Question on Chamber Polishing????

[Just1Mor]

So the issue is that i have an m1 garand that was converted to be a bm59 type. The barrel is a springfield that has been milled down .5 inch to .308. My issue is that i am having are stuck cases after firing. Bolt will not eject the fired case or rips of the rim. At first I thought i was over pressure but i have loaded many different loads all spec starting at 10% below list and working up with different powders, sources, etc. i live in phoenix and the problem seemed to be better in the cooler weather but still had the problem, its just worse when it heats up. So i desided to start taking some measurements of the spent cases and to my surprise and total confusion, there seems to be a point just forward from the web on the case that measures .472-.4725 or so i know that the demesions of the chamber should be .470 base just forward of the rim. I believe this is where i am having a hang up. i have tried scubing the chamber nut there is no difference. the only thing i can think of is to insert a dowl with some emry cloth and a power drill and take the high spot down a little at a time and then finish with some steel wool.

Any thoughts on how this might happen or a solution would be appreciated.

[leftiye]

I'd still be looking at the high pressure possibility. The barrel could be flexing enough to add that .0025". Do a chamber cast and see if there is a problem with a deformed chamber. The thing about higher temperatures is that they cause higher pressures. Some barrels just make higher pressures. Or if you've got a .308 reamer, turn it by hand a bit. It will show you if the chamber was cut wrong.

[Just1Mor]

Well i can tell you that i have tried loading down both h322 h335 and imr 4895 down pretty far, im talking about 5 gr or so below min but i have not tried to push to far over the min because of the stuck case problem. I have thought that maybe im not getting the pressure that i need for the barrel to come back down on the case after firing at proper pressure like it should.

i wish i did have a chamber reamer i know that would solve many of my questions right there. i like the chamber cast idea i think i will do that before polishing.

[StarMetal]

You can rent a reamer for about $35-40 from Elk reamers. Just look them up on Google. With your type action though you may have to have a pull through type reamer unless you remove the barrel.

[Just1Mor]

well i broke it down as far as i could without removing the barrel and it does look like the back .5 inch of the chamber is wider than it should be and after polishing with emrey cloth and steal wool i discovered some pretty deep scratches in the chamber and at this point for me to be able to take those out i would have to remove more material from the bore and im not sure how far from spec i can take it out without casing damage to the cases. at this point im wondering if i would be better of rebarreling the rifle instead of trying to fix what i dont think i can??? is there a cartrige close to 308 with a little wider body that i might be able to rechamber for???

[StarMetal]

Personally myself, it is within your means, I'd have it rebarreled with a new match 308 (if that is your choice of caliber for it) and you would have a really great rifle. Those BM59 are pretty decent.

[S.R.Custom]

...So i desided to start taking some measurements of the spent cases and to my surprise and total confusion, there seems to be a point just forward from the web on the case that measures .472-.4725 or so i know that the demesions of the chamber should be .470 base just forward of the rim...

Making assumptions about the dimensions of a chamber based on the measurements of fired brass is not reliable. I'd first make a chamber cast, and take it from there. Look for anomolies that result in high spots that taper back down.

Also-- scratches in the chamber wall that don't show up on fired brass *shouldn't* be causing a problem. If they are showing up, then yeah, it's probably causing some stickiness.

[Just1Mor]

Making assumptions about the dimensions of a chamber based on the measurements of fired brass is not reliable. I'd first make a chamber cast, and take it from there. Look for anomolies that result in high spots that taper back down.

Also-- scratches in the chamber wall that don't show up on fired brass *shouldn't* be causing a problem. If they are showing up, then yeah, it's probably causing some stickiness.

ya you can clearly see the scratches on the fired brass. i took a fired case and cleaned it with some steel wool and shoved it in the chamber (was really tight) had to hammer back open the action and the case had some definate scrathes in it.

[Just1Mor]

ill try and post some pick tonight so you can see what i am looking at

[waksupi]

You can rent a reamer for about $35-40 from Elk reamers. Just look them up on Google. With your type action though you may have to have a pull through type reamer unless you remove the barrel.

www.reamerrentals.com

1-888-777-3252

Just happened to have one of Elk Ridge's advertising pens laying here in front of me!

[mroliver77]

How do you polish a Garand chamber without pulling the barrel? That is polish it properly. From what I am reading I think you should take it (or send)to a Garand armorer.
Jay

[Dutchman]

It sounds like the barrel was gunsmithed poorly and the chamber is now damaged. I agree, it needs to go to someone familiar with this type of action. I think the barrel is toast. Polishing will not remedy this problem.

Dutch

[Just1Mor]

so in further measureing i actually took the back of the calipers and measured the chamber and like S.R. Custom had said the brass was inacurate and the chamber was really dirty and being my father in laws rifle before i just assumed that he had kept it clean. But it measured ok but there was a build up of something in the chamber and if i had to guess it looked like hornady case lube (really waxy). i tried using the grande chamber cleaning tool but was not having very much luck getting it clean. So i cleaned and polished as follows.

well what i had done is taken a dowl that was slightly smaller than the chamber and a little longer than a 308 case and cut a slit in the back of the dowl that would be polishing the back portion of the chamber and drilled and taped the front so that it would screw onto a brass cleaning rod that i slid down the barrel ( i did use a muzzle protector). i took some emry cloth and incerted on the slit on the back of the down still smaller than the chamber and attached the end of the cleaning rod to a drill. spun in and out of the chamber for about 20-30 sec with some wd-40. really brightened up the chamber but i still finished off with a brass cleaning brush with some steal wool wrapped around with some hoppe's to clean the wd- 40 out. So there are still some scratches in the chamber but they are not sticking up or adding friction. the chamber still measures the same but much cleaner and fires just fine now.

I quess i just assumed that being a battle rifle cleaning was not that important, but i learned a very valuable lessen on keeping firearms clean no matter what they are. thanks for all your input and help.

[mroliver77]

Good job J1mor.
Garands and M14 types need the chamber CLEAN. A clean chamber is a happy chamber:)
Jay

[Just1Mor]

Good job J1mor.
Garands and M14 types need the chamber CLEAN. A clean chamber is a happy chamber:)
Jay

ya i was very uneasy about messing around with the chamber but i figured if i took my time and went slow that i could stop before real damage was done. worst case i was looking at a rebarrel anyway but considering someone had already cut down a 30-06 barrel rethreaded and drilled for the gas port to make a 18 in barrel after machining .5 inch off the chamber side to fit .308 i was going to pay one way or another. Might as well do a little self learning while i was at it.

If i would not have had your guys caution, i dont think thing would have went as well. :bigsmyl2:[smilie=s: