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Discussion Starter #1
I've had a Marlin 1894 in 41Mag on order for some time. I'm about to order my fire lapping supplies. I've seen alot of posts on the various boards about the bores being rough. Darned if I can figure out why they went with Micro-Groove rifling on these rifles. The question I have pertains to fire lapping Micro-Groove barrels. Is there any different procedure involved with these barrels? Any tips or pitfalls involved with this procedure for this barrel type would be greatly appreciated.

Thanks,

Steven
 

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Discussion Starter #3
Jack,
I just re-read the Beartooth Technical Manual last night. I've never fire lapped a barrel that was of the Micro Groove variety. It sounds like it is the same procedure either way.

Since I'll be fire lapping this rifle when it arrives, I believe I'll do the same with my Blackhawk Hunter in .41 at the same time as my slugging indicates a little problem in the area where the barrel is threaded into the frame. The cast bullet accuracy has been good in the limited testing I've done with lead bullets in this revovler, but I'll be shooting mainly lead out of it in the future so I might as well do it at the same time.

From what the tech manual stated, this might take a bit of doing. Will gun degreaser or brake parts cleaner suffice for a quick cleaning of the chamber in either firearm, or is it best to give it a good scrubbing just to be sure there is no lapping compound in the chamber?

Thanks,

Steven

PS-The Canada trip this year was awesome, lots and lots of nice fish. The bottle of single malt I picked up at the duty-free wasn't too bad either.
 

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The Hog Whisperer (Administrator)
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Lapping procedure should be the same. I didn't do anything different when I did my .35 Rem.

One thing to consider, you need to ensure that the lapping bullet doesn't leave a bunch of lead in the barrel (bullet too fast), yet it also need to not get stuck either (bullet too slow). So there is a velocity window which may mean different loads for both the rifle and the handgun.

I've never stuck a lapping bullet in a rifle barrel, but have many times in a revolver. I think that the b/c gap has a lot to do with bullets getting stuck.

With the micro-groove, I'd brush it out every few shots. You could get some lead building up down in the grooves where it's hard to see and then it will impede the progress of the lapping.

Most lapping compounds are oil- or grease-based, so brake cleaner ought to do real well for cleanup, but I'd still run a patch through the chamber just to be safe.

Another thing that I've found, as the lapping progresses, the bullets have less of a tendency to stick in the bore (makes sense that they get farther down a smooth barrel. Loads that will stick a bullet every time when the process starts, zip right on out the muzzle by the time you're done.

So, if I was going to lap some new guns and didn't have any idea where to start the loads, I'd probably load up some a bit on the fast side, the bulk of the rounds somewhere in the middle of what I thought the powder charge would be, and then a few on the light side.

For example, for the .41 mag, probably a few at say 2.5gr. of Bullseye, a larger number at maybe 2.2gr., and then some at 2.0gr.
 

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Lapping the Micro-Groove barrels is the same as with any other rifling configuration. It's tedious and time consuming, but very rewarding, and not difficult in the least.

Brake cleaner is excellent for your cleanup between volleys of lap bullets. However, be VERY careful around your wood stocks! That brake cleaner will flat-out EAT stock finish! Take proper precautions, or you might have to refinish your new Marlin stock sooner than might be anticipated :D

You'll be amazed at the before and after group shooting ability of your Micro-Groove barrel once fire-lapped. The results are worth every minute of the work invested!

Let us know how things progress!

God Bless
 

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kciH...
I'm reading everything that I can find on the Marlin's and lapping as I hope to finish up my 444P this weekend. Do you have any advice to add to this topic that you started?

Thanks in advance!
Michael
 

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Discussion Starter #7 (Edited)
Ranch Dawg,
I have no further advice to add. The process laid out in the manual, with some caliber specific advice from MikeG, worked very well in the rifle in question. The rifle shoots great with minimal fouling. The brake cleaner works great, but heed Marshalls warning. I learned a few years back about brake cleaner destroying nearly any finished surface, like AUTO PAINT, that it comes into contact with.

The SBH Hunter took considerably more rounds than did the rifle, and with a great deal more work. I did take my dowel rods to the range, thank God.
 

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Thanks for the reply kciH...

I didn't get to the lapping this weekend. I had a friend come down to hunt and I couldn't stand him being out there and me just shooting the procedure. I've got a freezer full of pork but I'm addicted to still hunting big hawgs! Will work on it this week.

I've heeded the advice on the dowels and rods and have them prepared. I figured they might always be a good set of tools to have. Thanks again.

Michael
 

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The Hog Whisperer (Administrator)
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Michael,

If you get around to lapping the .35 Rem, one of life's great joys is the infinite selection of lead .357 bullets for such things.

A 148gr. wadcutter, and 3 grains of bullseye, will definitely suffice for the .35 Rem. Might be able to get by with a little less powder, but I didn't get any leading with that combo.

If you don't have any wadcutters, I have a couple of 500-count boxes of the Midway bulk bullets and can send you a handful. Living out in the boonies, that might save you some expense of ordering an entire box from somewhere.
 
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