, but no creating or ejector marks. I did learn one thing is I am using temp insensitive powers like H4350, 4831, 1000, & Varget. I only have one or two powders I use is a bouble base powers. Those loads were develop in hot weather, so I not worried about increase pressure do to temp change except for colder weather where the chamber should be decreasing.
That one thing here is you can live and learn something new here all the time. I never seen primer that look that before. So intreresting!

 

[Mike Matteson]

Sure have, every load I have ever put through both barrels have gone over the Pressure Trace. Well within parameters of Max Pressure as by SAAMI.

Cheers.

That a guideline, and most should stay in that range. Not all do, and I don't at times.