M-1 Garand - Will counterboring help?

3768 Views 15 Replies 11 Participants Last post by glock357x2, May 15, 2010

laveen1

Discussion Starter · May 9, 2010 (Edited)

I picked up what looks like an O.K. 1953 (wrong! it's a 43 or 44) SA 30-06 M1 Garand. The stock looks well used and appears to be an original issue. It's in one piece except for a small crack at the heel. The parkerizing looks good. The action cycles, loads, and ejects as expected. I peened one of the grooves and tightened the fit of the gas tube (the front sight blade was loose enough to move .008 to .010). I have not tried 100 yds yet, but I can get a 3" group @ 25 yds. The bore measures .3035 about 3/4 of an inch from the muzzle. The muzzle is about .315. There is only a hint of color telling that lands ever existed at the muzzle in the final 1/4 to 3/8 of an inch. The 3/8 just before that is where the lands just fade away to nothing. There is nothing to indicate that the barrel was ever counterbored. I think there was just a lot of cleaning with steel rods.

I prefer not to rebarrel, so I'm hoping I can counterbore this enough to give the bullet a clean exit. How much is too much on this gun? How close can I get to the gas port before it stops cycling? If necessary can I just open the port a little? How do I keep the counterbore concentric in the barrel?

I don't plan on entering any matches, but it would be nice to know that the gun is more accurate than I am. Any help is greatly appreciated.

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Beanstrung

· #2 · May 10, 2010

The problem with counter-boring a Garand is that the gas-port is so close to the muzzle. You only have about 1.5" from the muzzle back to the gas-port, and the whole operation of the gas-system depends on the "right amount" of gas being captured and diverted to the op-rod during that brief period after the bullet passes the gas-port, but before it exits the muzzle. In my experience, counter-boring a Garand more than .200" deep will cause gas-system problems like short-stroking, failure to eject, failure to feed, etc.

A bore diameter of .3035" would equal a Garand muzzle-gage reading of 3.5. Anything over 3.0 fails "Service-Grade" criteria. The fact that you have to go 3/4" down into the bore to hit the .3035" diameter tells me that you would be better off with a new or better condition used barrel.

laveen1

Discussion Starter · #3 · May 10, 2010

Is a rebarrel as straight forward on this gun as it looks?

I have machine shop and mechanic experience (but not recent). I have most tools and equipment found in a small shop along with architectural blacksmithing tools. If I don't have to do anything with the chamber, head space, etc. it looks like a relatively straight forward job with everything removed and out of the way. I like a challange, but I don't want to ruin an otherwise good gun. What is your thought?

If I have to have a gunsmith work on it, can you recommend a qualified gunsmith in the Phoenix AZ area? Or, do you know anyone in the area that might be able to recommend someone that works on M-1's?

Thanks for your help.

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John Sukey In Memoriam

· #4 · May 10, 2010

What you don't have is a proper reciever wrench. Let a gunsmith do the work.

laveen1

Discussion Starter · #5 · May 10, 2010

That is one of the few tools I don't have. If I didn't need it I would probably have one.

wayne in boca

· #6 · May 10, 2010

You don't necessarily need a receiver wrench,a large crescent wrench (18") will work just fine.You will need a barrel vise.

John Crusher

· #7 · May 10, 2010

laveen1 said:
View attachment 314525 I have machine shop and mechanic experience (but not recent). I have most tools and equipment found in a small shop along with architectural blacksmithing tools. If I don't have to do anything with the chamber, head space, etc. it looks like a relatively straight forward job with everything removed and out of the way. I like a challange, but I don't want to ruin an otherwise good gun. What is your thought?

If I have to have a gunsmith work on it, can you recommend a qualified gunsmith in the Phoenix AZ area? Or, do you know anyone in the area that might be able to recommend someone that works on M-1's?

Thanks for your help.

Try Gunplumber AKA Arizona Response Systems. Mark Graham.

Beanstrung

· #8 · May 10, 2010

You will need a Garand Receiver wrench, a Garand barrel vise, and a .30-06 FIELD gage for verifying that the headspace is OK after the barrel swap.

Links:
Wrench: http://www.brownells.com/.aspx/sid=3322/pid=25116/sku/Complete_M1A_Wrench
Vise: http://www.brownells.com/.aspx/sid=..._with__12____13_Steel_Bushing_I_D__M14_Garand
Gage: http://www.brownells.com/.aspx/sid=52840/pid=27542/sku/_30_06_Field_Gauge

Unless you plan on doing several, it's likely cheeper to pay the 'Smith. The 'smith in my area charges $80 to swap a Garand barrel, and to check headspace.

AndGunsForAll

· #9 · May 11, 2010

Seems like I read in a reprinted gunsmithing book by a gunsmith last name Dunlap that counterboring was done to garands in WW2, along with all other kinds of strange repairs to get battle used garands back in service. Maybe it all depends on how much you have to counterbore, or if the gas port has to be opened up some, who knows, I always steer away from worn bore garands anyway, but I have always wondered myself, seen some well used examples up front on the muzzle, a few that were well priced, most not well priced.
Of course, sending out guns to be rebarreled is always an option, I don't have the patience anymore to do such, not especially having to ship a rifle somewhere, seems I got burnt everytime I did.

Jeremy2171

· #10 · May 12, 2010

Your barrel is pretty much junk now....if you counterbore and you get short stroke problems you really haven't lost anything. Go back the 3/4" or so till you get fresh rifling.

Also check the diameter of your oprod tip...if it's less than .525 it's undersize and you will get cycling problems. If it's good at .525 or .526 you will probably be ok with the counter bore...

laveen1

Discussion Starter · #11 · May 12, 2010

If I do have to rebarrel, what kind of accuracy do you think I can expect from a standard barrel, such as Midway's? (Criterion Barrel M1 Garand 30-06 Springfield 1 in 10" Twist 24" Short-Chambered Military Contour Chrome Moly Parkerized)
I appreciate your input, thank you.

Freebore

· #12 · May 13, 2010

laveen1 said:
If I do have to rebarrel, what kind of accuracy do you think I can expect from a standard barrel, such as Midway's? (Criterion Barrel M1 Garand 30-06 Springfield 1 in 10" Twist 24" Short-Chambered Military Contour Chrome Moly Parkerized)
I appreciate your input, thank you.

This is a good question. I am thinking about rebarreling an M1 also.

Vaarok

· #13 · May 13, 2010

Counterbore. I did mine and it helped immensely. You get this constant static about ZOMG IT'S GAS OPERATED, but as long as you don't go too deep, you can at least restore it somewhat. Rather than cut back to uneroded rifling, maybe you're at only partially eroded, but it's better than nothing.

AndGunsForAll

· #14 · May 14, 2010

Any 3/8" diameter drill bit made for drilling steel, and able to do 7.62 to 7.92 bores, a good 3/8" or 1/2" reversible drill, and some cutting oil like atf fluid or even motor oil, for counterboring.
Turn the rifle from one side to the other repeatedly to make sure you aren't drilling too much to one side. Then you can recrown the false muzzle with something inserted and tapered, either a long screw with round head, or my favorite method for long counterbores, which is taking a pin punch(for automotive use or bought as a set at wal-mart), with the tapered and thinner end down in the bore to get a good recrowing down there deep, carefully, chucked in the drill and with valve grinding compound. Most of my experience comes from accurizing old cleaning rod worn bolt actions, mostly.

jjk308 In Memoriam RIP

· #15 · May 14, 2010

I was a little reluctant to post this because of some doubts about the gas system working - but I'll rely on your experience - anyway it can't hurt and if you have the very minimal equipment its cost free. Here goes:

Do NOT try to do a counterbore with a hand held drill But you don't need a full size drillpress.
I've never had a problem counterboring, even with my little chinese tabletop drill press. Just use a 3/8" top quality 45 deg. (standard) bit at the proper speed, set the barreled action up clamped vertical and parallel to the drill and so the bit will swing out right over the bore center. Make sure the drill is fairly tight, minimal wobble. Use plenty of cutting fluid or motor oil to keep it cool, make short cuts under enough pressure to cut the bore continuously. if you're too cautious and let it rub instead of cutting it'll just get hot. Pull the bit out and inspect for good rifling around the cut. When you hit decent rifling you're done. Knock any chips off with a piece of brass or plastic.
I've never had a problem centering either because the 45 deg. drill bit really wants to go right down the center of the bore or maybe because I'm so anal retentive I get it perfectly centered and straight. I've always gotten back within 3 moa. ( about 3 in group at 100 yds, benchrest, sandbags.)

You don't have to bother with "recrowning" as with a 3/8 in drill the cut is only .0335 inches into the barrel wall, not really noticeable. The real crown is made by the drill bit down in the counterbore.

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glock357x2

· #16 · May 15, 2010

I had excellent service from Arthur Morrison of the NIGHT OWL GUNSHOP in Prescott, AZ; he converted 2 M1 Garands to the 'Tanker' version for me back in the 1980s. He may still be in business but I don't know for sure as I have not had any contact with him since that time.

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