44 Rem. Mag Dimensions

[Pirate69]

I purchased a 434250 Mold because I was informed that the 44 Rem. Mag. Marlin 1894s and the BH revolvers likes a big bullet. This mold drops a 250 grain boolit at 0.434". I have loaded some rounds with 16.0 gains of 2400 and the results look promising. However, in the Marlin 1894, the rounds are a little tight to chamber. Not a lot, but some resistance. Just enough to leave shiney brass along the length of the seated bullet. Looked at the components and the rounds and found the following dimensions.

Brass thickness 0.014"
Boolit diameter 0.434"
Load round diameter 0.458"
Unload brass diameter 0.451"

Looks like I am expanding the brass by about 0.007" when loading the boolit. If the boolit was loaded without any resizing by the case, the theoritical diameter of the round would be 0.462"; but it is 0.458". Looks like I am getting 0.004" of resizing from the tight case; assuming the brass is not thinning.

Does this make sense? Does anyone see a problem with these rounds so long as they will chamber? Have not tried them in the BlackHawk yet.

[higgins]

You may not be leaving any room for the case to expand even a little bit to release the bullet in the rifle. You could try sizing the bullet down to about .432 and see if that helps. If you haven't already done so, slug the bore and see if you really need a .434 bullet. If you have a variety of brass on hand, mike different brands to see if you have thinner brass available. In a somewhat similar situation, I use R-P brass to load .45ACP so I can use unsized, tumble-lubed bullets and not encounter difficulty in either loading them into the cases or the chamber of the gun. The R-P brass I have on hand tends to be thinner than the other brands (or the military) that I have on hand.

[454PB]

Your numbers seem to indicate that the brass IS sizing the boolit. However, I have deliberately sized boolits .004", and it takes a lot of force.

You don't mention what alloy you are using, but for this to happen, it has to be soft.

I'd recommend you pull one of the seated boolits and measure it to confirm this sizing is really happening.

[Pirate69]

The alloy is a 50/50 mixture of wheel weights and range lead. It was heated to 400F and water quenched to give a little hardness.

[Pirate69]

The bore slugs 0.429" to 0.430". It is a Micro-groove barrel. I used an inertia bullet puller to disassemble a round. The bullet was still 0.434". This says that I am thinning the brass. This may be true since it did not take a lot of effort to remove the boolit from the case. So what do we think? Go with a 0.432 sizer? Don't want to change brass; I have just purchased 1,000 rounds of new brass of the same manufacture.

[454PB]

Yes, .432" will work fine, and should eliminate your tight chambering.

[Dale53]

Take a fired case. See how large a bullet you can slip into the case with finger pressure. That will demonstrate the largest bullet that can safely be used with that brass and bullet combination. Brass expands when fired and contracts a bit after the pressure is off. Any bullet of a diameter than can be slid in by finger pressure should be OK as far as safety is concerned. However, accuracy can best be determined by trying bullets of different diameters (below the diameter of the maximum bullet size as demonstrated).

You may have to bell the case (without expanding the case) to remove the crimp before trying the "finger exercise" as sometimes a partial crimp remains after firing.

Oftimes people try to remove a bullet from a loaded round, then measuring the diameter of the bullet to see if the case has reduced the diameter. To do this correctly, you really have to slice the case in a couple of places (ruining it in the process) as using an inertia puller to pull a bullet through a good crimp will often, in itself, reduce the bullet diameter.

FWIW
Dale53

[Pirate69]

Good comments, thanks all. On the round that I pulled the boolit, I measured the case thickness. The thickness is now 0.011". An unfired case has a thickness of 0.0014". That accounts for 0.006" of the 0.007" that was either bullet resizing or case thinning. Looks like the harden lead did not resize and it was case thinning.

I will have to try the fired case bullet measure. Good suggestion.