38 Super AOL

[Big Guy]

I usually load my rounds to around 1.235-1.240 (121s w/ 11.5 g of VV 105 out of a Brazos SX). However, I just got some 121s loaded with 9.2 g of IMR 4756 at 1.218.

Should I expect any issues for them being so short (e.g., over pressure, not feeding, etc.)?

[DRichardson]

I would pull a few of those apart. That is a lot of 4756 and I would think it would be very hard to get that short of a OAL with that much in the case.

[Guest]

I would agree with pulling a few to verify the powder charge, then do a little chrono work to ensure you are making major and of course look for pressure signs along the way. I know these aren't MG 121 grainers but for my guns I found when using a MG 124gr JHP with SR4756 it takes 8.4gr 1.235" oal to get to the minimum of 1335fps/165.5pf. A MG 115gr JHP with SR4756 @ 9.0gr 1.235" oal only got me to about 1410fps/162pf...and i stopped at this point as the case was very full and even with the 115gr bullet's dished in base it was compressed more than I cared for (the 121 is a 115 jhp with a filled in nose cavity).

Also, SR4756 is known to vary quite a bit from lot to lot.

However, I like SR4756 with the 124 grain bullet - accurate, loads easy, and shoots well. Don't really care for it with the 115gr bullet mainly because loading it is a pain as the case is very full at 9.0gr with my lot of powder and the load is compressed more than I felt comfortable with.

As for feeding, that is dependent on your gun so you just gotta try it but I tend to doubt that it would be a problem.

Edited August 24, 2013 by Bamboo

[Shadyscott999]

I load 9.3 of 4756 under a MG 121. The case is absolutely full. Sucks to load. I have to be there to make major using a Trubore with 4 poppel holes. I use 4756 for practice and club matches and 3n38 for majors. I am at 1.235 on OAL

[Big Guy]

Just in case, according to an email from Bob at BCG, he indicates a 124 g with 9.2 g of IMR 4756 @ 1.235 should make 168-170 pf.

[noylj]

Umm, not to be too stupid, but are you going to work up to that load or just hope it doesn't blow up your gun?

I would have thought that even starting at the .38 Super max of 7.6gn for SR4756 would make more sense (although my .38 super data all shows a COL (AOL is an internet site) of 1.245-1.265", so if I went even lower in COL I would start even lower in charge weight.

Then again, even my most excessive N105 load is only 11.0gn at 1.126 for 1475fps, and my major load is 9.9gn at ~1415fps (why go higher for no gain--that spells MAX effective load to me).

[DRichardson]

4756 is very temp sensitive and varies from lot to lot. That much, 9.2, of my current lot would be closer to 177-180 in my gun. I'm at 168 PF with only 8.5. YMMV