7.62x39 load data - all over the place!

[Toprudder]

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.

 

[Blue68f100]

1/2 gr increments would be better so you don't jump over a node.

 

[Toprudder]

1/2 gr increments would be better so you don't jump over a node.

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

 

[Curator]

20 to 23 grains of AA1680 works fine in my AR with 123 grain Hornady .310 soft point bullets. One thing I have learned about comparing loads with Hornady and Sierra bullets is that pressures seem to be higher with Hornady. Many years ago I toured their factory with an industry group and asked about this. Their "Ballistician" explained the both their gilding metal jacket material and their lead cores were softer than their competitors (Sierra, Speer, Barnes etc.) This gave better accuracy and higher velocity and pressure because their bullets obturated to seal the bore rather than allow the bullet to ride on top of the lands. Any time I switch from Sierra bullets to Hornady, I drop the powder charge a couple of grains and usually get the same velocity

 

[Toprudder]

20 to 23 grains of AA1680 works fine in my AR with 123 grain Hornady .310 soft point bullets. One thing I have learned about comparing loads with Hornady and Sierra bullets is that pressures seem to be higher with Hornady. Many years ago I toured their factory with an industry group and asked about this. Their "Ballistician" explained the both their gilding metal jacket material and their lead cores were softer than their competitors (Sierra, Speer, Barnes etc.) This gave better accuracy and higher velocity and pressure because their bullets obturated to seal the bore rather than allow the bullet to ride on top of the lands. Any time I switch from Sierra bullets to Hornady, I drop the powder charge a couple of grains and usually get the same velocity

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.

 

[Bfh_auto]

Did it say whay the test platforms were?
7.62x39 runs different bore diameters.

Hornady tends to be ultra conservative. This isn't always the case though because I have hit pressure signs at their max charges in the past.

 

[res45]

Target from my load workup several years ago in my Yugo SKS with .311" groove bore.

 

[Toprudder]

Did it say whay the test platforms were?
7.62x39 runs different bore diameters.

Hornady tends to be ultra conservative. This isn't always the case though because I have hit pressure signs at their max charges in the past.

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.

 

[Bfh_auto]

I used the Lyman data with xtp's. I never went to max because my SKS tried turning my brass into satellites.
I will be tuning the gas system and trying it some more after deer season.

 

[Toprudder]

I used the Lyman data with xtp's. I never went to max because my SKS tried turning my brass into satellites.
I will be tuning the gas system and trying it some more after deer season.

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

 

[Bfh_auto]

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

It was Russia's first attempt at space travel.

 

[ssyoumans]

I’ve worked loads using 123gr Nosler BT and compared them with factory loads from WPA, Hornady, Prvi, etc.
All data out of a 16” Radical Firearms AR. 1,080’ above sea level, 83 degrees.

123gr Nosler BT, 2.200”, 25.5gr AA1680 gave 2,280 FPS
26.0gr AA1680 gave 2,310 FPS
26.5gr AA1680 gave 2,348 FPS
All 3 loads shot very well with 1 - 1.5” groups.
By way of comparison, Factory 123gr WPA HP gave 2,366 FPS
122gr Tulammo HP gave 2,466 FPS
123gr Prvi Partizan SP gave 2,487 FPS
123gr Hornady SST gave 2,236 FPS.

I saw no reason to go any faster, had outstanding accuracy.
Note: All loads were safe in my AR, but may not be safe in yours! Work up any loads watching for signs of high pressure.

 

[Toprudder]

Thanks for the info, @ssyoumans !

 

[Toprudder]

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.

 

[Newtosavage]

Sorry, not a 1680 shooter here but I had excellent accuracy out of RL-7, that is until I tried CFE BLK powder. That's all I will ever use in my x39 from now on. Same or better accuracy and 100 fps more velocity than RL-17. I'm dropping 29 grains of CFE BLK in my Lapua brass and getting 2600 fps. with a 123 SST out of a 20" barrel (Howa Mini).

Good luck! The x39 is fun to handload for.

 

[Toprudder]

Sorry, not a 1680 shooter here but I had excellent accuracy out of RL-7, that is until I tried CFE BLK powder. That's all I will ever use in my x39 from now on. Same or better accuracy and 100 fps more velocity than RL-17. I'm dropping 29 grains of CFE BLK in my Lapua brass and getting 2600 fps. with a 123 SST out of a 20" barrel (Howa Mini).

Good luck! The x39 is fun to handload for.

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

 

[Newtosavage]

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

You're all set then. Enjoy!