Cleaning Marlin Microgroove Barrels


September 3, 2009, 04:10 AM

I was wondering if there's anything different that I should do when cleaning a micrgroove barrel.

What kind of brushes, cleaning rods, oil, solvents, patches etc. should I use?

How often should I clean it?

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September 3, 2009, 06:15 AM
As far as cleaning goes, I don't think there's much difference.

I clean my rifle by pulling a bore-snake through it after firing it hunting (ususally 1-3rds) just to prevent residual fouling from attracting moisture and causing rust/corrosion/pitting. At the end of the season, I remove lever, bolt, and extractor and give the barrel a good cleaning with bore solvent, brushing, ect. same as conventional rifling.

However, if I'm going from shooting jacketed ammo, to cast bulleted ammo, I WILL give it a much more thorough cleaning by wrapping a bore brush with a patch and soak it with either JB-bore paste or Remington Bore Cleaner and work it through the bore to remove most if not all the copper fouling. This results in the bore conditioning to shooting the lubricated cast bullets much quicker, resulting in much improved accuracy. I likewise do this with all rifles before shooting cast bullets after having shot jacketed bullets. Removing the copper fouling makes a big difference in accuracy.

The only really different consideration I give to the MicroGroove barrels is to use a larger than normal cast bullet. I've found that a .311" bullet is vastly more accurate through my MG barreled .30/30 than a .309". And, I get equally good accuracy through my .308" .30/06 with the .311" bullets, so, thats what I size all my .30's cast bullets........

After initial check of zero before the hunting season, (I do this each year because sometimes I'm switching loads/bullet design/ect from one year to next) I don't do the extensive cleaning as I feel that a super clean bore, and/or lubricated bore will make the "cold shot" effect of the first shot from the barrel to be further exagerated. I like my bore to be previously "fouled" so that accuracy of first shot is enhanced (or more correctly less affected). Hence, I feel that by just pulling a bore-snake, or just a clean dry patch with a rod, is sufficient for "between" hunting outings.
Others may have differing opinions, this is mine......... and it "works" for me.

September 3, 2009, 07:32 AM
A bit of advice that I learned the hard way. Always wanted a Marlin 39A and found an excellent used one a while ago. Went to clean the barrel with a brand new coated cleaning rod(not sure if nylon or teflon coated) and the "Microgroove" rifling stripped the coating completely off the cleaning rod. Almost wet my pants because I thought it was the rifling itself coming out of the barrel in long black strips. :D

Sav .250
September 3, 2009, 08:08 AM
I clean mine like the rest of them. Works for me........

September 3, 2009, 12:56 PM
bronze bush, some gun solvent (pick your favorite), patch, repeat, finish with light CLP. done.

Nothing special in the cleaning procedure for the microgroove barrels

September 3, 2009, 01:16 PM
Clean them like anything else, but if it's a .22, Marlin actually recommends against much cleaning - read the manual.

September 3, 2009, 01:30 PM
What GooseGestapo said, and well said I might add.

All I would add is that when removing the lever and bolt be very careful to snag the spring loaded ejector or it will disappear to a very hard place to find. One of the great advantages of Marlins is the relative ease of cleaning from the breach end, enjoy.

September 3, 2009, 02:30 PM
My question was more specific to the .22lr 925 I have.

September 3, 2009, 03:35 PM
My question was more specific to the .22lr 925 I have.

There is nothing specific that you have to do to clean a micro grove barrel in .22. .22 barrels do not need to be cleaned until you notice accuracy falling off. Clean the action as required for smooth functioning, and lightly wipe down the external metal with an oily cloth after each use.

Depending on how much you shoot it this could be awhile.

Stop by for lots of good .22LR info.

September 3, 2009, 07:20 PM
The barrel on my 39A has been cleaned once since 1980 when I got it used (probably 50k rounds fired in that time). I used hoppes and a jag. Maybe 2-3 patches.

September 3, 2009, 11:51 PM
the good thing about them, since they are not sharp or deep lands/grooves, they are easy to clean!!! just make sure you get the copper out, use a copper type solvent. and you will proly only need to clean it thorougly once!!!
after that, just clean like you regularly do, and really much less, and the marlin will go and go and go...

September 4, 2009, 09:16 AM
I have cleaned my model 60 once in the last 4 years and that was after the action was cruded up from Remington bulk pack ammo.

September 4, 2009, 10:11 AM
I do not use brushes on my Models 25 or 60. Just run a couple of solvent patches through to clean the black stuff out, then a couple of dry patches. Wipe down the bolt or breech face, a drop of gun oil and they are good to go.

September 4, 2009, 01:45 PM
I use a bore snake the majority of the time to clean my 336

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