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Headspace question

Orca1

Orca1

Well-known member
Anyone have any information on someone who can preform the reaming to help fix the headspace clearance on a M1 Carbine
using a pull through finishing reamer?
 
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Competent gunsmiths should be able to do it. I know one who is highly skilled but I don't trust him b/c he's high on mary-jane or the bottle. What a waste of talent. I've a couple of classmates (Trinidad College) who can and one is in Indiana and the other is in Missouri. I can but I don't have a FFL.
 
BTW, I would remove the barrel (requires wrench fitted to receiver or adapted through blocks to the receiver) to ream it. Insert reamer with pilot guide (keep it centered) and give it a few spins. Then reattach barrel and insert stripped bolt with first "go" gauge and then "no-go" gauge. If everything is good, then almost done (remove the barrel one more time to polish the chamber). If not good (won't close on go gauge) then remove the barrel again and insert reamer and give it a twist. You get the idea. PM me as to what state you're in and if you're in any state a good classmate is at (come to think of it I know someone in Montana) I'll PM you their contact info.
 
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Blackpowderresearcher said:
BTW, I would remove the barrel (requires wrench fitted to receiver or adapted through blocks to the receiver) to remove the barrel. Insert reamer with pilot guide (keep it centered) and give it a few spins. Then reattach barrel and insert stripped bolt with first "go" gauge and then "no-go" gauge. If everything is good, then almost done (remove the barrel one more time to polish the chamber). If not good (won't close on go gauge) then remove the barrel again and insert reamer and give it a twist. You get the idea. PM me as to what state you're in and if you're in any state a good classmate is at (come to think of it I know someone in Montana) I'll PM you their contact info.
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Thank you for your time and advice. I won't be performing the work needed but will take your advice and help with someone who can. I did find a gunsmith in my area who said he can do it. I will be going to his shop to see the set-up to get an idea of things to come.
 
If the right locking bolt lug notch is out of square and the metal worn down past the hardness that might cause less life to the project. Is there so much wear that the receiver is soft like a Plainfield carbine. How much wear is on the bolts lugs and that right lug on the receiver. I wonder if a new Criterion barrel with the same worn bolt and lugs will hold up. After 3000-5000 rounds you might be out of headspace again. Look at that USGI receiver's lugs. A gunsmith should be able to tell if too much of the hardened surface on that right lug is gone and if it is out of square and down to soft metal. You can always go with a new NOS round bolt, but the lug surfaces on the receiver, I do not know? Maybe better to just start with a USGI carbine that headspaces??? It all depends on cost. Maybe a money pit to do it correctly. It will be interesting what a gunsmith says. I assume it is so bad it jams and bottlenecks the cartridges when fired.
it would be interesting to see photos of the receiver's right lug and rail wear. Also the lugs on the bolt.
 
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I'll try to make this as short as possible: I'm buying the rifle and the seller will not sell it to me until the headspace issue is resolved because of safety concerns. So he was actively looking, as was I, for a solution with a gunsmith who is set up and capable of doing this procedure. As of today, I have found one & the seller will be shipping it the gunsmith. After all said & done, I will post the results and the cost. Thanks again for everyones opinions.
 
For clarification, barrel is on the receiver and the stripped bolt is used to check headspace. It should close on "go" gauge but not on "no-go" gauge. Field gauges are not needed but should it close on that, replace the barrel. Alternatively, the barrrel can be reamed, relined and re-chambered if you want to preserve the external markings.

Good luck and I hope that NPM is solid. I don't have a National Postal Meter myself.
 
Blackpowderresearcher said:
For clarification, barrel is on the receiver and the stripped bolt is used to check headspace. It should close on "go" gauge but not on "no-go" gauge. Field gauges are not needed but should it close on that, replace the barrel. Alternatively, the barrrel can be reamed, relined and re-chambered if you want to preserve the external markings.

Good luck and I hope that NPM is solid. I don't have a National Postal Meter myself.
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What I really wanted and found with this rifle, it has a US&S receiver with the proper "U" stamp.
 
For me most M1 carbines with normal to heavy war use and rebuilt can and do fail a NO GO headspace gauge, ( no biggy) I only avoid real beaters like the import marked dogs that fail a FIELD gauge. That is with an original barrel and worn bolt and receiver, drop a Forster Saami FIELD gauge in and lightly close the bolt and if it drops all the way down it fails a FIELD test. However, if it goes past the right 90 degree notch on the right side, and just slightly lowers (you do not apply pressure) it's a light feel thing then it still passes a FIELD test. Just that the rifle is very near the end of its life (but it still did not fail a FIELD gauge). Those generally have barrels with muzzles that gauge around 3/3.77. Rerally shot out beat dogs like Dunhams sold. I forgot where they were imported from. A M1carbine that fails a Forster gauge may still pas a USGI factory FIELD gauge. The square edge on the right lug may be rounded and allow a bolt to only very slightly turn in, but the bolt does not go down but a hair or two. You just have wear on the bolt lug and the rail corner is rounded. Those rifles still shoot and do not jam or bottle neck cartridges. Heck, some that fail a headspace FIELD gauge may still fire without backing out primers on the brass or causing jams. What ever you do, you must not gorilla paw a bolt when doing a headspace test. I have seen some pass a Clymer Field test, but then fail a Forster gauge Field test. I only worry if the bolt drops down into lock easy, brass has primers backing out and the rifle jams. Then its toast/garbage. All too many push too hard with a FIELD gauge and get a false reading. I would have some carbine guy do the headspace test or a Surplus rifle gunsmith do the headspace test. Did you gauge the muzzle of the barrel? What gauge are you using? Best have a NO GO and a FIELD headspace gauge if playing with carbines. If into US firearms best have a muzzle gauge. See https://www.fulton-armory.com/muzzleweargaugefor300-303bores.aspx
Not worth it if the muzzle is at .303 to do all the work. A new barrel and bolt and expense to pay a gunsmith. I never went that route. I just turned dogs into parts.

Did you see this video?

 
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