reloading 7.62x39 for Mini-thirty - bullet selection

[1stmarine]

1stmarine - I'll probably have to switch bullet tip styles then, with the pointy tip polymer bullet, it isn't going to happen. Thanks for the experience!

What COAL's do you run?

Hi,
These are 2.250 about 30thu off the lands from my chamber.
The best thing is to find out your max coal and then work back using small samples looking for the optimized load that is faster.
Try the 150gr sierras and 123gr speer in 308 and 310.
with good brass like lapua you can pump them up w/o problems.
SAAMI for this round is way too conservative for today's firearms and brass and can happily go above CIP.
Of course use hard cup primers and do not bump the shoulders too much and this will also save brass life.

 

[joneb]

1st Marine - COL's are running about 2.223-2.224". Max OAL per Speer is 2.200", but I was getting compressed loads way before their manual said I would, so I set it out as far as I could and still feed in the -Thirty magazine. It's not touching the lands, nor is it possible to touch the lands in this setup...and I'm not sure touching the lands is a good thing in a semi-auto??

Horsey - I guess what I meant by "underpowered" was "if I am going to select a gun for bears, a 7.62x39 is going to be pretty darn far on the list", not that it's completely incapable. I feel like if I keep it realistic with distances, this gun will make it happen...and if the first shot doesn't happen, I have 19 more right behind it! And yeah, if I can throw a 125 at 2500 fps, that would be great. I feel like the groups should close up if I can get some more velocity out of it. The lowest power loads were vertically strung, mid powered loads weren't, and the highest powered loads were vertically strung again...hoping I could find another place where they tighten up again, but I wasn't going to get there with R7 or 322. Hopefully A1680 gets me there.

Joneb - Thanks for seconding the 1680! Hows the H 4198 for velocity?

With Extreme 123 plated FP I have had good results with H-4198 at and a few grains above the starting charge for fmj. I have not chronoed these loads yet bet they seemed quite accurate.
The starting loads dropped the fired cases about a foot and haft from my SKS ☺
Extreme puts the limit at 2000 fps for this bullet.

 

[hq]

Please let me know if you track down the powder type and loading for sure.

I called my friend for information. I didn't remember the powders correctly. The powder in the .311 150gr Barnes TSX load is Norma 200, primer is CCI, loaded in once fired or unfired Lapua brass and it's a borderline compression load. He was wary of publishing any more details online but mentioned that it's fairly easy to work up the load from Norma's recommended starting level. Another load we chronyed at the same time, .311 125gr Sierra Pro-Hunter @ 2480-2495fps used the same powder/primer/brass combo.

The words "adjustable gas block" and "smaller gas bushing" came up a number of times, otherwise these loads beat up the action of your Mini pretty hard.

 

[DLrocket89]

1stmarine - I was wondering about SAAMI being low. Just felt like I was leaving a lot on the table. Also discovered that the neck OD was .012" bigger after firing than after resizing!! Feels like the chamber is big to me. I'm also going to check if I can fit more powder in a once-fried piece of brass and that they just needed to be blown out to fill the chamber correctly. I full length sized them, but all it seemed to do was size the neck down.

hq - Thanks for sending in info along, much appreciated. I plan on eventually getting an adjustable gas block...my 1600fps 125 grain loads cycled the action just fine, so I'm guessing this thing is way over gassed. I did put a 1911 buffer at the end of the op rod where the large weight batters into the receiver, so there is some padding there at least.

Everyone in general - does a .012" growth in the OD of the neck on firing feel like a lot? Because it does to me...

 

[1stmarine]

1stmarine - I was wondering about SAAMI being low. Just felt like I was leaving a lot on the table. Also discovered that the neck OD was .012" bigger after firing than after resizing!! Feels like the chamber is big to me. I'm also going to check if I can fit more powder in a once-fried piece of brass and that they just needed to be blown out to fill the chamber correctly. I full length sized them, but all it seemed to do was size the neck down.

hq - Thanks for sending in info along, much appreciated. I plan on eventually getting an adjustable gas block...my 1600fps 125 grain loads cycled the action just fine, so I'm guessing this thing is way over gassed. I did put a 1911 buffer at the end of the op rod where the large weight batters into the receiver, so there is some padding there at least.

Everyone in general - does a .012" growth in the OD of the neck on firing feel like a lot? Because it does to me...

A fired case is your best friend and your baseline gauge for doing this so you can load according to your chamber.
With modern brass like lapua for example one can load up to 50K psi w/o problems that is the average operating pressure +/- 2K psi folks are using with the grendel as well.
Either casing is very strong at the base and on the body too. I have done nice loads with fiocci and winchester but it is not near as good as lapua.
I have been using the same lapua brass for the 35 gunner cat and pumping up to 55Kpsi w/o issues given one understands how to work with loads and has a modern firearm with
modern bolt that can take the pressure and thrust of hotter loads vs. mild commerical ones.
I would only say that if you go very hot the brass will not last as long (obviously) and that one should work with ones chamber fireforming and avoid bumping the shoulders too much
something that contributes to over stretching and decreases brass life. SAAMI for this cartrige gives you some general guidelines but modern brass, bullets and actions are way
ahead of SAAMI and CIP.
Also popular software like quick load gives you an indication but it cannot account for all variables so what the software says might not be necessarily what one experiences with
careful testing and observation. The primer alone is not a good indicator or one could use a soft primer as an early warning indication but pressures signs come in two or threes
so you will have to measure everything. When in doubt stop, check, then check again and after that check a little more.
Lots of good loads w/o getting into the red as dictated by those components if they are of good quality.

 

[HankC]

Extreme puts the limit at 2000 fps for this bullet.

Is it heavy plated concave base? This one? http://www.xtremebullets.com/7-62X39-123-FP-p/xc762x39-123fp-b0500.htm
Unless heavy plate, Extreme website says 1500 fps!
http://www.xtremebullets.com/Bullet-Load-Info-s/1952.htm
Which says "Our Copper Plated Bullets can be run at mid-range jacketed velocities or higher end lead velocities. We recommend keeping velocities to less than 1500 FPS (Feet Per Second) and using only a light taper crimp
Any velocities over 1200 FPS we recommend either our Heavy Plate Concave Base or Hollow Point products for superior accuracy. We recommend keeping velocities to less than 1500 FPS (Feet Per Second) and using only a light taper crimp"

 

[1stmarine]

I don't see the benefit of plated bullets in rifle and even for pistol given the amazing fmj value packs for comparable cost or just a bit more.

http://rmrbullets.com/shop/bullets-...ine-110-gr-fmj-round-nose-new/?v=7516fd43adaa
http://rmrbullets.com/shop/bullets-...r-sinterfire-lf-frangible-new/?v=7516fd43adaa
http://rmrbullets.com/shop/bullets-...-gr-fmj-boat-tail-bullets-new/?v=7516fd43adaa

 

[joneb]

Is it heavy plated concave base? This one? http://www.xtremebullets.com/7-62X39-123-FP-p/xc762x39-123fp-b0500.htm
Unless heavy plate, Extreme website says 1500 fps!
http://www.xtremebullets.com/Bullet-Load-Info-s/1952.htm
Which says "Our Copper Plated Bullets can be run at mid-range jacketed velocities or higher end lead velocities. We recommend keeping velocities to less than 1500 FPS (Feet Per Second) and using only a light taper crimp
Any velocities over 1200 FPS we recommend either our Heavy Plate Concave Base or Hollow Point products for superior accuracy. We recommend keeping velocities to less than 1500 FPS (Feet Per Second) and using only a light taper crimp"

The plating is thicker for the 2000 fps bullets.
Call and talk to Xtreme.