300 Blackout AAc 150 grain lead cast bullet load, Anyone gottem to cycle in a AR

[Jupiter7]

What OAL length are you guys loading the Lee 312-155-2R to? I'm starting to work this up with W296 and #41 primers. Water dropped wheel weight alloy and copper gas check sized to .309. Gun is AR15 16" parkerized heavy barrel, 1:8 twist, carbine gas.

Not exact but to the crimp groove.

[6622729]

Not exact but to the crimp groove.

Ok, that should put the COAL just inside of 2.020".

[Jupiter7]

Ok, that should put the COAL just inside of 2.020".

Sounds about right

[6622729]

Sounds about right

Ran 14 rounds through the chrono. Same 15 grain powder load of W296 but varied COAL with the Lee 312-155 cast boolit. Ran great and bolt locked open on last round. One round didn't cycle the action but this is not my battle gun and it is brand new so either way I'm not concerned. All fired, no fliers and an average of 1800fps. Very happy with the start. Barrel looks clean.

[Blammer]

14gr of lilgun cycles mine just fine.

[6622729]

I use 15.3gr h110/w296 with the lee 155 312 boolit. Gives me about 1850fps in out 16" uppers.

Just starting with a 155gr casting and 15gr W296/H110 is 1800fps. Perfect cycling and great accuracy. I have yet to read anyone having much success with the 309-150 bullet in an AR. I'm using the Lee 312-155-2R with copper gas checks applied in a Lee .309 sizer. From a load standpoint 150gr is going to be very similar but the shape of the Lee 309-150 might be a pain in an AR. The 312-155-2R on the other hand works great in an AR loaded to a length of about 2.010-2.015. That's where the crimp groove is. That is going to be THE cast bullet in 300AAC for me. The flat base mil-spec M2 copper FMJ is my other 300AAC projectile. I'm only shooting supers, no subs.

[Rwoods61]

Has anyone worked up a load for the Lee C312-185-1R sized down to 309 for sub-sonic shooting.

[Moonie]

Has anyone worked up a load for the Lee C312-185-1R sized down to 309 for sub-sonic shooting.

Generally weights above 200gr are required for proper cycling, however if it isn't an AR, or you aren't worried about cycling it can be easily done.

[Rwoods61]

Moonie, I really did not put enough information in my original post. I will be shooting from a AR platform. I have not bought the upper yet. I am looking at a 16 inch barrel with a carbine length gas system. I might have to go to a pistol length gas system to get the gas pressure to cycle the action. still lots of reading and questions to ask else where. I was hoping for some experience from others who have gone before me to keep me from duplicating the same mistakes.

rwoods61

[6622729]

Moonie, I really did not put enough information in my original post. I will be shooting from a AR platform. I have not bought the upper yet. I am looking at a 16 inch barrel with a carbine length gas system. I might have to go to a pistol length gas system to get the gas pressure to cycle the action. still lots of reading and questions to ask else where. I was hoping for some experience from others who have gone before me to keep me from duplicating the same mistakes.

rwoods61

I am shooting the 312-155-2R in a 16" carbine length AR. Bullets are COWW tumbled lubed with 45/45/10. Loaded to the crimp groove and medium crimped. CCI #41 primer 15.3gr W296 and copper gas checked. About 1850fps. Cycles fine, does not always lock bolt back. May change the buffer spring.

[6bg6ga]

The solution is simple. Pistol length gas systems are the answer. I shoot anything in my 300 blackout with its pistol gas system and it functions flawlessly. Want to tweek it a little? Its a simple answer adjustable gas block.

[Loudy13]

Guys I have a Ar 15 300 AAC rifle with a 16" barrel, full length gas tube. I have been pouring cast bullets, but have not tried the 150 grain lead cast as of yet. My mold is the Lee 2 cavity 309-150. Have any of you had luck with a good load that will cycle well with this mold size? I have plenty of "Lil Gun" powder, and have great success cycling with a 150 grain fmj bullet using 15.5 gr. Do you think the load will come close to the same as the fmj bullet I've been loading? I know I'm venturing into different territory here with a lead cast bullet, and also I am Epoxy coating these bullets, and going to be trying them out without a gas check.
Thanks You Guys

Have you set a COL for this round? I just cast about 80 of them last night and looking for some place to start as far as seating depth.

Thanks

[BlackoutBuilder]

Is 20.0 gr Accurate 1680 too hot for 150 gr Powder Coat ?

[Moonie]

Moonie, I really did not put enough information in my original post. I will be shooting from a AR platform. I have not bought the upper yet. I am looking at a 16 inch barrel with a carbine length gas system. I might have to go to a pistol length gas system to get the gas pressure to cycle the action. still lots of reading and questions to ask else where. I was hoping for some experience from others who have gone before me to keep me from duplicating the same mistakes.
rwoods61

We have had a couple of 16" carbine length gas and with the correct powders they cycle just fine with standard BCG, carbine buffer and spring. Powders in the 1680 range do very well for subs, RL-7 is the one I've had the best luck with for subs (200+gr). We have had good luck with 15.3gr of W296/H110 with the Lee 155gr.

[Moonie]

Is 20.0 gr Accurate 1680 too hot for 150 gr Powder Coat ?

Should be fine, I would start a little below that and work up as it appears to be close to a max load to make sure though.

[tygar]

I have tried several cast & jacket loads in the 147-155gr range & all cycled fine. No idea of speed cause havn't chronyed but all worked. All were loaded so ogive was a little off l&g.

[MK111]

Just ordered a 10.5" upper and a pistol lower in 300 BO. I believe the barrel has a carbine gas tube length.
I always shot RCBS SIL 165 gr. cast bullets when shooting SIL with my TC Contender 30 M1 Carbine. It would shoot good sub 1" 5 shot groups off sand bags at 100 yds.

Any recommended loads for the 165 gr lead hard cast in the 300 BO?

[popper]

16 of 1680 under a 170 PB works fine in my 10" pistol.

[jimb16]

I must be the luckiest guy in the world. I have yet to find a load that didn't cycle! I've tried 7 different powders and run charges from 2 gr below recommended start up to near top. I use plain base 130 gr and 150 gr cast, powder coated. My AR is a home-built .300AAC with a carbine length gas tube. Some of the loads weren't very accurate, but they have all functioned perfectly.

[tygar]

Shot a bunch of 150-160GC yesterday & while all cycled fine, I had to really seat them deep to chamber them & none shot very good at 100. Best was about 4" for 5 shots. Tried several powders H110, 4227 & a couple others.

Went to 130 SPGC & 125GC which cycled & loaded fine at crimp groove. Still did not shoot any better than the others.

Jackets from 147-155 shot OK but not great 2-3". Using a red dot so putting scope on it to shoot next time.

Don't see how I can even get heavier bullets to seat.

Just not getting accuracy any where near the 223s.