243 RPM window with 85/87 grain bullets

[MOLON LABE]

Can someone here help me out, or maybe steer me towards the data for an optimum RPM window for 85 and 87 grain bullets, if it exists exactly or in approximation. Specifically I'm dealing with the 85 grain TSX and the 87 grain Vmax. All I want to know are those numbers, I'll take it from there. Both manufacturers have been a bit less than helpful. I have searched a little here, and googled quite a bit. Thanks in advance.

Molon Labe.......

 

[tuttlefarm]

This is the formula for calculating bullet RPM... Bullet RPM = MV times 720 divide by the Twist Rate (in inches) Example your velocity is 3300 ft/second times 720 equals 2376000 divide by your twist 9 your RPM would be 264000. The higher your RPM the more likely to have bullet jacket deformation from the stress of too much twist. Too low of RPM and you would have stability problems. RPM depends on bullet length. Short range shooters will need around 175,000 RPM and long range shooters would need 200,000 - 260,000 RPM. I personally have shot the 87 v-max at 252,000 RPM out of a 6mm AI. Hope this helps.

John

 

[MOLON LABE]

That helps a little. I have the Miller Formula so calculating an RPM isn't the issue. My issue is knowing the right RPM range for those bullets. The 85 TSX carries a potential .333 BC and the Vmax a .408. Not completely horrid but I don't want to cheat them any either. There are valid reasons for me sticking with those bullets.
With a velocity wall of around 3000 or 3100 fps max I need to balance twist, velocity, and barrel length to achieve full BC value. Barrel length will be 22", and the reason for the question is the decision on twist. I've crunched a ton of numbers through the Berger calculator and everything that route is pointing to an 8ish twist. I just want to be positive before I order a barrel. Most makers have a lengthy lead time right now and I'm looking for a quicker turn around. Looking at what's available off the shelf with the makers and a few distributors. Limited choices in some cases. Lots of "should work" answers out there to my question but I'm looking for the "will work" answer.
You mentioned 200,000 to 260,000 RPM, where did those numbers come from? I appreciate you stating your personal experience with the 87 Vmax.

 

[spaniel]

I've shot them at 297,000 out of a 243AI. 1/3 MOA groups and haven't had any fail to reach the target yet.