guzma393
Active Member
TLDR; Anyone cast for 300 blackout? Mainly looking for a plinking round at 100 yards. I want to load both Supers/Subs.
I recently built a 300 blackout using an Anderson lower and a BCA 7.5", 1:8 twist complete upper. With 308 FMJ bullets coming out to 20 cents a pop, I found it way more economical start casting and powder coating my own.
The casting lead i started out with is straight WW lead, at ~14-16 bhn. Fluxed and pours fine.
I had terrible luck with the 230/309 lee double cavity mold. Upon inspection of the casts, the land located close to the middle of the bullet and just ahead of the lube grooves mics at 305", making these casts undersized. On top of that, there is a boat tail on the mold that many accounts causes further inaccuracy and gas cutting (getting leading). I decided to cut my loss on this 20 dollar mold (perhaps i got a lemon?) and buy a 6 cavity .312 160 gn mold instead.
A buddy of myn owns the 312/160 and gave me some casts (16 BHN) to try out. After powder coating and resized to 309, they shot alot better and cleaner (no leading) but still getting minute of paper (8" group) at 100 yards. Granted, I probably had my crimp set too heavy (still set from those undersized 230/309 bullets), and using 17.5-19 gns of h335 (i know this powder is too slow, but it cycles the round and chronos around ~1500 fps).
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Despite of all of this, i'm pretty optimistic about this whole venture. I heard people modifying the 230/309 mold by reaming out the boat tail with a 5/16 reamer. Will probably start with this before trying to ream out to the undersized land.
I have some imr4227 powder at hand and will use this stuff instead of h335 on the 160/sized 309 supers. I also have a 311 sizer on the way for loading these bullets up in a 7.62x39.
Furthermore, I am aware that gas checks are also a must for supers, and i got those on the way as well as a lyman cast 4th edition book for a formal read and reference on casting.
Anyone doing/had done this? Any tips/tricks/advice is accepted. Thanks!
I recently built a 300 blackout using an Anderson lower and a BCA 7.5", 1:8 twist complete upper. With 308 FMJ bullets coming out to 20 cents a pop, I found it way more economical start casting and powder coating my own.
The casting lead i started out with is straight WW lead, at ~14-16 bhn. Fluxed and pours fine.
I had terrible luck with the 230/309 lee double cavity mold. Upon inspection of the casts, the land located close to the middle of the bullet and just ahead of the lube grooves mics at 305", making these casts undersized. On top of that, there is a boat tail on the mold that many accounts causes further inaccuracy and gas cutting (getting leading). I decided to cut my loss on this 20 dollar mold (perhaps i got a lemon?) and buy a 6 cavity .312 160 gn mold instead.
A buddy of myn owns the 312/160 and gave me some casts (16 BHN) to try out. After powder coating and resized to 309, they shot alot better and cleaner (no leading) but still getting minute of paper (8" group) at 100 yards. Granted, I probably had my crimp set too heavy (still set from those undersized 230/309 bullets), and using 17.5-19 gns of h335 (i know this powder is too slow, but it cycles the round and chronos around ~1500 fps).
----
Despite of all of this, i'm pretty optimistic about this whole venture. I heard people modifying the 230/309 mold by reaming out the boat tail with a 5/16 reamer. Will probably start with this before trying to ream out to the undersized land.
I have some imr4227 powder at hand and will use this stuff instead of h335 on the 160/sized 309 supers. I also have a 311 sizer on the way for loading these bullets up in a 7.62x39.
Furthermore, I am aware that gas checks are also a must for supers, and i got those on the way as well as a lyman cast 4th edition book for a formal read and reference on casting.
Anyone doing/had done this? Any tips/tricks/advice is accepted. Thanks!