Cooey 10A aperture sight for Sht. .22 MkIV

[Sapper740]

Quick recap for those unfamiliar with this Canadian made Cooey 10A rear aperture sight: Conventional wisdom has it that Harold W. Cooey designed a base to mount a Ross MkIII rear sight onto a SMLE or a Sht .22 MkIV early on in WWII so as to allow Canadian servicemen to re-familiarize themselves with rear aperture sights after decades of shooting SMLEs. I recently picked up a Canadian stamped LSA Sht .22 Mk IV with the Cooey 10A sight and finally got it to the range today. I started out at 15 yards to ensure it was on paper and then sent the target to 50 yards. It was very easy to get tight 3/4" groups with the sight shooting CCI 40 gr. Standard Velocity Target ammunition although the groups were 8" high above the aiming point even with the sights on the lowest setting. At 15 yards the center of the POI was 3" high. Since my BSA Sht .22 Mk IV* with the PH5A sight is more accurate and more adjustable i.e. I can hit the bullseye at 50 yds it will be my go to .22 for competitions but for rarity nothing beats the LSA Sht .22 Mk IV with the 10A sight.

[tiriaq]

Nice rifle!
A higher front sight to get elevation zero?
Many years ago, I saw some No.2 Mk. IV rifles which were still in use. Apparently the Cooey sights didn't stay tight on the receivers - so dabs of braze had been applied to secure the bases to the receivers.

[Sapper740]

Nice rifle!
A higher front sight to get elevation zero?

Thank you! Yes, it's a beaut. There probably isn't a front sight tall enough to make up the difference but next time I take it out I'm going to shoot it at 100 yds, probably bang on at 100.

[CoatiMundi]

My No2 with a Cooey sight is an LSA as well. I’ve had similar results at less than 100 yards. I haven’t taken it out further than that yet.