********************* The rifle is a noble weapon... It entices its bearer into primeval forests, into mountains and deserts untenanted by man. - Horace Kephart
Posts: 6653 | Location: Switzerland | Registered: 11 March 2002
I have two 30-338 one has 1/10 other 1/12 twist barrel the 1/12 shoot the 180gr real good the 1/10 twist doesn't groups all that well with 165 gr bullets. I think my next 30cal barrel will be 1/11 twist from Lilja. I have a Broughton 1/12 twist 30cal barrel on a 300wsm and it handles the 150,165/180gr bullets doesn't do well with the 190 or 200gr.
VFW
Posts: 1098 | Location: usa | Registered: 16 March 2001
GUys there is a variable you aren't taking into consideration on the 1-12 twist. The design of the ogive. I am jogging memory here but if a recall correctly a long ogive needs a fast twist, and a shorter ogive will work in a slower twist.
Cutting through the techical goop, some 180 gr bullets need at least a 1-11, and others are going to work well in a 1-12. A suprise may be to some that 165 grs work well in 1-10.
BOttom line its the ogive design and how long it is, which of course is governed by bullet weight. There are variances between manufacturers and designs though, and real course example is a Sierra match boat tail, and a Hornady roundnose are two really different ogive designs. If you recover the two bullets look at where the lands cut on these two examples on the RN I would expect land cuts almost the entire lenght of the bullet, on the boat tail only a 1/3 of the bullet might have land cuts.
Posts: 1486 | Location: Idaho | Registered: 28 May 2004
