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Originally Posted by EZM
Genuinely curious to read studies (actual experiments) to show the effects of gain twist, and a few other things like 5 grove/ 4 grove barrels and what the results are for velocity and, more importantly accuracy.
If anyone has any neat articles ….. shout it out. Would make for an interesting read.
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I don't have any documented evidence but what I have found is that gain twist eliminates the possiblity of pressure spikes and is easier on projectiles, especially those with lighter jackets.
My reasoning is that std rifling is trying to do two things simultaneously with the projectile- allowing them to accelertate and starting rotation at the same instant , causing higher pressures upon the bullets contact with the lands. Slowing the initial rotation down by 50 %, or more, at the outset requires less pressure and causes less bullet stress resulting in a pressure curve rather than a possible spike.
Secondly, there is no real need to have the bullet spinning at over 150,000 rpm, for almost the complete length of the barrel. A few (4 or 5) inches of a given twist rate near the muzzle is enough to give it the required rotation.
Accuracy is not affected in any way and may even be enhanced as all my RKS gain twist barrels have proven to be exceptionally accurate, probably due to the progressive twist rate more than anything else I can think of, including lapping. Just my thoughts, cloudy as they are.