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. 308 over Pressure or bad chamber

Michael1992

Private
Minuteman
Mar 4, 2024
12
3
Missouri
Reloading for my .308 remington 700 switch barrel. Barrel is a heavy varmint 5r. Load is 44 grain of varget. 20 thousands of the lands 2 thousands shoulder bump. I have high brass build up on the bolt after shooting and looks to be Crack brass 1/4 inch from the bottom also ejector marks. Think I pushed to hard or a bad chamber job
 

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Looks like you are about to get some case head separation. I know you said 44 grains of varget but what bullet? How many times have these cases been loaded?

With the ejector marks on the case head it looks like a headspacing issue. 44 grs of varget isn’t that hot.
 
I did forget to say 168 Sierra tmk. I don't want to say who chamber it because he is getting old and everything else he has done has been good. The barrel is a b12 It would be a sheldon or a douglas I think.
 
Federal has pretty soft brass but 44 grs under a 168 tmk is fine.

Either that brass has been loaded to many times or you have something going on with your headspace. Brass is showing high pressure.
 
Ok it's is the second reload for the brass winchester and federal. Is their a was I can test his work to see if he slipped up
 
I have a Christensen arms .308 I shoot 165 sgk hpbt 44.5 gns of varget fed case in my gun I didn’t see pressure signs till 45.5 I know it doesn’t help much with your problem but the match king and game king are same besides jacket thickness
 
If the Winchester brass is doing the same thing something is up with the chamber or headspace. Winchester brass is decent brass.
 
Okay good input. If I buy a box of factory winchester and it does the same then it's head spacing? If not then I need to buy good brass a bump the powder back ?
 
You need to measure your fired brass to see how far forward the shoulder is getting blown when you pull the trigger.
Or buy a go gauge and see how many layers of scotch tape it takes until it fills the chamber.

It looks like your chamber was reamed too deep from here. But to get an actual answer you are going to have to measure.

Edit: but now not since he didn’t actually measure anything and lied in the opening post
 
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Okay looked at reloading notes I have the only thang I did measure is the lands and I am 20 thousands off the lands the rest of the brass was sized to factory die setting. I was thinking it would work because everything was new. Normally if I full length size to saami it works in everything. I know it over works the brass going back to saami. If the head space was right I should be able to put something factory in it and it work correctly.
 
So you didn’t measure the headspace or shoulder bump?
 
You need to set the die to the desired headspace or shoulder bump on the brass. The die from the factory probably is not set correctly for your chamber. Sounds like a sizing issue and not so much a chamber issue.
 
Okay looked at reloading notes I have the only thang I did measure is the lands and I am 20 thousands off the lands the rest of the brass was sized to factory die setting. I was thinking it would work because everything was new. Normally if I full length size to saami it works in everything. I know it over works the brass going back to saami. If the head space was right I should be able to put something factory in it and it work correctly.

Saami max chamber + saami min brass can equal up to something like .014” .

So, you can easily be pushing shoulders too far and both chamber and brass can be within saami.
 
Okay so what has happened is. I have made to much shoulder move meant. Watch makes the brass move into the bolt face and makes high brass billed up on the bolt. To find its headspace. Should gauge correct?
 
Okay right and the shoulder need's to be bumped .002 back.

Not until your shoulder has expanded enough. If you have a chamber closer to max saami and brass closer to min saami, it may take a firing or three to get the point where you need to bump the shoulders back for proper chambering and extraction.

Which is why checking your brass with a comparator and checking for smooth chambering is important.
 
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Okay Makes sense. if a round doesn't need shoulder bumped. It needs to be full length sized without bumping the shoulder? When I get back from work I will measure a before and after and put it on this thread. It will be the middle of next week. If questions seem stupid. It's because I am just really getting in to all this.
 
Okay Makes sense. if a round doesn't need shoulder bumped. It needs to be full length sized without bumping the shoulder? When I get back from work I will measure a before and after and put it on this thread. It will be the middle of next week. If questions seem stupid. It's because I am just really getting in to all this.

Yea, you'll just screw your die down where it F/L sizes, but doesn't push the shoulder back (if its not needed). Usually you'll actually push the shoulder forward (since body is squeezed) until you hit the point where the shoulders are at the same spot as pre-sizing. Then you'll move past that spot and start pushing the shoulders back.
 
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Okay just getting back at it. My fired brass measures a 1.650 and the brass I sized measures 1.632. Think I over worked it and screwed up.

Yep, that'll be it. lol

I'd probably pull the components and toss any brass you haven't shot that is 1.632. I guess you could try running it in sizing die without touching shoulders and see if it stretches back, but that's probably a pipe dream and will still be stretching the case. Hopefully not a lot of brass sized that small.
 
Glad you got it figured out. When I started reloading 12 years ago one of the things I noticed was that the reloading manuals I had did not get into specifics of setting headspace on a cartridge. I haven't looked at any of the newer manuals but I hope that they have improved.
 
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