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Correct twist for pistol bullet at rifle speed

Hi, newbie to this board. I'm peppering different gun sites with a few questions, hopefully hitting the expertise I need.

I'm planning to build an AR-15 gas-op upper in 10mm auto.

I've got a number of issues to address.... but one big question is "What's the correct twist for a 10mm rifle?"

My choices are limited to 8T, 16T and 25T.

I've found a little information on the Greenhill and Culp formula. When I run the Culp formula against some recorded 10mm velocities and bullet lengths and diameter, it appears to give twist information that matches common pistol twist and velocity. It also gives me a 25T for a 10mm bullet coming out of a 16" barrel at 1600 fps.

But I have no clue if these formulas are known to be accurate or appropriate for pistol-length bullets.

Anyone know if there's an appropriate twist formula for handgun bullets?
 
From 165 to 200 probably.

Long as I can get 180's to give me good velocity with best accuracy, they'd probably be the prime candidate for my loads,xtp's, gold dots, or gold sabers most likely).
 

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