28 Nos Flat Primers

Rflshootr said:

Add shims where?

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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.

tomcat818 said:

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.

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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.

tomcat818 said:

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.

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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

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

Cheers.

Hikinghunter said:

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

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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.

tomcat818 said:

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.

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

Hikinghunter said:

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

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

Hikinghunter said:

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

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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!

MagnumManiac said:

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.

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

I wouldn't count on using factory ammo as a guage, lots of "factory" ammo from nosler and other companies look like this out of my gun in the beginning. Overpressured ammo in almost all my wsm and saum rifles isn't uncommon.

Jam the bullets .020" into the lands, middle of the data charge, and shoot a few, I think as Rflshooter has pointed out you will see this 'problem' go away, you will also see that it won't take 3 loadings to fully form the brass. One loading will get the majority of the work done and the second loading will be good to go, so much so that I stop fireforming after one loading and start shooting.

Personally I think you are making a mountain out of a molehill. Factory ammo is never loaded that will cause an over-pressure. From what I can see, this is not an issue that needs to be discussed. It is what it is with this rifle and if there are not bolt lift issues most likely can be ignored. If there are bolt lift issues with factory ammo you have a chamber issue.

Well there is this:

PRODUCT RECALL NOTICES & WARNINGS

Safety Recall Notice for 28 Nosler 175gr AccuBond Long-Range Trophy Grade Ammunition

Nosler has received reports from customers who experienced excessive chamber pressures while using 28 Nosler 175gr AccuBond Long-Range Trophy Grade Ammunition (Part #60155). Excessive chamber pressures may result in firearm damage and/or personal injury.

The reported excessive chamber pressures are limited to three production lots of 28 Nosler 175gr AccuBond Long-Range Trophy Grade Ammunition (Part #60155). These lots were shipped between October 7, 2022 and December 28, 2022. No issues have been reported with other lots of this ammunition manufactured outside of this timeframe. If you have ammunition with lot numbers that differ from those listed below, no action is required.

The lot number can be found on the box above the SKU barcode as follows:



Recalled Lot Numbers:

• 1837082
• 1837701
• 1838813

All customers should cease using this ammunition immediately and contact Nosler customer service directly for a free replacement, by phone at (800) 285-3701 x1046 or by contacting us via contact form. Please include a reference to 28 Nosler Recall in your communication.

Not sure why it took so long for them to recall it except maybe a lawsuit. This notice is currently linked on Noslers home page.

Those brass pictures 6mm06guy posted are very close to piercing primers. I agree with the previous poster that most factory ammo is loaded on the mild side but Nolser may be pushing the envelope a bit.

In looking at the petty pictures, they all seem to have problems. Creating, and ejector makes. It's my understanding that nosler brass is soft. I don't had any experience with their cases. I have some but never have used them. (rainy day items) I have seen more than one time that factories have had problem with overloaded cases. The proof is in the recall above. I like noslers BT & AB bullets, and have used them for year without any problems. I generally reload my ammo!
If those round are factory loads I wouldn't use them any longer, and write the manufactors about them or email them. If they are reloads, back the powder back and start up again. Look on how you are setting up in your loading process too.