Floating barrel on the Mosin 91/30?

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fonestar

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Watching some videos last night and some people were saying they squeezed another bit of accuracy out of their Mosin 91/30 by sanding the barrel channel in the stock down so they could run a dollar bill underneath it from breech to muzzle. Then others had said their rifle keyholed after this (can't imagine it having that much of an impact) and still others said it was a waste of time (I think they were just talking about not wanting to invest the time in a $100 rifle though). Just wondering if anyone had tried it on their Mosin and what the results were? Also, would the upper hand guard have any effect on barrel harmonics as well? Looks too thin to bother messing with..

Thanks...
 
Typically with a full length stock such as the Mosin you should bed the reciever out to the chamber and free float to the last inch or 2 of the forend where there should be upward pressure applied to the barrel. Upper HG should be free floating. Tune for a specific load by adjusting upward pressure with shims until you find the tightest groups. I dont know if free floating completely would work or not, but I bet with such a long, thin barrel it would degrade accuracy much like it does with an Enfield. Hopefully some of our Mosin experts will be along soon to set the record straight. Handloading with .312" bullets seems to be the best way to accurize a Mosin.
 
I did this with my 91/30 but the net videos are misleading and somewhat incorrect.

The purpose behind sanding the channel isn't to "free float" the barrel exactly.

Over time the long forends of the 91/30's tend to warp and put pressure on spots along the length of the barrel where there shouldn't be.

The dollar bill trick is to gauge where those spots are and where you need to sand.
The bill should pass freely from just behind the stock cap up to the receiver.

The stock cap should be contacting the end of the barrel at the end of the stock.

Here's the kicker though, when I did this, the rifle shot worse.

So what I did was get some small cork shims and filled the gap between the barrel and the stock at 3 places putting just a little upward pressure, almost none at all. I corked about 2 inches ahead of the receiver, directly in the middle of the barrel and about 3 inches behind the stock cap.

I am not sure about the upper handguard, if you sand out the channel in the spots where it has warped, then the upper handguard should stay exactly where it was intended to anyway.

My rifle shot noteably better after this. I brought it to a weapon tech buddy of mine and got the muzzle recrowned which also made it slightly more accurate. If I bedded the receiver it probably would have improved quite a bit as well.

Still the best thing to do before heading down this time consuming road is to make sure you pick a good condition Mosin with a solid bore in the first place.
 
do not free float you mosin barrel. It is WAY too thin walled for this. I tried (after being advised not too) and it made the performance worse. The technique Travis describes is what I did after and it made the rifle great. rubberized cork gasket can be bought at any CT or auto source. get the 1/16" as the 1/8" is just too thick. Mine took some adjustment at the range with the piece of cork near the stock cap. It started 1" from the end and ended up at 2 3/4" at the end of my range session.
 
The barrel seems pretty standard as far as milsurp rifles goes doesn't it? I already channeled out the groove in the stock so I can get card paper to slide freely from breech to forearm. I did use some leather near the end of the barrel where the first ring goes on, so I guess it's just a partial float. I will have to see how it groups now and if it is worse (wasn't bad to begin with, about 4" 100 yds offhand) I will take your recommendation and stick some cork in there too.
 
fonestar said:
The barrel seems pretty standard as far as milsurp rifles goes doesn't it? I already channeled out the groove in the stock so I can get card paper to slide freely from breech to forearm. I did use some leather near the end of the barrel where the first ring goes on, so I guess it's just a partial float. I will have to see how it groups now and if it is worse (wasn't bad to begin with, about 4" 100 yds offhand) I will take your recommendation and stick some cork in there too.
Click to expand...

Man, 4" at 100 yards for a Mosin is pretty damn good lol
Quality ammo will shrink your groups a little but 4" out of a Mosin with surplus ammo means yours is shooting about as good as it was ever expected lol

The upper methods are to correct a Mosin that is shooting sewer lid sized groups or larger at 100 meters lol

I always say if it ain't broke don't fix it ;)
 
Well I got it partially for the history but also to tinker with. Using the Bulgarian(?) 1967 copper coloured stuff, may not have quite been 100yds. Will pick up some 1/16" cork gasket, shoot from a rest and see what it can do.
 
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