Figuring out the size cast I will need for my Marlin 1984s

[Stopsign32v]

So I'm trying to wrap my head around this. The revolver stuff seems easy...Chamber size and bore size. The lever actions got me a little more stumped. This is some information I found, but you guys tell me what else I need to know:

"Most Marlin Microgroove .44 barrels I have measured run .430-.433" in diameter. The easiest solution is to get a mold which casts .432-.433 and to cast bullets SOFT, no harder than 12 BHN, wheelweights are OK, then lube the as-cast and unsized bullets with 45-45-10 or Lee Liquid Alox and load them into sized-expanded brass to depth only. Then SEPARATELY crimp them using either the Lee Factory Crimp Die or the Redding Profile Crimp. This will ensure cartridges will enter the chamber, and if necessary the bullets will be lightly sized by compression inside the case. In my experience the Lee FCD is MUCH more difficult to use and adjust correctly. The Redding die is far superior if you follow the instructions.

To make a "pound cast" for a .44 Magnum rifle the easy way is to take a dead soft, pure lead .457 round ball, drop it into the chamber. Then use a 3/8" diameter brass rod to drive the ball just barely into the orig of rifling and knock it out. If you don't over-drive the ball you will capture both the chamber mouth diameter and the chamber transition from the case neck to the "throat", or conical "forcing cone" section at the origin of rifling."

[mr surveyor]

"Then SEPARATELY crimp them using either the Lee Factory Crimp Die or the Redding Profile Crimp. This will ensure cartridges will enter the chamber, and if necessary the bullets will be lightly sized by compression inside the case. In my experience the Lee FCD is MUCH more difficult to use and adjust correctly. The Redding die is far superior if you follow the instructions."

Before this thread runs off on a LFCD bashing tangent, I'd only add that the LFCD mentioned in the OP is probably regarding the collet style die and not the dreaded "post sizing" die. There are two styles of LFCD


jd

[Stopsign32v]

"Then SEPARATELY crimp them using either the Lee Factory Crimp Die or the Redding Profile Crimp. This will ensure cartridges will enter the chamber, and if necessary the bullets will be lightly sized by compression inside the case. In my experience the Lee FCD is MUCH more difficult to use and adjust correctly. The Redding die is far superior if you follow the instructions."

Before this thread runs off on a LFCD bashing tangent, I'd only add that the LFCD mentioned in the OP is probably regarding the collet style die and not the dreaded "post sizing" die. There are two styles of LFCD


jd

I've only ever seen one LFCD. Now you have me curious

[JonB_in_Glencoe]

The short answer is the rifling should be .431 per SAAMI spec, so use a .432 boolit.
I'd load up some and shoot 'em. If there is a problem then I'd consider slugging the barrel to find the Groove diameter and if it's over size, then make the boolits that size or .001 larger.

[Cosmic_Charlie]

Going softer on the alloy with good lube or powder coating allows you to shoot boolits close to bore diameter. This is particularly helpful when your bore slugs oversized a bit. I've got a Henry single shot .44 mag that slugged at .431" and that is what I size my boolits to. Very accurate and no leading. I also have a couple revolvers whose cylinder throats are right at bore diameter and it works great for them too.

[mdi]

What's wrong with drivind a .440" slug down the barrel amd measuring the slug? This has worked for me for nearly all my firearms (except most 22 rimfires and my AK).

Most Marlin Microgroove .44 barrels I have measured run .430-.433" in diameter. The easiest solution is to get a mold which casts .432-.433 and to cast bullets SOFT, no harder than 12 BHN, wheelweights are OK, then lube the as-cast and unsized bullets with 45-45-10 or Lee Liquid Alox and load them into sized-expanded brass to depth only. Then SEPARATELY crimp them using either the Lee Factory Crimp Die or the Redding Profile Crimp. This will ensure cartridges will enter the chamber, and if necessary the bullets will be lightly sized by compression inside the case. In my experience the Lee FCD is MUCH more difficult to use and adjust correctly. The Redding die is far superior if you follow the instructions

. Then what? Shoot them?

[Cosmic_Charlie]

So sorry, in my above post I meant groove diameter. Bore diameter is the top of the rifling and smaller than groove diameter. When you slug a barrel you are measuring the larger groove diameter.

[oley55]

Going softer on the alloy with good lube or powder coating allows you to shoot boolits close to bore diameter. This is particularly helpful when your bore slugs oversized a bit. I've got a Henry single shot .44 mag that slugged at .431" and that is what I size my boolits to. Very accurate and no leading. I also have a couple revolvers whose cylinder throats are right at bore diameter and it works great for them too.

Charlie, I have a couple revolvers whose chambers and bore are very nearly the same as well. For the 'softer' alloy, would a 50/50 mix of coww and soww get me into the softer range for better bullet obturation/seal?

[Cosmic_Charlie]

Charlie, I have a couple revolvers whose chambers and bore are very nearly the same as well. For the 'softer' alloy, would a 50/50 mix of coww and soww get me into the softer range for better bullet obturation/seal?

I think you meant groove.

It depends largely on how hot a load it is. I've been shooting a powder coated 173 gr. boolit over 7 grains of HS-6. Goes about 1000 fps and the bhn is 10. I mix 5 of pure to 2 of ww to get there. This is .357 load. Max is 7.5 grains of HS-6 with that weight boolit. A bhn of 10 seems a good target for medium revolver loads. The powder coating is a big factor in preventing leading too.

[oley55]

yes groove and thanks for your mix ratios.