What is the thinking on this? I see that the GAP 6.5 SAUM is 8.5 or 8.75 twist. I'm building a .260 and found a Bartlein barrel #3 contour 1:8" twist, any reason not to jump on it? Will be using 120-140 gr bullets.
- Thread starter Graywolf.260
- Start date
My 6.5-06 AI duplicates SAUM ballistics and uses an eight twist, loves 140s.
8 so you can shoot 140 hybrids in one hole
that's what I thought, but wondering why they are using 8.75 for the 6.5 SAUM
I have 2 6.5 SAUMS, one is 8.5 the other is 8.75.. They both shoot fantastic. I have (2) 8 twist 6.5x47's and (2) soon to have (3) 8.5 twist 6.5x47's.. They shoot all 6.5mm bullets equally as well as the other... A friend of mine has a 9 twist 6.5x47L and he shoots 139 Scenars into one ragged hole..
8.5 is enough, but many use 8tw because the "faster is better" mentality is hard to overcome. I use 8.5 for 260s and creedmoors unless customer requests otherwise
My 260ai in 8.5 that greg built me shoots lights out with 130vlds. Shoots great out to 1000 so far if I do my part.
i have a 1-8 260 and 1-8.5 6.5 creedmoor, both shoot the 120-140 great, no worries there. a 1/2 twist won't make a dif.
cheers/
cheers/
Because less twist (provided you are certainly stabilizing the projectile) has several advantages, most notably - less inaccuracy due to bullet imbalance.
The 6.5 SAUM achieves way WAY more than enough speed to get very ample stability factors, even with an 8.75+ twist barrel.
There is no particularly good reason to use more twist than is necessary.
Generally you see 1:8 for like 6.5x47 or 6.5 Creed at the speeds they can send a 140gr, then in my range (modern 6.5 Swede) I can easily get away with 1:8.5 due too my 3000fps velocity, then when you're entering 6.5 SAUM territory 8.75 is no problem.
8.5 will work great with a 139.....I have yet to see a 8.5 shoot 140 hybrids good in a 47
