What am I doing wrong?

[Fourmocajuns]

I cast 230 gr boolits from the lee mould. I am using wheel weights and powder coating. My 7in 300 blackout will shoot 1" groups at 100 with 190 sub x . With my cast fodder we are talking 6+ in groups. Ugh is it my alloy possibly?

[Winger Ed.]

I've found that such things are not always so simple. There's several things to look at and work on.
Powder type and charge, seating depth, crimp, sizing, etc. The alloy alone is probably not the place to start.

I'd dig around in old posts & archives.
You'll often find discussions from folks that have had the same problem, and see what their solutions are.

[Conditor22]

Welcome to CB.
with trouble shooting cast we need to start from the beginning.
Have you slugged your barrel and gotten the diamiter? we usually go .001-.003 over the sluged diamiter (my 300 BO shoot well at .309)
how big are you sizing them?
a powder that works good for jacketed bullets may not work well with cast bullets.
What is the twist rate of the barrel? (I'm guessing an AR platform?)
how much of what powder are you using?
How soon are you shooting these after you cast them? cast boolits take 2-3 weeks to achieve full hardness.

[gpidaho]

fourmorecajuns: Welcome to the forum. As mentioned above I'd try changing a few other things before the alloy. First thing I'd try would be the powder charge I would also explorer other cast bullets as well, I believe the 230gr. Lee should be run as a subsonic. (others may have found loads that work well super-sonic but I haven't) I have good luck with a Noe 129 SP sized .309 in my Blackout. 17gr LilGun is my supers load with the 129. Gp

[Neverhome]

Guys here know their stuff. Share more details about your load and process and it’ll give the subject matter experts more to work with to help you out.

[GhostHawk]

Fit is king, get that right first, all other variables trail after.

You probably need to do a pound cast to know what size you need.

Is it keyholing? Shotgun patterns?
2 or 3 thousandths can make a huge difference.

Some rifles have a definite preference for a certain size range.
The more details you give us the better chance someone can make a connection to a problem they solved.
So all rifle specs plus load, everything.

[dtknowles]

What do the groups look like. Vertical stringing, shotgun pattern, or a flyer or two?

What sort of inspection do you do of your bullets? Base flaws can really open up groups. Weight variation can cause vertical stringing.

What kind of crimp are you using and do you bell the case mouths to avoid shaving the bullets?

Tim

[Rich/WIS]

Did you remove any copper fouling in the bore?

[atr]

Fit is king, get that right first, all other variables trail after.

Ghosthawk is correct
That is most often the problem and where I would first look. Just a change in the diameter of a cast boolit will usually have a great deal to do with overall accuracy.
atr

[carolina sorillo]

It could also be that the twist rate won't stabilize bullets that long. Are you bullet holes round or are they oblong?

CS