X-Caliber barrels on Savage and Howa Mini

[Biodsl]

This fella has dived in deep. He has a Savage 110 and Howa Mini with X-Caliber barrels that it appears he plans to use in PRS competition. If I have this correct, the Savage's running a 7.7 twist and the Howa a 7. Factory 108 ELDM ammo is running over 2800 fps out of his 26.5 inch barrels.

https://www.youtube.com/watch?v=VihvrkDzSgg

[grayfox]

I would be willing for 22" or 20", don't want a 26" as I don't do PRS.

[Lemonaid]

More testing testing by Eagle Eye. Interesting theory about how fast burning powders will erode less than slow burning powders. https://www.youtube.com/watch?v=x5EWXnvqvvY
https://www.youtube.com/watch?v=soTy1PHYdA8

[grayfox]

I watched the first one. His main piece of evidence seems to be his ability to grab the 6Arc barrel at about the 20" length, so warm but not hot.
I would not attribute this to burn rate, rather to burn volume or mass. The 6 Creed is running ~40 grs of powder but the 6Arc is running ~30. That's 25% less powder to burn. AIRC powder burns tend to all be around, what, 10-15" of barrel, it is the shape and peak pressure that determines the energy put forth to drive the bullet and heat the barrel.
Also, the 6 Creed is running at higher pressure so this would tell me it's running hotter temps also.
Last, the CFE powder was designed with a copper inhibitor that tends to, as a side benefit, make a longer pressure curve at somewhat lower pressures.

Those 3 reasons would be more what I would think, go towards his barrel temperature theory.

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I'd also add that, (I think) while the bullet is in the barrel, gas velocity is the same as the bullet's velocity pretty much. It's a closed cylinder so expansion occurs at pretty much one speed...

[Lemonaid]

His theory is the opposite of mine, that slower powders give a longer time/distance of the peak pressure so that the throat is subject to lesser stress (the damage is spread out over more area so is less concentrated in the first few inches).
But in the absence of proof his idea could be just as right or wrong as mine.
His magazine was interesting as well, looks like plenty of room to seat bullets long if needed.

[6ARC904]

I have a 6 ARC built by Kenny and it does exactly what he said it would. 5 shot group 1/2 MOA or better at 100 yards. I have the 26.5" X-caliber barrel with the MTU contour with a 1-7.5 twist rate. So far my best 5 shot group is .416' at 100 yards with Hornady Black 105's.