Home Forums Hunting & Shooting Express Rifles and Big Bores Only Best bullets for 444 Marlin slow twist

Buttstock,

Ok, might have the cart before the horse here.

Ordered the Zero 240gr (500) and they came in today. Measured a few with my Starrett 0 - 1" micrometer and they sure enough measure .431" very consistently. None were over that diameter.

Then, I decided I better slug my bore just to be sure. It measures .430" on the soft lead slug driven entire length of the bore with Imperial die wax as a light lube. Slug came out in good shape showing good lands and grooves.

How do you think this is going to work out? Am I going to see too much pressure?

Question from OP:

"How do you think this is going to work out? Am I going to see too much pressure?"
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Don't know.

Use safe loading practice, and work load up with a non pistol powder. 4198 (IMR or H) is a classic 444 Marlin powder. Start at ~ 75-80% of max, and work up a grain at a time, observe pressure signs ( case head expansion, sticky extraction, primer flattening etc). Maybe load up 3 rounds each at a powder level, increase a grain with another 3 rounds, wash rinse repeat. Same strategy for any bullet being evaluated in reloading.

A slugged barrel/groove diameter reading of "whatever" diameter doesn't mean the entire barrel's groove diameter is that reading ( could be), but it does reflect the TIGHEST groove diameter. It may open up with shooting. Search for "fire lapping" a barrel with grit/cast bullet to address tight barrel spots or thread choke.

0.001" isn't much (0.430-0.431"). Enough to be careful in loading, but may not be a huge ( or any) issue. Be smart. Be safe and take it one loading level at a time.

Get a "pound cast" reading of your chamber throat. Barrel (bore groove/throat) measurements are important, which is why I recommended doing them to get accurate info on your barrel for bullet selection. Good luck.

Buttstock,

Did a quickie pound cast, 50 cal soft lead roundball, half into the rifling, back half still in chamber.

~ End of "chamber" measures .4565"

~Area between end of chamber and beginning of rifling is about 045" or 050" long and is .4315 dia. up against the "shoulder" of the chamber.

~Beginning of the rifling measures .431"

~And of course the full length slug measured .430"

Use standard safe reloading practice in developing a load. As stated above, start at a reduced powder level and work up. I would use a "stick" powder (not spherical powders, which may provide wonky pressures at reduced charges).

What powders do you have? Stick powders in the burning rate like 4198, Reloader 7 or slower (ie 3031)would be a good start for powder selection.

Preaching to the choir on all that Padre.

Thanks for your input. I'll see what I can come up with.

I have a first year production 444 Marlin, rifle, not the carbine. I started out to make it shoot. First up, I put a tip-off Weaver scope mount w rings on it and 2 1/2 x Bushnell steel body USA made scope on it. The original sights just suck ditch water. Next I slugged the barrel, micro groove.... So decided to run very hard cast to see if the Lyman 210 or 240 SWC moulds would work. Both work and do hold the lands, sized to groove diameter. With 12 grains of Unique under the 210 my 444 rifle from a rest will actually hold 1" at 200 yards. When you shoot a deer behind the shoulder, it just quivers like jello and drops, DRT. Bullet makes about a 45 caliber hole in and out, does not stop. Pretty much like the 45-70 with a bit less recoil. Son shot his first deer with the rifle, at about 100 yards, same result, just blew the contents of the chest cavity out the back side. Made field dressing it easy.
Shot that gun and load combination in Cowboy Silhouette maches, any sight, for about 10 years, pretty easy to shoot 40 rounds off hand with it.