Thread: Projectile Length to Ogive

Really interested to hear the V Max 60’s are stable in a 1:12. I tried some 50 gr Barnes Varmint Grenades which are 0.853” (0.020 shorter than the V Max) at 3,000 fps and got keyholes at 25m! The JBM Ballistics stability calculator gives the V Max 1.263 (apparently 1.3 is stable) so I guess it’s on the cusp - might give it a try…

Originally Posted by Croc

Really interested to hear the V Max 60’s are stable in a 1:12. I tried some 50 gr Barnes Varmint Grenades which are 0.853” (0.020 shorter than the V Max) at 3,000 fps and got keyholes at 25m! The JBM Ballistics stability calculator gives the V Max 1.263 (apparently 1.3 is stable) so I guess it’s on the cusp - might give it a try…

Greetings @Croc,
I couldn't find my stability calculations so went back and did them again for both my old and new projectiles. I got much the same result as you. I have previously fired the 60 grain AMAX at 200 metres and got excellent accuracy. My VSSF rifle has a 26 inch barrel but have yet to chronograph the loads but should be able to achieve around 3,100 fps, or maybe a little more. This rifle and load will only be shot at 300 yards (275 metres) so we will see how it goes in September. Our range is only 60metres above sea level which may help. I used a .223 T3 Lite last season which has an eight inch twist with the 69 grain SMK projectiles so will have that with me if it all turns to custard.
Regards Grandpamac.