OK all you gurus, I wish to fire M1 carbine ammo in my .308 Mauser.
In saying this I am about to attempt to make an adapter cartridge.
Now I know you might ask why ?
Well I can only answer that with "because it seems like a good idea" & I have a significant amount of M1 carbine ammo which is useless for anything else here in Australia.
My question relates to the M1 chamber inside the .308 adapter - Can I bore the chamber without a chamber reamer ?
I have a lathe & a good selection of boring bars ranging from big, right down to small enough to get into a small diameter chamber like the M1 carbine.
Where can I find the chamber dimensions of the M1 carbine round ?
Should the .308 adapter internal neck diameter be the same as a resized case or larger ?
Is it proper to headspace the M1 carbine round off the front of the case, i.e should the front of the case (neck) bear up against a shoulder within the adapter ?
Many many questions I know, but I want do this without damaging anything or anyone (in particular me).
Thanks in advance for any advice.
If this works out OK I might try .22 rimfire in .222 Rem, that sounds like fun too.

Cheers Morton

quote:

Originally posted by morton3:
Can I bore the chamber without a chamber reamer ?
I have a lathe & a good selection of boring bars ranging from big, right down to small enough to get into a small diameter chamber like the M1 carbine.
Where can I find the chamber dimensions of the M1 carbine round ?

Is it proper to headspace the M1 carbine round off the front of the case, i.e should the front of the case (neck) bear up against a shoulder within the adapter ?


Cheers Morton

In general,

Yes, you can bore a .30 Carbine chamber with a boring bar.

You can determine these dimensions from a piece of factory brass. However, if I were machining a .30 Carbine chamber with a boring bar, I would not want the finished and "polished" chamber to exceed this: Rear diameter .354, front .338, Ove all length from mouth of case to bolt face 1.285 (1.280-1.290)

The cartridge headspaces off the case mouth. It requires a sharp, clean shoulder for the mouth of the case to bear up against.

http://www.mcace.com is in business. $20.00 US for the adapter.

Allot of people laugh at that little carbine round, but under a 100 yards it’s pretty effective and not all that inaccurate.

You can buy them ready-made at the below link. I don't know how much trouble it would be to get them into another country. I have a couple of them, but never fooled with them enough to say for sure just how accurate they are. I do remember the guy told me to rotate them and then mark the most accurate position. I have a 30/06 to 30 carbine adapter that seems to function ok, but it would work best in a break-action single-shot, such as a Thompson Encore.

http://mcace.com/adapters.htm

Hope this helps! kg

Morton,

If I were doing this I would simply regrind a reamer to the dimension needed.

Also, since you already have the ammo, I would take my measurements from them rather than from drawings.

quote:

Originally posted by Mark:
Morton,

If I were doing this I would simply regrind a reamer to the dimension needed.

Also, since you already have the ammo, I would take my measurements from them rather than from drawings.

Mark, Thanks for the tip. I must admit I`d never thought of that.
I don`t have a grinder capable of such accurate work though.
On top of that I only possess 4 reamers, .45acp, .45 Long Colt, 9mm Para & .22 rf.
I bought these reamers with the lathe & haven`t actually used any of them yet.
Obtaining reamers here in Australia is probably not as easy as it is in the states.
Having said that we can get them, but reamer suppliers are pretty thin on the ground over here.
I am very new to this gunsmithing caper, but hey we must all start somewhere & make mistakes etc.
I am very interested in this headspace businness & have purchased the book on gunsmithing by Roy Dunlap.
The book is quite good & explains most things in good detail.
Unfortunately I am an "A" type person who benefits far more from seeing rather than reading, so I`ll do as you suggest & measure from the factory ammo & go from there.

Many Thanks Morton