After all of the above testing (and more in that last link I shared), I decided to put my "magic" 1:36 slow twist poly back in my USFT. That means it's going back to .177, from .20. End on a high note with the last match of the .20 I suppose. And that means that, as a 24" barreled .177, it's a long son of a ....gun again. I'm working on a solution to be the best combination of quiet and length, but when you've got a 24" barrel, it can only be so short. I went through some mental gymnastics with this one, as I REALLY like shorter versus longer OALs. My internal justification was that, at least for field target, dealing with the length is worth it for the improved accuracy and resistance to wind deflection.
So, I figured that would mean some adjusting of the hammer tension, and possibly the transfer port restricting grub screw. And that it did, because the first few shots over the chrono after the barrel swap back to .177 were in the 950s with 10.34s. That makes it squarely illegal for field target. I found it interesting that the same hammer tension and port restriction for 800-805 with .20/13.73s was 950 with .177/10.34s. I suspect most of that relates to 6 more inches of barrel with the .177.
Anyway, this graphic shows the 70 shots that I took with the chrono, after minor adjustments to hammer tension and TP grub screw...
I purposely overfilled slightly, and shot longer than the likely refill pressure.
All 70 shots were from 1500psi to 1100psi.
For practice I'll probably run it from 1450 to 1150, for 60ish shots.
And for matches I'll probably fill to 1400 and refill at 1150psi. That's for an ES of about 25, which is the same sort of ES that I've always ran from this gun. That's an ES that will put them all inside of a field target kill zone. I am 100% NOT a single digit ES kind of guy, kinda like pellet sorting, there's just no point in chasing either endeavor for field target. Success can be had without them, as correct wind reads and reducing mental mistakes are a much higher valued proposition.
This barrel has always been exceptional with an average fps of 915-925 for the 10.34s, and so that's where I am.
In this particular string, I've got 2-3 semi-illegal shots, as the 20fpe cut-off for 10.34s would be 933fps. And my three highest are: 933.7, 934.6, and 935.9. There is also a 2% allowance that would get me up to 952. I don't like to rely on that 2%, but in this particular case, only 5% of my entire string is over the limit, and only over the limit by 2-3fps, not 18fps. So I'm a bit closer to the legal line than I like to be, but still well under the 2% rule for all shots, and inarguably under the actual limit for 95% of my shot string. If the match chrony reads higher than mine, easy adjustment on the hammer tension, but I don't foresee that being likely, as my chrono has never varied enough from that used at matches to make me fail a prematch chrono variation.
Pretty decent, for a non-regulated gun working on 25 year old technology.
Some consider it outdated, but in my opinion performance doesn't go out of style.
Here is the shot string data that was plotted above. Pressure in left column, fps in right.
So, I figured that would mean some adjusting of the hammer tension, and possibly the transfer port restricting grub screw. And that it did, because the first few shots over the chrono after the barrel swap back to .177 were in the 950s with 10.34s. That makes it squarely illegal for field target. I found it interesting that the same hammer tension and port restriction for 800-805 with .20/13.73s was 950 with .177/10.34s. I suspect most of that relates to 6 more inches of barrel with the .177.
Anyway, this graphic shows the 70 shots that I took with the chrono, after minor adjustments to hammer tension and TP grub screw...
I purposely overfilled slightly, and shot longer than the likely refill pressure.
All 70 shots were from 1500psi to 1100psi.
For practice I'll probably run it from 1450 to 1150, for 60ish shots.
And for matches I'll probably fill to 1400 and refill at 1150psi. That's for an ES of about 25, which is the same sort of ES that I've always ran from this gun. That's an ES that will put them all inside of a field target kill zone. I am 100% NOT a single digit ES kind of guy, kinda like pellet sorting, there's just no point in chasing either endeavor for field target. Success can be had without them, as correct wind reads and reducing mental mistakes are a much higher valued proposition.
This barrel has always been exceptional with an average fps of 915-925 for the 10.34s, and so that's where I am.
In this particular string, I've got 2-3 semi-illegal shots, as the 20fpe cut-off for 10.34s would be 933fps. And my three highest are: 933.7, 934.6, and 935.9. There is also a 2% allowance that would get me up to 952. I don't like to rely on that 2%, but in this particular case, only 5% of my entire string is over the limit, and only over the limit by 2-3fps, not 18fps. So I'm a bit closer to the legal line than I like to be, but still well under the 2% rule for all shots, and inarguably under the actual limit for 95% of my shot string. If the match chrony reads higher than mine, easy adjustment on the hammer tension, but I don't foresee that being likely, as my chrono has never varied enough from that used at matches to make me fail a prematch chrono variation.
Pretty decent, for a non-regulated gun working on 25 year old technology.
Some consider it outdated, but in my opinion performance doesn't go out of style.
Here is the shot string data that was plotted above. Pressure in left column, fps in right.
1500 | 898.9 |
893.1 | |
903.6 | |
899.9 | |
898.2 | |
900.1 | |
1450 | 907.6 |
905.4 | |
909.8 | |
906.1 | |
909.2 | |
910.5 | |
910.3 | |
911.5 | |
912.7 | |
911.5 | |
904.9 | |
1400 | 914.1 |
915.1 | |
917.7 | |
917 | |
924.4 | |
921.5 | |
923.9 | |
926.3 | |
1375 | 924.6 |
922.2 | |
923.8 | |
923.9 | |
927.3 | |
928.9 | |
1350 | 927.4 |
925.1 | |
929 | |
929 | |
929.5 | |
929.5 | |
929 | |
1300 | 931.3 |
933.7 | |
932.8 | |
934.6 | |
935.9 | |
932 | |
932 | |
932.5 | |
928.2 | |
932 | |
1250 | 930.5 |
929.7 | |
928.1 | |
926.9 | |
927.5 | |
922.5 | |
925.8 | |
1200 | 923.9 |
923.4 | |
924.1 | |
920.3 | |
922 | |
920.3 | |
1175 | 913.3 |
916 | |
913.1 | |
910.3 | |
1150 | 905.9 |
909.3 | |
906.6 | |
901.8 | |
1100 | 899.3 |
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