Oversized chamber in M1 Garand?

[RABAZ]

After looking at pics of your brass you can see the tiny imprints of the pits. The primers are not flattened, But you are getting flow into the firing pin hole, Which is real close to a pierced primer. The firing pin hole may be eroded. I have a rifle that does that too, It keeps shooting without any problems. SO I don't think the loads are too hot, However use a data book that has "Service Rifle Loads" As you can damage them if using the wrong powders.

Am using the "service rifle" loading data.

 

[RUFFIAN R - NY]

The Garands I know are 30-06 and have loaded and fired thousand rounds with-out a problem using 147-150 gr FMJ and LC Match brass. What is left of it .

 

[orcldba]

BTW; I polish chambers on every rifle and barrels waiting to be changed out in the last 25 years. Not much time/energy to do it. I've had one stuck case, and that was 25+ years ago.
I also trim .002-3 under spec for growth and use small base dies. Overkill I know and brass doesn't last as long, but never an issue.
I still use LC67 Match; great brass!

 

[RABAZ]

BTW; I polish chambers on every rifle and barrels waiting to be changed out in the last 25 years. Not much time/energy to do it. I've had one stuck case, and that was 25+ years ago.
I also trim .002-3 under spec for growth and use small base dies. Overkill I know and brass doesn't last as long, but never an issue.
I still use LC67 Match; great brass!

Advice on polishing my chamber? Have never done it before. Thx!

 

[emp1953]

Springfield makes a good solid rifle. Perhaps someone else had it and shot the bejesus out of it. I vote for scrutinizing the chamber walls, and whether or not it passes muster I'd still polish it up Get rid of those spots that are imprinting on the brass to make extraction smoother. Dont give up on that puppy. You don't mention what primers you are reloading with. The primers in the photos show metal being flowed into the firing pin hole. That's an over pressure sign. None of us are set up to measure or gauge pressure, we can only guess at it.

 

[emp1953]

Springfield makes a good solid rifle. Perhaps someone else had it and shot the bejesus out of it. I vote for scrutinizing the chamber walls, and whether or not it passes muster I'd still polish it up Get rid of those spots that are imprinting on the brass to make extraction smoother. Dont give up on that puppy. You don't mention what primers you are reloading with. The primers in the photos show metal being flowed into the firing pin hole. That's an over pressure sign. None of us are set up to measure or gauge pressure, we can only guess at it.

Semi-autos are merciless at stretching brass. Full length sizing doesn't always accomplish what you expect in these rifles. As was previously mentioned the case sticks for a millisecond while the action is starting extraction. Extracting while the case is stuck results in stretching. I've see it where the rim was folded slightly downward which is just before the rim failure that your photo shows. Before your polishing effort make an attempt at getting as much carbon out of the chamber and throat as you can.

 

[RABAZ]

Thanks much for your advice. Will clean and polish chamber. Would it be beneficial to shoot steel cases, vs brass?

 

[emp1953]

Not really. You cant reload them and your Garand is made to work fine with Brass casings. Didn't say what mfg brass you were using. Some is softer than others. I ended up loading F-C (Federal) cases and found them to be harder than most. I'll bet that during WW2 in the Pacific some Garands saw thousands of rounds through them under the worst conditions possible and they continued to eject, no stuck cases. I doubt anyone took the time to look at the spent brass for damage. Try the carbon removal / polishing route before switching ammo. You might want to pursue why the primers are flowing into the firing pin hole in the bolt face though. Crud in the chamber could constrict the case mouth thus increasing pressure getting the bullet out of the case. Remember that all this happens in milliseconds.

 

[RABAZ]

Springfield makes a good solid rifle. Perhaps someone else had it and shot the bejesus out of it. I vote for scrutinizing the chamber walls, and whether or not it passes muster I'd still polish it up Get rid of those spots that are imprinting on the brass to make extraction smoother. Dont give up on that puppy. You don't mention what primers you are reloading with. The primers in the photos show metal being flowed into the firing pin hole. That's an over pressure sign. None of us are set up to measure or gauge pressure, we can only guess at it.

CCI 34 primers being used, to avoid potential for slam fires.

 

[RABAZ]

Basic issue/question for you guys: My M1 Garand 308 spent casings show growth in diameter of +/- 10 thousandths, and are tough to FL resize, while my AR10 308 spent casings only expand by a couple thou. Is that a safety issue in the Garand? I ended up FL resizing the "Garand brass" but ended up pitching them as didn't really trust them. Thoughts?

 

[orcldba]

I wouldn't shoot steel case shells in an M1 no matter what. Also, unless it was converted to a 7.62x51 by using a "Navy Sleeve" to shorten the chamber, or 3rd party barrel, as the rifle was designed for the 30-06. The '06 is about 1/2" longer than the 7.62x51 NATO. Also, the 308 Winchester is a higher pressure case than the 7.62 nato.
Either way, Butch's Bore Paste on a thick mop and some hand work will polish the chamber
If you use something like Flitz paste be cautious as it more aggressive than bore paste.
Then make sure you remove any trace of the polishing paste from the chamber & barrel, then inspect & a very light coat of oil, then clean & dry the chamber as you don't want oil in the chamber.

 

[cohunt]

...

 

[RABAZ]

...

I wouldn't shoot steel case shells in an M1 no matter what. Also, unless it was converted to a 7.62x51 by using a "Navy Sleeve" to shorten the chamber, or 3rd party barrel, as the rifle was designed for the 30-06. The '06 is about 1/2" longer than the 7.62x51 NATO. Also, the 308 Winchester is a higher pressure case than the 7.62 nato.
Either way, Butch's Bore Paste on a thick mop and some hand work will polish the chamber
If you use something like Flitz paste be cautious as it more aggressive than bore paste.
Then make sure you remove any trace of the polishing paste from the chamber & barrel, then inspect & a very light coat of oil, then clean & dry the chamber as you don't want oil in the chamber.

10-4.

I wouldn't shoot steel case shells in an M1 no matter what. Also, unless it was converted to a 7.62x51 by using a "Navy Sleeve" to shorten the chamber, or 3rd party barrel, as the rifle was designed for the 30-06. The '06 is about 1/2" longer than the 7.62x51 NATO. Also, the 308 Winchester is a higher pressure case than the 7.62 nato.
Either way, Butch's Bore Paste on a thick mop and some hand work will polish the chamber
If you use something like Flitz paste be cautious as it more aggressive than bore paste.
Then make sure you remove any trace of the polishing paste from the chamber & barrel, then inspect & a very light coat of oil, then clean & dry the chamber as you don't want oil in the chamber.

yes, it is a 308 chamber. And I have another CMP Garand that is also 308. Not disputing your info, but still don't understand why not to shoot steel cases. Is there a technical reason? Thanks for info bore paste!

 

[orcldba]

Steel cased ammo is mild steel, not as hard as barrel steel, so it won't hurt the chamber, unless the TFE coating is scratched and the steel rusts and can cause contamination. I had extractors break with steel cased ammo on other platforms. The M1 barrel is a pain to replace (as opposed to an AR), so I always use brass and keep pressures down with an adjustable gas plug as bent operating rods do happen.
Remember that this a tool designed around slightly looser chamber tolerances than commercial AR10/LR/308's. If you dropped a loaded clip in action you would shake it off and load it.