Cast Bullets In Marlin 30 30

[MN91311]

Will a fairly new Marlin 30 30 shoot accurately with cast bullets ?

How do I know if a particular rifle has microgroove rifling ?

Can you tell the type of rifling with a borelight and naked eye ?

I have a chance to buy one from a friend, as yet sight unseen. Probably will not if it has no chance of shooting well with cast bullets, of course.

[Maven]

MN91311, Yes you can tell the type of rifling with the naked eye: Microgrooves look exactly like many small grooves (12 or 16?) when viewed at the muzzle itself (looks something like a 12 or 16 pointed astersik with a hollow center) rather than 4 or 6 as in "normal" rifling. And yes, MG rifling does handle cast bullets as well as standard or even Ballard rifling. The trick will be to determine whether that .30-30 requires a .310" or a .311" cast bullet and which design it prefers. Btw, I have 2 Marlin MG leverguns and 1 .22 bolt action and they all handle lead (the .22) and cast bullets extremely well. In fact, one generally doesn't hear many bad things about the accuracy of Marlins.

[Buckshot]

...........MN91311, MAven described the MG rifling well. They use similar in tube artillery. Marlins philosophy was to lightly engrave the boolit many times, vs heavily engrave it a few times. Supposed to distort it less. The MG rifling is shallow compared to more conventional types.

For argument's sake, lets say most rifling is .004" deep in respect to the lands, or .008" deep in overall diameter in relation to the lands. So you have the .300 x .308 dimensions for example. By contrast, the MG rifling form is maybe .0016" deep as compared to the lands. In a 30 caliber the grooves are still .308" diameter, but as a consequence the bore is closer to .304".

People have had great success with MG, and these are the folks who undertand what's going on. As a rule you want the fattest slug (Hense Maven's NOT saying .308" or .309") and usually a HARD cast slug. It follows that a regular 30 cal bore riding design with it's .300 or .301" nose might not work so swell.

For some reason though, it appears that in the 1895 Marlins chambered to 45-70 and sporting MG rifling, you can get some pretty impressive shooting with almost pure lead slugs to 1800 fps!?

...............Buckshot

[Char-Gar]

I am having great luck with 2 Marlin 30-30 MG. What the other boys had said is very true. Without getting into redundant theory here is what I have found.

1. A sizing diameter of .311 is the trick. Anything larger is too large for the Marlin throats. You might get by with .310, but .311 will do just as well.
2. If you are starting from scratch, buy SAECO 305. This is sold as a bullet for the 303 British, but is the best over the counter bullet mold.for the Marlin MG 30-30. The bullets will come out .314 on the body and .304 on the nose. Just right for the MG barrels. The length, meplat and crimp groove is just right for the 30-30 case.
3. Straight air cooled WW metal is hard enough for MG barrels
4. With a bullet that fits the MG barrel, you can run the bullets at a full 2.2K fps with the same accuracy you can expect from factory condom ammo.
5. Take as a whole, I have gotton better accuracy with the Marlin 30-30 MGs than the Winchester 94/64s in 30-30