What hardness should I be using for .300blk subsonic 230gr?

[Pyrex]

I'm actually using the NOE 247 and crimping in the groove. Bought a Lee 230 but it looked like **** out of the box and I didn't and I endied up not using it

Yeah I had burrs around the bearings. Not the prettiest die, but I drops okay, have to pop it open rather violently to get a clean drop, but it works. If I can get it shooting decent and this turns out to be a solution for me I'll have a custom mold made without any lube grooves.

[dh2]

I am using 100% COWW having no problem with it

[Pyrex]

I am using 100% COWW having no problem with it

What are you sizing to? My mold drops a .310-.311, and I'm resizing to .309 to start, see how that does.

[Pyrex]

well, rather disappointing trip today. I was getting keyholing (as in 90* to target) at about 20-30 FEET. So definitely having some stability problems. I'm guessing 1:8 twist isn't enough on a 6" barrel to stabilize. Looks like I will have to go to a 1:7 to get these 230gr to fly right.

[runfiverun]

that or speed them up a little.
I use thinner brass [prograde] that just allows me to get a 310 boolit in the case and chamber it.
I save the thicker 223 brass for 308 projectiles.
the LEE boolit is tapered from the drive band forward [mine is anyway] allowing me to move the boolit in and out of the case if I single shoot them.
the length is just right if I seat out to my longer bolt guns magazine, instead of the normal oal for an AR magazine.
I know this isn't much help but the brass thickness to your chambers diameter might help alleviate or point you to your issue.

[MGnoob]

My concern is I'm firing them out of an m16 on full auto, so the barrel is going to heat up quickly. I'm not sure if hardness plays a role in leading with that.

They're not in the barrel long enough to matter, i guess unless you have a round chambered and not firing....and even then it won't matter

i found it interesting in my full auto tests that if a particular loaded projectile had an imperfect drive-band/base you could feel it when firing due to a slight interupsion in the consistency of cycle speed...I really enjoy when i fire it and it's a total consistent sewing machine. it puts an even bigger smile on my face knowing i have achieved "perfection" whilst reloading..

Now with the little subsonic experience i have, IMO it's ideal to have the alloy as soft as possible, it is where i found my best accuracy.
As you increase in speed(supersonic) you may need a slightly harder alloy or different bullet profile to prevent "nose slumping"

*edit* speeding them up may help, but if your goal is sub-sonic you may not be able to go faster
Also they need to be hard enough or seated deaper to withstand there trip from magize ,feedramp,chambering.
If the projectile gets bent they can jam..usually they'll still chamber and fire but makes for inconstancy in accurcy

[243winxb]

http://www.bergerbullets.com/twist-rate-calculator/ Fine the twist rate needed. Harder alloy is needed. High rate of twist with soft alloy may let the bullet strip the rifling.

[Pyrex]

http://www.bergerbullets.com/twist-rate-calculator/ Fine the twist rate needed. Harder alloy is needed. High rate of twist with soft alloy may let the bullet strip the rifling.

That calculator is showing my barrel has plenty of twist, but it also has no provision for barrel length. However the industry as a whole switching to a faster twist of 1:7 in short barrels, which leads me to believe it may be barrel. I ran a .309 and a .311 bullet and noticed no difference in the stability. About 80% were stable, 20% were badly keyholing. Maybe the hardness is the issue as you said... but many have said they are running a 5 or 6 brinell and had no issues. I wonder if it may be barrel length combined with this. I think I'll pickup a 1:7 twist 7.5" barrel and see how it does.

[runfiverun]

try the harder boolits first.
they are trying to move forward, the rifling is trying to twist them.
you don't have a lot of distance to get them to do both.
if you have any slippage or any leading you will destroy either the diameter of the next one, make it harder to grip the rifling where the leading is, or just plain out not stabilize the slipping [skidding] ones.