Thread: 300BLK questions

Hi all

I'm very new to reloading (and firearms in general) but I've been successfully reloading subsonics for .308 for a couple of months but also want to reload for 300blackout.

My thinking is to use the same lead cast projectiles as I use in the 308 reloads (Robs 151gr's) and the same powder (7.5gr Trailboss) but would be keen to know if anyone else has any recipes for 300blk loads.

Also, just wanted to check, is this the correct die set I would need for 300blk?

https://www.gunworks.co.nz/shop/item...300-aacwhisper

Regards
Ash

Hi Ash. The 300BLK case is a lot smaller than the 308 case. You won't be able to get 7.5gr of trail boss in there without compressing it (which is big no no with that powder).

From memory, 6.2gr was a full case for me using a 125 Speer TNT and that was doing about 850fps. Lead projectiles have less friction and get moving easier, offsetting some of the weight, so I'd estimate about 800fps for 151's with a similar charge.

For that reason, I much prefer using AP70 or AP100. They're more dense than trail boss and you can fit enough in to get 150 to 220gr bullets up to 1050fps. They're still very fast burning which means they suppress nearly as well too.

Originally Posted by Pommy

Hi Ash. The 300BLK case is a lot smaller than the 308 case. You won't be able to get 7.5gr of trail boss in there without compressing it (which is big no no with that powder).

Thanks @Pommy

I did wonder about the case size and powder capacity. I'll check out the other powders.

Many thanks
Ash

Im looking at doing the same thing with roberts lead projectiles after using them in 308 and getting myself a 300blk
ill be interested to see how you get on.

$2.5 is very ouch for a gun i want to shoot rabbits and peacocks with for subx

also i have the hornady dies and they mash the top of the hollow point on the 151s far worse than my lee 308 dies did
so id avoid them knowing what i know now

No worries. @Bill999's absolutely right and I had a similar experience getting the buggers seated. Ended up buying a Lyman 30M1 expander die which helped and used the hot glue gun trick on a spare seating stem.

what is the "hot glue trick" @Pommy?

Putting a drop of hot glue into the seating stem and then squidging a bullet in there to mold it to the shape of the bullet. Spreads the seating force and stops the bullet deforming so easily.

Might find some of this load info handy.
AR2205 is the best powder for cast subs in blk.

https://www.nzhuntingandshooting.co....-300blk-44692/

My pet load was 10 grains of AR2207 behind the 240 grain SMK. Just over 1000 FPS in the, now crushed, AR.

what is the likelyhood of me having success with 2208 or 2209 with cast subs?
subs are the name of the game for me

Originally Posted by Bill999

what is the likelyhood of me having success with 2208 or 2209 with cast subs?
subs are the name of the game for me

I think you will need to use a faster burning powder.
I’ve been using AR2205 for subs and supers in 4 different 300
BLK rifles.

thanks mate ill get some this afternoon

Originally Posted by tikka

I think you will need to use a faster burning powder.
I’ve been using AR2205 for subs and supers in 4 different 300
BLK rifles.

Is it a dick move on my part to ask what your loads are?

to save me a little trial/error

I had good success with lil gun as well. I have a bunch you can have for cheap if you want too haha. No use for it. In fact I have dies brass and projectiles sitting doing nothing