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unspellable · 10-13-2003, 01:15 PM

As always, slug the barrel. The nominal barrel size is 0.311. My Ruger P89 is this size. If you have a 0.308 barrel, it was probably rebarreled in the US using 0.308 barrel stock. The thing to watch out for is the outside case neck diameter. You must leave room for it to expand inside the chamber neck or pressures will climb. Current US made brass is thick enough in the neck walls to make this an issue if you use 0.310 to 0.312 size bullets.

I talked to an engineer at one of the bullet companies about the question of re-sizing jacketed bullets for the 7.65 Luger. He was not too keen on it on the grounds that the jacket will tend to spring back more than the core and may seperate. On the other hand I've heard of others doing this and no serious complaints as of yet.

For the absolute ultimate in accuracy the jacketed bullet shoud be groove diameter and the case necks shaved or reamed if neccesary to get proper case neck to chamber clearance. The maximum outside diameter of the loaded case neck should be 0.001 smaller than the inside diamter of the chamber neck. Another test is take the pistol apart and fully chamber the loaded cartridge in the barrel. When the barrel is pointed straight up the cartridge should fall out of its own weight.

This raises another aspect of the 30 Luger cartrdige project. I'll have to make some chamber casts and see how the neck diameters actually run.

10-13-2003, 01:15 PM	#3
unspellable User Join Date: Jun 2002 Location: Iowa Posts: 768 Thanks: 0 Thanked 19 Times in 11 Posts	As always, slug the barrel. The nominal barrel size is 0.311. My Ruger P89 is this size. If you have a 0.308 barrel, it was probably rebarreled in the US using 0.308 barrel stock. The thing to watch out for is the outside case neck diameter. You must leave room for it to expand inside the chamber neck or pressures will climb. Current US made brass is thick enough in the neck walls to make this an issue if you use 0.310 to 0.312 size bullets. I talked to an engineer at one of the bullet companies about the question of re-sizing jacketed bullets for the 7.65 Luger. He was not too keen on it on the grounds that the jacket will tend to spring back more than the core and may seperate. On the other hand I've heard of others doing this and no serious complaints as of yet. For the absolute ultimate in accuracy the jacketed bullet shoud be groove diameter and the case necks shaved or reamed if neccesary to get proper case neck to chamber clearance. The maximum outside diameter of the loaded case neck should be 0.001 smaller than the inside diamter of the chamber neck. Another test is take the pistol apart and fully chamber the loaded cartridge in the barrel. When the barrel is pointed straight up the cartridge should fall out of its own weight. This raises another aspect of the 30 Luger cartrdige project. I'll have to make some chamber casts and see how the neck diameters actually run.