Tight 44-40 chamber

[fourarmed]

I posted this on the barrel board, but didn't get much help. Some years ago I had the barrel on my '73 Winchester relined by Redman. He advertised .428 groove diameter. It turned out to be .431. A .431 bullet seated in any of the readily available cases chambers too tightly for my comfort in a '73. What I would like to do is open just the neck of the chamber a few thou. I thought of turning a short cylinder of brass that would screw onto a cleaning rod, then coating it with lapping compound or emery cloth and pulling it into the chamber from the muzzle using a cleaning rod, and spinning it with a hand drill. Any suggestions are welcome. I'd prefer not to take the barrel off.

[MtGun44]

Probably would work, but I'd modify a case as a mandrel/guide/protector. Maybe a smaller
diameter tail on the lapping portion - say 1/4" diam extending back through the case
head of a modified (shorten to shoulder and drill primer out to 1/4") case.

Bill

[smithywess]

I posted this on the barrel board, but didn't get much help. Some years ago I had the barrel on my '73 Winchester relined by Redman. He advertised .428 groove diameter. It turned out to be .431. A .431 bullet seated in any of the readily available cases chambers too tightly for my comfort in a '73. What I would like to do is open just the neck of the chamber a few thou. I thought of turning a short cylinder of brass that would screw onto a cleaning rod, then coating it with lapping compound or emery cloth and pulling it into the chamber from the muzzle using a cleaning rod, and spinning it with a hand drill. Any suggestions are welcome. I'd prefer not to take the barrel off.

Fourarmed,

This is a topic which interests me but doesn't seem to do the same with others. I collect and shoot vintage Marlin leverguns in most calibres. Some of these were manufactured in the blackpowder cartridge era prior to 1898 and as such the manufacturers paid little heed to exacting tolerances in their bore diameters because blackpowder would always obturate to seal overbore barrels. The problem arises when we wish to load smokeless propellants which don't have anywhere near this propensity to obturate bullets, even very soft ones, and even with very fast powders like Unique. The result of firing underbore bullet sizes is massive inaccuracy with tumbling bullets and leading with cast bullets as blow by gases cook and melt the base and sides of the bullet. The cure is to fire a bullet one to two thousandths overbore and this measurement is obtained by slugging your barrel. The problem that arises is then the one you have encountered. The loaded round with it's bullet won't seat in the chamber because it sticks in the throat. I have 4 pre 1898 rifles in which this problem arose, two .40-65's, a .44-40 and a .38-40. The .44-40 slugged to .431". As you say even a bullet of this diameter wouldn't chamber. Now some folk have got around this problem in pistol type cartridges ( 32-20, 38-40 and 44-40) by accepting an underbore bullet, which when seated will chamber without problem, by adding a polyethylene shot buffer as a compressed filler over the powder (a mid speed one) and under the bullet. The filler acts as a flexible gas check ( Scovill) preventing blow by gases. Certainly I`ve tried this and the accuracy is indeed greatly improved, but this is not applicable to the larger calibres in my view and is at best only a forced solution to the pistol type cartridges. What I have done, with great success, with all four of my rifles was to hand ream their chamber throats until the bullet of my choice ( two thousandths of an inch over groove diameter) would chamber without difficulty. As for the pistol type calibres I still use the Buffer as a filler but some might consider it anal thinking but it can do no harm. My rifles made after 1898 have been built to a much tighter tolerance concerning bore diameter and for instance another .44-40 I have in a Model `94 built in 1905 has a groove diameter of .427" and it chambers and shoots a bullet sized to .429" very well. I won't go into the practical details of the reaming operation unless you wish but you don't require a gunsmith and it's not complicated, but each reamer is about $78.00. I don't want to bore anyone.

Hope this helps.