I'm working with a new barrel in a 270 wildcat slightly larger than a 27 Nosler and I'm getting some very odd groups so far while breaking in the barrel. The barrel is a Broughton 1-8.5" twist that had 45 shots though it before these groups were shot. I've had barrels that didn't start to shoot well until they had 50-75 rounds through them, but never quite like this. These 3 groups were shot at 150 yards from a bipod with a rear bag with 3 different bullets, each seated .030" off the lands, and the same powder charge for each bullet. All cases are once fired in this chamber, from the same lot and prepped the same. The black dot is 1.2" to give some scale. 145gr ELDx 140gr Nosler BT 140gr Sierra TGK What's throwing me off is the fact that these groups were fired "round robin" style with one shot from each bullet fired with 1 minute between shots, and then the gun was allowed to cool for 15 minutes before the next string. If all of the groups were stinging either vertically or horizontally I'd start looking at bedding issues or my technique. If they were all grouping poorly but symmetrically I'd look at either the scope or my technique. To confuse myself even more, I put a proven barrel, with similar ballistics/recoil back on this action and shot a .5 MOA group at the same range, which is exactly how that barrel always performs. I haven't ruled out the idea that this barrel just really hates this powder or bullet weight range and I have other bullets and powders to test still. I've just never seen 3 loads print 3 very different groups like this.