Reloading .30 Luger for my “No Matching Parts 1900”.
 

I have on hand some 78 gr .32 coated cast bullets I use for my .32 S&W short breaktop H&R and my 1935A 7.65 Long French pistol (the much less expensive ancestor of the SIG P-210). I’ve been loading 8MM Nambu for over ten years, so I have experience with bottleneck pistol cartridges. I used a load of 5 grains of Unique in Starline cases with Winchester small pistol primers. I’m using Lee dies, I’ve had good luck with Lee dies in the past, but I’m not all the happy with these and have RCBS dies on order. I did a number of dummies to make sure they would feed and extract. I loaded 10 rounds on a single stage press. The loads locked the action open on the last round and shot to about the same place as the factory ammo. Recoil felt just about the same. I have my Dillion 550B set up for .30 Luger. The first two dummies would not allow the action to close completely. I seated the bullet a bit deeper and they cycled fine then. OAL is still a bit more the Fionchi cartridges but well under max OAL. I have a few cast .32 cal 84 gr bullets, I’ll load a few of those up as well.

You didn't indicate the diameter of the bullets that you are using but it sounds like they are probably .311"-.312"? The 7.65x21 bullet should be .308"

If your barrel is worn then you are probably OK with shooting these but you might experience failure to feed issues with some brands of cases if they are thick enough that a .311 bullet will bulge the neck to the point that the reload won't fully enter the chamber.

Graf's carry PRVI 85 grain .3065 7.65 Luger bullets for $19/100 ct. (+tax & shipping) in case you're interested. They work fine in my Lugers. My apology if you already know this info.

-Bob

https://www.grafs.com/retail/catalog...roductId/29125

The 30 Luger bullets I have measure .309 and weigh 95 grains. I load Bullseye powder (because it burns clean in my short (4.5 inch) barrel). and my Lee dies work great! When shooting, my 1920 commercial tosses the brass into never never land.

I tried the Graf's .3065 a couple of years ago, as Bob said work fine. Went to order more - out of stock.
So when they got back in stock I got 1,000

I drive with 4.5grains of SR7625
Which is interesting as my PP/K uses 2.9 for a .380 pushing a 100grain pellet.

Like the OP, I also had bad luck with Lee dies in 30 Luger caliber. The sizing die looked like it was finished with a rattail file. I bought RCBS dies and installed them in my Dillon 650 press. Once set, I have turned out many, many thousands of rounds. I load .309in FMJ 91 gr. and .311 lead 91gr bullets. I like the caliber, and have pistols that shoot it.....not just Lugers.

When I started reloading 9mm for my P.08's with an undersize die it made a huge difference as far as reliability is concerned. The die is only .001" undersize, but it really helps, IME.

However, as far as I know, no undersize die for .30 Luger is available.