A little history...
A friend contacted me and asked if I would shorten a barrel on a BRK Commander to make it legal for pistol EFT. He was interested in that one because of the solid construction and bottle, which meant a good number of shots at the 20 ft lb level, vs the Atomic, which gets only a few shots at that power level. Now, the reason I am posting this is because I see so much misinformation about "what is the best caliber"... especially for FT. I am not trying to say that some won't work... only that there may be better choices if you have the option.
With that in mind, a 22 cal Commander arrived at my place. I contacted him and he wanted to shoot 18.1's at 700. Now that is NOT optimum in my experience so I set out to prove what might be a better choice before starting to cut on anything. I then tested 177 10.3s at a couple of velocities, 177 13.43's, 177 13.43 MRD's, the 22 18.1's, 22 15.89's, and 22 14.3 Cros Premier (old batch.... just to see). At the same time, I was conferring with @Franklink because he and I had done some testing in this link ... https://www.airgunnation.com/thread...eally-would-like-to-know.1274941/post-1334060 . His Veteran that had a 20 cal LW barrel I fitted for him has been such a good shooter, I wanted that as a consideration. I had picked up several 20 cal barrel's back in the 90's and all have been wonderful, so far. Here is a spreadsheet (thanks @Franklink) that shows a synopsis of a lot of our efforts.
A friend contacted me and asked if I would shorten a barrel on a BRK Commander to make it legal for pistol EFT. He was interested in that one because of the solid construction and bottle, which meant a good number of shots at the 20 ft lb level, vs the Atomic, which gets only a few shots at that power level. Now, the reason I am posting this is because I see so much misinformation about "what is the best caliber"... especially for FT. I am not trying to say that some won't work... only that there may be better choices if you have the option.
With that in mind, a 22 cal Commander arrived at my place. I contacted him and he wanted to shoot 18.1's at 700. Now that is NOT optimum in my experience so I set out to prove what might be a better choice before starting to cut on anything. I then tested 177 10.3s at a couple of velocities, 177 13.43's, 177 13.43 MRD's, the 22 18.1's, 22 15.89's, and 22 14.3 Cros Premier (old batch.... just to see). At the same time, I was conferring with @Franklink because he and I had done some testing in this link ... https://www.airgunnation.com/thread...eally-would-like-to-know.1274941/post-1334060 . His Veteran that had a 20 cal LW barrel I fitted for him has been such a good shooter, I wanted that as a consideration. I had picked up several 20 cal barrel's back in the 90's and all have been wonderful, so far. Here is a spreadsheet (thanks @Franklink) that shows a synopsis of a lot of our efforts.
12/13/2022 Additional data collection session
These were mostly completed at my place at elevation of 3100 ft. There is a lot to look at here and I will expand on this more later and it's likely that there will be input from the others involved in this project. Here is a pic of the project "pifle" A couple of details: And a test target at 50 yds: Now I want to point out where the original 22, 18.1s would have been ... a bc of 0.0223. Note that the WORST 177 in our previous testing was a bc of 0.0293 and the best 177s and both 20s are well above that. I fully realize that the bc is not all there is to wind drift but it comprises the bulk of the equation. I will jump back into this and show some examples but you can easily run the numbers in Strelok and draw some of your own conclusions. The bc was derived from the difference between the 0 yard velocity and the 50 yard velocity and I did multiple shots averaged to find these numbers. Also, having shot all of these except the Veteran 20 of @Franklink extensively, I'm confident that the bc's pretty well line up with pellet drop and wind deflection. Again, not saying that this is all hard and fast for choices of ammo but it was quite easy to see the difference in wind sensitivity of the 22 cal 18.1s, 15.89s and the 177 16.1s to the 10.34s and 13.43s and also the 20 cals. It's easy to see why @Motorhead uses the 20 for FT, as well as a few others. Bob |
