115 DTAC twist?

[RobertB]

I live in Louisana so altitude is not on my side. What is the slowest twist you can get by with shooting a 115 DTAC? It will most likely be a "straight" .243 but might live life being a 6XC. FOund a 8 twist but wasn't quite sure how that would work. Thanks

 

[Mike]

Re: 115 DTAC twist?

Eight would be the bare minimum I would use and only if it's a true 1:8.

1:7.5 or 1:7.7 is better.

 

[JCH]

Re: 115 DTAC twist?

I have an 8 twist from a well respected barrel maker, it wasn't enough to stabilize the 115.

If you have an 8 twist look at the 105 berger hybrid....if you have the chance, get a 7.7 or 7.5

 

[wnroscoe]

Re: 115 DTAC twist?

1-8 for 105/108
1-7.5 for 115

 

[JC Steel]

Re: 115 DTAC twist?

If there is a slower shooting cartridge like the 6x47 shooting the 115 I would go with 1-7.5 twist. BUT, Is it even smart to shoot the heavies in the 6x47???

 

[105amatt]

Re: 115 DTAC twist?

Im running a 25", 7.7 Bartlein, works great.

 

[leadbullet]

Re: 115 DTAC twist?

my 243 AI has an 1-7.5 benchmark barrel and is a lazer with 115.

 

[Frank Green]

Re: 115 DTAC twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jcvibby</div><div class="ubbcode-body">If there is a slower shooting cartridge like the 6x47 shooting the 115 I would go with 1-7.5 twist. BUT, Is it even smart to shoot the heavies in the 6x47??? </div></div>

What do you consider slow? My 6x47 Lapua is a 30" finished length barrel. 7.5 twist. I'm shooting 115 Berger VLD's at 3030fps. The gun is a laser. Consistent sub 1/3moa at all distances even at a 1k. The load is 39.0 of H4350. I have run it up to 40.0gr. but my groups doubled in size at 1k yards. Barrel is 5R with a .237 bore.

According to my twist calc's the the 115 Bergers at like 2800fps. need a 7.77 twist if I remember correctly. I went 7.5 for my gun.

In my 1-8 twist barrel 6mm Remington the 115 Berger's wouldn't shoot. The DTAC's we're o.k. but I feel it was on the ragged edge.

Later, Frank
Bartlein Barrels

 

[JGorski]

Re: 115 DTAC twist?

Read what David has to say, ok, 8 twist worked just fine.
http://www.6mmbr.com/6XC.html

 

[JGorski]

Re: 115 DTAC twist?

They said a 9 twist wouldnt stabilize a 105 Hybrid, too. Ill have to beg to differ on that one, shot one group that was an inch and another measured 1.723", at 300yds. factory 700 6mmREM.
Though I did pull one of these shots, grrrr

 

[JC Steel]

Re: 115 DTAC twist?

Frank, I guess I was just comparing to something like a 243 which is a little more potent. I'm trying to decide on a bullet for my wife's 6x47 lapua right now. I have 1,000 dtacs and a bartlein 7.5 twist barrel. Was just thinking I was not going to run it very hot either.

Would that still work? Maybe running at 2900?

 

[Jaxdialation]

Re: 115 DTAC twist?

I asked Dana English to build my 243AI specifically for DTACs. We went with a Kreiger
28" 7.5 twist.

So far so good! 1/2 MOA fire forming loads work for me any time

This thing will be insane with
the AI formed cases. The question is, is there accurate nodes in that 3050-3200fps range.

 

[Frank Green]

Re: 115 DTAC twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jcvibby</div><div class="ubbcode-body">Frank, I guess I was just comparing to something like a 243 which is a little more potent. I'm trying to decide on a bullet for my wife's 6x47 lapua right now. I have 1,000 dtacs and a bartlein 7.5 twist barrel. Was just thinking I was not going to run it very hot either.

Would that still work? Maybe running at 2900? </div></div>

Yea it should be fine. My original hope was to make 2900fps. Wasn't sure if I would or not.

On to other comments about the twist and bullets. Yea some guys can get say a 105-107gr. bullet to stabilize in a 8.5 or a 9 twist and the 115's in a 1-8 twist etc...and then some guys cannot. I think it comes down to where you shoot /altitudes, weather conditions, velocity etc....these are all variables we cannot control. So I tend to error on the faster side of the twist.

Look at some of the short range bench shooters shooting light bullets. Back years ago 1-14 and even 1-15 twist barrels. Guys noticed that the 15 twist barrels would stabilize bullet X but as the temps. etc...dropped and changed the gun wouldn't shoot as well but the guys shooting 14 twist barrels where not having a problem. As benchrest shooters bullets have changed to different length jackets even though the bullets might have only gone from 65gr. to 68gr. in weight they found that even in some cases a 14 twist barrel might be on edge of being stable. Point is there are a lot of variables to contend with. Bullets, velocities, conditions etc....

Later, Frank
Bartlein Barrels

 

[steve123]

Re: 115 DTAC twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Frank Green</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jcvibby</div><div class="ubbcode-body">Frank, I guess I was just comparing to something like a 243 which is a little more potent. I'm trying to decide on a bullet for my wife's 6x47 lapua right now. I have 1,000 dtacs and a bartlein 7.5 twist barrel. Was just thinking I was not going to run it very hot either.

Would that still work? Maybe running at 2900? </div></div>

Yea it should be fine. My original hope was to make 2900fps. Wasn't sure if I would or not.

On to other comments about the twist and bullets. Yea some guys can get say a 105-107gr. bullet to stabilize in a 8.5 or a 9 twist and the 115's in a 1-8 twist etc...and then some guys cannot. I think it comes down to where you shoot /altitudes, weather conditions, velocity etc....these are all variables we cannot control. So I tend to error on the faster side of the twist.

Look at some of the short range bench shooters shooting light bullets. Back years ago 1-14 and even 1-15 twist barrels. Guys noticed that the 15 twist barrels would stabilize bullet X but as the temps. etc...dropped and changed the gun wouldn't shoot as well but the guys shooting 14 twist barrels where not having a problem. As benchrest shooters bullets have changed to different length jackets even though the bullets might have only gone from 65gr. to 68gr. in weight they found that even in some cases a 14 twist barrel might be on edge of being stable. Point is there are a lot of variables to contend with. Bullets, velocities, conditions etc....

Later, Frank
Bartlein Barrels </div></div>

Frank,

What gain twist would you recommend for DTACS out of a 26" barrel? I saw a few guys were having exceptional accuracy with your gain twists for the 105's.

 

[Frank Green]

Re: 115 DTAC twist?

Most common seems to be a 9 to a 8 twist and or a 8.45 to a 7.7 twist for the 6mm's in general. If it we're mine with the 115's I would go with the 8.45 to 7.7.

Later, Frank
Bartlein Barrels

 

[Hoser]

Re: 115 DTAC twist?

I am running the 115s at 3,000 in an 8 twist. No issues.

Any slower than 2,800 I would look at a 7.5 twist.

 

[steve123]

Re: 115 DTAC twist?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Frank Green</div><div class="ubbcode-body">Most common seems to be a 9 to a 8 twist and or a 8.45 to a 7.7 twist for the 6mm's in general. If it we're mine with the 115's I would go with the 8.45 to 7.7.

Later, Frank
Bartlein Barrels </div></div>

Thanks for you're advice!

 

[Kino]

Re: 115 DTAC twist?

I am running a 7.5 Brux and it shots awesome. In fact, I just finished a 260 on a Brux and it shoots awesome. I have never tried a Brux until this year and I must say that I am super impressed. Tim at SAS has built about 6 rifles or so with Bruxs in the last 4 months or so and every single one of them has been stellar. Call Greg (Bugholes) at Southern Precision Rifles who sells several brands of premium blanks and ask him what he runs in the 6mm class......