I would like to reload for my Rob Arms XCR-M in .308, but the case mouths are getting severly dented in when the rifle ejects them. Is this common for a semi auto? The gas preasure on the rifle is turned up to maximum as recommended for the break-in period. I did not take any pictures of the damaged brass, but the mouth has a dent in it covering 25% of the mouth. I am assuming these cases are not salvagable. Any advice would be appreciated.
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Semi auto crushing case mouth???
- Thread starter TRPAUBREY
- Start date
Re: Semi auto crushing case mouth???
When I first started shooting my 16" AR .308 I had the exact thing happening. Recently it stopped doing that. The mouth being bashed in and sometimes a dent where the brass casing chamber meets the shoulder, it just stopped happening. If this new trend continues I will just mark that down as the rifle getting broke in. Perhaps the extractor has found it's happy place?
I don't know but I hope this is the case.
And those dented cases, yes I resized them and reloaded them and shot them again no problems their.
Good luck, brother!!
When I first started shooting my 16" AR .308 I had the exact thing happening. Recently it stopped doing that. The mouth being bashed in and sometimes a dent where the brass casing chamber meets the shoulder, it just stopped happening. If this new trend continues I will just mark that down as the rifle getting broke in. Perhaps the extractor has found it's happy place?
I don't know but I hope this is the case.
And those dented cases, yes I resized them and reloaded them and shot them again no problems their.
Good luck, brother!!
Re: Semi auto crushing case mouth???
this is fairly common on s/autos_cases are salvageable_a good gunsmith can modify in some way (filing,often) one of more of the parts involved in the process to resolve this (really minor)problem_Remind that military-style semi or full autos never have been engineered,since their first drawings, to pamper the ejected cases_
this is fairly common on s/autos_cases are salvageable_a good gunsmith can modify in some way (filing,often) one of more of the parts involved in the process to resolve this (really minor)problem_Remind that military-style semi or full autos never have been engineered,since their first drawings, to pamper the ejected cases_
Re: Semi auto crushing case mouth???
Mouth dents aren't bad unless you can't fit an expander ball into them to resize it.
If you can resize it, it will be fine. Just realize that all of that work hardening will cause a neck split sooner than if it wasn't happening.
edit: My M1 Garand, and sometimes my AR15 dent mouths. Not a big deal.
Mouth dents aren't bad unless you can't fit an expander ball into them to resize it.
If you can resize it, it will be fine. Just realize that all of that work hardening will cause a neck split sooner than if it wasn't happening.
edit: My M1 Garand, and sometimes my AR15 dent mouths. Not a big deal.
Re: Semi auto crushing case mouth???
brass is fairly pliable, you can reshape through your sizer, if the mouth is really badly caved in, use a small needle nose pliers to reopen the mouth until the expender ball of your sizer die fits in and you are good to go.
You can also glue a small piece of foam rubber, like a camping matt, in the spot where the brass hits to soften the blow.
brass is fairly pliable, you can reshape through your sizer, if the mouth is really badly caved in, use a small needle nose pliers to reopen the mouth until the expender ball of your sizer die fits in and you are good to go.
You can also glue a small piece of foam rubber, like a camping matt, in the spot where the brass hits to soften the blow.
Re: Semi auto crushing case mouth???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: attherange</div><div class="ubbcode-body">You can also glue a small piece of foam rubber, like a camping matt, in the spot where the brass hits to soften the blow. </div></div>
Velcro can be had in self adhesive strips and the "soft" loop side could be substituted for the foam rubber. It works fairly well on AR's.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: attherange</div><div class="ubbcode-body">You can also glue a small piece of foam rubber, like a camping matt, in the spot where the brass hits to soften the blow. </div></div>
Velcro can be had in self adhesive strips and the "soft" loop side could be substituted for the foam rubber. It works fairly well on AR's.
Re: Semi auto crushing case mouth???
I put a Slash's heavy buffer in my MWS when I went to the A-2 stock. That, with the stick-on velcro on the deflector lump, cleared up the dented cases.
I put a Slash's heavy buffer in my MWS when I went to the A-2 stock. That, with the stick-on velcro on the deflector lump, cleared up the dented cases.
Re: Semi auto crushing case mouth???
One of the reloading tool die manufactures sells tapered expander balls that will straighten the dents out as you size your brass. Check in the Midway catalog.
One of the reloading tool die manufactures sells tapered expander balls that will straighten the dents out as you size your brass. Check in the Midway catalog.
Re: Semi auto crushing case mouth???
The smashed case mouths are from the brass hitting the ejection port/case deflector/receiver upon ejection.
Remember, military rifles were designed to shove cases in and rip them out in a reliable fashion across all different environments. The military doesn't reload their brass.
However, if you can get an expander ball down in their you'll reshape the mouth no problem.
The smashed case mouths are from the brass hitting the ejection port/case deflector/receiver upon ejection.
Remember, military rifles were designed to shove cases in and rip them out in a reliable fashion across all different environments. The military doesn't reload their brass.
However, if you can get an expander ball down in their you'll reshape the mouth no problem.
Re: Semi auto crushing case mouth???
I've had cases with mouth's dinged so bad I had to open them up with a Phillips screwdriver shank before the expander ball would fit into it. No problems. Might be a good idea to put these cases aside until you have a quantity of them and then just anneal them before straightening out. Reduces the work hardening and lessens the chance of cracking necks down the road.
I've had cases with mouth's dinged so bad I had to open them up with a Phillips screwdriver shank before the expander ball would fit into it. No problems. Might be a good idea to put these cases aside until you have a quantity of them and then just anneal them before straightening out. Reduces the work hardening and lessens the chance of cracking necks down the road.
