Quoted:
Quoted: Ammo Oracle also makes an interesting point that the faster twist bbls may also provide enhanced fragmentation with M193 due to the extra fast rotation of the bullet in the 1-7 bbls vs. 1-9 or 1-12.
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Show me where the Oracle says that.
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+1
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www.ammo-oracle.com/body.htm#m193accQ. Will M193 be accurate in a 1:7 or 1:9 twist barrel?
It may be
marginally less accurate due to the fast twist rate, particularly in 1:7 twist barrels.
Unless you're trying to use these rounds for benchrest shooting, though, it shouldn't be enough to matter.A bullet's flight is disrupted slightly as it leaves the barrel and after traveling some distance, will "settle down" into an even spiral, similar to a thrown football. The faster a bullet is spinning, the longer it takes to settle down. The most accurate twist rate for any length of bullet will be just a bit faster than what is required to stabilize it for its entire flight path (1.3 SG). But note that bullet
quality plays a much bigger part in this equation. A uniform bullet will spin true; a non-uniform bullet will wobble and be inaccurate. As a general matter when shooting M193 or M855 (as opposed to match ammo) its better to err on the side of a faster twist rate. Regardless, both 1:9 and 1:7 twists seem to shoot M193 and M855 very well.
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-Troy