M48 Mauser testing (pics included)


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coloradokevin
October 4, 2009, 02:35 AM
Well, I have to say that I'm thus far fairly impressed by German engineering. On a whim today I decided to drive up to the mountains to do some load testing with my M48 8mm Mauser (a Yugoslavian Mauser).

I've had this rifle for about 5 years now, and originally bought the thing still packed in cosmoline for $90. The guy who sold it to me owned a gun store and was going out of business, so he also threw in a few hundred rounds of old surplus ammo that was dated around 1935 or 1939. Not bad for $90, at least in my estimation!

M48 Mauser:
http://i126.photobucket.com/albums/p85/coloradocop/IMG_1519.jpg

http://i126.photobucket.com/albums/p85/coloradocop/IMG_1525.jpg

http://i126.photobucket.com/albums/p85/coloradocop/IMG_1526.jpg


Anyway, until now I've just been using suprlus ammo in my value-priced rifle, but I recently decided to load some hunting ammo in hopes of someday fielding this rifle as an elk gun.

I loaded 175 grain Sierra Spitzer (soft point) bullets on primed and prepped Remington cases, and then charged these cases with H380 powder in groups of three, ranging from 48 grains of powder to 53.2 grains of powder (for a total of 7 three shot strings). Because this was to be my initial load testing on this rifle/bullet, and due to the fact that I only had 21 pieces of brass available, I started at a charge that was about 10% off of the published maximum charge, and then increased my charge weight by 0.9 grains per string.

The rifle was shot prone, just shy of 100 yards (because I couldn't find 100 yards to use on short notice), using the original sights, and under fairly poor lighting conditions.

My results were a bit variable, which I've come to expect when developing loads. However, when I averaged the 7 strings I came out with an average group size of 1.73". This included two groups with called "flingers"; one of the groups with a flinger had the other two shots sharing a single ragged hole. I also recorded my best 3-shot group at 0.77 inches, and the second best group at 1.02 inches.


BEST GROUP:
http://i126.photobucket.com/albums/p85/coloradocop/IMG_1522.jpg



Because these groups were shot at a distance of approximately 220-250ft, I'd estimate that this would extrapolate out to an overall average group size of around 2.36 inches, with the best two groups being at 1.05" and 1.40", respectively. Still, given that I was shooting an old Mauser without the benefit of modern sights or a legitimate bench rest, I can't complain with these results in the least! I certainly expect that I'll see improvements in accuracy as I refine my loads for this rifle, and I'm happy to report that my best group was produced using 52.3 grains of powder (which is in a range I'd be comfortable to use for elk loads).

Through this load testing I learned that the windage on my sights needs some serious adjustment, with all groups sitting about 3 inches to the right of my intended target. Unfortunately the old Mauser doesn't come with a "click adjustable" sight system, and I'll have to drift the front sight to correct this problem (I've never found a precise way to accomplish such a task, other than to guess and test... which is tedious).

I also noticed something strange with the extracted spent cartridges from this test. Each cartridge appears to have a black film around the case mouth, and it appears to be something other than burned powder residue. I'm guessing that this could be some leftover packing grease in the chamber? Anyway, I'm open to all suggestions on this one!

Unfired cartridge next to a cartridge that exhibits these strange black marks:
http://i126.photobucket.com/albums/p85/coloradocop/IMG_1528.jpg




Anyway, I just thought I'd share my Mauser experience for the day! I know these groups aren't at all impressive by varminter standards, but they'll do for me given the platform they were fired from, and the manner in which this testing took place (at dusk from the cold ground, using original sights).

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atlanticfire
October 4, 2009, 02:48 AM
Nice write up! To me those groups are impressive, especially given the condition. I also shoot and load for an old Yugoslavian Mauser and get very similar results, maybe not as good even:banghead:. And oddly enough get those same black rings, although I have never really figured out why.:uhoh:

coloradokevin
October 4, 2009, 03:31 AM
And oddly enough get those same black rings, although I have never really figured out why.


Hmmm... now I'm even more intrigued by these black marks. Out of curiosity, do they go away for you after tumbling? I haven't done anything to my brass since shooting today, but I was wondering if the brass would clean itself up nicely in the tumbler!

NCsmitty
October 4, 2009, 09:44 AM
Thanks for sharing your work up information with us. That's a nice example of the M48.

The ring of carbon deposits at the mouth of the case is absolutely normal. Most often this will appear farther down the case with the lighter loads, and higher up towards the mouth with the heavier powder charges. All you are seeing is the sealing of the case under pressure, and the higher pressures generated by the heavier powder charges, usually create a better seal between case and chamber. Different powders can give different case smoking results, depending on the burning characteristic of the powder.
I have seen cases that had the smoke down past the case's shoulder and most often that indicates a low pressure ignition and a lack of proper case expansion and seal.
The fired case that you show is nearly ideal, IMO.

H380 powder usually works best with a magnum primer because it's a spherical powder.


NCsmitty

something vague
October 4, 2009, 10:46 AM
I agree with NCsmitty. The end of the black carbon ring is where the case finally sealed the chamber from the blast. IMO that ring is a small one, indicating that your getting a great seal at an optimum point in the blast. Most of it should dissapear after a tumble, may still have a bit left over but nothing out of the ordinary. Depends on tumble time.

coloradokevin
October 4, 2009, 04:33 PM
Well, I'm glad to hear that the black marks aren't anything to be concerned with. I've seen "smoke marks" on lightly loaded pistol cases before, but these marks just looked a bit different to me on the Mauser (maybe due to it being a higher pressure caliber?).

rcmodel
October 4, 2009, 04:44 PM
The ring does look a bit unusual to me, in that it is so uniform with a clearly defined edge where it stopped. Usually, there will be more of a scalloped appearance where the final chamber seal occurred.

Just for the heck of it, wrap some 0000 (extra fine) steel wool on a bronze bore brush and spin it with a cordless drill with Nitro Solvent and give the end of the chamber a real good cleaning.

Could be there is hard carbon fouling right at the end of the chamber you can't get out with patches & brushes.

rc

coloradokevin
October 5, 2009, 06:46 AM
Just for the heck of it, wrap some 0000 (extra fine) steel wool on a bronze bore brush and spin it with a cordless drill with Nitro Solvent and give the end of the chamber a real good cleaning.

Never thought of that. I assume that the steel wool won't harm the chamber if you are recommending such a procedure?

sniper5
October 5, 2009, 09:39 AM
If the steel wool makes you nervous (it shouldn't), the pick up some brass wool (my ACE hardware carries it) and use that. It DEFINITELY won't harm the chamber.

rcmodel
October 5, 2009, 12:15 PM
Bronze wool definatly won't take out hard powder fouling either.

I just tried it yesterday afternoon to clean a chamber on a friends Model 39A Marlin that gets a steady diet of .22 Short CB caps..

After several minutes, with no results, I switched to 0000 steel wool and finished the job in seconds.

Bronze wool may be good for something on guns, but I just haven't figured out what yet.

BTW: No, 0000 (extra Fine steel wool & oil will not harm a chamber, revolver clyinder.
Or even bluing if used with some restraint. It is used in hot bluing to remove bluing salts residue and give the new bluing the "final finish".

rc

jjohnson
October 5, 2009, 12:28 PM
Hey, let me know when you get bored with your $90 rifle. I can find it a god home. :evil:

The 8mm is up to moose/elk sized game with good bullets. Heck, the Swedes think the world fo their 6.5mm Mauser for elk. My 98k shoots very well with 196gr "schweres Spitzgeschoss" (heavy spitzer bullet, great for machinegun use) ammo. Handloads with something in the 200-grain range with a good bullet has enough thump power for game that size.

coloradokevin
October 6, 2009, 07:07 AM
Hey, let me know when you get bored with your $90 rifle. I can find it a god home.

The 8mm is up to moose/elk sized game with good bullets. Heck, the Swedes think the world fo their 6.5mm Mauser for elk. My 98k shoots very well with 196gr "schweres Spitzgeschoss" (heavy spitzer bullet, great for machinegun use) ammo. Handloads with something in the 200-grain range with a good bullet has enough thump power for game that size.

Thanks for the offer, but there is just something about this gun that I've always liked, and with a whopping $90 invested in it, I doubt I could ever walk away from it and feel financially whole again! :)

While I haven't actually elk hunted yet at this point (being from Ohio originally means whitetail hunting, not elk), I can say that I've always felt that this rifle would be up to the task when I do head out.

The cartridge is certainly more than capable of downing an animal of that size, with full-power 7.92x57JS ammo producing ballistics that are very similar to the .30-06. In fact, from a historical standpoint I guess we would be more accurate in saying that the .30-06 produces ballistics that are similar to the 8mm Mauser! The second factor I really needed to consider before hunting with this gun was the rifle's inherent capabilities... My initial testing has led me to believe that this gun should have no problems once the sights are properly adjusted!

I tend to be one of those folks who likes to defy the conventional ways of thinking. Since many of my friends have 2-3 thousand dollars invested in their elk guns, I figured that it would be nice to take an elk with a gun that has less than $100 invested in it (in fact, my Mauser is the second most affordable gun I've ever owned, sitting next in line only to a $45 surplus .22lr I bought some years ago).

Because I intend to field this gun with open sights, I wouldn't really look for more than about 200 yards worth of capability for hunting use. The good news is that I doubt I'll have any problem achieving acceptable 200 yard elk-accuracy, at least if these initial handloads have been indicative of any degree of future performance :)

interlock
October 6, 2009, 08:22 AM
with an original claw type mount you could get a scope on this without making it a modern looking hunting rifle and deliver some top drawer accuracy

interlock

X_m1tanker
October 18, 2009, 12:44 PM
I agree with the other posts, that the soot marks are normal. I think that as pressure is building in the shell, a little seeps around the neck untill full pressure is reached. Then the rest of the case is stretched and pressure sealed against the chamber. I find that I get more soot on case necks on lighter handloads than heavy loads, so I believe it has something to do with pressure sealing.

Beagle-zebub
October 18, 2009, 09:37 PM
I've heard that these military Mausers have "cavernous" throats. If that's right, is that a limiting factor of accuracy?

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