Keeping this as simple as I can for a bit of a convoluted pair of projects.

I have a Shilen Bull in 30-06 (special order, there simply are NO heavy barrel pre sits out there in 30-06) and an X-Caliber Bull in 308. Both the standard 1-10 twist, 26 inches.

I would rate them both equal. I think the X-Caliber bull was an Apache done barrel (I got it through Jim and he was working with Dennis)

One problem I have had is that my shooting is not as nearly as good as I think it should be, makes it tough to sort through the shooter, the gun, optics or the barrel.

One reason I have those two was to get two sources that should be pretty solid barrels (Shilen with a longer record than X-Caliber) and that removes barrels as an issue.

I caused myself some grief with the new stock (EABCO) I seem to have that sorted out. I like the Thumbhole, it just needs to get setup right.

I have had some good (to me) 1/2 and 3/8 groups with the Shilen and some 3 and 4 shots once or twice a shooting session into one hole.

The X-Caliber was working down in that area as well and got a group Saturday that I have yet to fully figure out.

Pretty much tore up the paper in something around 3/8 or 1/4 instead of neat holes (or hole) (all 5 shot strings)

Loads for both guns are getting dialed in, so a couple weeks ago the Shilen shot the best groups, this week the X-Caliber.
Loads all use 168 gr Hornady Match or ZMAX.

Any difference as near as I can determine is how well I am shooting one gun or the other, the better optics is on the Shilen right now, stocks are a split, EABCO is heavier and more solid but fighting the cheek riser that I have to grind down so my muffs don't hang up on it.

I believe both barrels are good for 3/8 if the shooter and the loads can do it.