AR Sponsor
Posted: 9/18/2012 8:21:50 PM EDT
| what is a good twist rate for a 20'' barrel for hunting. also i hear for an 18'' the 1:8 twist is good. not sure any ideas ? |
|
Quoted:
Depends on the ammo. ^ this Specifically the weight of the bullets you are using. Heavier bullets need a faster twist to stabilize coming out of 'short-ish-er' barrels, lighter bullets stabilize quicker with slower (higher number) twist rates. 1:7 very fast, 1:12 very slow. 16" barrel with a 1:7 twist is ideal for 70 grain bullets and just OK for the lighter 60 grain. 16" barrel with a 1:12 twist is great for 55 grain bullets, not enough twist for the 70 grain. 16" barrel with a 1:7 twist is not ideal for 55 grain bullets as they can come part or partially fragment due to the spin inertia (I think that is what it is called) in rare instances, and just OK for the lighter 60 grain. Lengthen the barrel to 20" and you can get away with a 1:9 twist on the 55 grains and it is a bit more forgiving on the slightly heavier 60-62 grain weights. Mind you that barrel quality, material, chrom/no-chrome etc can all add tiny affects to the bullet as well so take all this with a grain of salt. |
|
Quoted:
what about a 24'' barrel. 1:7 ? Again, it has more to do with what bullets you intend to shoot than anything else. Also, when it comes to bullets and stabilizing them, it isn't so much the weight that matters, as it is the length. Most of the 70gr and up bullets are longer, therefor need a faster twist rate to stabilize. If your intended use is hunting bigger game such as deer/hogs, I would recommend you stick with 1:7 or 1:8 twist in an 18"-20" barrel. |
AR Sponsor