reloading 7.62x39 for Mini-thirty - bullet selection

[DLrocket89]

Hi everyone,

Just got back into reloading (and firearms in general) after about a 10 year hiatus. I bought a Mini-Thirty Ranch Rifle (new production, 583-xxxxx S/N). Yes, I know it's a .310 bore and I'm shooting .308's out of it...no biggie.

I picked up some Reloder7 and H322 based off of various recommendations online and in reloading manuals. Also picked up some Hornady SST 125gn and 150gn, loaded up 50 rounds of each bullet/powder combination in differing levels of powder charges. Results have been a mixed bag, usually a 2" group or so, a couple 1", many 4". I do realize this is about what you can expect from the Mini-Thirty. Unfortunately, the best accuracy seems to be from the 150gn SST, which really isn't going fast enough to get the bullet to expand reliably from what Hornady says.

So, that said, here's my question:

With reasonably accurate loads, getting about 2150ps (~1280ft-lbs) in my 125 grain loads and about 1950fps (~1260ft-lbs) in my 150 grain load. Assuming my mission for this gun is deer hunting out to 150 yards, and defense of the farm (from black bears and smaller critters), what would people recommend for a bullet?

Per Hornady, their SST's need to be going about 2000fps or faster to reliably expand, so I'm worried the 150 grain isn't the best option. I have some 150gn Nosler Ballistic Tips sitting here, was going to try loading them up but I'm also worried they won't be going fast enough. I know there are a bunch of varmint bullets that may work, but also might expand too much?

Thoughts?

Thanks in advance!

Dustin
Wisconsin

 

[horsey300]

Thought the sst was 1600fps, nosler is 1800 at impact. I'm a HUGE proponent of the Sierra prohunter and they DO start to open at 1800. You can go bonded on the 125 as well. Another option that may be worth considering is to push a Barnes 110 as fast as you can. Pushing the .308 down the larger bore will still lose slight amounts of accuracy and velocity. Hornady offers the 123 sp and sst for that 7.62 bore as well.

 

[DLrocket89]

Ahh!!! Hornady's recommendation for the SST is a minimum MV of 2000fps, not impact, so one would assume 1600 fps at impact is reasonable.

As far as accuracy goes, I've been happy with the 2MOA out of it. I'll be shooting open sights (peep on the back, globe with a post in the front) and I can't do better than 2MOA. Also - mounted a scope for accuracy testing so I'm feeling good that I'm shooting it to its capability.

Thanks for the reply Horsey!

 

[Decoy80]

It is dependent totally on how much you want to spend on components. Casting bullets is an option too. The cost of the brass being your largest item on the budjet. The job you have for it to do is not going to be hard to load for. You should be pleased with its reliability. Failure to fire is not acceptable.

 

[horsey300]

Ahh!!! Hornady's recommendation for the SST is a minimum MV of 2000fps, not impact, so one would assume 1600 fps at impact is reasonable.

As far as accuracy goes, I've been happy with the 2MOA out of it. I'll be shooting open sights (peep on the back, globe with a post in the front) and I can't do better than 2MOA. Also - mounted a scope for accuracy testing so I'm feeling good that I'm shooting it to its capability.

Thanks for the reply Horsey!

Absolutely, 2 moa is still dead at 150. Just making sure you knew about the 123s. And I'm not on the Barnes wagon, but if you find you need more punch than the 125-150s will offer, don't rule out the 110 coppers, they'll push through I'm sure, and the velocity should be impressive comparatively. I don't know how bad your bears are up there, but you brought em up so it's a thought too.

 

[Another_Kelley]

With reasonably accurate loads, getting about 2150ps (~1280ft-lbs) in my 125 grain loads and about 1950fps (~1260ft-lbs) in my 150 grain load.

Hi Dustin, I just have a quick powder suggestion for ya as I think you may be leaving some velocity 'on the table' so to speak - and that's A1680.
I've become a pretty big fan of it with 123gr .310s in my x39s. It produces excellent velocities without stressing your brass ~2500fps at muzzle in my 16'' M77 and an AR.

 

[DLrocket89]

Decoy - Reliability with cheap russian ammo was what made me look into reloading for the Mini anyways. Everyone says that the hammer spring isn't strong enough in the Mini-thirty to break hard Russian primers..I disagree. I put a heavy hammer spring in it and it didn't help at all. If you look at russian steel case, the primers tend to be recessed pretty far in. I think the Ruger firing pin doesn't protrude from the face enough, it's only .025" on mine. My handloads have been 100% (150 rounds down range so far) reliable, even cycling and locking the slide back with underpowered loads (20% under the starting load).

Regarding cost, running Prvi brass at present. It's kinda crap, in particular neck thicknesses. But whatever, it's not a benchrest gun, and the brass is cheap.

Horsey - Sounds good, think I'll try some 110's and see what happens. A few years back the state record black bear was shot about 10 miles away. 700+ pounds. So, yeah...20 rounds in a magazine, and faith in 100% reliability is the name of the game here, lol. I know it's underpowered for bears, but it's the gun I have so I'm trying to optimize it for the role.

 

[DLrocket89]

Kelley - Holy moley, that's excellent! I'll see if I can locate any of that. I have a Cabelas, 2 Ganders, and a good "Shooter supply store" nearby. Hopefully one of them will have that.

 

[DownInTheDark]

I know a guy that shot a black bear with a mini-30. I never did ask him what type of bullet/ammo he was using. I load soft points for my mini-30, 310 cal.

 

[DLrocket89]

Thought I'd put some pictures up. 100yards, 25F, 15mph wind.

Here's the best group of the day (22.5gn RL7, 150 grain SST, 1836fps - 14 SD - 28 ES):



And here's one of the worst (23.2gn RL7, 150 grain SST, 1911fps - 24 SD - 25 ES):


The difference between them? 0.7 grains of Reloder7. The Mini-Thirty is waaaay sensitive to load levels.

 

[DLrocket89]

Also forgot to mention, had a couple groups that were crazy consistent on velocities. Had one group that was 6.6 SD, 13 ES but was only 4 MOA, but they were vertically strung and at that point there was a lot of elevation change from powder charge to powder charge in there, so I guess I'm not surprised even though the velocities were really consistent.

 

[1stmarine]

Hi Dustin,
What is your max coal for each bullet imposed by the chamber or magazine whichever comes first?
With 308 bullets I suggest you stick them to the lands if you can.

 

[horsey300]

Decoy - Reliability with cheap russian ammo was what made me look into reloading for the Mini anyways. Everyone says that the hammer spring isn't strong enough in the Mini-thirty to break hard Russian primers..I disagree. I put a heavy hammer spring in it and it didn't help at all. If you look at russian steel case, the primers tend to be recessed pretty far in. I think the Ruger firing pin doesn't protrude from the face enough, it's only .025" on mine. My handloads have been 100% (150 rounds down range so far) reliable, even cycling and locking the slide back with underpowered loads (20% under the starting load).

Regarding cost, running Prvi brass at present. It's kinda crap, in particular neck thicknesses. But whatever, it's not a benchrest gun, and the brass is cheap.

Horsey - Sounds good, think I'll try some 110's and see what happens. A few years back the state record black bear was shot about 10 miles away. 700+ pounds. So, yeah...20 rounds in a magazine, and faith in 100% reliability is the name of the game here, lol. I know it's underpowered for bears, but it's the gun I have so I'm trying to optimize it for the role.

Underpowered? I think not, I'm not the biggest fan on the x39 (though a mini thirty is on the list) but you can still get a lot done with it if you'll be realistic of your expectations.Look at the figures on the .35 rem, it's nowhere near the almighty .300 wm but it's killed a few Alaskan brown bears. You're well within the range limits of that gun/cartridge. Low recoil, forgiving velocity windows (you don't have to worry about over expansion and bullet blowups at muzzle impacts), and a decent chunk of lead/copper flying downrange........it's definitely lethal enough at 150 yds and you can follow up as many shots as you need to just as quick as any ar but with more knockdown than a .223 the trick will be the right bullets for the job, which is something we all face anyway. Another Kelly brought up another powder to try for more speed, and a 125 accubond at 2500 fps, will expand at 1800 and remain in tact about as good as a Barnes, allowing you more energy as well, so for a 700 lb bear, any of the bullets that have been listed should suffice if you put em where they need to be. You won't get the spectacular hydrostatic shock of a FAST bullet, but your cartridge isn't under powered either.

 

[joneb]

My SKS likes Xtreme plated with H 4198, or Accurate 1680.

 

[Decoy80]

I dont have a mini 14 or 30 either but they are reliable platforms for shooting. I had no idea of the issue shooting the cheap ammo. I am currently feeding a Draco and it just wants more, brand doesn't matter ,steel,brass or poly coated it will gobble it up. What ive mostly been doing is pulling bullets and powder and loading the cheap steel cased ammo with my own receipe. The brass cased ammo is double the cost of the cheap stuff at present. I wonder if the issue striking the primers on cheap ammo is with all the mini 30 variants or something Ruger might fix if you sent it back. Once again failure to fire is not optional.

 

[DLrocket89]

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?

 

[DLrocket89]

Decoy - Ruger won't acknowledge there's a problem with it, though I'm about 99% positive it's the firing pin length. It's been totally reliable with the stock firing pin and heavy hammer spring on my reloads to date. Agreed, it needs to be 100%. And FWIW, I love the action design, how the gun functions, the weight/feel, etc. Great great gun, this is why I'm spending the time getting a good load worked up.

 

[1stmarine]

If you want more accuracy you have to explore the COAL relative to those lands. barely touching is ok. And also you willl be able to get more speed.
With Lapua brass and sierra 135gr + 27gr of R7 I get 2404 avg. from a 16" siaga. pretty accurate for a little carbine.

 

[DLrocket89]

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?

 

[hq]

Decoy - Ruger won't acknowledge there's a problem with it, though I'm about 99% positive it's the firing pin length.

Tip: check the bolt face around firing pin hole. More often than not there's a circular burr that can be reamed away with a drill bit, turning it carefully by hand. This fixed mine and it has shot all bulk and surplus ammo with no problems since.

As far as bullet selection is concerned, I'd look into actual .311 diameter bullets first. 150gr Barnes TSX might be a good starting point for an all-round deer load and it can be pushed to V0 of 2300fps+ from a 18.5" barrel if need be.

 

[DLrocket89]

hq- Yeah, I heard that, I did have a burr and knocked it back some. Didn't help in my instance. I'm guessing that the length of the firing pin is on the ragged edge of working with steel case and mine is just on the shorter edge of the spectrum.

Wow! I'm really down on velocities then. Do you recall what powder was used with that?

 

[hq]

Some aftermarket firing pins like Brownell's are slightly longer and need to be sanded or machined down to correct protrusion from the bolt face. If you're daring enough, you can remove ever so slightly material from the firing pin stop and see if it helps. Don't overdo it, though, or you risk puncturing primers.

IIRC the powder for that particular load is either Accurate A-2015 or Vihtavuori N130. I don't know the specifics as it's just one of my friend's loads I've chronyed and I'm just beginning to do my own load development for the Mini. The numbers a few of his loads have clocked so far are promising.

 

[DLrocket89]

HQ - my balls aren't big enough to mess with the stock firing pin. I did buy an aftermarket firing pin for it, but being a metallurgist I did a hardness test on it and it was dead nuts soft. Checked online and there were reports of the firing pin bending over on the bolt face, which raises the possibility of the gun going full auto. Passing on that option. I'm OK not shooting steel ammo in this gun, so I'm going to just keep reloading.

OK, sounds good, I'll see if I can find either of those. Please let me know if you track down the powder type and loading for sure.

Thanks everyone, the feedback has been great and really appreciated!

 

[Jesse Heywood]

For the best accuracy use bullets sized to the bore. You have a .310 bore, use jackets sized .311, lead .311-.314.

I had great results using Sierra #2300, 150 gr. sized .311. This is in an SKS using pulled steel cases. Not bad for aging eyes through a cheap 4X scope.

 

[HankC]

My SKS likes Xtreme plated with H 4198, or Accurate 1680.

Xtreme plated 150 gr? I thought it is only good to 1500 fps. What is your load?