247 grain Noe 300 blackout help needed.

[Crocks and Socks]

So in trying to use the Noe 247 mold in my 16 inch 1/8 twist 300 blackout. Bullets feed and fire reliably and stay subsonic right at 1050fps and will stack like cord wood out to 30 yards or so. After that distance they group about as good as my 12 gauge shooting buckshot. I have tried these sized at .309 .310 and .311. I have adjusted the coal both ways from one extreme to the next. I am getting 6 inch groups at best at 100 yards. These bullets have been powder coated then sized to the finished diameter. If anyone else is using this mold and has worked through a similar issue I would greatly appreciate some helpful hints. I have also had 10 different friends try these loads and their results where exactly the same. I am using Redding dies as well as a Lyman m die 30 expander and a 30 carbine powder funnel under a dillon measure. I am applying a decent crimp.

[tzzler44]

Not sure about everyone else here, but I never crimp cast bullets except to get ride of the case flare.
Do you have the plain base or the gas check version of the mold?

[jcren]

A non linear dispersion like that indicates loss of stability. Any key-holes? You May be just starting to come apart at 100, if possible try 150 and watch for oblong target strikes. Know anyone with a 1/7 twist to test on? Bumping velocity will also increase stabiliy, if only as a diagnostic test.

[Crocks and Socks]

I have the plain base mold. I wasn't aware that I shouldn't crimp. I will try that tomorrow and report back. No keyholes at 100 will shoot a little further tomorrow as well

[Gunor]

I see you are using a Lyman M die - is opening it the necks without size the bullet down?

[Tackleberry41]

I don't crimp my subs either, just enough to get rid of the flare. And sizing to .311 won't do much good if the case dies are sizing for .308. The Lee mosin dies come with a .308 expander, I bought the .311, but had to make one for .314. You can feel the difference when pushing a .314 bullet in vs the smaller expanders.

247gr seems a bit heavy and therefore long to stabilize. I know my .314 198gr NOE mold using WW lead comes to 211gr. So you might be at nearly 260gr, doubt it would stabilize very well at that velocity.

[Crocks and Socks]

I'm using Lino and Bullets are actually dropping at 237 with coating and all. I also have a Lyman m 31 die that I may try. My only concern is that with the 31 will it open the necks up past .334 and cause jams. I have a football game for the lil one today then I'm gonna get in the shop and try some things out

[Tackleberry41]

Lino is a bit overkill for subsonic use. Might be better off with a softer alloy.

[Gunor]

Lyman 31R has steps at .310/.314.

NOE has their Lee expanders with more choices.

http://ps-2.kev009.com/ohlandl/Cast_Bullet/Lyman_M-Dies/Lyman_M-dies.html

Belling (with the Lyman 31R) of the case - I use the Lee factory crimp dies (I know the horror...) with the barest of crimp.

[osteodoc08]

I think stability is gonna be your issue here. Sig is producing their bsrrels
with a 1:6 twist of that tells you anything.