Noob Question

[GrkPranksta69]

Can someone explain to me if I could reload the 300 BLK using higher grain 308 bullets? Why is it that you can shoot 220 gr subsonic and only like 125 gr supersonic bullets? Is the difference due to how far the bullet will stick out not allowing for it to chamber? Hypothetical situation could you just hand chamber like 180 gr 308 bullet into the barrel and shoot or would that not work? Thanks in advance if I'm not making much sense

[Magos_Mal]

IMHO, it has more to do with reliable cycling than bullet length (220gr are super long, they just sit farther back in the case).

My handloads are currently 145gr and 150gr supersonics (using H110). I have not tried any 175-180gr supersonics yet, but I do know subsonics of those weights will not cycle my 12.5" gun as I do not have a suppressor (which would add back pressure) and I've not tried any 200 or 220s yet (cannot afford them).

Sadly, I just found out my 247gr NOE mold will be on order until NEXT year So I will be sizing some 185gr I cast for .303 and 7.65arg to .308 and see how they go.

[SomeOtherGuy]

Supersonic loads with bullets up to 180gr work just fine. You can get around 1800fps with a 180gr bullet.

You can do supersonic loads with the 200+ gr bullets but they won't be supersonic by a lot. I think I saw a load for 220gr SMK that was clocking 1300fps or so.

[JohnInNH]

Gas gun does not help .. a bolt you can seat the bullet out farther and add some more slow burning powder.

I am trying to work up some 175 and 180 gr supers (as well as my M2 ball bullets) I am slightly surprised at the heavier bullet performance the 125's and 130s work well .. the 150 seems to be a flat spot (unless I find a better powder) then the 175-180 seems to work OK.

Unfortunately my load development is on hold. Micro7 is in transit back to AAC, new Chronograph to be ordered.

So I am flying blind and am back to playing with the 357 max, 44 spl, and 9mm.