300 blackout question for those who might know.

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03-09-2017, 01:26 PM
Jeppe333

300 blackout question for those who might know.

Hey guys:
please forgive my ignorance as I am new to forums and have never asked a question on one before. I have been reloading now for the better part of 15 years but my experience has been primarily in metallics. I have been casting now for a little over 2 years and just recently started to cast for my 300 blackout. I am using primarily wheel weight lead and water quenching the bullets for hardness. I am using the Lee 312-155 mold and sizing them down to .309 using a lee sizer die. I am then lubing them with Lee liquid alox and gas checking them with a copper check. I am fairly confident (emphasis on fairly) that the bullets are working decent as I'm keeping a 4" group at 150 yards. However the issue I am having is I can only get about 1-3 30 round magazines out before the bolt is so gummed up it seizes forward due to either lead or carbon powder in the BCG and star chamber.
I am using Lit'l gun powder at 15 grains. Again if this were metallics I wouldn't be having the issue as I have been able to fire well over a 1000 rounds of FMJ's with the same powder through the same gun with no issue.
So I guess my question is am I doing something wrong? Or has anyone else had the same issue? Is there a fix to this or am I just kind of stuck cleaning a BCG and chamber after every mag?

Any help would be greatly apreciated thank you in advance for any advise or imput.
03-09-2017, 01:33 PM
Boolit_Head

Known issue with Lil Gun. Switch to a different powder and powder coat the bullets and your problems will disappear.
03-09-2017, 03:07 PM
Jeppe333

Any suggestions for powder?
03-09-2017, 04:00 PM
Moonie

My preferred Lee 155-312 load is 15.3gr H110/W296.
03-09-2017, 04:03 PM
Boolit_Head

That works well for me as well.
03-09-2017, 07:32 PM
Boolseye

16 gr RL 7 works good
03-10-2017, 01:41 PM
Jeppe333

Thank you
03-11-2017, 06:47 AM
Smk SHoe

I have no issues with Lil Gun in my 2 300 Blkouts. Im running Arsenal 170's. I have used a number of different cast 30 cal's and really had no issues with the BCG gumming up. My issue was more of a fitment (really tight chamber) and feeding issue ( flat nose's). I would bet if you PC'd you would solve your problem.
03-11-2017, 12:39 PM
popper

Quote:

stuck cleaning a BCG and chamber after every mag?

Chamber too? Suspect something else is a problem in addition to the l'gun. Try different sizes or slug it. What is gas port size/ pistol port?