Hornady OAL gauge and my Mosin?


May 12, 2013, 12:09 AM
I was trying to use the Hornady OAL gauge with my Mosin and a nice, modified case to see how far out I should seat my bullets. I was using two different Hornady bullets, and both touched the rifling when they were out of the case! I checked each one several times, used a dowel to push the bullet off the rifling and then used the tool to work it back and forth, as suggested in the directions.

I have cases for 8mm Mauser and 7.5 Swiss, so I have some other rifles to experiment with, but is it really possible that my Mosin's throat is so burnt out that a bullet barely seated in the case would still come nowhere near where the rifling begins?? And this rifle actually shoots well with surplus at 100 yards when I do my part.

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May 12, 2013, 12:19 AM
I think the Russians just built them to be able to chamber any old ammo of the correct caliber. You have to remember that the rifle was originally designed to fire something like a 220gr bullet that is longer than the standard 147gr surplus ammo most of us are accustomed to. So unless you are using those heavy bullets, chances are you probably won't hit the rifling. In both of my Mosins I can take a 150gr bullet just barely seated in the case, chamber the round, and the round won't touch the rifling at all. You'll probably just have to experiment with seating depth to figure out what you rifle likes the best.

May 12, 2013, 01:09 AM
As kansas said most if not all mosins have a long leade

May 12, 2013, 07:37 AM
So in that case, should I just keep the OAL somewhere on the cannelure? I know that seating too deep would only raise pressure, and we don't want that.

May 12, 2013, 08:51 AM
Typically in a situation like that you just want to make sure you have at least .312" of bullet length inside the case. Whatever the diameter of the bullet is, use that number, for rifle loads anyways. But yes the cannelure is generally a good place to start. You can seat them deeper , just make sure you work up.

May 12, 2013, 10:47 AM
i load 150 to 180gr bullets for my 4 91/30s. when i started out coal length was 2.99 and that gave a lot of open space in the case for the powder being used. now i have settled on 2.86 coal with .311 bullets and the spread in fps for 5 shots through the chrono is much closer with no change in accuracy. just make sure your bullet seating die is not giving you too much runout. the more bullet you put in the case will keep that to a reasonable level. no need to get close to the throat on these guns.

May 12, 2013, 04:51 PM
While there are many Mosin Nagant rifles which are very accurate that rifle is a combat rifle, not a target rifle. Iike said above, they were built to be able to shoot any ammo if the correct chambering. You can't treat surplus battle rifles as if they are match rifles so you can't load the ammo for them like match ammo either.

May 12, 2013, 05:46 PM
I soldered a 174 grain bullet (.311 or so) to a brass rod so it could be used in the Hornady OAL gauge, marked some lines on the rod to allow me to measure throat erosion, and headed to a gun shop with a case full of Mosins. The purpose of the rod was to prevent "sticking" the bullets embarrassingly into their rifles' bores.

I tested over ten rifles and I think in every single one the bullet was at or out of the neck when it touched lands. There was some variation: the best of them were a good 0.100 inches, maybe .150 inches closer lands than the worst of them. I bought several of the ones with the closest lands -- and passed off one or more to customers who were curious as to what I was doing.

Amazingly the store owners put up with this. I took gloves and paper towels and a little kit to pull this off.

My recipe for 150 grain Sierra .311 hunting bullets is a coal of 3.025. I made a neck collet die from a .308 Winchester die by affixing 3mm worth of spacer on the bottom of the collet.

That has given groups of 1.5-2" at 100 yards. I then added a sleeve on the barrel of one Mosin and got the groups down in the 1" range.

One particular Mosin had the usual very long leade via the above technique, but strangely would jam the bullet if a .312 bullet was used, resulting in powder all in the action if it were pulled back without firing....I think the chamber and rifling in that particular gun aren't perfectly alighned or something, which can happen. I suggest your slug your barrels (1/8 or 1/4 ounce fishing weight, lubed, from the muzzle end, successive 6" segments of hardwood dowel) and then measure carefully on the slug what is the grove (bore) diameter and what is the lands diameter.

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