Well it's unlikely to be 1:40 shown that way.
So my pick is 270 grain conical with a 40 grain load of FFG
Seems a light load so might have been set up to the requirements of who ever ordered it from Tony Hawkins
Maybe a good target load that doesn't beat you up.
I use 80 grains FFFG behind a 395 grainer in my 50 cal.
Hence why i think its a light target or small game load.
I use FFFG because my barrel is only 25"
Bookmarks