Micro Grove


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Joe732
December 31, 2011, 10:09 PM
Happy New Year.
Need some input. Just bought a Marlin 1895SS 45-70 with a micro grove barrel.
Some guys at my range say that this barrel is really made for jacketed bullets.
I would like to shoot Laser lead Bullets through barrel will there be a problem with accuracy.Also said I should keep speed under 1000 fps
Thanks for any input
Joe

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GRIZ22
December 31, 2011, 10:27 PM
I shoot a hard cast lead bullet at about 1250 fps from a 336 with micro-groove. I find they shoot well but groups start to open up after 50 rds or so. A few passes with a brush and Hoppe's #9 and its ready for 50 more.. My Marlin in 44 magnum performs in about the same way. I know some shooters have problems with microgroove barrels.

Dmitri Popov
December 31, 2011, 10:31 PM
My understanding is that they work best with factory, jacketed ammo.
With 45-70 maybe use a little lube, and like griz said, clean the barrel when accuracy starts to suffer

glockky
December 31, 2011, 10:39 PM
If u go over to the marlin forum they all say that u have to slug the barrel and get a bore size. They claim you usally need a bullet .002- .005 oversize.

I was gonna try this in my 44 but never got around to it. So i have no experience with this but it would be something to check out.

BrocLuno
December 31, 2011, 11:14 PM
Even in micro-groove barrels, I think most lead fouling is because of too much speed. Keep it down to 22 velocities and it should be OK for at least a range session or two :)

BobMcG
December 31, 2011, 11:33 PM
I think using the Laser lead bullets is the key to the question.

I just asked a good friend this same question last night. I saw he was using cast lead bullets in a Marlin Micro-grove rifle (.44) and I asked him how it works out. He said by casting the right size and hardness bullet, you'll have no problems. I noticed he was using gas checks on his bullets and I asked him if he was pushing them @ 1,700 to 1,800 fps and said yes, accurate and no leading problems @ 1,700 fps.

He's been casting and shooting BP competition since the '60s so he's my go-to guy for casting & BP questions. He crono's everything he does as well.

Abel
December 31, 2011, 11:38 PM
You can get it to shoot very well by going slightly over the bore diameter and using properly gas checked bullets. Also use hard lead, not soft lead. Here is some reading:

http://www.shootersforum.com/big-bore-lever-guns/21525-45-70-marlin-microgroove-cast-bullets.html

Jeeping
December 31, 2011, 11:49 PM
Got one in 35 rem, shooting gas checked bullets at 2050fps with great accuracy. Load non gas checked up to 1400fps with no leading and great accuracy. Don’t listen to those guys, micro grove barrels shoot lead just fine.

336A
January 1, 2012, 12:01 AM
Here is another well written piece on the subject that should help you to understand the Microgroove rifiling too http://www.lasc.us/FryxellMarlin-MicroGroove.htm

greyling22
January 1, 2012, 12:14 AM
good article 336a. I find that my microgroove 357 1984 does a little better with .358's than a .356 or .357, none of them are good enough for golf balls at 100 yds, but they are devastating on cans at 50. Given a choice, I'd pick a ballard rifled gun, but microgroove is not going to make me sell mine. I push them around 1150 fps.

Curator
January 1, 2012, 10:31 AM
The great Harry Pope rifled his extremely accurate target rifles with "micro-groove" riflng. Pope also shot cast bullets

GRIZ22
January 7, 2012, 11:04 PM
I noticed he was using gas checks on his bullets and I asked him if he was pushing them @ 1,700 to 1,800 fps and said yes, accurate and no leading problems @ 1,700 fps.

The gas checks put a totally different spin on the issue. I know guys who run gas check bullets well over 2000 fps with no problems. The problem is most places you can buy gas checked bullets they cost about the same as jacketed.

Most bullets lead not because of velocity but the pressure is too high fir the hardness of the lead and deforms the base of the bullet. There is a good explanation of this in the Lee manual.

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