Your 300 AAC loads?

[DukeInFlorida]

Not enough velocity to stabilize that heavy bullet. Combined with the short barrels = key holes

Is there a reason to use those heavy bullets?? I have wonderful performance with 150 grain bullets.
Most people loading the 220 bullets are striving for shooting them through a suppressor, and staying SUBsonic. You didn't mention that in the post.

So, unless that's your goal, go lighter on the bullets, and you'll have much better success.

BTW, I ONLY EVER use Lil Gun powder for my 300 Blackout loads. It's got a perfect burn rate for the chambering.

And, properly neck sized (Full length sizing only!), there will be enough friction between the necks and the bullets to hold onto the bullets while the powder all burns inside the case , before the bullet leaves the case mouth. So, no need to ever crimp (unless you are seating cast lead bullets, after "M Die/Lyman" expanding the necks.) Otherwise, no crimps, and you will get better consistancy of the velocities.

[tsubaki]

I bought or had a few differing weights and styles of bullets and felt the need to try them.
It got so bad I also started buying more firearms to experiment with too!
The 300aac has turned into a very interesting caliber for me! My only real interest is for hunting purposes. No real intent for the need of subsonic or suppressed.
In the 7 1/2” barrel the favorite has become the 150gr Hornady RN with 1680. With the 16” barrel the 135gr Sierra HP has become the favorite.
The cast powder coated Lee bullet loads was basically because I had all the components on hand. I will play with them a little closer in the 11 1/2” barrel.

[Mbaker78]

My go to subsonic load was 9.X gr of IMR4227 under a 240gr cast coated bullet with the 10.5” 1:8” barrel, since switching to a 9.5” 1:7” barrel I’m getting keyholes (but it was about 40 degrees cooler than when I first worked up the load) and baffle strikes. Luckily there’s no damage to the can, but I was getting lead pieces clear back in the fire control group. So that load will be saved for warmer weather and retried (without the can first).

My next task is to get some of the lee 230gr cast to try them out, probably with 1680 as I have a pound of that on the shelf.

[b2lee]

Tomorrow...unless I can't handle the cold...I'm going to shoot some 150gr plated flatbase flat nosed bullets I got from everglades ammo....I got loads from 8gr to 17gr loaded in .5gr steps...going to measure speed, deviation of 5 shot groups, accuracy...and keyholing....and at the top of the range at 2000+fps...how well they work since they are warned as low velocity bullets due to copper plate...we'll see.

Edit...this is with Lil'gun.

[Mbaker78]

If it’s abnormally cold, your velocities could be lower than expected. And it seems like lilgun is somewhat temp sensitive.

[b2lee]

It was 28F when I shot...data was a little off from what I expected...I think I'll go out and test 12gr-17gr once the temp rises above 60F...I think it was more of a: "me get out of the house and go shoot" thing...than it was an actual gathering of good data...was fun...but now time to warm up with some KY Bourbon and watch YouTube videos of 300PRC rifles...since that is my next project.

[Mbaker78]

I think my next project will likely be a decent bolt action 22lr, it should be a decent challenge to shoot it out to 300 yards effectively, and a lot cheaper than my 308

[DukeInFlorida]

After you fire the .22 LR bolt action rifle, save your brass to make these:
http://castboolits.gunloads.com/show...tart-to-finish

Free bullets, which makes your AR15 reloading very cheap. I make those by the tens of thousands, and my only cost of reloading is the primer and powder.

And, I also make my 300 Blackout and 308 Win bullets from scrap 5.7X28 FN brass (as the donor jacket):
http://castboolits.gunloads.com/show...-x-28-FN-brass

I also make 380 auto (100 gr) and 9mm (125 gr, Both from 223 Rem Brass); and .40 (165 gr from 9mm brass); and 44 caliber (various weights from .40 S&W brass); and 45 ACP (230 gr from .40 S&W brass); and 500 S&W Magnum bullets (from 45 ACP small primer brass), all virtually for free. Check out the SWAGING area of the castboolits site for details on how to do this. The tools are expensive, but have paid for themselves many times over at this point. Some guys with machining skills even make their own tooling. The swaging is all done on a modified RCBS Rockchucker (the old model) press. Grade 8 pivot pin for the bottom of a custom ram (1/2-20 threads at the top instead of the normal T-Slot.

[b2lee]

I do the .22lr to 5.56 using a set of corbin dies....I do the 9mm to 40S&W using some BTSniper dies. I've made enough 40 to last a lifetime.....and I'm only about 5k bullets into my 22lr to 5.56 journey...but a fun journey it is.

[Pacomdiver]

im still saving up to complete my 223 bullet making set, ive gotten them a piece at a time. i still need the point finisher die and a core mold

[Mbaker78]

I’m nowhere near being able to afford the dies to make my own jacketed bullets yet... I still need to get set up to try casting for the pistols.