Info is limited on any powders but the common ones for the .30 M1 carbine loads. I got a bunch of Power Pistol and 110 gr Lee 309-110R boolits around so I tested some.
Warning: venturing outside of published loads is SUPER DANGEROUS and according to the google-box, you will blow yourself up, destroy firearms and stain the carpet all at the same time! Don't do this at home or on the range.
Since the 30 carbine and the 357 mag are very similar in case capacity, I used the 357 as a reference.
Power Pistol is a medium slow powder made for high pressures and works great in magnum cartridges. In fact most people think Power Pistol is too flashy (a property from being too slow and having powder still burning as the bullet has exited the barrel.). Well, try using Alliant 2400 in a pistol! talk about flash! I tried it in .40 once and got anemic velocity and a fireball. But I digress.
Published loads for the 357 range up to 9.7 grains of Power Pistol with a 110gr lead boolit. Published pressure for that is 32000PSI according to my Lee manual.
SAAMI max for 30 carbine is 40000 PSI, so I'm looking to stay within the same ranges.
Now the 110gr 30 carbine has more friction than the 110gr 358 because of the larger bearing surface. I also have a gas check on the cast boolit, so I'm gonna play it safe and start very low and just go up to where I get functioning of the CMP Inland 30 Carbine. I'm not worried about getting max velocity, just a usable round for the carbine that works with the cast and is not so darn loud as factory loads. I've always felt that the M1 carbine would be nicer to shoot if it wasn't as LOUD. (I'm getting more sensitive to noise, not sure why.)
So starting lower than I thought necessarry (which is often just fine for me!), I went with 4 grains of PP. I was going to try up to 8 gr but had second thoughts after seeing nearly a full case of fast powder in the case! So test loads were 4 to 7 grains.
DATA:
Mixed 30 carbine brass, mostly LC in the 50's.
Wolf small rifle primer.
Lee 309-110R cast boolit, with Hornady gas check.
Scrap linotype lead with some scrap bird shot mixed in, pretty hard for cast.
Lubed with LLA. Sized to .309".
Inland M1 carbine with a Inland GM barrel.
5 shot strings
Grains powder, Hi, Low, Average, Spread, SD, notes
4gr, 1312fps, 1297fps, 1305fps, 15fps, 6, mild-ejected 2'-did not cycle.
5gr,1460, 1439, 1449, 21, 8, mild recoil and noise- ejected 2' did not cycle.
6gr, 1664, 1626, 1639, 38, 16, ejects 2.5'- CYCLED NEXT ROUND- easy to shoot
7gr, 1780, 1756, 1769, 24, 10, CYCLED NEXT ROUND- not as loud as factory rounds- still mild recoil.
At 7gr I notice the primers are flattening out a bit compared to the 4 grain LIGHT load. No overpressure signs, the fired cases fit in the case gauge and do not need to be trimmed. I see no reason to go any faster/hotter.
I did not have time to shoot groups, and now that I have a good starting point I can work up an accurate load.
While you still need hearing protection for these, they are way more quiet than a full pop factory round, and still plenty fast enough for varmint hunting/self defense/plinking or whatever you use your M1 for.