223 twist rate dilema

[Lightload]

Rebarreling my 223. Old barrel was a 24" 8t and I could do pretty well with it out to 1000 with 80gr smk's. New barrel will be 26inches and it will be chambered with the ISSF reamer with the .169 freebore. I ordered a 7.7t figuring I'd be able to go to 90smk's . I'm thinking maybe I should go to a 7t so it will handle the 90's better but the barrel will only be 26 inches so I'll be losing some velocity.
I shoot groundhog matches and steel plate shoots out to 1000 but mostly I just like to hit stuff at long ranges.
So, will the 7.7do it or should I drop down to a 7? The lightest bullets I would shoot out of it would be 69s and the closest I would shoot would be 200yds.
Any thoughts?

 

[DukeDuke]

7.7 won"t do it. 7 or faster.

 

[XTR]

7.7 won"t do it. 7 or faster.

What he said. If you plan to stretch it out with the 90s I'd get at least a 28" 1:7

 

[r bose]

What he said. If you plan to stretch it out with the 90s I'd get at least a 28" 1:7

Living at sea level I use a 6.5 twist for 90's. You'll give up some BC using a 7 according to Berger.

 

[Lightload]

Thanks for the replies. Spoke with Kreiger and the barrel is done and ready to ship. They offered to redo it but I would have to wait months again to have a new barrel made so I'll stick with the 7.7 and shoot 80's.

 

[XTR]

Living at sea level I use a 6.5 twist for 90's. You'll give up some BC using a 7 according to Berger.

Personally, I never shoot my 223 past 600 yards, and a 1:7 seems to work fine to that distance. I've never made it to Houston to shoot, every other range I've ever shot on has been at least 900ASL.

Bryan Litz (and the Berger calculator) do agree that at sea level a 1:6.5 or 1:6.75 is going to yield a little better BC, but Bryan Litz also says that the gyroscopic forces from the higher twist rate can result in less precision. Shooting for Xs at 300, 500, 600 I run a 1:7.

 

[stacy]

I'M AT A 1000' ABOVE SEA LEVEL AND MY 223 ACKLEY 30'' 1/7 SURE DOES A FINE JOB WITH 90GR BERGERS!

 

[Topstrap]

7 twist. I haven't shot 90s though. All the guys at our local 1000 yards steel plate matches use the 80 VLD or 80.5 fullbore. A shooting buddy uses 90s in his 223 but only at the 900 and 1000 yard station and last match I attended he ran all 3 targets at each distance.

Topstrap

 

[7Fingers]

7 twist. I haven't shot 90s though. All the guys at our local 1000 yards steel plate matches use the 80 VLD or 80.5 fullbore. A shooting buddy uses 90s in his 223 but only at the 900 and 1000 yard station and last match I attended he ran all 3 targets at each distance.

Topstrap

I think the 90s are better at 900-1000 too, I used the 80VLDs hit all 3 at 900 but dropped 2 at 1000. The 80s go subsonic at 930ish in the 16" .223 pistol that I used in that match. The .223s also dominated the .308s in that match last year.

 

[Topstrap]

I'm going to try the 80's this weekend in the new 223 pistol. Don't have any settings at all, still tweaking the load but will have a 100 yard zero. Hopefully won't look too bad first trip out. Will have to pick up a couple boxes of 90's for the last two stages. Might have them by next month and also plan to use this gun up at S.T.A.R.T. if they shoot this year.

Not sure which day I'm going yet, depends on Chris' schedule. Might need some of your settings but Strelok should get me on target for first round hits depending on the wind. My velocity is running around 2520 to 2550 depending on which load I go with. Had a couple good groups with the 24gr of 8208 along with the 24.5 of Varget. Playing with seating depth now a bit, does seem to like being in the lands though. Opened up the throat up so the bottom of the BT is flush with the shoulder. Same depth as the Criterion Match Chamber barrel on the rifle.

Topstrap

 

[Huckleberry75]

I went with a 7twist and throated for the 80.5's. Need to finish up load development, but it's looking like a winner with 8208.

 

[manitou210]

I went with a 7twist and throated for the 80.5's. Need to finish up load development, but it's looking like a winner with 8208.

Varget 24.5 to 24.9 will be your friend, Kissing

 

[Huckleberry75]

Varget 24.5 to 24.9 will be your friend, Kissing

Probably more than that. Mine is an Ackley. That blown out shoulder and the 80.5's hanging out at 2.49" looks killer. Looks like I am going to be around 2950-3000fps. Definitely punching way above its weight.