recrowning the muzzel

Rome · December 23, 2000, 07:50 AM

Dear fellow TFLrs,

Can someone provide me with a simple description of what crowning is and how it helps a rifle? Also, can an M1 be crowned? I've done some reading about this subject but would like it if someone with some experience could describe it. For instance, how far back can you crown?

Any help will be appreciated. My M1 has a good barrel with an excellent bore and low TE but the muzzle is worn. Can it fix this without replacing the barrel?

Rome

George Stringer · December 23, 2000, 09:13 AM

Rome, crowning squares or trues the ends of the rifling in your barrel. If they aren't square then they don't react uniformly on the bullet. The lack of this equal action can cause inaccuracy and tumbling or keyholing. Yes the M1 can be crowned. Any barrel can be. I'd recommend you have a gunsmith do it as it is best done in the lathe. Unless otherwise requested by a customer I use a 11deg crown on the muzzle which protects the actual crown from getting dinged through day to day use by recessing it slightly. If you don't have anyone near you to do the work e-mail me. I'd be happy to do it for you. George

Rome · December 23, 2000, 09:44 AM

Thanks, George. I'll look around here first. I can also send it to Orien which is only the next State West of Ct.

Merry Christmas!

r

James K · December 24, 2000, 11:21 PM

Hi, folks,

A note on crowning the M1 rifle. Any cutting or crowning that cuts the length of the barrel by 1/4 inch or more may lead to malfunctions, since the bullet needs to remain in the barrel a certain distance past the gas port to allow pressure to function the rifle. If the barrel is shortened, the pressure will drop too rapidly and there will not be enough sustained pressure to function the operating rod. There is a similar problem with M1 rifles that have been backbored; this can allow escape of gas past the bullet and result in a premature drop in gas pressure.

Jim

BBBBill · December 25, 2000, 12:16 AM

So, Jim, that brings up the question of how to deal with one of those washed out muzzles with an otherwise pristeen bore. I've seen a bunch of those out there, probably from ROTC units where they got "cleaned" a lot, but never shot. Won't shoot for beans now with the crown washed out from cleaning rod drag. Can they be saved?

James K · December 25, 2000, 07:33 PM

Hi, BBBBill,

What is "washed out" is not so much the crown, which is outside the bore, but the first half inch or so of the rifling. Since the wear is not even, the bullet exits with gas rushing out by its base on one side before the other, tipping it and causing inaccuracy. Drilling the muzzle out to remove all the rifling for 3/8 - 1/2 inch or so and leaving a clean exit point inside the barrel can sometimes work to restore some semblance of accuracy. But with the M1, it can sometimes lead to enough gas loss to create malfunctions. I have seen this in some M1s which were used by foreign nations which did not have funds for new barrels and had used the technique on bolt action rifles.

I have never done this myself, but if I were to do so, I would use a minimum size drill for the job (.308? .310?) and see what happens. But I certainly would not give any guarantee of results. In any case, in spite of what someone said on another site, it is a job for a lathe, not a hand drill. It might be as easy to install a new barrel; the expense would be greater, but there would be more likelihood of good results without a lot of trial and error.

Jim

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December 23, 2000, 07:50 AM	#1
Rome Senior Member Join Date: February 5, 2000 Location: Connecticut Posts: 420	Dear fellow TFLrs, Can someone provide me with a simple description of what crowning is and how it helps a rifle? Also, can an M1 be crowned? I've done some reading about this subject but would like it if someone with some experience could describe it. For instance, how far back can you crown? Any help will be appreciated. My M1 has a good barrel with an excellent bore and low TE but the muzzle is worn. Can it fix this without replacing the barrel? Rome

December 23, 2000, 09:13 AM	#2
George Stringer Staff Alumnus Join Date: October 12, 1998 Location: Earlington KY Posts: 2,299	Rome, crowning squares or trues the ends of the rifling in your barrel. If they aren't square then they don't react uniformly on the bullet. The lack of this equal action can cause inaccuracy and tumbling or keyholing. Yes the M1 can be crowned. Any barrel can be. I'd recommend you have a gunsmith do it as it is best done in the lathe. Unless otherwise requested by a customer I use a 11deg crown on the muzzle which protects the actual crown from getting dinged through day to day use by recessing it slightly. If you don't have anyone near you to do the work e-mail me. I'd be happy to do it for you. George

December 23, 2000, 09:44 AM	#3
Rome Senior Member Join Date: February 5, 2000 Location: Connecticut Posts: 420	Thanks, George. I'll look around here first. I can also send it to Orien which is only the next State West of Ct. Merry Christmas! r

December 24, 2000, 11:21 PM	#4
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Hi, folks, A note on crowning the M1 rifle. Any cutting or crowning that cuts the length of the barrel by 1/4 inch or more may lead to malfunctions, since the bullet needs to remain in the barrel a certain distance past the gas port to allow pressure to function the rifle. If the barrel is shortened, the pressure will drop too rapidly and there will not be enough sustained pressure to function the operating rod. There is a similar problem with M1 rifles that have been backbored; this can allow escape of gas past the bullet and result in a premature drop in gas pressure. Jim

December 25, 2000, 12:16 AM	#5
BBBBill Senior Member Join Date: January 5, 2000 Location: Alabama Posts: 197	So, Jim, that brings up the question of how to deal with one of those washed out muzzles with an otherwise pristeen bore. I've seen a bunch of those out there, probably from ROTC units where they got "cleaned" a lot, but never shot. Won't shoot for beans now with the crown washed out from cleaning rod drag. Can they be saved?

December 25, 2000, 07:33 PM	#6
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Hi, BBBBill, What is "washed out" is not so much the crown, which is outside the bore, but the first half inch or so of the rifling. Since the wear is not even, the bullet exits with gas rushing out by its base on one side before the other, tipping it and causing inaccuracy. Drilling the muzzle out to remove all the rifling for 3/8 - 1/2 inch or so and leaving a clean exit point inside the barrel can sometimes work to restore some semblance of accuracy. But with the M1, it can sometimes lead to enough gas loss to create malfunctions. I have seen this in some M1s which were used by foreign nations which did not have funds for new barrels and had used the technique on bolt action rifles. I have never done this myself, but if I were to do so, I would use a minimum size drill for the job (.308? .310?) and see what happens. But I certainly would not give any guarantee of results. In any case, in spite of what someone said on another site, it is a job for a lathe, not a hand drill. It might be as easy to install a new barrel; the expense would be greater, but there would be more likelihood of good results without a lot of trial and error. Jim