Lee 230 cast tumbling/300 blackout

[sfcairborne]

Ok guys need a little help here:

300 Blackout AR
9 1/2 KAK barrel 1x8 twist
Pistol buffer and spring

Round:
230 lee cast Blackout mold, they cast out at 225 grns and are .309 in dia, the one coat of tumbled powder coat still left them below .310.

Powder coated
10.5 1680
COAL: 2.180
Medium crimp
is a sub load, don't have a crono, so I don't know the actual velocity
Results:
Loaded last night, fired at 0730 this am at 25 yards to mainly check function.
All rounds had positive feed, extraction and bolt hold open on last round. Now here's the quandary.
First round out of a 3 shot string, showed a perfect entry hole, next two tumbled.
Fired 3 more strings of three rounds each, cleaning between string. Same result on all three strings. First round entered perfectly, next two tumbled. On the last 3 shot string I even cleaned between each round and had the same results. I'm going to try the same powder charge, but crimp at the actual crimp grove.

Any thought gentlemen? My 208 Amax and 220 SMK's fly great, so I'm a little stumped.

Sorry if if this need to go in the Military cast load section

Thank you

[petroid]

That boolit needs a 1:7 twist to stabilize which is why it is keyholing. Can't explain the first shot but mine never keyhole even at 850 fps

[sfcairborne]

Thank you, it was just bugging me as the amax and smks fly great. Trying to get the NOE 247 mold, will it stabilize in my 1x8?

[leadman]

I have shot the same boolit in my 1/8 twist 18" Contender barrel in 300 Whisper with no tumbling even below 1,000 fps. You do not state an alloy or hardness.
I did find out that when casting these you have to wait longer to drop them out of the mold as the will bend if too soft.
Also since the first cartridge that is loaded into the chamber by hand works ok than I would repeat the firing but remove the first cartridge that is loaded by the gun into the chamber and check it for any damage.

I have shot the Sierra 240gr jacketed bullet out of my Contender and it did stabilize. I had not heard of a twist faster than 1/8 until the Blackout was chambered in the AR. The 300 Whisper and Blackout are almost the same cartridge except for neck length.

[sfcairborne]

For my lead, I'm mixing 50/50 soft lead and wheel weight, with a little tin. The first round is cycled from the mags as well. Do you think the lead may be to soft.

[Moonie]

That boolit needs a 1:7 twist to stabilize which is why it is keyholing. Can't explain the first shot but mine never keyhole even at 850 fps

Both of our 1-8" uppers stabilize it perfectly, and my 30-06 1-10" stabilizes similar length boolits just fine at 1,950fps.

I do water drop, and use gas checks in the 30-06.

[sfcairborne]

Hmm, I water drop them as well, the ones I'm shooting were cast a month ago. May bump my powder charge and seating depth and see what happens. Gonna make them a little longer.

[sfcairborne]

Moonie,

are you running subsonic out of you blk out ? If so what is your COAL. I'm running A1680 @ 10.5 grn

[petroid]

Both of our 1-8" uppers stabilize it perfectly, and my 30-06 1-10" stabilizes similar length boolits just fine at 1,950fps.

I do water drop, and use gas checks in the 30-06.

Maybe I should have been more specific. Most people find that this boolit requires a 1:7 twist to stabilize it at subsonic speeds. Some have success with a 1:8 twist. For slower twist barrels, a higher velocity is required to give the boolit the RPM it needs to stabilize, i.e 1:10 twist at 1950fps. I think the OP is one of the many that only achieve marginal stability at the twist of his barrel and velocity that he is shooting. If he can bump his load up a little and still maintain his subsonic goal, then he may be able to get the stability he is looking for. Without a chronograph or a suppressor, there is no reliable way to determine if the boolit is remaining subsonic.

[Blammer]

I think you are on the very edge of stabilization. Kick it up just a tad for velocity and see what happens.

[sfcairborne]

Thank you for the replies. I do have a suppressor , had it with me, but I wanted to make sure they were flying straight before i attached the can. Good thing I didn't base my results after the first round or I would have had some baffle strikes. I think Im going to just shoot the rounds I have powder coated then remelt the remaining ones to make them a little harder and better fill out. Plus going decrease the seating depth and plus up the powder charge. I just checked the diameter of a handful of my cast and they run from .307 to .310 and damed if some don't read out of round, I mean I can take a measure from four different places and get 4 different readings in diameter.

[3006mv]

up to 11.2 gr at least, report back.

[petroid]

Thank you for the replies. I do have a suppressor , had it with me, but I wanted to make sure they were flying straight before i attached the can. Good thing I didn't base my results after the first round or I would have had some baffle strikes. I think Im going to just shoot the rounds I have powder coated then remelt the remaining ones to make them a little harder and better fill out. Plus going decrease the seating depth and plus up the powder charge. I just checked the diameter of a handful of my cast and they run from .307 to .310 and damed if some don't read out of round, I mean I can take a measure from four different places and get 4 different readings in diameter.

How are you sizing your boolits if they are still out of round? If you are PC'ing them you really should run them through a push through sizer at least after PC if not before as well. the PC can add up to 4 thousandths to the diameter. And how can they possibly be .307? Well, I guess if those are not PC'd yet and the mold drops small...

[sfcairborne]

That is correct , the rounds in the above paragraph have not been sized thru my lee sizer. I ran roughly 45 thru the push through die before I powder coated the batch. But almost all of the rounds went straight thru the sizer never being touched. So I powder coated them by the tumble method, baked, then ran them back thru the lee .309 sizer, same thing. Maybe only half sized, the rest went straight thru. This probably accounts for the tumbling more than anything I think. So gonna melt what's left of the un powder coated, and try again and see how about 10 measure out. The powder coated ones will just get shot for fun, I do not like to pull bullets and reload the cases.

[petroid]

Ok here's me suggestion FWIW. Make sure your calipers are accurate. Check them against jacketed bullets to make sure. Better yet, get a micrometer. Slug your barrel if you haven't already. Cast HOT! These boolits are hard to get good mold fill out without a hot mold and alloy. Add a little tin if you haven't. It makes a big difference. You may be able to lap the mold a little bit or beagle it if still casting small. The PC should add at least two or three thousandths to the boolit. If not, you're not getting good coverage. Size before and after PC and go one to two thousandths over groove diameter. Best of luck

[sfcairborne]

Thanks guys, gonna give it another try.

[Moonie]

Maybe I should have been more specific. Most people find that this boolit requires a 1:7 twist to stabilize it at subsonic speeds. Some have success with a 1:8 twist. For slower twist barrels, a higher velocity is required to give the boolit the RPM it needs to stabilize, i.e 1:10 twist at 1950fps. I think the OP is one of the many that only achieve marginal stability at the twist of his barrel and velocity that he is shooting. If he can bump his load up a little and still maintain his subsonic goal, then he may be able to get the stability he is looking for. Without a chronograph or a suppressor, there is no reliable way to determine if the boolit is remaining subsonic.

I have shot this boolit subsonic in both of our 1-8" uppers, round holes, no signs of instability using RL-7. I have done the same with the Accurate molds 245gr which is the same length, no instability shown on target out to 100 yards. Lots of people were shooting even longer condom bullets before the 1-7" barrels came out.

[petroid]

Moonie, I'm not arguing with your results nor others who have had success with 1:8 twist barrels. I'm happy they work for you. Most of what I have heard from people who have tried is that it is not well stabilized at that twist rate and velocity. Since the OP is having stability issues, I was simply relating my and others' experiences with this boolit and attempting to give some insight and perhaps ideas on how to make it work, if it will indeed work for him.

[runfiverun]

long boolits stabilized by slow rpm's don't fly all that straight.
sometimes they don't fly point on or backwards either.

[popper]

I pull the bad ones with wire cutter/crimper & a length of PVC pipe. Fast, easy and save the powder & primer. Powder is not easy to come by now. Recyle the bad ones. Beagle or whatever - 309 doesn't fly very well.

[Moonie]

I understand, I'm simply pointing out that there are other things that can cause this issue, stripping and undersized being 2 likely culprits.