Not to sound stupid/overly graphic, but is this because of the axial cutting added to the longitudinal cutting, if the petals on a TSX or Gold Dot get to "spinning"? How do they enhance it?Originally Posted by DocGKR
Not to sound stupid/overly graphic, but is this because of the axial cutting added to the longitudinal cutting, if the petals on a TSX or Gold Dot get to "spinning"? How do they enhance it?
The increased rotation rate can enhance upset with bullets hitting at lower velocities...
Facts matter...Feelings Can Lie
HP/SP, AND yaw dependent OTM, or just OTM?
It is my understanding that the drawback to faster than necessary for stability twist rates is increased chamber pressure for a given powder load as the higher spin represents a higher impedance for the bullet acceleration. At least, that was one of the reasons given for pressure spikes in the original 6.8 SPC SAAMI chamber. Is that true? I am wondering why barrels are not often made with faster twist rates.
Is this obsevation valid mostly with 5.56, or also with 308?
It has been noted with both 5.56 mm and .308; particularly with bonded JSP's shot from shorter barrels, hitting at lower impact velocities.
Facts matter...Feelings Can Lie
This is a terrific thread. I am learning a lot and hope that you all keep it going.
Since rotational velocity decays much slower than forward, can it also be presumed that say, a 1/7 twist 5.56 shooting a JSP may well expand at a meaningfully further distance than a 1/9 twist, when fired from a 14.5-20" barrel and impacting at say, several hundred yards, or would the difference be academic in nature (say, velocity variation from shot-to-shot playing a larger role)? Basically...how meaningful is this?
It can be quite meaningful, particularly when shooting 10-12" 5.56 mm barrels.
Keep in mind this is NOT new information, we have talked about this from over a decade...
Last edited by DocGKR; 05-31-2016 at 12:38 PM.
Facts matter...Feelings Can Lie
It probably shouldn't be new to me--but it is. I'm finding it very helpful.
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