After reading an article that suggested if there is more than 30 fps variation, rimfire ammo will not be accurate.
My main testing was with various lots of CCI MiniMags in my two CZ455's ( American and Varmint).
The first groups were not kept as it was also a sighting in session at 100 yards.
The Velocity of the RN is suggested as 1235 and the HP at 1260. Only once of did the RN exceed 1235 and never did the HP drop below 1300 FPS.
With the HP's, both rifles recorded a 1355.
With one lot of RN from the American the variation was 4 fps and the group measured 0.49. That same lot from the Varmint showed promise when the first three had a 9 fps and the group was a 0.28 but the 4th dropped 20 fps and was an inch lower and the 5th dropped another 40 fps and was another inch lower.
I had wind flags up so was able to dope some of the changes however some low variations in the 20's were over 2" but variations of 46 - 54 fps were under 2".
Using lot numbers that produced better results at 100 were then tested at 190 yards. The two best groups at 190 measured 4" x 5" and 5" x 5". The narrowest group at 190 was 1.5 but it was also the longest at 8".
I also ran five rounds of Eley Team with a published velocity of 1085 that averaged 1043 with a variation of 25 fps. That is a test that will be reserved for another day when using my 22BR rifles.
My main testing was with various lots of CCI MiniMags in my two CZ455's ( American and Varmint).
The first groups were not kept as it was also a sighting in session at 100 yards.
The Velocity of the RN is suggested as 1235 and the HP at 1260. Only once of did the RN exceed 1235 and never did the HP drop below 1300 FPS.
With the HP's, both rifles recorded a 1355.
With one lot of RN from the American the variation was 4 fps and the group measured 0.49. That same lot from the Varmint showed promise when the first three had a 9 fps and the group was a 0.28 but the 4th dropped 20 fps and was an inch lower and the 5th dropped another 40 fps and was another inch lower.
I had wind flags up so was able to dope some of the changes however some low variations in the 20's were over 2" but variations of 46 - 54 fps were under 2".
Using lot numbers that produced better results at 100 were then tested at 190 yards. The two best groups at 190 measured 4" x 5" and 5" x 5". The narrowest group at 190 was 1.5 but it was also the longest at 8".
I also ran five rounds of Eley Team with a published velocity of 1085 that averaged 1043 with a variation of 25 fps. That is a test that will be reserved for another day when using my 22BR rifles.
