What causes inaccuracy in a 9mm Broomhandle Mauser?

Just got back from the range after testing my 9mm C96 Broomhandle, and I was not able to get better than 12" groups at 25 yards [] , and yet the pistol is tight and the bore is virtually pristine (I also drove a 9mm FMJ bullet from the chamber to the muzzle with a nylon hammer and brass rod, and the bullet definitely engaged the rifling as it took quite a few strong whacks to finally drive it through the bore). :banghead:

My Mauser C96 looks and feels almost like a new gun, and with the inherent Broomhandle attribute of the sights, slide, and barrel being part of a single mono-block, I don't see how a Broom with decent rifling could shoot less than stellar groups. (FYI: the bore shows some slight pitting just after the freebore).

Any thoughts?

[Further info below after pictures].


Thanks!

-Bill










My Broomhandle's Dimensions:

DIAMETER OF BARREL AT LANDS (1" past muzzle): 0.351"

DIAMETER OF BARREL AT GROOVES (1" past muzzle): 0.359"

DIAMETER OF CHAMBER AT START: 0.383"

DIAMETER OF CHAMBER AT CENTER: 0.380"

DIAMETER OF CHAMBER AT END: 0.375"

DIAMETER OF FREEBORE: 0.357"

Thanks guys.

Yes, Jim and Jim are correct, this is a BTC (Bricklee Trading Company [Fed Ord]) rework of a selective fire (Schnellfeuer) M712 Mauser Broomhandle from China. They removed the old barrel and chamber and installed a new 9mm one in the 1980's. However, the frame itself could not be imported (BATF!), so BTC had new semi-auto frames built (I believe in China).

The rework of the Bricklee C96's is supposed to be pretty darn good, and to my semi-trained eyes it is. The gun, as I said, is tight, and the bore is not rusted (a bit rough, yes). And, as I said, I drove a 9mm JHP through the bore with a heavy cleaning rod and a hammer, and it was quite a chore (but should it have been even MORE difficult? I don't know. Please see pics below).

The "new" BTC barrel/chamber appears perfectly attached and tight.

I even tried 147grain ammo to slow down the bullet and to get better purchase on the rifling, just in case the 115 grainers where skipping over the rifling; but it didn't seem to affect the accuracy any.

Picture of the 9mm jacketed bullet that I drove through the bore (Should it have been more indented by the rifling?):






-Bill

Boy, am I behind the times!!

Ahh, now I think I see your point RCmodel and Jim(s). Believe it or not, I just learned that a modern bullet should be the same size as the groove diameter of the bore, unlike the minie-balls of old with their expanding, gas-checking bases! I think I'm a wee bit behind the times.

Looks like I need to handload now, which I wanted to avoid, and take RCmodel's advice and use a .38 Special bullet with a 9mm case. (Boy, do I see trouble brewing with my complete reloading ignorance and the mixing and matching of case/bullet calibers!! )

-Bill

PS: Given my Broomhandle's "generous" bore diameter of .359", is even a .38 Special bullet going to be big enough to hack it?

Hi Owen,

With the combination of a long sight radius and a mono-block that comprises the slide, sights, barrel and chamber, the C-96 is similar to a .22LR pistol, which are far more accurate than most 9mm and .45 cal locked-breach recoil operated firearms, which of course use separate barrels and slides flopping around (and most centerfires also have the sights riding on the slide, and not on the barrel).

So, C-96's have all the makings of an extremely accurate weapon, except that mine, unfortunately, has a bore groove diameter of 0.359"! And there doesn't appear to be any solution to my problem except for a barrel reline; but I don't like waiting six (or more) months for that job to get done by Redman's! (Reloading looks out of the question too due to chamber dimensions that won't accommodate a much larger bullet). :banghead:

Best,

-Bill

I had the exact same problem, Peter, with my 9mm detachable mag C96, originally re-furbished by BTC (Bricklee Trading Company) in the '80s.

I had bought it from Ebay (when Ebay allowed such things) for a good price, but after it would double and triple on me a few times, it so scared me to death that I actually put my Broom away for the last ten years.

Then a few months ago I said the heck with it, and I studied up on the workings of C-96's so that I could fix the problem myself. This basically involved increasing sear engagement and replacing all of the coil springs. Now I never have doubling at all. (However, it would make me feel much better if I could somehow add a coil spring to bear down on the sear so that no matter what, the sear will re-engage the hammer notch. But that would be belt and suspenders...)

Carl, I wish my C96's chamber could fit a larger bullet, but it is too iffy. Plus, I don't reload. (BTW, The pic of your target is not showing up in my browser...).

Best,

-Bill