.44-40 Throat Dimensions.

[smithywess]

I have a vintage Marlin Model '94 in .44-40 built in 1905. It slugs to .426" and will chamber factory Dominion ammunition ( miked at the neck with a jacketed bullet at .441") without difficulty. I want to handload 200 grain R.C.B.S. flat nose flat base cast bullets sized to .429" but loaded in Dominion cases, and even most Winchester cases, the outside neck micrometer dimension is .446" and these shells will not chamber in my rifle. Even cases holding bullets sized to .427" will not chamber. What is the collective wisdom as to how I can overcome these difficulties ? I really don't want to be loading jacketed bullets, and the only solution I can come up with is to open up the throat a little to .448". This may be the wrong part of this forum for this question ? If it is please advise me.

[9.3X62AL]

If I read your text correctly.....the area of conern is more the forward or neck area of the chamber, as opposed to the barrel's "throat". Am I correct?

[sliphammer]

Why not try sizing your bullets to .426? If that doesn't help you could chamfer a bit off the inside of the case necks to reduce the outside diameter.

[smithywess]

That's correct 9.3. I mean the area of the chamber where the neck of the cartridge lies. I call that the throat. The area in front of that I call the leade into the rifling. Sliphammer, the case necks of the .44-40 are already paper thin and to consider removing material from them would leave nothing left. At best I might get one load before the neck splits. I havn't had any luck with cast bullets in my rifles when I size them to groove diameter. O.K.for jacketed but not cast. I find that leading is much reduced if sizing is made two or even three thousandths over groove diameter, and even with gas checks on. Certainly I've found accuracy to be much better with bullets sized as I've suggested. I wonder if other folk have run into this issue? Thanks for the replies.

[Jon K]

.426??? Bore or Groove? Chamber or muzzle end?

Did you slug or chamber cast the throat area?

I have a Marlin 1894 built 1901...groove diameter is .4305", I am shooting a cast boolit sized .4305"/Win brass(.0065-.008 avg thickness). Loaded size is .445-.446. I opened the neck area of the chamber to .4485 for clearance.

I use only WW brass. Starline & Remington average =.010+ which is too thick.

This has the ugliest looking bore, but is one of my best shooting levergun, with smokeless or BP. :p Second from the bottom in avatar.

Your other alternative option is to put a liner in it .420x.428.

BTW, I have the RCBS mould, and it will only drop a .428 boolit(ww/12% lino) pour @825* I use Saeco #420 sized to .4305, for BP 20:1 lead/tin @.430"

Good Luck,
Jon

[KCSO]

You can pull the barreland run a modern Mansen reamer in it and that should do the trick. I can measure my reamer but it worked for the last gun I had to open up.

[smithywess]

Thanks Jon,
The .426" I quoted for the diameter of my barrel is groove diameter and not bore diameter and slugged from the muzzle;and no I have not done a cast of the throat. I have elected to follow your steps and open up the throat to .448" which will give me ample room for the .446" neck diameter of my present handloads ( with a bullet sized to .429"). Thanks for the tip Re Remington and Starline brass being too thick. I normally use W.W. exclusively anyway. I suspect that Dominion brass is also very thick. I don't have a tube micrometer so I don't know how thick. It's a pity that smokeless powders don't upset even mostly lead bullets as does blackpowder. Thanks for the suggestion to reline my barrel but the outside finish on the rifle is too good to possibly interfere with any value that a collector might want to put on the gun. Moreover the bore is excellent with good sharp rifling and no pitting.

[9.3X62AL]

Smithywess--

You "nailed it" with the description of the issue of discordant chamber and bore/groove diametric relationships, and the old reliance upon blackpowder "bump-up" to resolve the problem. In 44-40, I'm lucky enough to own a Win 73 in which all the notes make good music together. Jon was a BIG help to me with my 44-40, recommending SAECO #446 as a boolit to suit its palate.

I agree that relieving a few thousandths from the neck area as you describe is a viable solution to the related issues of boolit fit and boolit release. Best of luck with your project.