7.62x39 load data - all over the place!

Decided to work up some x39 loads using 1680 powder. The following load data are what I found:

Max charges using Hornady .310" 123gn FMJ bullets.
Hornady - 23.9gn
Lyman - 25.7gn
Western - 27.3gn

Speer - 28.2gn (using Speer bullet, not Hornady).

I decided to work up loads from 23.0 - 27.0, in 1.0gn increments, 3 rounds each charge, just to get a ballpark idea for now. This will primarily be for a 16" AR, but I also have a Ruger Mini-30 (and, yes, it has a .310 bore).

Anyone have a pet load in x39 using 1680 powder?

I also have some Berrys plated .310 bullets to try as well.

 

I agree. I'm just trying to zero in on a smaller range to concentrate on right now.

 

Thanks for the info. I may load up a few with charges lower than 23.

I agree about the gilding metal. I had a conversation with the guy from Shooters World about the load data for their "Auto Pistol" powder. They had what I thought was really high load data for 230gn bullets. They developed the load data using Nosler bullets. He went back and did testing using Hornady bullets, and the max charge for that was less than the min charge for the Nosler bullets. I'm sure there were other factors, but he basically confirmed what you said about the jacket material.

The data I listed above, from Hornady, Lyman, and Western, were all for the same Hornady bullet. And they were all over the place.

 

Western lists "21" barrel, 1-9.5" twist, .310-.311 bullets".
Hornady lists "SKS Carbine, 1-7.5 twist, 20".

I don't have the Lyman manual in front of me right now, but Hornady and Western were at the extreme ends of the charge ranges for the Hornady bullet.

 

My SKS will launch cases into low earth orbit - factory ammo.

 

Thanks for the info, @ssyoumans !

 

Well, I had loads worked up in 1.0gn increments, from 22.0 to 27.0 of 1680, with Hornady 123gn FMJ bullets. I shot them yesterday.

22.0gn, 2088fps
23.0gn, 2089fps (these were shot first, cold clean barrel, may have affected the results).
24.0gn, 2209fps
25.0gn, 2294fps
26.0gn, 2370fps
27.0gn, 2442fps (primers just starting to flatten, but no cratering, no ejector or extractor marks).

I only had 3 rounds each, so I consider the standard deviation and extreme spread numbers to be questionable, but the best SD and ES were with the last load, 27.0gn, and also the best group, about 2" @ 100 yards, which for a non-free floated barrel and stock AR trigger is pretty good. I think I will load up a few more between 24.5 and 26.5 in 0.5gn increments to try out.

I went back and looked at the data from when I was testing loads in my Ruger Mini-30, and there I had very good SD and ES numbers using H335 powder, so I think will try some new loads with that. I ran some numbers through Quickload and noticed that H4895 had very good case fill and lower velocities, so I will probably try that powder with the plated bullets just so I will have an inexpensive short range plinking load.

 

Great info. I've got RL7 and 300blk in my stash. Something else for me to try.