Hornet twist rate
I just started reloading for my Hornet, it is BRNO ZKW465 with a 20" bbl having a 1 in 16" twist. I have been looking at the different loads for this gun including those on powder manufacturer sites. On the VihtaVuori site amongst the loads given are one for a 50gr and one for a 55gr bullet. This in itself is not, I believe, unusual but the test bbl used in their load developmment was 231/2" long with a 1 in 16" twist. I had always understood that a 1 in 16" was too slow to stabilise a bullet over 45gr.
Is this a suck it and see thing for individual guns, or is there a law of physics that governs this?, need your help.
[ 07-20-2002, 15:40: Message edited by: JAYB ]21 July 2002, 02:42
<eldeguello>I believe this is a "suck it and see" situation, as you put it! I have a 1/17" .22 Hornet, and it will shoot some flatbased 50-grain bullets with a fair degree of accuracy (it isn't great with ANY weight I have tried so far!!).
21 July 2002, 02:51
<eldeguello>I should have included the information that there are formulae for computing the rifling twist required to stabilize bullets. The determining factor is the LENGTH, rather than the WEIGHT, of the bullet. Short, stubby bullets stabilize at rotational speeds less than long pointed ones of the same weight. The formula I have always used is the Greenhill formula: twist (IN CALIBERS) = 150/length of the projectile (IN CALIBERS). T^his formula is outdated by more precise ones, but it will give a pretty good approximation of what is needed to stabilize a jacketed bullet at velocities in the 2000-3000 FPS velocity range.
21 July 2002, 03:37
Pecos41Jay, years ago when I had my K Hornet I tried so 55 gr spitzers and at 100 yds they were clearly wobbling along and going thru the target yawing badly. HOWEVER, if you can find any ROUND NOSE or nearly round nose bullets these might work. I think part of the problem is the long spitzer shape simply requires more velocity to stabalize correctly than a round nose. Unfortunately I don't know anyone who makes such a bullet.
In all likelyhood, you're going to have to be happy with what you can get or get a bigger gun like a .223.
Thanks for your time gents, I should explain that I am not real anxious to load these bullets I was just curious, can always learn something and I'm not too proud to ask. The only thing is I shall probably now have to try some just to satisfy my curiosity.
Cheers
John