Fed 22's good

[capstan]

I tested my 4 inch diamondback,6" Official police, and 6" S&W model 17 today with various 22 shells including some Russians, some remingtons,winchesters,wolf target match,CCI mini mags, and others.
I found oddly enough, for all 3 revolvers, the Federal 40 grain LR plated bullets were the most accurate. I was kinda surprised because I always thought the mini mags were the best. They are in my remington model 581 bolt action rifle but not so in the revolvers.

group size as follows: diamondback under 2 inches at 15 yards

Official police Under 1 inch at 15 yards

Mosd 17 S&W under 1 inch at 15 yards

sandbag rest

the diamondback has the worst trigger pull by far so that may have something to do with the worst group of the 3

[ccw1911]

Compared to the other two the Diamondback had, less sight radius, lighter weight, and probably had a smaller grip. These could be factors as well, maybe you just don't shoot the Diamondback as well. I've always found them to be very accurate. You're lucky to find 22 ammo all your guns like, I don't think there is anything more picky about ammo than a 22.