Tom,
Do you reload? Or do you know someone that you trust to reload properly?
This is my favorite .30 Luger load. If functions flawlessly and is very accurate.
100gr Hornady XTP hollow point
3.9 to 4.1 grains of 700X
I start out with 3.7 grains in an unknown pistol and work my way up watching for pressure signs. 3.9 grains is the best average I have found.
A carbine may work fine with the 4.1 charge. Or even higher.
<JUST FOR THE RECORD>
( ~A cover my a** disclaimer, for this age of litigation.~ I am not recommending this load to anyone, and will not be held responsible. Use at your own risk. I have used it with excellent results in several vintage .30 Lugers.)
Ron