Hi damienph,

Thanks for the reply. I'll give it a try, my pal has some of that powder.

I'm guessing your rifle is a later model with the steel bedded tubes. I bet a little bedding material will cure your stringing problem. I'm assuming your barrel is full floating as my later 308 is.
The stock on my older 223 has the over-molded stock which had a few snug spots that seemed to move from shot to shot.
My gunsmith did his bedding magic, which happily solved any shot to shot variation. Any poor shooting is totally the fault of the guy behind the rifle.

Be well & enjoy life,
broom