I recently picked up a Garmin Xero chronograph thingy. I have to say, using this thing is so simple and convenient that I seldom shoot without it.
Anyway, I was shooting some of my 22's and set up the Garmin to gather more information.
The 22's were a Model 52 with the barrel set back and rechambered with a 52D reamer
A Model 75 Winchester with a Gaillard barrel, chambered with the same reamer.
A CZ552 varmint, factory barrel and chamber.
Ammunition was S-k standard plus, Norma Tac, and Sellier and Bellot Canadian Match.
With all ammunition, the 52 was most accurate and showed the lowest spread and SD, the 75 was a close second, and the CZ a distant third. I strongly suspect this is strictly due to chamber dimensions. The CZ is a little loose in headspace and barely engraves the bullet on chambering. It strings vertically, as one might expect given the SD recorded (over 21fps as opposed to 11 or less for the others. The other two are chambered at .041HS and engraved the bullets significantly. My next move is to rebarrel the CZ with a Benchmark barrel which was gifted to me and see what effect. At the same time, I may set back the factory barrel. The Benchmark barrel was previously fitted to a Stiller action and shot OK but not exceptionally. I re-barreled that rifle with a Lilga and it does now shoot exceptionally well for it's owner. The chamber in the Benchmark is a bit homely and I'll cut the new chamber with my 52D reamer.
By the way, the S&B ammo turned out to be slightly supersonic so I shelved it. WH
Anyway, I was shooting some of my 22's and set up the Garmin to gather more information.
The 22's were a Model 52 with the barrel set back and rechambered with a 52D reamer
A Model 75 Winchester with a Gaillard barrel, chambered with the same reamer.
A CZ552 varmint, factory barrel and chamber.
Ammunition was S-k standard plus, Norma Tac, and Sellier and Bellot Canadian Match.
With all ammunition, the 52 was most accurate and showed the lowest spread and SD, the 75 was a close second, and the CZ a distant third. I strongly suspect this is strictly due to chamber dimensions. The CZ is a little loose in headspace and barely engraves the bullet on chambering. It strings vertically, as one might expect given the SD recorded (over 21fps as opposed to 11 or less for the others. The other two are chambered at .041HS and engraved the bullets significantly. My next move is to rebarrel the CZ with a Benchmark barrel which was gifted to me and see what effect. At the same time, I may set back the factory barrel. The Benchmark barrel was previously fitted to a Stiller action and shot OK but not exceptionally. I re-barreled that rifle with a Lilga and it does now shoot exceptionally well for it's owner. The chamber in the Benchmark is a bit homely and I'll cut the new chamber with my 52D reamer.
By the way, the S&B ammo turned out to be slightly supersonic so I shelved it. WH