Cast bullets for AR

[darkman]

I was thinking of buying Lyman's bullet mold #225415 for my new stag rifle. It has a twist rate of 1in 9. I have two questions. 1. If I use 9.0 gr. of Red Dot per Lyman manuel, will that be enough powder to cycle the action properly? 2. Should I size this bullet to .225 or .224?

[fcvan]

I'm using that boolit with IMR4227 as it is in the same realm as other powders on the burn rate scale. Red dot is far too fast to cycle the action. It will propel the projectile to the desired velocity but lacks the volume of gas needed to sustain the pressure wave all the way to the gas port.

I size to .225 and have shot with White Label BAC, but lately I've been powder coating. I use an electrostatic gun, bake, and then apply the gas check when I size. My AR and Mini 14 love this boolit!

[darkman]

Thanks. I will go ahead and order that mold, and try the 4227.

[grampa243]

i size to .226

[GabbyM]

Specs on a 5.56mm NATO chamber have a .2270" lead and a bunch of free bore.
223 Rem chamber spec is a .2245" throat. I size all my 22's to .225" and they fit my two 223 rem Chambers. They are just undersized if I shoot them in my NATO chambered rifle. .225" is all the larger my Lyman #225646 drops a bullet.
For a 1-9" twist AR with a NATO chamber. I'd go to one of the heavy bullets that cast .227" bullets. 70 grain bullet will help with achieving recoil function on the bolt at low velocity.

[upnorthwis]

I tried 4227 in my 1:9 with a 55 gr. RCBS per a recommendation and it didn't work at all. By the time I got enough powder to even move the action, the primers were flattened. Was also shooting an 18" pattern at 50 yds. Went to 22 gr. Accurate 2520 problem solved. Tried to chrono but Oehler 35P has trouble in the cold. Should have brought a hot water bottle and blanket with me.

[GabbyM]

That sounds like typically reported results upnorthwis.
I got my 20 inch to work with 4198. But it held the bolt back on last shot by the mag follower. Tells me the bolt isn't coming back all the way behind the mag body. That's pretty close to not working. It's my bolt action rifle load of 14.5gr H-4198 under the Lyman #225646 which weighs a full 60 grains from 2:6 alloy not the 55gr advertised. I'd choose a notch slower powder for a dedicated AR load. H-322, Benchmark, 4895 area. Reloader 7 may work as it takes a little more powder than 4198. 16 inch barreled AR's with the short gas system are easier to feed gas pressure to.

[Cmm_3940]

HM2 225-62-1 using 22" 1-8 bbl. 17.8gr Accurate 2230 works fairly well for me.

[upnorthwis]

Got the Oehler 35P working today. Remembered that last year in the cold had to wrap it in a beach towel to keep it warm. First shot was with my thread #6 load of 22gr. Accurate 2520 and 55gr. RCBS = 2660 fps. Lowered 2 grains to 20gr. = 2360 fps. Still locked bolt. Then 19 gr. = 2305 fps extracted but did not lock. Will start with the 20 gr. load at 3-gun matches until I have a failure to feed, then start going higher. These were only one shot apiece over chrono and sized .224 in 20" barrel. Accuracy is good enough for 3-gun. Big targets @ short range.

[knobster]

Great thread. I'm currently looking for a good recipe for my AR. So far my attempts with IMMR 4227 and 55gr boolit have failed. Will eject spent case but will not chamber the next round. Found a Varget recipe on another forum that I have yet to test. Once the temperature climbes above -100 I hope to hit the range again.

[Jailer]

Try some 4895. 18gr would be a good starting point and you'll likely get better accuracy with a slower powder. I get proper functioning and decent accuracy at 19.5gr H4895 in my midlength and rifle.

[fcvan]

Wow, 14 grains of 4227 behind the Lyman 55 gr 225-415 has been my go to load for my Mini 14 and my AR. Of course, the AR needed some break in before it would fully cycle. That, and a bolt sloppy wet with oil. After about 60 rounds of factory/full house reloads, the Lyman boolit consistently cycled in the just built AR.

The 14 gr load of 4227 is supposed to give 2193 fps at 23,200 CUP according to the Lyman 49 manual. I need to chrono my loads and compare lubed lead and powder coated to see where things are shaping up. For the guy who was getting full cycling with 4227, I read where a guy was having a similar problem in his 300 blk. It turned out his gas port was either too small or partially blocked by misalignment of the gas block. In any case, 14 grains works very well for me.