What size boolit would you run for this?

[Stopsign32v]

It's a modern "44-40" so basically a 44 Special setup. Anyways the chamber throats measure .430-.431 at the ends and the bore is .426 at the smallest. Keep in mind this will be loaded in 44-40 brass.

What mold would you guys be looking at? Boolits will normally be powder coated but I might pan lube them for black powder as well.

[Dusty Bannister]

Rules for sizing bullets to the revolver cylinder throats do not change with caliber. Size to largest throat.

Understand that the minor diameter in a barrel is a bore diameter, the major diameter in a barrel is groove diameter. With the smallest being that much difference you might have thread choke in the barrel at the frame. That will be a problem all it's own.

[Stopsign32v]

With the smallest being that much difference you might have thread choke in the barrel at the frame. That will be a problem all it's own.

Explain that to me again?

[Der Gebirgsjager]

The old time measurement for .44-40 was .427", but modern guns are almost all .429". It sounds like your chambers are modern, and your barrel closer to the original. Barring any gunsmithing, I think I'd try .427" for starters. A squeeze down from .429" might give poor accuracy and leading. If Dusty is right, and your tight spot is where the barrel is threaded into the frame, then you may want to consider re-barreling. But I'd experiment with the bullet diameters first.

DG

[Stopsign32v]

The old time measurement for .44-40 was .427", but modern guns are almost all .429". It sounds like your chambers are modern, and your barrel closer to the original. Barring any gunsmithing, I think I'd try .427" for starters. A squeeze down from .429" might give poor accuracy and leading. If Dusty is right, and your tight spot is where the barrel is threaded into the frame, then you may want to consider re-barreling. But I'd experiment with the bullet diameters first.

DG

Tight spot is at the end. I was measuring the bore by pounding in a 45 cal lead ball into the muzzle of the barrel. After the muzzle it got easier to push down the bore.

[243winxb]

.427"

[Walks]

.428 for Me, works into 2" groups at 50yds off hand in a older Uberti 73 clone.

[Dusty Bannister]

Sorry, was busy last night so did not respond earlier. Also, your message box is full.

You say that the cylingers measure .430 to .431". The Bore measures .426".

Is this by slugging or pin gauge? If slugging, the cylinder, it is common practice to size the cast bullet to a size that passes through the cylinder throat with slight resistance. If you measure with a caliper, you may have some error in the instrument. Not the end of the world, but not the best accuracy. Too small a bullet will allow hot gasses to pass around the bullet and introduce leading in the barrel of the gun.

Next you say the bore is .426" at the smallest. This is most likely a simple miss use of correct terms. I suspect you mean the groove is .426". Again, the largest diameter (Groove diameter) is the guide. Knowing if there is a difference in this measurement at any part of the barrel will tell you if you have another problem to deal with as well. Correct usage does prevent bad information being shared. Another common error is to not count the grooves in the barrel and have an error in reading if the barrel has an odd number of grooves.

Thread choke is such a common topic, I did not think it needed explanation. Thread choke occurs when a barrel is threaded tightly into the frame of a revolver which actually squeezes the barrel smaller at the frame. There are a number of ways of resolving this problem, most gunsmith fixes are not cheap.

Simply stated, if the bullet fits the throat, no gas goes past. If the bullet is still larger than the groove diameter, no gas goes past. If the thread choke is present, the gas will go past and you get leading forming after the barrel constriction.

https://castboolits.gunloads.com/showthread.php?288697-Cast-Bullets-Sized-for-Revolver-Cylinder-or-Barrel&highlight=size+throat+groove+diameter

If you would like further explanation, clear out your message box and PM me. Duaty

[Cosmic_Charlie]

You might try powder coating some boolits and sizing them to .430" with a softer alloy, perhaps a bhn of 9.

[JonB_in_Glencoe]

I'm gonna throw in a curve ball here.
Loading 44-40 can be a pain, because the case mouth walls are very thin.
Seating a fat boolit will easily cause case crunch.
So you want to use the smallest boolit that will work for your gun.

For your revolver, if I have boolit sizing choices, I'd start with .427
then increase size if accuracy or lead fouling require it.

Side note, My Buddy has a modern Marlin levergun in 44-40, I didn't have the gun to check barrel size, but others recomended .430
I tried loading the .430 boolits, but had problems seating the boolits, then I tried .429 sized boolits. I had better luck seating them and in the end, they worked just fine in the rifle.

[Stopsign32v]

I'm gonna throw in a curve ball here.
Loading 44-40 can be a pain, because the case mouth walls are very thin.
Seating a fat boolit will easily cause case crunch.
So you want to use the smallest boolit that will work for your gun.

For your revolver, if I have boolit sizing choices, I'd start with .427
then increase size if accuracy or lead fouling require it.

Side note, My Buddy has a modern Marlin levergun in 44-40, I didn't have the gun to check barrel size, but others recomended .430
I tried loading the .430 boolits, but had problems seating the boolits, then I tried .429 sized boolits. I had better luck seating them and in the end, they worked just fine in the rifle.

I believe using a 44 Magnum/Special expanded die will solve this issue. At least this is what Mike (Dualist1954) told me.

[JonB_in_Glencoe]

I believe using a 44 Magnum/Special expanded die will solve this issue. At least this is what Mike (Dualist1954) told me.
I'm sure it will, BUT...and this is a big BUT...that will surely reduce case life, and may even split new cases. That case mouth wall is thin, especially with R+P brass.

If you try this (which is something I didn't try), report back with your results.

[Wayne Smith]

Use a Lyman M die to expand the case mouths.