Recently ran some Buffalo Bore and Underwood 305gr ammo over my then new Labradar.  Guns/bbl lengths - 2 3/4" S&W M69, 4 1/4" S&W M69 and 7 1/2" Ruger SRH.  Thought the results might be of interest:

Buffalo Bore, 305 LBT LFN HC rated 1,325 fps
Underwood, 305 LFNGC Plated (HiTech?) rated 1,325 fps
LabRadar muzzle velocity at 33 deg F Buffalo

S&W M69 2.75" ===> BB 1,195 fps ===> Under 1,147fps
S&W M69 4.25" ===> BB 1,276 fps ===> Under 1,248 fps
Ruger SRH 7.5" ===> BB 1,395 fps ===> Under 1,315 fps

Paul

I have an early Colt Delta Elite 10mm that was accurized by Alex Hamilton (10 Ring Precision) in the late 80s.  It was always an accurate pistol, but has been a safe queen for the last 20 years or so.  I wasn't sure what springs were in the gun, so I fitted an EGW square (small radius) firing pin stop, 23 Lb Mainspring and a 22 Lb slide spring.  Also added an extra power firing pin spring.

When I took it to the range, the POI was 3" to 4" high at 25 yards with the rear sight bottomed out.

Could the cumulative effect of the above changed the lock up enough to change the point of impact?

Any thoughts?

Thanks,

Paul