Traded for a German Guild rifle. The bottom barrel flat is stamped 7.7mm. Which I assume means its a .318 bore?
Any source for bullets?

flinter6 out

I would slug it first. The 8mm J is .3185"

Try Buffalo Arms . They have .318 bullets in several weights. Most of these are, I believe, resized .323 bullets (although some of their non-standard diameters may be custom swaged). They work fine in J bore 8 mm's, and are reasonably priced.

I use a ring sizer from Fred Zeglin (Z-Hat), and it does a good job as well for sizing .323 bullets down to .318 using a standard reloading press. Once you buy the resizer body you can buy various diameter rings and posts in most any diameter that you need at a very reasonable cost.

Jim

Hawk @ hawkbullets.com & Woodleigh, from Midway, both carry .318 bullets. Like Savage said, slug the bore for an exact fit.

Make sure you don't get a "slug" stuck in the bore. The slug should be soft lead of course but the big thing is that the largest diameter must be very short in length. You don't want more than 1/8" of metal at full diameter. Turn the rest of the slug to less than bore diameter so that you can start it in the muzzle with your fingers.

If you don't have a lathe to turn a slug with then a .30 cal cast bullet can be squeezed in a vise length wise but again start small on the diameter.

I made my own sizing die for the 8mm J as mine slugged .3185". I use Hornady 170 gr 32 Special bullets that are .321" to start.

I'd slug the bore before assuming it is a .318". 7.7mm is closer to .303". The original German infantry round was marked 7.9mm., which worked out to a .311" bore and .318"groove diameter. So you may be dealing with some obscure German cartridge. I think a chamber cast is in order as well as slugging the barrel.

8x57J=.318" Bore, not groove.
8x79JS (J=I=Infantry) = .323 Bore. S=Spitzer
7.9 = 8x57
7.92 = 8x57JS

There are rimmed versions of all, e.g., 8x57JR, 8x57JRS

Measure the groove to fit the bullet. Norma still makes 7.9 (0.318") and probably RWS, if you can find them. Old Western Scrounger is a start place.

Cast bullets are an excellent choice. I had an '88 with similar problems. Much variation from rifle to rifle.

Geo.

Fritz offers good advice. I recently got a box of .404/350/.423. When I started loading I had several drop thru to the powder charge. I measured all of the bullets in the box & half were .416. They replaced them promptly when I dropped them a note. Now if i can just get my rifle from the gunsmith!

The "S" caliber 8x57 has a groove diameter of .323" the original "J" barrels had groove diameter of .318". The rifle in question was stamped 7.7mm that is about .311."

Some errors in here. Please see the following quotation from eldeguello, to set the record straight:

"Actually, the ONLY 8X57mm or 8X57mmR rifles that had true .318" bores were some of those with gunsmith-made barrels. The original Gewehr M1888's issued to the German Army were made with .322"-.323" BORES, despite the fact that they were originally firing .318" BULLETS through them! A lot of these rifles were converted after 1905 (when "S" ammo was adopted) by German Ordnance to safely fire the later .323" S-size bullets by merely opening up the chamber throats so the cartridges freely released the larger bullets when fired, even though the M '88's are now considered "too weak" for "S" ammo pressures!! "

Some good history here about bore and groove diameters.

-Bob F.


7.9mm Mauser
Cartridge Board - Gil Sengel
HANDLOADER magazine
February - March 2004 Volume 39, Number 1

Full article is at:
http://www.riflemagazine.com/magazine/article.cfm?tocid=1224&magid=86


Most widely debated is the variance of internal barrel dimensions and bullet diameters of early 7.9mm arms and ammunition. The topic often makes use of the terms J-bore, Z-bore, S-barrel, J-bullet and S-bullet. This writer has reviewed at least eight different explanations over the years and no two are exactly alike! Let�s look at a few facts, then see if we can figure out what was going on.

The first fact is that bore diameter (hole reamed in barrel before rifling) for the 7.9mm cartridge has always been 7.9mm (.311 inch). Why some call it an 8mm is unknown. The M88 cartridge used an 8.1mm (.3189 inch) diameter bullet (J-bullet). Rifling depth for the M88 barrel was 0.1mm (.0039 inch). Simple addition now reveals that barrel groove diameter (J-bore) and bullet diameter were identical at 8.1mm.

When M88 ammunition with its long, hard jacketed bullet pushed by the new smokeless powder was fired in these barrels, the rifling quickly wore away and barrels ruptured, split or just plain blew out in various locations near the breech. Such was not desirable. Failures were blamed on the bullet being too large in diameter, though erosive, unstable powder was more likely at fault.

As a remedy, rifling groove depth was increased from 0.1mm to 0.15mm. We now have a groove diameter of 8.2mm (.323 inch). Neither bore nor bullet diameter were changed. These barrels had a Z stamped on them (Z-bore). Gas leakage past the bullet stop�ped barrel blow-outs and deeper rifling gave longer barrel life. Remember, Germany was after better field results from the average soldier�s rifle, not smaller bench�rest groups.

When the 7.9mm S (Spitzgeschoss or pointed bullet) cartridge was adopted in 1903, its bullet was 8.2mm (.323 inch) in diameter (S-bullet), very pointed and only 154 grains in weight. Velocity is given as 2,930 fps. Smokeless powder employed was of a more highly developed type using deterrent coatings to control burning rate. Gas leakage past the bullet was no longer necessary. Bullets were shorter, which reduced jacket fouling and rifling wear.

New barrels on the strong Model 98 actioned rifles were chambered for the S-cartridge. Weaker Model 88 rifles having the larger Z-bores were rechambered for the S-cartridge by opening the chamber neck diameter and freeboring to further relieve pressure. These barrels received an S stamp (S-barrel).

If this isn�t confusing enough, military J-bore barrels were sold to private gunsmiths for many years. Riflemakers also continued to produce barrels having J-bore dimensions long after they were dropped by the military. Thus where they may show up is anyone�s guess. Any early sporter or Model 88 rifle should have its bore slugged before firing. Pushing a jacketed .323-inch slug down a .318-inch barrel could damage a fine, old rifle.

Thanks for all the replies! I ran a pure lead slug thru it

& as close as I can measure = lands .311, grooves .322.

I'm waiting for UPS to get here with some Cerrosafe.

I'll post back with the results. Thanks again!!

BTW anyone know of any research sites on this type of

rifle? Also on the receiver ring is stamped

3g G.B.R. under thatS.G

flinter6 out

I believe you can still get Lee bullet sizing dies which work from the bottom up - i.e. there is a ram that pushes the bullet from the bottom into and through the die. While these dies were originally intended for cast bullets I found that they work nicely with jacketed bullets as well when used with a greaseless case lube such as Lee resizing lubricant. The bullets spring back so you may have to use an intermediate sizing die and do it in two stages as I had to do sizing .458 diameter bullets to .454 and finally to .451 where th ey emerged .4515 - perfect for my .454 Casull and a lot cheaper than Freedom Arms name brand bullets. < !--color-->

Incredible. It's really incredible and mind-boggling for anybody a bit familiar with the history of the M/88 cartridge and with German rifle history to see what kind of crap finds its way into print. The author (Gil Sengel) did not even bother to do *basic* research, such as to avoid some of the more glaring flaws.



Longtime readers know how Dave Scovill as editor has drawn the once-famous "Handloader" deep into the gutter, over the years, but the really distressing thing to ponder is that probably many trusting US readers without familiarity with European cartridge history will take this error-ridden bullsh*t at face value. :-(



Thoroughly disgusted,

Carcano

I have to agree with carcano91. Both Handloader and Rifle are not getting any better. Never thought about Scovill being responsible, but he is the editor.

I believe there's an outfit called MOLOC that also makes oodd-size bullets, including .318"

Please let us know when you find out exactly what the GROOVE diameter of your rifle turns out to be!!

I agree with Carcano that Handloader and Rifle aren't as useful as formerly.

This is either due to the fact that I've learned a lot since they first came out, or that all the good, knowledgeable authors are dead, like Harvey Donaldson, et. al.

When Ken Howell left as editor that was the turning point.

Ken wrote a tutorial over at 24 hr on how to write articles. It's quite valuable.

He also wrote an explaination on how to motivate gun writers. It's buried in some gun argument but it was brilliant.

Chamber cast = 8x57JS .322 groove .311 lands
Headspace great. Throat just right.
Gonna shoot it ? You betcha !
So what did I learn?
You can find german proofs & cartouches. Some digging required
And carcano91 doesn't care much for Handloader mag!!

flinter6 out