Thank you for the input, gentlemen. I do appreciate it. Yes, I agree that match-grade rimfire ammo would likely yield the most consistent, repeatable groups with such a firearm and that would be my first choice during regulation of the barrels.

As for RimfireCentral--nice bunch of folks over there. I've posted there a few times on various topics, including this one.

The points made on a "cape" gun project and off-setting sleeves inside the barrels to negate bushing the firing pins are also well-taken. Thanks again.

Best Regards,

"LightningTwice"