223 ammo

[malsav]

what is the heaviest bullet head that can be used through the 223 savage 1:9 twist barrel at moment working with sierra 69g bthp an h335 powder 22.5g and shooting 1/2 inch groups at 100yrds just experimenting with this round at moment

[BoilerUP]

75gr HPBT, 77gr Nosler/SMK.

Might have luck with the 75gr Berger VLD and maybe, possibly, with the 75gr Amax but that's doubtful.

[pisgah]

You never can tell until you try, but I would say BoilerUp's suggestion sounds about right.

[BoilerUP]

Bullet length is more important than weight when it comes to stability.

Case in point: both the Hornady 68gr HPBT and 75gr HPBT are 0.987" long. In a 1:9 barrel at 500' ASL, 29.92Hg and 59F the 75gr HPBT has a stability factor of 1.35. The 68gr HPBT, which is 7 grains lighter but the same length, has a stability of 1.26.

Given the same length, a lighter bullet will be less stable. Given the same weight, the longer bullet will be less stable.

A 77gr SMK is 0.994" long and @ 2500fps has stability of 1.36; the 77gr Nosler CC is 0.973" long and @ 2500fps has a stability of 1.45.

And in the extreme case...the 75gr A-Max is 1.11" long and at 2500fps has a stability factor of 0.96 (ie. unstable): the 80gr SMK is 1.066" long and at 2400fps has a stability factor of 1.14.

[Maztech89]

The 75 Amax might be on the edge, my buddies 10" twist couldn't stabilize them at all no matter how hard they were pushed. Couldn't hit paper at 100 with a setup that puts the 68 bthp match in sub half minute 5 shot groups.