Whitetail and the 6X45

[lamar]

Hey from the deep south. I plan on hunting deer with an AR platform and settled on the 6X45, 16-18" bbl. Shot ranges out here are 20-150 yrds. My question is twist rate, 1:10 vs 1:9. Seems like the faster twist the better, but was advised that the 1:10 would work better for me.
Thoughts?

[letaz77]

I believe it will depend mainly on the bullet weight you are planning to shoot rather than the distance to target. If you keep it with light bullets then either the 1:10 or 1:9 will work very well. The 1:9 is not incredibly fast so that it would "over stabilize" (if such thing is even possible) you bullets.

Personally, I would lean more towards the 1:9 just to keep open the option of using heavier bullets. Just my .02 cents

[Deleted]

The 1 in 10 will stabilize everything up to 100 grains. The case length is the problem here. If you are loading to maximum magazine length 2.260. You will have to stop around 95 grain bullets. After that it is not a question of bullet weight, it is case capacity. 100 grain bullets have to be seated so deep to feed through the magazine you loose about 40% of the usable case.

Here are a few rules we can't change.
You can not over stabilize a bullet but you can over rotate it.
Twist rate has to do with bullet length, not weight.
You can't give up case capacity and still have speed.

I would load a 85 grain Nosler Partition with a stout load of H335. That will work well beyond 300 yards.

[lamar]

1:10 it is. By no strange coincidence I'm just get started in to reloading and picked up some H335 as well as Varget and TAC (trying a few out to see what works for me).

[GLSHOOTER]

Aug 9, 2011 12:57:39 GMT -8 lamar said:

1:10 it is. By no strange coincidence I'm just get started in to reloading and picked up some H335 as well as Varget and TAC (trying a few out to see what works for me).

Another good one that carries the mail is 748. I would also look at the Barnes bullets for a good deer performer.

Greg

[Deleted]

I use H335 in my "heavy" loads which are the 80g to 95g bullets and they all print under 1" @ 100 yds in my 1/10" twist 24" bbl.

[Deleted]

The stabilization has nothing to do with the weight and everything to do with the length, shape and the speed of the bullet.
Normally there is a correlation between bullet weight and length but if you stay with classic lead cored bullets. Once you get into some match hollow points (longer) or solid copper ones (even longer) then the picture changes completely.
The 10 twist will stabilize a 87gr and 90gr fmj bullet but some longer ones like the 87hornady v-max will start to show some considerable yaw past 300 yards. You will see that on the paper.
But then the hornady 87gr in HPBT version is not so bad because it is shorter.
Most 100gr will not properly stabilize nor it is a good idea to shoot them anyway unless you are single feeding, have a long pole that equals more speed, have the freebore to do it and/or use a VLD magazine.
You cannot over stabilize a bullet but angular momentum (the force that keeps that bullet spinning) wears off so you might put additional twist to make sure accuracy doesn't suffer. This is specially critical as you approach trans-sonic speed and the rotation is not enough to keep the bullet stable. Not a big deal for the average folks doing the average hunting or 100 yard weekend shooting but a huge deal if you are shooting longer shots whether is for competition or for fun.
The gravity is the same for everyone in this planet, including all bullets, and the most predictable and solid constant we have in external ballistics so think of it this way: For how many seconds is my bullet exposed to gravity and other external forces? That determines the drop and other behaviors otherwise not often considered.
Best thing is to follow the recommended twist from the manufacturer. Some do a good job about this (specially with match bullets) and some don't.

Also do not assume that if someone says this should stabilize this or that, then your barrel and load is going to do it. There is a big difference between "it should" and "it shall" but, w/o getting into semantics, it means that what you are going to use must be tested with the same load, with the same barrel and with the same type of rifling at the same intended distances. If you enjoy accuracy and the occasional long shot then take the best bullet you consider, specially if you are borderline with the desired bullets, and this might mean that you up your twist by 1".
Ballistics software (including some free versions) will help you with your decisions but ultimately will depend on the tests. I am sure you can find some good literature online too.
The 10 twist can use some pretty nice bullets but then the best bullets the 6x45 can shoot are out of the menu.