I know most people try either 208/220gr for subsonics but I wonder if anyone has tried any 240gr in their 308/300win mag? I figure since we are limited to ~1100 ft/sec why not maximize the bullet weight for more energy at least. When I calculate 240 gr at 1075 ft/sec, 10 twist, 30 cal, 50 deg temp and bullet length of 1.5" I get a stability factor of 1.32 which is higher than the 1.2 cut off so it should be stable. I have looked at some other 240gr bullets that are RN and flat bottom that are shorter like 1.35" which pushes the stability and improves it to 1.81 which is optimal. Any experience would be appreciated.
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Re: 240 grain subsonic ?
The 240 grain SMK will need a 1:7" twist to stabilize. We have tried in a 1:8" blk out, and it will not stabilize at 1050 fps. The shorter bullets would be good, but they won't work in a 1:10" twist. The heaviest you could go would be a 190 or maybe 200 grains in a 1:10" subsonic.
The 240 grain SMK will need a 1:7" twist to stabilize. We have tried in a 1:8" blk out, and it will not stabilize at 1050 fps. The shorter bullets would be good, but they won't work in a 1:10" twist. The heaviest you could go would be a 190 or maybe 200 grains in a 1:10" subsonic.
Re: 240 grain subsonic ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">The 240 grain SMK will need a 1:7" twist to stabilize. We have tried in a 1:8" blk out, and it will not stabilize at 1050 fps. The shorter bullets would be good, but they won't work in a 1:10" twist. The heaviest you could go would be a 190 or maybe 200 grains in a 1:10" subsonic. </div></div>
So do you think even a a Hornady 220gr RN which has a short length of 1.26" wont work? When i plug that length and 10 twist it shows stability factor of 2.2 which is way over optimal? Does the formula not work?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">The 240 grain SMK will need a 1:7" twist to stabilize. We have tried in a 1:8" blk out, and it will not stabilize at 1050 fps. The shorter bullets would be good, but they won't work in a 1:10" twist. The heaviest you could go would be a 190 or maybe 200 grains in a 1:10" subsonic. </div></div>
So do you think even a a Hornady 220gr RN which has a short length of 1.26" wont work? When i plug that length and 10 twist it shows stability factor of 2.2 which is way over optimal? Does the formula not work?
