I'm looking for successful loads in 223 Rem using Speer #1053 70 grain bullet with H-380. There are loads listed in the Speer manual. The rifle is a CZ Lux with a 1:12 twist. I've searched the web and haven't seen much useful information. Is anyone using this combination? Or should I look at another powder, IMR 4198 or RL-7
Cheers

a bit too slow for such a tiny case .. h335/tac are my go to ..

70gr bullet and a 1:12 twist I would use blc2 or varget.

The only way you will really know if it works is to try the H380 in your rifle. If you follow the Speer manual it should be safe. Won't know if it is accurate until you try it. If it doesn't work, then I would try BL-C(2). It works well with the 63 gr. Sierra in my .222, as well as 45 to 55 gr. bullets. If BL-C(2) doesn't work, keep trying powders Speer lists until you get the performance you want.

I shoot a pair Savage 223's a bolt heavy barrel 1:9 twist and a AR 18" 1:8 twist with a Wylde chamber. 52 gr sierra bullets work pretty good in both.
I have shot 69gr sierra 1 1/2" groups in the AR. 68gr nosler were just ok.. 2" groups
I think I will give the slower powders a try.
let us Know how yours worked out

I'm looking at the small case and heavy for caliber bullet and figure a slow powder would the right idea. I've used one 4064 and didn't get the accuracy I'd want, so this is Is the move.

I have never tried 70g bullets in 223 but my guess would be Varget, IMR4320, W748 or Rel 15 would be best. Nosler reloading book list W748 giving top velocity with 70g bullets.

just noticed it has a 12 twist .. not likely to workout well

H335 / W748 works well with all 223 bullets wrights