View Full Version : Deep Throat.

March 12, 2008, 13:21

I got an M1 barrel that swallows a field gage when buttoned up to my receiver. The plan is for me to chuck it up and cut a full turn off it, re-profile everything. Then I'll use a reamer and gages to get it headspaced.

I looked in Kuhnhausen's Rocket Surgery book concerning this. The illustration on page 132 gives the minimum dimension from the face of the gas piston to the front of the gas plug hole in block as .080".

I suspect a typo, of course.

I cannot recite the threads per inch on an M1 barrel, but turning a full turn off is a lot. Anyone care to comment ?

March 12, 2008, 13:36
I'm going by memory, but a full thread from a M1 barrel is .1".

The clearance between the piston end of the op-rod and the gas plug could be 0.08", that seems perfectly reasonable to me.

But -.02" does not! :rofl:

March 12, 2008, 14:26
That looks about right, "a tenth".

I best mock this thing up and do some measurbating first. I can grind some off the piston face, the piston is new on my op rod, hell the op rod looks new (refurb).

Measure thrice and cut once't.


March 12, 2008, 14:50
Have you considered trying to find a bolt that will headspace properly?

If I couldn't find a bolt that worked, I'd just get a new barrel before I went to all that work to make a totally nonstandard M1. Hacking a major component that is in-spec to compensate for one that is out of spec is just wrong on these rifles.

New M1 barrels are readily available and comparitively cheap. Not true of good, in spec op-rods.

March 12, 2008, 14:57
Good thought, Steggo. Been having it often.

March 12, 2008, 20:49
Owl- I sent my beater Garand out to a smith and he encountered the same thing using a used barrel.

Looked like I'd have to get a new barrel, even though he had a good one on hand.

He opted th swap bolts and found one that would allow him to headspace the rifle.

I should have it back in a few days. I'm too much a sissy to wrench on my M-1.

March 12, 2008, 21:35
Slow and I pulled a bolt out of one of his Garands and it did the same thing. Sure, I might just find a bolt that would work. Question is, where is a box of bolts to try ?

Anyone ?

March 13, 2008, 04:02
U would probly have to take it to a show and go through some bolts if any1 had them and would let U.

Unless U R stuck on that barrel, I would get a short-chamber commercial barrel from Fulton or Criterion (or Citadel 2 save U moniez) and set it up how U want it.

Survey Punk
March 13, 2008, 04:42
Hooty Owl,
Dude, I tol' you you'd go blind reading 'at Kuhn... er, Koon.... THAT GUY!
New Barrel, short chambered. Only way to fly.
An average commercial barrel is at least as good as the best GI barrel. No shame in having a rifle that shoots well. :biggrin:


March 13, 2008, 05:15
Yeah quit readin Kuhnski, get the Assembly Guide by Big Walter Kuleck, put her together and go blasting.

March 13, 2008, 08:58
I don't have a pile of bolts to try, but you can narrow it down a little before you start.

I can't remember off the top of my head which one, but one of the WWII Springfield bolts is generally regarded as being the longest, maybe the -12 heat lot.

March 13, 2008, 13:41
Winchester bolts are the "tightest" bolts you'll find.
If that don't work, it's new barrel time for sure.

March 13, 2008, 14:20
Welcome aboard, Sir!!

Good to have you with us.

March 13, 2008, 14:49
All the comments by the learned ones on here and those I have solicited elsewhere all point to the same thing.

Another barrel. (no making chips on the one we have now)

Done. (wait mode again)

March 13, 2008, 22:12
My beater Garand that got the used barrel/bolt swap is one of those Korean imports and is pretty well worn. Lots of new or reconditioned parts, but a worn out muzzle.

My good M-1 is on it's way back from Glen Riddle and it got a new Fulton Armory barrel.

I went in the hole trying to get these guns in good condition before the impending wierdness begins. I'll be able to pass them down in good condition.

March 14, 2008, 06:58
Yeah, I hear ya, MTS. I am inna hole to Slowman some but not gonna get no deeper to get this M1 fixed. Gonna sell off an extra .22 and an extra Imbel . THEN we'll get back on this full bore.

March 15, 2008, 14:59
if you dont have a barrel with a NEW muzzle, your just standing in front of the brake making scrap metal. get another barrel to play with.
turn a remington 700 barrel back a couple turns instead.