15 March 2009, 01:36
303GuyVelocity, twist and accuracy relationship
quote:
If I need more horsepower than that combination affords me, I have other rifles to take over where that one leaves off.
That makes sense. It also give one a good reason to use our other rifles.
But there are heavier bullets designed for slower twist rifles - round noses and semi-points. My understanding is that the 7-08 is a very versatile caliber so I can understand the desire for a fast twist but the 140gr bullet seems heavy enough for most uses.
Can someone explain why the 6.5 Swede with it's long throat has a reputation for accuracy with such a wide range of bullet weights?
15 March 2009, 02:43
jwp475I think that Brian Litz Bergers Ballistician explained it quite well
quote:
Actually the window of proper stability is quite large. On the low end, you have to use at least the minimum recommended twist. On the high end, well, most of the adverse affects cited for over stability are myths. The most adverse effect of very high stability levels is extra spin drift. Other than that, elevation is not affected and BC is not affected.
I think most of the myths about over stability stem from imperfect understanding of the sights including: imperfect zero, click adjustments not being true, canted reticle, etc.
15 March 2009, 07:29
303GuyThat's fair comment but some rifles seem to be very fussy about bullet weight or length. Is that one of those "nothing to do with twist rate" things? I know my 303 Brit won't shoot 123gr or 125gr spitzers well at all. I think that has to do with throat design entirely.