Type 56 SKS with IMR 7383 and Blue Dot today

[Maven]

As you know from my earlier posts, I've had difficulty finding a suitable propellant locally. (By suitable, I mean one which will operate the action.) Yesterday, just for grins, I decided to see how many grains of IMR 7383 a FL sized 7.62 x 39mm case would hold when topped with the NOE 316SP-GC CB seated to 2.125". Using Jim Conner's method,* repeated 5X for reliability, I came up with 22gr. In spite of dire warnings from several people on other boards, I loaded 3 such cartridges with that load and with great trepidation, fired them earlier today. I was also able to chronograph those 3:


22gr. IMR 7383 (uncompressed) + NOE 164gr. CB @ .3155" & 2.125" OAL -> 1,389 fps +- 26 fps.


There was no sign of excessive pressure; all 3 cases ejected and cleared the rifle; and accuracy @ 50 yd. was good (3 in 1.5"). Btw, there was little unburned powder left behind and the cases weren't smudged in the least. I'll next try 21.5gr. 7383 with the same OAL v. 22gr. and 2.215" OAL, but I'm beginning to think the shorter OAL is more accurate (see below).


The remainder of my testing today (at 50 yards) was with 12gr. Blue Dot (11.8 -11.9grs. in fact) and the NOE CB seated to 2.125". 6 of the 10 went into 1" and 4 of those into 3/8"! The remaining 4 grouped into 1", but 1" higher than the others. That was probably the best accuracy I've obtained so far with this particular SKS. Here's the chronograph data:


11.8 - 11.9** gr. B. Dot + NOE CB @ .3155" & 2.125" OAL -> 1,531 fps +- 30 fps






*Drill out the primer pocket on a FL sized case; seat CB to OAL you'll be using; fill case to origin of primer pocket (tap the case to get a proper fill); weigh and repeat to get an accurate reading.




**what my Lyman pistol powder measure throws with rotor 10S

[Yodogsandman]

It's interesting that you tried IMR 7383, is it the surplus powder?

[Maven]

Yes, it's a surplus powder, but my #7 jug doesn't have a lot no. However, it mimics IMR 4350 in the .30-06 with jacketed bullets, but is a tad slower in the .243Win. with 85 - 90gr. jacketed bullets. Btw, I loaded 10 new cases with 22.0gr. (weighed) 7383 and the NOE CB and 10 more with 22.5gr. and the NOE CB (22.5gr. is almost 103% loading density). I'll chronograph both loads and examine each case for pressure signs, which I hope won't be present.

[Yodogsandman]

I sure hope one of those work for you. A clean, accurate load, that works the SKS action AND is a cheap, available, surplus powder....now that would be just perfect!

What type of sights are you using? That's some great shooting if it's with the original military sights!

[Maven]

The rifle is entirely "as issued." However, I did have to adjust the front sight for windage and elevation for the more anemic charges of Unique and Blue Dot. Eventually I'll test it at 100 yd. to fine tune things, but anything better than 3 m.o.a. at that distance will be a gift.

[nekshot]

huh,7383 that isn't supposed to work!! I have a jug of that and I am gonna try some this week. I settled on levrolution powder for mine for serious shooting. I rebuilt my stock and ran a bolt into the rear spring housing to keep it snug against wood at all times but it did not help accuracy as much as I hoped for. Still shoots good all things considered as yours is also!

[Maven]

nekshot, If some of the responses I got about using 7383 in the 7.62 x 39mm cartridge are to be relied upon, you'd think I was inviting a Zombie Apocalypse or worse:

"I suggest you don't load this powder below 100% density at your 22gr. 7383 (uncompressed). This is shooting safely for you. Reducing below that is heading toward danger and dirt. IMR7383 is safe to compress. heading carefully in that direction monitoring pressure signs should be productive with the powder. 103% of your capacity load will likely be the ticket if there are no pressure signs. 22 + 3% = 22.66 gr IMR7383."

I loaded 10 more (new brass) with 22.0gr. and 10 (also new brass) with 22.5gr., but need to wait for a cloudy or partly sunny day to chronograph them. The 3 rounds I fired ejected with almost no unburned powder or soot/smoky necks left behind. They even hit the target in a nice group!:shock:

[Yodogsandman]

Maven, I just ran into a problem that could lead to disastrous results for you! I found that without crimping, my boolit was pushed back into the case when loading from the magazine. Wouldn't that over compress that IMR 7383 to the possible point of being a dangerous load? I don't have any experience with IMR 7383 and might be full of beans!

Is it possible for your boolit to be pushed back when feeding?

I got a Lee universal expanding die and a NOE expander plug .313"x.318". I adjusted it so the case neck would barely fit all the gas check into it. I sized my HT'd boolits to .314" using 2500+ lube. I'm currently working with dummy rounds to get the length right. At 2.115" the boolit is pushed back to 2.090" and engraving. I'm thinking about lightly crimping at 2.095" to take advantage of just a little engraving without the boolit being pushed back on me. Still thinking...

[Maven]

Yodog, I replied to you on the NOE Forum, as I visited it before coming here.

[Yodogsandman]

Just glad you were aware of the possible problems before I thought of it!

[nekshot]

Just glad you were aware of the possible problems before I thought of it!


If you get the boolit to set back with 22 gr of 7383 you are in reeeaall trouble in more ways than one!!

Shot the 22gr of 7383 in my 7.62x39 bolt rifle with the lee 160 grainer and the boolits were culls but that was as nice of a recoiling load as you could want. I am gonna try more of this stuff in small cartridges!

[Maven]

nekshot, The occasional setback that I got was with a longer OAL and 10 -12gr. charges of Blue Dot. I.e., there was plenty of room for the CB to move backward into the powder charge. With 22gr. 7383, not so much!

Btw, I'm glad 22gr. is working for you. Although 7383 is certainly different, if you're careful with loading, charge wts. compression, etc., it is no more dangerous than any other propellant I've used and won't bring about Armageddon (in spite of what's been said on the internet):shock:. When using 7383, the chronograph is definitely your friend.

[Maven]

I tested the 22.0- and 22.5gr. loads of 7383 with new Privi Partizan brass and the NOE CB (164gr.) today, but couldn't get a chronograph reading because of the sun. (Wouldn't you know it, not 10 minutes after I put it away, the clouds rolled in.) What I can tell you is (1) that both loads cycled the action perfectly, although the 22.5gr. charge did so more vigorously. (2) There was neither leading or unburned powder in the bbl., but perhaps as much as 15gr. in the magazine well. (3) Based on only 3 chronograph readings, I estimate the 22.5gr. load produced 1,400 - 1,450fps. (It certainly was less than the 1,529fps I got from 11.8 - 11.9gr. Blue Dot*. It struck the target about 1" lower too.) (4) The extra 0.5gr. seemed to tighten the group as well, but I'm not certain since I'd put the chronograph away** and only had to focus on the target and where the brass landed. (5) The fired brass was essentially clean with only a barely noticeable layer of soot on its surface.


*What my Lyman pistol powder measure throws with rotor 10s
**When I chronograph my loads, I have to focus on the machine & target (so I don't hit the former), the reading so I can record it, and with the SKS, where the ejected brass lands so I can recover and examine it. In short, I rarely shoot as accurately when it's in place.

[nekshot]

I drilled some extra holes in my gas tube as Larry Gibsons thread outlines and now the sks is actually fun to shoot. Alot less clanging and the brass doesn't disappear as easily.

[nekshot]

I drilled some extra holes in my gas tube as Larry Gibsons thread outlines and now the sks is actually fun to shoot. Alot less clanging and the brass doesn't disappear as easily.

[Yodogsandman]

I have a selector switch on my Yugo's that shuts the gas off and I can run them in single shot mode. I've heard that if you remove the gas rod in yours, it can be run as a single shot, too. No more chasing the brass!

[Maven]

It is true, Yodog.... Removing the gas piston does make it a straight pull rifle. Indeed, I used to routinely do that with my first Type 56. However, I think accuracy was better with the piston in place even though I don't relish chasing brass either. Btw, on the next cloudy day, I'll chronograph 22.0, 22.5, and 22.7 loads of IMR 7383. Also, if you use this propellant, check the magazine well for an accumulation of unburned powder.

[madsenshooter]

Your 7383 must not be from the same lot Jeff is selling now.

[Maven]

madsen...., No it's from a lot I purchased years ago for very little $$ for a 7lb. jug. Btw, the 7383 I'm using seems to be the same "speed" as the 1st jug (I bought 2), but there is no info. on the jug re lot no. or any other pertinent data.