243AI twist rate Question?

[slayer_21420]

I plan on putting a 243AI together within the next few months, I plan on exclusively running 107-115gr bullets, mostly DTAC's if they shoot up to my expectations.

My question is, Is a 1-7" twist too fast for the 243AI with this weight bullet? I picked up a Kreiger 1-7" .236" bore #17 contour, hoping to use it for this project, but i've done a little talking with people and some say it'll do fine, others say they have seen the exact combination in use and the velocity had to be backed off significantly because bullets were coming "unglued" on there way to the target with max loads. What do you guys think I should do?
Should I sell this and pick up a 7.5" or 7.8" twist?

thanks in advance for any advice you can give me,

Steve

 

[LWolken]

I'd think its a little too fast. Several guys on here are shooting 115's with a straight 1-8" twist. You might want to get that 1-7.8" twist just to be sure. I have shot up to and including the 107 matchking's, 105 Lapua's, Berger's Hornady's with a 1-9" twist with no issues.

Lance

 

[blawton]

I'd think its a little too fast. Several guys on here are shooting 115's with a straight 1-8" twist. You might want to get that 1-7.8" twist just to be sure. I have shot up to and including the 107 matchking's, 105 Lapua's, Berger's Hornady's with a 1-9" twist with no issues.

Lance

yes a 7.5-7.8 twist is what your looking for. The 115's are stable in a true 1-8 twist barrel but when temps get low they dont want to be stable. If you want to insure stability all the time you will need a bit more twist then 8.

 

[Chuckhunter]

slayer_21420, In my 243AI, I shoot both 105 Berger VLD's and 107 Sierra SMK's with a full throttle load of H-4831 Sc. at velocities over 3200fps. from a 26" nine twist Hart Barrel. No problem with stabilization and I think with an eight twist you should be able to stabilize 115 Grainers with little problem. Most cut barrels will give you a true 8 twist and the ackley will give you the needed velocity.

 

[LWolken]

Chuck,

How much H4831SC? I fireformed with about 42.5gr. and 105 Amax.

Lance

 

[Chuckhunter]

Lance, I'm shooting 47.5 Gr's. from a 9 twist hart barrel with Moly coated 107 SMK's. That's running at the uppeer limit. If you're shooting naked bullets, I'd back off several grains and work up slowly. The load shoots very well out of my rifle.

 

[22243win]

I shoot a wildcat based on 6.5x55 necked down and improved. I have run 115 DTAC's to 3400 fps. They seem to shoot best around 3200 fps. I'm running an 8 in twist krieger. Just had a couple of gain twist 8.75 to 8.3 chambered. Trying to reduce stress on jackets, so hopefully I can take advantage of extra velocity. The 8 twist stabelized the 115's from 600 to 8000 feet in altitude.

 

[blawton]

A 8 twist will work in most cases. But it is borderline at best even running 3400 fps. Your best bet is to use a 7.5-7.8 twist. When being that close to being stable or not it doesnt take much to turn things the wrong way quickly. Some rifles will work just fine with a 8 twist and some just wont. Thats why most people are putting 7.5 twists on them to make sure they work all the time. Plus you will get some extra accuracy at the longer distances having that little bit of extra stability. Bullet weight has about nothing to do with stability and the bc/length is the key factor. Maybe the DTAC's wont fly straight but the Burgers or JLK's might. Thats just another option if you are stuck with a 8 twist and want to shoot the high bc bullets.