Mosin Accuracy

[reloader762]

I read the old post on this subject so I decided to just start a new thread.  Around 10 years ago I bought a fairly nice 1945 M44 for $75 and a couple 300 rd. tins of Bulgarian brass case LB and HB ammo for $30 per tin.

The LB ammo shot fairly well at 100 yds. the HB not so well.  Group sizes really didn't change all that much with the bayo in or out it just changed position.  I had already planned to reload and cast bullets for this caliber and being a hand loader and liking to tinker I slugged the bore and found the groove to groove dia. to be .312"

I took a small batch of the Bulgarian rds. apart and measured the bullet dia. weights as well as the powder charge weights of each cartridge.  Needless to say components vary a lot and you also have to understand that commie 54r ammo is loaded to European CIP standards which is generally on the warmer side of SAAMI standards.  Regardless of how accurate a rifle you may have or try and build it's only going to be as good as the ammo you put through it.  You may see some accuracy improvements from various modifications you do to the rifle but the ammo is going to play a big part. 

Not all surplus ammo is the same some is better than others.  The best stuff I ran across and bought a decent stash of about five years ago was surplus berdan primed brass case copper jacket and lead core 54r ammo made by Prvi Partizan,I gave just under $3 per 15 rd. box.  This stuff shoots under 2" at 100 yds. all day long. Yugoslavian 1976 7.62x54r Lead Core Heavy Ball  SGAmmo has some in stock as of today but it a bit more expensive than what I bought five years ago.



As I said I like to tinker so I took some of the Bulgarian ammo and broke down a few hundred rds.  To start off with I reused the original components and basically rebuilt the ammo from the case up.  The brass is easier to work with than the steel so I trimmed all the case to spec most were long,I resized all the case necks and seated the bullets to the same OAL.  As to the powder I weighed a random number of charges and averaged it out over the lot for the tin.  I dropped the charge weight two full grains and loaded a set of test loads in one half grain increments till I got back to the original average charge weight.

Best results that were on par with the PPU surplus with the loads using the hollow base LB 147 gr. bullets with a 1.5 to 2.0 gr. powder charge reduction the HB surplus bullets still didn't shoot well at all probably due to the poor quality,I saved a few and loaded those up in some heavy thumper loads for the SKS and sold off the rest.  The primer also looked much better as well.

Before with factory loads.


After with the reduced or Mexican Matched loads.


Equally good results were obtained by Mexican Matching the Bulgarian surplus ammo with commercial SP bullets of equal or lesser weight depending on if I used the LB cases and  or the HB cases and powder types.  Excellent results were obtained using either the Sierra 125 or 150 gr. .311" SP or the Speer .311" 150 gr. SP .  In my M44 150 gr. J bullet or lighter seem to shoot the most accurately and with cast lead 160 grs.or slightly heavier shoot the most accurately.  I tried a few of the .312" dia. bullet but accuracy was not as good as the .311's  the bullet makes a lot of difference when it comes to the accuracy potential of your rifle.

Some of the various J bullets I used with the Mexican Matched loads as well as the pulled HB and LB surplus bullets.


Back before I acquired a good supply of reloadable 54r brass I made all my hunting ammo from surplus  HB ammo and replaced the bullet with a Speer 150 gr. .311" Hot-Cor.


A couple years ago while I was laid off for awhile I took a few days and refinished my M44 I refinished the stock,cork bedded the action as well as free floated the barrel inside the covering so that the barrel only rested on a cork pad at the end of the forestock.  Being my eyes are not getting any better and seeing the irons clearly is a problem I mounted a S & K steel ring scout mount and a 3 x 7 x 32 scout scope.  With my cast  handloads I get pretty much these kinds of groups all day long.  This particular five shot group was my first test group at 50 yds.

[Blicero]

Nice composition. And nice shooting!

I don't understand what I'm seeing in the different sets of primer pictures. Elaborate on that for me please. What makes the "better" primer pictures better?

And if your bore is .312, doesn't it stand to reason optimal accuracy would come from .312 projectiles? It seems like you'd be losing surface contact and stability with .311s. I'm sorry if these are dumb questions. You're a bit outside my comfort zone here.

Regardless of how accurate a rifle you may have or try and build it's only going to be as good as the ammo you put through it. 

No kidding. That's why I really want to get deep into the loading experiments. I can shoot mind-bogglingly well (by my standards at least) with some milsurp ammo, it's amazing to consider the rifles' potential with consistent, quality loads. 

[reloader762]

I don't understand what I'm seeing in the different sets of primer pictures. Elaborate on that for me please. What makes the "better" primer pictures better?

Well it's kind of a mixed bag,the first primer picture if you notice show a cratered primer,notice the raised area around the firing pin strike when the primer material flows back into the firing pin hole.  On the second better photo by downloading the surplus ammo the problem was removed.  In general cratered primers can be caused by several issues in rifles,headspace,enlarged firing pin hole or overpressure loads.  In some cases on certain firearm the area around the firing pin hole are beveled on purpose so cratered primers are the norm.

In my case I know the headspace on the rifle is correct as I check all my Mil-Surplus rifles with the appropriate gages before I ever fire them with said ammo.  I also know that the firing pin hole is not enlarged as this doesn't happen with commercial or reloaded ammo loaded to SAAMI specification and it only happens with the bras case Bulgarian surplus ammo that has been unaltered.   The Bulgarian ammo is definitely warmer and I would also suspect it is slightly overpressure or it's entirely possible that the primer metal used in these rds. is very soft as well which will also lend itself to cratered primers.  I have a few rds. still left intact of the LB & HB ammo that I plan to fire across my chrono sometime this summer or early fall,those number referenced agents the factory spec should give me some valuable info.  Would be nice to have access to some pressure testing equipment but that's above my pay grade.

And if your bore is .312, doesn't it stand to reason optimal accuracy would come from .312 projectiles? It seems like you'd be losing surface contact and stability with .311s. I'm sorry if these are dumb questions. You're a bit outside my comfort zone here.

You would think so but it's not always the case,as an example my .312" groove Mosin and SKS rifles all prefers different dia. bullets.  The Mosin shoots the .311" dia. J bullets regardless of weight best  .312" bullets not so accurate.  With cast lead a .314" dia. gas check bullet at a moderate velocity shoot more accurately than the J bullets.

In my SKS rifles which both share a .312" groove bore as well both shoot a .310" dia. the Most accurately while the .311 or .312" dia. J bullet open up at an equal range by a couple inches or more.  Then again the cast lead gas check bullet at a moderate velocity sized to .314" shoot just as accurately as the J bullets.

There can be a lot of difference in accuracy depending on the Jacket/core of the bullets make up.  Sierra target bullets have undersized cores and bump up like cast lead bullet do under pressure to fill the grooves. Optimum bullet dia. is an individual compatibility thing in each rifle,your barrel,load and sometimes bullet dia. as well as the bullets make up will determine which is the most accurate.