While testing different ammo to show the importance of finding the right combination at 100 yards, my Marlin Mountie produced 1.5" groups with CCI Select.
It will produce 1" groups with CCI MiniMags.
The target used was the 100 yard Unlimited, and it was scoped with a 3-9 Sightron.
Now try to find CCI Select is the problem.
With my Bench guns, striving for under 0.25 at 50 yards and under one inch at 100 but the cost of quality ammo is a bit much for some.
However, the person that pays $40.00 for a box of 45 ACP and blasts it away in 10 minutes, should not criticize me for paying $20.00 for a box of RWS R50 or Eley Tenex.
Plus the pattern produced with that 45 proves nothing. Many of my five shot groups at 50 are smaller than a "one shot group" with a 45 . . .
These were produced while working the tuner.
Rim thickness is my current venture, and Eley Tenex and RWS R50 vary about 0.001. Eley Match about 0.002 and Team is under 0.003.
Next is to test some CCI (Select, SV, and MiniMags).
The trick is to find what your rifle likes. Trying to convince someone to try 5 - 10 different brands and designs is sometimes difficult.
What is acceptable to one is not to another. A grouse's head is an excellent standard for a hunting scenario . . . plinking at a pop can is another.
While I really like the CZ line of rifles, I sold two to buy the 40XB. The BSA has more than doubled in value with the addition of scope and base as well as some gunsmithing and the tuner.
It is just money and I have heard you can't take it with you!!!
2014-06-14: Did not rim thickness measurements.
Eley Target: 0.36 (10%), 0.37 (40%) and 0.38 (50%).
CCI MiniMag: 0.40 (20%) and 0.41 (80%)
CCI SV: 0.40 (50%) and 41 ((50%)
CCI Select: 0.40 (25%) and 0.41 (75%)
I may check the Eley through the BSA but the CCI was only for interest sake.
With the CCI, a few rounds would be less that 0.40 and a few would be over 0.41 but for all intensive purposes not far enough to make any statistic difference 3.14 693 percentage points 19 times out of 20 (in other words . . .not a tinker's dam)