223 Twist Rate?
I have a DPMS upper in a 223 with a 1 in 9 twist rate. What bullet weights are best for this twist rate? If I use Barnes bullets will that make a difference due to the Barnes bullets being longer in each bullet weight since they have no lead to increase weight?
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The 9 twist is optimum for the 68-69 gr match boattails and the M855/SS109 service bullet. Sometimes it will work with a 75 gr bullet, sometimes not.
Yes, it is length that matters. It appears to me that the 62 gr Barnes would behave about like a 75 gr lead core, possible but not certain.0 -
dreher,
The 1 in 9 will handle anything up to the 69-70 grain lead core bullets. I do believe that it will like the 62 grain Barnes TSX bullets also. Notice I said handle, as some say you cannot over stabalize a bullet. I have found the 1 in 7 twist does not like the 40 grain TAP rounds, or the 40 grain Ballistic tip loads, as well as they do the 62 grain and up loads.
That said, I have a short 16" RRA Varmint upper, with a 1 in 8, and it loves the 62, and 70 grain Barnes TSX bullets. It truly turns this into a deer rifle out to 200-300 yards, WITH GOOD(in the vital's) shot placement. For everything else, I have been shooting the 68 grain Hornady Bottail Match bullets. I have started exclusively using CFE 223 with those loads. I find this to be a phenominal powder.
Your barrel will like stuff from the 55 grain, to 69 grain range for lead core, and the 62 grain Barne's TSX.
Best0 -
As noted, the 1-9 rate was an answer to stabilizing the military's (then) new 62 grain bullets, as the old 1-12 just wouldn't cut it. Now M-4's are coming in with twists as fast as 1-7, and some units are using bullets to 75 grains. (I have one 1-7, but I've only used 55 and 62's in it so far) All of my 1-9's like 50-69 grainers just fine. 0 -
quote:Originally posted by Riomouse911
As noted, the 1-9 rate was an answer to stabilizing the military's (then) new 62 grain bullets, as the old 1-12 just wouldn't cut it. Now M-4's are coming in with twists as fast as 1-7, and some units are using bullets to 75 grains. (I have one 1-7, but I've only used 55 and 62's in it so far) All of my 1-9's like 50-69 grainers just fine.
M16A2's started at 1-9" then changed to 1-7" so they could stabilize the M856 tracer bullet, which is extremely long. Many feel the old 55 gr. bullet was the best. I personally think the 77 gr. Mk 262 is better than the current M855. I can imagine though how hard is to make a tracer bullet to match the trajectory of it though.
Dreher,
If your rifle can stabilize 75-77 gr. match that's the bullet I'd use. You may find that it will stabilize Hornady 75 gr. hollow points but not A-max's. Mine was like that. If it won't stabilize and accurately shoot the 75-77's then bump down to the 68-69's. I don't say 70 gr. Bergers because they are closer in length to the 75-77's. But it never hurts to get a few and try them.0 -
I have used both the 1-7"twist (issued and owned) which I didn't like and the 1-9"twist (owned) which I prefer and have used both light through heavy grain weights and noticed no significant difference in performance or stability with either. I was able to easily cut the black out to 500 meters with open sights with small groupings every time using different ammunition and grain weights again with no problems although personal preference is the heavy grain weight ymmv.
Regards0
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