Soupcan tests in the M1 Carbine

I just finished up tabulating the results of several months of testing with the Lee soupcan (C113FN) and 820 surp powder. I tested them at various charge levels, with and without gas checks, two different alloys, and with both CCI small rifle and small pistol primers. The test rifle is not a GI carbine, but one made after the war by Universal from surplus parts. We got it brand new and have put somewhere around 2500rds through it, mostly jacketed until these tests. I doubt based on the results that it will ever see another jacketed bullet. It is way more accurate than any mil carbine I have ever fired. It will keep jacketed loads, both mil and handloads in less than 4" @ 100yds all day long. This is what I learned:

1. After more than 500rds fired, all the lead in the gas system was cleaned out with one swipe of a qtip. This is a very cast friendly rifle. No feeding problems at all throughout the test until gunk buildup in the breech from the lube prevented lockup at around 520 rds. I tumble lubed them with liquid alox and sized them to .310, and some of them were a bit over lubed. In the future I think I will wipe off lube from the noses of loaded rounds with a cloth and some mineral spirits.

2. Once I found the optimal powder charge using gc's and srp's I started experimenting. Accuracy was on a par with 110 jacketed bullets, under 5" @ 100yds. I won't post charges as it is a surp and every lot is different. (I will use 2400 when I can't get the surp 820 but had plenty of it for these tests.)

3. There was no measurable difference between spp's and srp's in average group size, and no signs of flattening on the spp's. I did not chrono them but POI was the same.

4. There was a slight opening of groups without the gas checks, but 5 and 10 shot groups were all still under 5". No change in POI.

5. There was no measurable difference in average group sizes between WW bullets and 1:4 (WW to pure) alloys, but there was a slight shift in POI.

There is no need for gc's with these bullets, and if the noses are wiped clean of tumble lube after seating they feed and fire without a hiccup just like jacketed loads.