300 Blackout cast & poeder coat - trial notes

[StromBusa]

I had a day off and ran some experiments with 300 blk cast loads.

Mold - Lyman 2660410 , WW + tin, sized 0.309", HF Flat Black PC, sized 0.309
Weapon - AAC MPW SBR (9")
Powder -IMR 4227
COL 1.822

Section 1: Speed testing (~4 shot averages)

14 Gr. 1424 fps
15 Gr. 1536
16 Gr. 1659

comments: speeds were consistent, no evidence of leading

Step 2 - accuracy testing

50 yards

poor "groups" at all above loads

Step 3

downloading

12 gr. (cut holes, won't cycle)
13 gr. (cycles good, locks bolt back on last round-group opening up)
12.5 gr. (cycles good, bolt not locked on last round, group intermediate to 12 & 13 gr. 3 shot -1.25")

Conclusions:
accuracy load is closer to 12 gr, however not cycling - wish I had a bolt to check it - Ruger Ranch.....or a can.

It was getting dark when I finished, so I will resume testing at 12.5, not too worried about bolt not locking back for bench work.

13 grains will likely be my goto for close work on the steel targets
lighter loads are tighter groups
nice to see that the hotter loads did not lead
it will be a long time before I cut holes @ 100 yards with this boolit...
I'm thinking about flaring the cases a little and trying some sized, coated, loaded - someone wrote that it tightened groups.
I will chrony the light loads.

Final conclusion...SBR is fun! Need massive supply of WW....:veryconfu

[popper]

Fps/load looks about right for that AK boolit, you may need to H.T. after coating. Try manual loading to see if accuracy improves, using a scope or irons?
lighter loads are tighter groups A sign that your alloy is not hard enough for that twist. Try coating the base & bands heavy, size then oven treat. Adding some Cu to the alloy will probably help also. You might find some IsoCore from here, it seems to shoot good and is cheaper, similar to COWW. Yea, just made another 10# of alloy yesterday, sure go through boolits fast in the BO.

[StromBusa]

Thanks Popper, I have lots to work on, I will plan another round with heavier boolits. This is all preliminary "rough" evaluation. I used 6 power VX-6, but no bags.... My cheeks were hurting from rattling the iron (permagrin), figured it's time to see what I can do on paper... Can I really alloy Cu with the lead @1984 degrees F, I have pennies to spare? I think the AAC has a 1 in 7 twist, pretty fast. I never even slugged it due to I had to gather up components while waiting for the class 3.... Do you mean coat, cure, size, heat treat - Temp? Perhaps water dropping could also help?

[cs86]

I just finished an ar-15 300 black out build. Has a 16" barrel with a pistol gas system on it. I took it out last weekend to run some functionality tests. Tried 3 bullets and 4 powders. Found that 2400 didn't work well at all for any bullet. Had luck with lil gun and H110 when using a 150gr jacketed. I tried some cast with carnuba red lube and the results varied with h110, lil gun, and 5744. I was testing a lee 180gr and a NOE 188gr boolit. The lee mold seemed to lock the bolt back more often then the NOE bullet did. I was surprised that I wasn't getting full functionality with all my tests with the barrel design I went with.

[Sgtonory]

I am doing some testing with a 230 Lead bullet from the group buy that A.C.E did. I am trying to find something that will cycle the action. Out of a 16 inch gun with carbine gas system. I took all the weights out of my buffer and that helped a little. Next i took about 5 coils off my recoil spring going to test that tonight and see if it will cycle. My load so far is 11 to 13 grains of Alliant 300 MP

[StromBusa]

H110 cycled flawlessly for me, more "abrupt", but speed varied considerably @ light loads.

[kweidner]

I have 3 blackouts. One in an encore, one in a 16"carbine length and one in a 10.5 shorty. Shorty will cycle everything including 2400, 1680, 110, and 4227 subsonic with a 250gr cast. There is a reason I got the shorty. The frustration level of the carbine even with .125 gas port in bbl was enough to make me almost loose my religion. I cut springs too to get carbine to cycle even 1680 with cast and subs. The shorty digests it all suppressed and non with full lock with regular spring. Carbine is for my swaged bulllets now I use cast in shorty and encore.

[kweidner]

give this a read. I have found this to be very reliable. Also about a grain lower of suggested loads in jacketed gets you real close in cast. http://micromoa.com/?page_id=496

[wlc]

I am doing some testing with a 230 Lead bullet from the group buy that A.C.E did. I am trying to find something that will cycle the action. Out of a 16 inch gun with carbine gas system. I took all the weights out of my buffer and that helped a little. Next i took about 5 coils off my recoil spring going to test that tonight and see if it will cycle. My load so far is 11 to 13 grains of Alliant 300 MP

I've got the same mold. So far what I have found with my rifle, also a 16" carbine gassed AR, is that 1680 is the most reliable to get complete cycling and BHO while remaining sub-sonic. I have about settled on 10.2gr of 1680 under that bullet (mine actually drops at about 225-226gr) sized at .309 and an OAL of 2.22(IIRC, Notes not close right now) with a firm crimp. I shot a 20 shot group that was roughly 1.5+- at 50yards with it while function testing. RL7, IMR 4227 have also given acceptable results, but not the consistency of function that 1680 does.

If you are not concerned about subsonic loads then you should be able to get several powders, including those I mentioned above to cycle just fine with that bullet and your gas system.

Do you shoot with or without a suppressor? Mine have all been suppressed shots other than stability checking all new loads.

[fcvan]

I have 2 300 blk, both built from Model 1 Sales with E R Shaw barrels. First one is a 16" carbine, the next is a 9.5" pistol with pistol gas port. The only powder I've used has been 4227, and I've burned up 8lbs already. I started out using the Lee 312-155 2R powder coated with a starting charge of 14 grains, working up to 15.5 gtains. I was running loads through my neighbors 300, make unknown. 14 went 1800 fps, 14.5 went 1900 fps, 15 went 2000 fps, and 15 went 2100 fps. We then tried some that were lubed with 50/50 liquid Alox and mineral spirits, 2 thin coats. Those were also loaded to 15.5 and went 2300 fps. We were shooting at 6000 feet. Those same loads when fired at 250 feet above sea level were on average 150 fps slower than at altitude.

the Lee 155 was too fat for my 300 as they hung up when clambering and some of the boolits would get stuck in the bore. I picked up the Lee 309-230 5R and ran it with ESPCd and ASBBDT without a hitch. 10 grains gives a consistent 1075-1100 fps, but I've only fired them from the pistol. Next time out I need to compare the subsonic loads in the carbine. I did do a side by side between the carbine and pistol and had a consistent 50 fps loss with the pistol.

i recently bought the NOE 309 150 SP and LOVE IT! What a fine mold, cast keepers right out of the box. Well, after I scrubbed it down and lubed with 2 cycle oil on the pins. I've loaded up a bunch, sized to .311 using home made aluminum checks, and shooting is a hoot. 4227 just seems to be the powder for my shooting needs with this cartridge. Well, that and my .308 AR 10. The NOE over 28 grains gave me 2050 to 2065 fps, lowest spread I've ever recorded. But that is another gun, another cartridge, and another new obsession :)

[popper]

StromBusa - look at my 31-145C experiment thread (145 gr FN PB). Started with a 1:7 carbine but gave it to SIL last week, using 1:10 now. I use 8/2 isocore/Pb and add ~800 gr. CuSO4 @ 750-800F. Skim off the residue (dispose of carefully and use a painter's mask), cast ~ 720F. IsoCore is ~ like (old) COWW. Targets I posted there are leaning over the rifle, which is on bags, not very good. Gotta make a riser for the range chairs. I am using HF red (base coated too), cook, size, H.T @ 420F for 1 hr, then into cold water. I've loaded some @ 17.5 gr. 4227, need to chrony them but they are really hard on brass (PP).
My best load in 308 is using H335 - 2500+ fps, ~ MOA @ 100. 4895 does almost as well.

[cs86]

You guys crimping your cases for the 300blkout? I tried with my seating die and all it did was crush my case. I have a lee factory crimp die coming. I'm hoping that works.

[Smoke4320]

yes I use a Lee FCD and doing so gets me more consistent burns and smaller groups ..Light crimp... enough to hold the bullet but not swedge it down

[Faret]

Anybody try 11.5 gr of 4198 with the lee 309-230-5r?

[Smoke4320]

StrumBusa
If I can make a couple suggestions ...
first I would try some bullets sized .310 and .311.. My gun and several other I have worked with locally saw accuracy improvements at powder coated and sized 311... all measured bore sizes of 308 or 3085.. Why it got better I do not know just know it did

Also applying a light crimp using a lee Factory Crimp die helped both velocity consistency and accuracy

[Moonie]

I like around 14.5-15gr of RL-7 with my 230-235gr boolits, cycles both of our carbine length 16" 300's.

[StromBusa]

Thanks for all the help guys, too cold right now for trials. No Accurate 1680 to be found in these parts, yes crimping is fussy with the Blackout, I think I'll get the Lee factory crimp (update: ordered...er...backordered). I better slug the gun & experiment with the sizing die. Planning to try some sized & coated (to leave upsized) before I hone out my die. I guess I better get a Lee set for that too... I don't want to hog up the RCBS lube sizer. Then there's my alloys.... And I have yet to mess with the jacketed varieties on my shelf.... Next up...Ice fishing...new gear this year :-P

[Moonie]

I use the Lee FCD for all of my rifle cartridges, especially those used in semi's

[sparky45]

Follow Smoke's advice, you'll get excellent results.