The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

meles meles wrote:why so ?

Trail Boss fills the case up at light loads (cos it's doughnut-shaped). In my .300Whisper I don't use it as the 240gr boolit (cast) takes up so much space.

I use T Boss in .308 subs (180gr Hornady round nose.)

I haven't tried either of these at supersonic velocities, though I wouldn't be optimistic about 300yd accuracy.

Yes, that's the approach we had in mind originally: filling the case up to prevent flash over and the subsequent potential for a low order detonation of the powder rather than a smooth burn. However, others have suggested that a small quantity of a very fast powder is just as good and doesn't suffer from the risk of detonation: it's designed to burn extremely quickly and there is plenty of empty case for it to expand into, thus limiting any pressure spike...

When I say "wouldn't be optimistic about 300yd accuracy", I am thinking about the 240gr cast load in the Whisper. No reason the 180gr round nose in .308 shouldn't perform fine at supersonic velocity to 300 and beyond!