115 DTAC's in a 1:8 twist .243??

[BgBmBoo]

Ok...I am sure this has been addressed before...my search reults did not turn up what I wanted...but does anyone here shoot the 115 DTAC's in a 1:8 twist barrel?

My 6XC was a 1:7.5 as well as my DTA SRS in .243. They shot the 115's very well.

Any input would be great!

Take care,Stan

 

[Sendero_Man]

Re: 115 DTAC's in a 1:8 twist .243??

yes, they will shoot fine where you are at ...

no worries at all.

 

[sawgunner2001]

Re: 115 DTAC's in a 1:8 twist .243??

Works fine in my 243 at 2975fps at the elevation I'm at (~ 60' ASL).

 

[9H_Cracka]

Re: 115 DTAC's in a 1:8 twist .243??

DTubb told me personally at dinner a year ago that the 115 was designed with the 8 tw in mind given the number of them out there but that the 7.5 was optimal.

It should work fine.

 

[BgBmBoo]

Re: 115 DTAC's in a 1:8 twist .243??

Thanks gents. I knew I could count on fast, intelligent, replies.

Take care,Stan

 

[JRose]

Re: 115 DTAC's in a 1:8 twist .243??

Mine is in 8 twist, but make sure it's a true 8 twist. Most put them through a 7.5 for insurance incase their 8 twist is really a little slower than 8.

 

[BgBmBoo]

Re: 115 DTAC's in a 1:8 twist .243??

Its a Krieger barrel...I will assume it should be pretty close to a true 1:8?

Take care,Stan

 

[JRose]

Re: 115 DTAC's in a 1:8 twist .243??

I was pretty much told that cut rifled barrels were true, buttoned rifles could be a little off.

Just what I was told. My barrels have all been Rocks or Bartleins so I never worried about it.

 

[mattmcg]

Re: 115 DTAC's in a 1:8 twist .243??

I believe GAP is recommending a 7.7" twist with their 243 Win for DTAC rifle builds. Sounds like a happy medium.

Also, if you use the Miller Rifle Twist Formula, the 1.290" DTAC has the following stability ratios for the given twists at 3000fps and 0 Density Altitude (29.92 pressure, 59F):
1:8 twist = 1.465
1:7.7 twist = 1.582
1:7.5 twist = 1.667

Also, anything over a ratio of >1 is stabilized while a ratio of >1.2 is recommended to provide a safety buffer. All the above look to work just fine.

Slower muzzle velocities and colder temps would reduce these numbers FWIW so a 1:8 would run into issues before the others.

 

[rksimple]

Re: 115 DTAC's in a 1:8 twist .243??

I have a 1 in 8.1 Broughton and push the 115s at 2930 or so. I've shot them down around 200ft DA to 1k with no problem whatsoever.

 

[spot69221]

Re: 115 DTAC's in a 1:8 twist .243??

8 is fine for most applications, the insurance comes into play when you get out and shoot at really low temps.

7.7 twist is recommended by Bartlein