cast boolits and the ar platform

[possom813]

What are the pros and cons of using cb's in an ar platform rifle, as far as the gas system is concerned? Namely .223 and .300aac

[oldandslow]

p813, 10/26/13

I cast and reload for rifles (0.223/556, 30-30, 30-06) and a number of pistol calibers.

For my LMT-AR 1:7 twist carbine I use a NOE 70 grain mold which drops at 72 grains with wheel weights. I heat treat and water drop to a BHN of 16. I use 20 grains of 4064 and get about 1950 ft/second. I gas check and pan lube. I have 600 rounds through my AR with no leading of the gas tube, bolt or carrier. Shooting it has become boringly reliable.

Problems- I had to find a COAL that would both fit the mags and not suffer too much boolit deformity with chambering a round. I started at 2.250" and had much boolit deformity and went shorter till 2.190" got no boolit deformity and good feeding from the magazine.

I could get higher velocities with more powder but as loads exceeded 2000 ft/second accuracy decreased and the boolit nose would twist off the boolit base at 2200 ft/second. I did have to put in a Wolf reduced power buffer spring as I was getting short-stroking with the standard buffer spring and the reduced velocity loads (compared to FMJ rounds at 3000 ft/sec.). The Wolf spring was available from Brownells. No more short stroking with the new spring.

I use a Lee push-through sizer to 0.225" and size and chamfer each case and use a Lyman M-die. I load these on my single stage RCBS and on my Dillon 650 where I have the M-die in the first position instead of the resizing die (I've already resized the cases on my RCBS before trimming any oversize cases).

So yes it can be done casting and reloading for a .223/556 AR but it sure is a lot of extra steps and time compared to just dropping in an FMJ bullet. When FMJ's were unobtainable casting was the only option. Now if you can get a good deal on FMJ's it may be a lot simpler. Good luck.

best wishes- oldandslow

[ofreen]

I shoot cast in 2 7.62 x 39 AR's. I built the 16" specifically for cast and it has never had a jacketed bullet through it. With the Lee 155gr bullet lubed with liquid alox and AA1680 at 1750 fps, accuracy is great out to 300 yards. No leading of the adjustable gas tube or BCG has occurred over 1500 rounds. I shoot cast in the 5.56 occasionally as well. There are no issues with leading of the gas system.

[AlaskanGuy]

There is a hole thread about casting a 62 gr MiH mold designed by fiver for the AR somewhere around here... Worth a look...

[fcvan]

I've been casting the Lyman 225-415 55 gr for .223/5.56 for a couple of years now. (Pistol calibers since the mid 1970s) Sized to .225 over 14 grains of 4227 has been the ticket for reliable cycling and decent accuracy. I will admit, working with the little tiny boolit has been a learning experience.

Getting good boolits to drop from the mold was almost instantaneous. In fact, the first two cast fell out of the mold and were keepers. Pre heating the mold and keeping the temp right is a must. I've lubed with Rooster Red, Lyman Moly, and settled on White Label BAC.

I played with copper electroplating and found it worked well (still needed a gas check) but was rather labor intensive. Now I powder coat with a Harbor Freight PC gun using flat black. I have a PatMarlins .22 CheckMaker pre ordered for when he ads that caliber.

Yesterday, I took out a new AR, sighted it in, and commenced to 'breaking it in.' The first 20 rounds were factory to adjust the sights. After 60 rounds of hand loads (as above) the rifle fully cycled and locked back on the last round every time. Pretty much the same result as when I finished and broke in my wife's AR two weeks ago.

Next month, I will be ordering the kit to finish a 300 blackout (I already have the lower) along with the dies, mold, and a push through sizing die. I already have a die for my Lyman 450 but really like the ease of pushing through a powder coated boolit. I already have a 30 cal CheckMaker die.

I'm getting decent accuracy with cast in the .223/5.56 but the 300 has a proven record of working very well with cast boolits. Powder coating has taken over as my method of choice for lubing boolits, and performance in my pistols and rifles has been awesome. And the cost factor. Yesterday, I fired about 170 rounds of .223 and it cost about $16 bucks. You can't beat that.

[capt.hollis]

There are definitely no cons casting for an Ar platform once you get the Oal,and load right. The toughest issue I had was getting the Oal correct. I had some great help on here getting there . On the 155-312 mold the sweet spot was 2.050. Very very sweet bullet !