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Marlin Micro-groove rifling and cast bullets?

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01 October 2002, 20:00
micmac
Marlin Micro-groove rifling and cast bullets?
Can anyone here tell me about problems shooting lead bullets in micro-groove rifled barrels? Is it like shooting lead in a glock? I've been told it isn't recommended, but wanted a definative answer.

Thanks
Mike
02 October 2002, 00:37
aladin
quote:
Originally posted by micmac:
Can anyone here tell me about problems shooting lead bullets in micro-groove rifled barrels? Is it like shooting lead in a glock? I've been told it isn't recommended, but wanted a definative answer.

Thanks
Mike

Micro's might be the best barrels for cast bullets IF the bullets are large and hard enough. Marlin micro's often run large as to size-- 30/30's might go as large as 311 and 45/70's might make .461 on the extremes. Determine your groove size [shoot an unsized cast bullet thru slowly] and make sure the use of those larger slugs if needed will chamber safely.

One of the first barrels I shot cast otta was a Marlin 30/30. Managed a Lady Luck grouping one day going two inches-- this at 200 yds for five rds.
02 October 2002, 01:03
Englander
Micmac~

I shoot home hard cast bullets in my micro-groove Marlin .444 and have NO complaints what so ever, infact i seen no use in using jacketed in it, WHY ? My 325 gn hard cast gas checked at 2000 f.p.s will kill just about any thing with minimal meat loss.

Yes size is important ! I would recommend slugging your barrel soft lead bullet simply tap it though from the muzzle.

My Lee 310 mould produces bullets of 0.4315 although i size them to 0.430 and have had good groups and no leading trouble.

Have fun !

Regards Englander
03 October 2002, 11:24
beagle
micmac...These fellers have hit it right on the head. Make your bullets hard and make them as big as the throat will take and they'll shoot in MG rifling. They won't give you tack driving accuracy as with conventional rifling but you'll get acceptable hunting accuracy and good accuracy for plinking and varmints. I've also noted that a gas check seems to be a magic group enhancer in MG barrels. They don't like PB bullets from my experiences which has mainly been with the 30/30./beagle
03 October 2002, 14:13
aladin
Gotta tell you John the two micro's I shot extensively [both 30/30's] were top end shooters- then some.

Micro's get the bad rap cause the unknowing put slugs too small in them, too soft or a combo of both conditions. Bad news travels-- the truth appears to be some dark secret little known at times.
04 October 2002, 17:05
woody1
micmac, Was your question generic microgroove or do you have a cartridge in mind? My microgroove 30-30 does dandy with homecast Lee309150 FN gaschecked sized .309 believe it or not. I'm hunting with same rifle using Lymans 311291 gaschecked and sized .311. I'm also playing with a Marlin 375 and plain base bullets that's shooting well enough for hunting also. Regards, Woody
04 October 2002, 18:45
micmac
Had a 45/70 in mind. Was looking at the Lee 340gr mould, but it has a .457 bullet diameter, and I read on beartooththat a dia of .4595 is best for the micro-groove. Can you shoot hollow base bullets in a 45/70 with smokeless powder at high vel?
05 October 2002, 01:57
aladin
quote:
Originally posted by micmac:
Had a 45/70 in mind. Was looking at the Lee 340gr mould, but it has a .457 bullet diameter, and I read on beartooththat a dia of .4595 is best for the micro-groove. Can you shoot hollow base bullets in a 45/70 with smokeless powder at high vel?

Your first assumption is incorrect, saying the 'Tooth sez about such and such. Your gun might be larger-- or much smaller, ya gotta measure IT..

The Lee 340 I have dropped bullets 4595 otta ww alloy when new. Those vary per manufacture too.

Many use the hollow base with smokeless successfully. I see no reason for a hollow base though.

Hi velocity-- as in how fast? Your shoulder will tell you when to quit first. That and your barrel-- for much above 1400-1600 with Plain base bullets requires some tinkering.
05 October 2002, 02:12
Pecos41
quote:
Originally posted by aladin:
Gotta tell you John the two micro's I shot extensively [both 30/30's] were top end shooters- then some.

Micro's get the bad rap cause the unknowing put slugs too small in them, too soft or a combo of both conditions. Bad news travels-- the truth appears to be some dark secret little known at times.

You're right Aladin. This is exactly the mistake I made with that .44 Ruger and it wouldn't shoot worth a flip until I started using hard, oversized bullets.
05 October 2002, 08:25
z1r
I used a Mariln 1894 in .44 mag for lots of cowboy shoots. Shot many a perfect score with that rifle. Mine slugged out on the larger side, memory is fading, about .430". I always sized bullets to .430" and used a harder alloy. Gave great accuracy and little or no fouling. I used to use the Lee 240 gr roundnose mold. Although in more than a few instances I was forced to use Lyman 42798 bullets and they dropped from the mold at .4295". Technically they were undersized but they shot just as well.

I think as others have stated, keep the alloy on the harder side and the projectile on the large side.
05 October 2002, 09:45
aladin
IN regards to micro's, I have a 30 caliber Marlin microgroove blank here- unturned all of it's 21" plus. Thing is undersized to thread to my 700 actions, but did consider a sleeve made to increase dia. It's goes 3085 x 03033 and the feel pushing a slug thru is oh so very uniform. Think it'd make a great cast gun-- but what to mount it on?? Hole is off center too.....
05 October 2002, 12:01
MrUREasy
MicMac - go to beartoothbullets.com - there's the most informative article I've seen on the site. Marlin's microgrove rifling has worked well for years until several unknowlegeable "experts" took it upon themselves to blame that type of rifling for their lack of ability. Enjoy.
05 October 2002, 18:10
micmac
Help me out. Suggest some molds for 300-405gr bullet weight. Wheel-weight recipies for hard bullets?
06 October 2002, 03:00
beagle
micmac...Now you're getting serious here. My all time favorite is the RCBS 45-405-FN hollow pointed, another is the #018 Saeco which runs about 412 grains ready to fly. The #457122 Lyman is an old classic and runs normally about .457+ out of the mould...it's also a HP. Any of these, you can shim the mould halves with aluminum tape and come up with .460+ diameter bullets. Using WW alloy and water quenching will probably give you what you need but you'll either have to shoot unsized or order a special order .460 sizer. I just finished making a hollow point cavity pin for a 457122 this morning...an old Ideal with the bevel base. It cast .457+ as I figured it would. I shimmed it and now it drops .463. I'll size to .460 and see how it does in a week or so here. No doubt others will chime in with their favorites including some Lee moulds but these are the bullets I usually go to for the 45/70 Marlin./beagle