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View Full Version : MAS36 conversion to 45-70



Buckshot
07-08-2005, 02:42 AM
...........Due to Linstrums post re: MAS36 I figured I'd post photo's of the conversion. Hadn't done so on this board, so here goes.

http://www.fototime.com/4CE0AE555332580/standard.jpg
The entire rifle. Obviously I utilized the original stock. It took a few watery eyes and noses to learn about keeping my thumb knuckle tucked away to one side. The stock only has a 12.5" pull so it doesn't take any stock crawling to have it smack you in the nose with heavier loads.

http://www.fototime.com/D84C26951C36B50/standard.jpghttp://www.fototime.com/0E6605AE3358FFB/standard.jpg
In the left photo you can see the relief I ground into the left feedrail to allow the rim to pop up under the extractor. The inside edges also had to be smoothed. The smaller diameter of the French round and the milling they'd done inside as cartridge guides would scratch the 45-70 cases and groove the rims.

The right photo just shows the breechface relationship to the end of the magazine. The extractor needed a couple mods. Due to it's design, you cannot merely shorten the claw back to clear the larger 45-70 rim. The extractor slides back into a milled slot like on the 1891 Argentine's bolt. To keep the extractor from being pulled out, on the underside it has a lug, which fits into a mating hole in the bolt body. After grinding as much of the claw back as possible, I made a shim and put it in the hole to cause the extractor to stand further out.

This then required that the extractor be thinned down on it's outside surface as it wouldn't clear the action ring when closing the bolt.

http://www.fototime.com/6B73F57ED82F5AB/standard.jpghttp://www.fototime.com/C8BB51747ADBFB5/standard.jpg
The barrel was a 1.25" unchambered 45 cal rifle blank from GPC. I think it was $44 if I'm not mistaken. I had my gunsmith turn it to a straight taper from action to muzzle. I made the front sight base from a piece of keystock and cut the dovetail in with jeweler's files.

The forend is the fuzzy photo to the right, and is hung with one screw. The band is in the same position as the issue one, which was a bit narrower and thinner. I used a piece of 1/8" x 3/4" HRS, and filed it to a more rounded outside shape. Then I cold forged it to shape, which is to say I beat it profusely with a hammer around a suitable piece of pipe and other things.

The rear of the forend has a metal plate which fits into a mortice in the lower front of the action, which is issue. The screw in the photo goes up through the band and the forend, into a lug that had been dovetailed into the underside of the barrel. Since the bayonet was carried reversed inside the stock, there was a rather large round hole down through it, so a forend cap sealed the end off. Inside I laid a piece of 3/8" allthread in the hole and poured in bedding epoxy.

If it were not for the routed out channel around the forend to carry the band for the handguard, you could just use an escutcheon under the forend. The cut is not so deep that if you had a smaller barrel OD you could probably sand the forend down thinner to make it disappear and do away with any kind of band.

I've used Ruger #1 45-70 data in reloading for it without a wimper from the rifle. Several wimpers from me in reaching those levels :D . Oddly enough, in several instances when loading ammo with data shown for the Marlin 1895, in some loads the velocities matched book data for Ruger loads. Finally when loading with the Ruger data, velocities also exceeded some of those. I should take off that steel buttplate and put on a recoil pad. Even though I don't ever plan on loading any top loads again, the extra pull length would be welcome.

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

Johnch
07-08-2005, 02:58 AM
Looks good .
It looks like you did it right.

I have had a Mosin-Nagant M91/30 sitting around for me to convert to 45/70 .
But I keep finding other things that need to be done first.

Johnch

Linstrum
07-08-2005, 01:54 PM
Hey, there, Buckshot, thanks for the reprint. You were sort of reading my mind!

I guess every MAS 36 owner eventually finds out the hard way about keeping the thumb off to the side to keep from having it collide between his nose and sighting eye! It doesn't take .45-70 strength recoil to accomplish, either, although that cartridge would guarantee making it happen every time. I wondered why the French chose a 139-grain projectile over say a more efficient 180-grain, and when I tried a 180-grainer I found out why - - - after it ran my thumb knuckle in between my nose and eye. I can only imagine what happens with a Ruger #1 full power load.