I am trying to find out some information about a old drilling that I have marked in
7.7x57R. I can not find anything on this old cartridge. Can you please help!!!

Thanks!!!

You need to make a chamber-cast so this can be measured. There are a series of possibilities, one being as simple as the .303 British, the others being more speculative. Without a decent casting of the chamber, identification is going to be pure guesswork.

I answered something like this a while back at shooters.

7.7 mm means J bore. This was nominally .318 bore, but in their search for precision some gunsmiths of that era cut very tight barrels.

For a first try .313 ( nom .303 ) bullets might be possible, but as it was quite surely designed for .318, if the gun is sound, try those. Use a long RN bullet of > 180 grs.

You have to check: standard 8x57IR case or 8x57R 360? The 360 means based on the olr 360 British round. Either you look up COTW, or you compare cases: if the rimmed case is about the rim/base size of a .30-30, it would be the 8x57R360. If you have any rimmed case for comparison: if it is the same rim/base size as 7x57R, 7x65R, 8x57IR !!, 8x57IRS, 9.3x74R its the other.

Loading data can be found by RWS, one pound powder from them won�t ruin you.

Tell me: is the forearm of the drilling missing?

Have a gunsmith ( a real one ! ) check the gun.

Hermann

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Good info!! I have an old J.P. Sauer double that was marked 7,8X57R, and was later rechambered to 8X60R. The bore mikes .322 groove, and I have always used .323" s, but found out that the original 8X57J barrels on the M88 Commision rifles often had .322" groove dia. bores, despite being used with .318" bullets. It is possible that my rifle had "J" bores, and was used with .318" bullets. However, my case necks expand plenty on firing, easily releasing the .323" bullets, and I have never had a pressure problem using them with loads that develop +2400 fps with 200 grain bullets. Accuracy is also acceptable.

Eldeguello, you got the point! The most important thing is that the case is able to release the bullet. There will be a little more pressure if the bullet is squeezed down the bore, but you have to work up anyway.

There are still .318 bullets available: RWS and Sellier & Bellot, perhaps Norma ( I am speaking of affordable priced bullets, not custom made ). If I had a I bore 8 mm, I would just use those bullets if accuracy is o.k. If not its time to check the throat ...

Good shooting! Hermann

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aHunter, thanks. I knew that there were sources for the .318" bullets. My barrels indicate the gun was regulated with 198-grain bullets. I have used both the Speer 200-grain and the Nosler Partition 200-grain .3123's. My load is 55.7 grains of H205 (still have about half a pound) with RWS 7X65R cases trimmed to 59mm, neck expanded, Fed. 210 primers. The Nosler load will often put left and right barrels (fired in that order) into less than 2" at 100 meters, so I think I will stick with the .323" bullets. The Speer doesn't do that well, even with the same powder, primer, etc.

The gun is either chambered for the 8 x 57 R 360 or for the 8 x 57 IR, as aHunter pointed out. Two quite distinct cartridges both as far as shape & size, and as far as performance are concerned.

Carcano

[This message has been edited by carcano91 (edited 03-15-2002).]