6xc twist for 105 and 115

[CLance]

If the chose is either 7 or 8 twist and you wanted to shoot both 105 and 115 which twist would you chose.

 

[Corjack]

I always use a 7.5 twist. Never an issue with 115 DTACs and 105 Berger.

 

[CLance]

That would be what I would do also but it doesn't fit my timeframe. I can get either a 7 or 8 that are ready to go. Just not sure if the 7 is to much for the 105's . Has anyone had any experience with this combo and how did it work.

 

[dnellans]

not benchrest here but i am currently running 105's out of a 29 inch 7 twist at 3150 FPS without issue. 115's shot fine as well (but not as good as the 105's, so thats what i'm running).

good enough for PRS... as they say.

that said, i think 7 is probably overspinning the 105's with no advantage and I'll move back to a 7.5 when the time comes.

 

[CLance]

So if the consensus would be that a 7 twist is to fast for the 105's should I just plan on using 105's and a 8. I was originally planning that and just "testing" the 115's but was fairly sure the 8 twist wouldn't be enough for the 115's. This is my first venture Into the 6mm's so I am all open to new to me ideas

 

[spclark]

8’s OK for 105’s though myself I prefer 1:7.8 (my first 30” 6XC barrel) or 1:7.5 (all the rest). For 115’s (don’t shoot ‘em) I’d have to believe 1:7 would be best if you want to avoid brass-trashing speeds and the load profiles that produce them in a 1:7.5.

Remember it’s not speed that wins it’s accuracy; in a fast twist you can achieve reliable stability with less velocity than what’s necessary when bullets don’t get spun up as much.

High speed + fast twist is a recipe for flyers, or worse.

 

[cmillard]

7 twist will be my next 6mm barrel. Shoot 8 twist right now and the 105 hybrids get kinda squirrely at 600 and will be switching back to 105 hunting vlds until I rebarrel

 

[CLance]

Forgot to mention and not sure what difference it will make but I will be running a 28 inch barrel.

 

[urbanrifleman]

Tubb says 7 twist for his bullet.

 

[6xcshooter]

I shoot 115 dtaks in a 8 twist no problems what so ever.

Tubb says 8 twist stabilizes the dtack. Go to his website and read it

 

[CLance]

Is there a downside to running a 7 twist with the 105's

 

[BenPerfected]

Is there a downside to running a 7 twist with the 105's

I think a 7 twist barrel is spot on with 105’s. Most all of my 6mm barrels are 7 twist and I now shoot exclusively 105 gn bullets. Look at the info on the Berger website, it will give you some confidence. I stopped shooting the 6mm 115gn Berger’s so i don’t have to change the powder load. Just tweak my tuner and never change my Varget load. At my age, simplicity is good.
Ben

 

[CLance]

That makes me feel better. I have looked all over Berger and other sites trying to get ready for this barrel. I have even spoke with Berger. They said 7 was fine but when you start looking at their calculator it got me to thinkimg of 7 may be too fast. Was hoping the folks at Berger we're not just saying what I wanted to hear or I wasn't just hearing what I wanted to. Was looking for first hand info.

 

[dnellans]

I don't think you'd be unhappy with a 7 twist, particularly at 3000-ish velocities. If you want to run them fast 3100+ wait the couple weeks for a 7.5 twist. I think 7.5 is the magic number to run anything 105-115 and not have to think twice about it.

 

[spclark]

Is there a downside to running a 7 twist with the 105's

Yes if you try to push ‘em past 3000 fps too much. 3,050 might work for you, might not. Depends on the barrel character, bullet consistency, altitude you shoot at (air density). Much past that point & they’ll be spinning so fast the inevitable inconsistencies in all of those qualities will be working against you.

 

[SLAYIN'SWEDE]

In my 26" 7 twist PRS rig I run 105's @ 3020 and 115's @ 2915....you'll be fine!

 

[eddief]

My son and i ran our PRS rifles all year with 7.5tw PROOF's steel tubes. 105's and 115DTAC, hammers with both out to 1050yds, furthest we shot.

 

[Dgd6mm]

My 7.5 twist Krieger's run the DTAC's just fine. These have all been in a 6mm Competition Match cartridge, 3150-3275 fps.

Don Dunlap

 

[spclark]

My 7.5 twist Krieger's run the DTAC's just fine. These have all been in a 6mm Competition Match cartridge, 3150-3275 fps.

Yes but trying to achieve accurate results using the 6XC cartridge at those speeds will be frustrating if not downright dangerous.

There's a range of velocity + twist combinations that will stabilize most any bullet. Faster velocities generally need slower twist rates to avoid the problems 'over-stabilization' will inevitably cause.

John Whidden has won more than one NRA Long Range National Championship pushing Berger 105's to those speeds in his 243-chambered rifles but I don't know what his preferred twist rate is. Somehow I very much doubt if it's 1:7... but I'll ask!

 

[Dgd6mm]

I don't know what twist John is using, but he told me his barrel life was 1300ish rounds running it like that.