Anyone here into firearms?

Rusty · 10-11-2015, 08:30 PM

Quote:

Originally Posted by synolimit

i finally got out to shoot the new powder for my Hornady 75gr's. If you remember I was using a powder not recommended but Accurate or Hornady but one that others had tried with 69gr's and i was only getting around 2460ftps with a very compressed load deforming my tips.

I found out RL 15 would work ok. So I loaded up low, medium and high charges per Hornadys 5.56 manual. But my speeds are way way under what they say. The max at 24.9gr should be 2850ftps. I'm only getting 2642ftps. I take it they don't use a 16" barrel then for the manuals and use a 20". I tested my 16" vs 10" and averaged 310ftps slower or 51ftps per inch. So 2642+204=2846 or almost dead on for 24.9gr per Hornady, way to go manual!

Anyways I started loading more powder to see if I could get more speed and watch for signs of over pressure. Was that bad? I got up to 25.5gr and again started to compress the load and deforme the tip a little Speeds got up to 2710 and the cases looked good after being shot but pretty flat primers though but no damage or hurt cases. I ran out of brass but shot 4 rounds at 25.5gr. First cold barrel shot was 3-4" left from shots 2 and 3 which were sub MOA on top of each other. Shot 4 was again 3" away but right of 2 and 3. After writing all this I'm answering my own question probably by saying the charges were to hot and probably wild and the deformed tip probably wasn't helping. Shots 2 and 3 might of just had more room in the case or less deforming making them good at 25.5gr and 2700ftps. So maybe I'll just stick with 24.9gr at 2642ftps with the 75gr bullet and redo the accuracy testing.

FYI every 0.4-0.5gr averaged about 60ftps for all the loads I tried out.

3 powders you can try also. IMR4198, ARCOMP, and Ram Tac if you can find it. Alot of people like the Ram Tac, then the ARCOMP. IMR 4198 use to be the powder for .222, .223, and like size cases.

Are you using a chronograph? If so, which one? I never get what the manual says for velocity.

When you deform the tip of the bullet. Kiss your accuracy good by.

When you try for more velocity. And are starting to see over pressure signs. You will see the flatten primers. But what you don't see is inside the case. Look for a bright ring around the outside of the case, just above the case groove. If you see that. Your case is about to separate there. Also your case will grow in length. So keep an eye on case length. Watch for splits in the necks too. Because as the case grows in length. The neck will get thick, and work hardened.