1st rounds after adding the C88 18cc plenum to the Avenge-x, and a new scope, DNT 7-35x56 aka "The One." While I really like the scope, this is about the C88 mod.
Performance results - From what I've read increasing plenum space can provide additional regulated shot count, or higher power potential. I'm testing for shot count based on the FPS/StdDev of the shot group.
BLUF: Before C88 mod I typically got 60-65 regulated shots. After, I see 85-90 regulated shots. Transfer port always set for High.
Details:
1. I use JTS 22 cal Dead Center 18.1 grain pellets. Just opening the tin they are impressive, little to zero dust, and very few deformed pellets. I get them from Pyramid Air, actually cheaper than Amazon for now, and they pack them very well. Have not tried any others yet. Likely I will try JSB/others once I switch to the 25 cal barrel.
2. Prior to the C88 plenum mod I ran the out of the box tune ( HS 2.5 @2000 psi on the reg). My StdDev stayed under 5 fps. Avg speed was 927 over 1000 or so shots.
3. After mod I set the Reg for 1800 psi and adjusted HS (1.25) until I saw StdDev of 1.5 fps at best, 5 fps worst, with 3 fps being the avg over 20 groups of 5 rounds each. Pellet speed started at 850 fps with 0.25 HS, as I increased HS looking for a solid StdDev I ended up at HS of 1.25. This gave me an avg speed of 910.
4. Finally I tested shot count. I ran 3 fills of the onboard tube reservoir (210cc). Shot from 4350 to 2000 psi and/or until pellet fps dropped to 899. I easily got 85-90 shots for each fill.
I attached my target boards for the day. The first three were shot at 32 yards and the last at 50.
Fun with air rifles!
Notes:
1. The 50 yard card is likely due to me. I still have a hard time getting centered behind the eyebox. My eyes are old and it's a work in progress, thus the bigger, higher magnification scope.
2. I erroneously wrote 2000psi on the target cards. It really is about 1800.
Performance results - From what I've read increasing plenum space can provide additional regulated shot count, or higher power potential. I'm testing for shot count based on the FPS/StdDev of the shot group.
BLUF: Before C88 mod I typically got 60-65 regulated shots. After, I see 85-90 regulated shots. Transfer port always set for High.
Details:
1. I use JTS 22 cal Dead Center 18.1 grain pellets. Just opening the tin they are impressive, little to zero dust, and very few deformed pellets. I get them from Pyramid Air, actually cheaper than Amazon for now, and they pack them very well. Have not tried any others yet. Likely I will try JSB/others once I switch to the 25 cal barrel.
2. Prior to the C88 plenum mod I ran the out of the box tune ( HS 2.5 @2000 psi on the reg). My StdDev stayed under 5 fps. Avg speed was 927 over 1000 or so shots.
3. After mod I set the Reg for 1800 psi and adjusted HS (1.25) until I saw StdDev of 1.5 fps at best, 5 fps worst, with 3 fps being the avg over 20 groups of 5 rounds each. Pellet speed started at 850 fps with 0.25 HS, as I increased HS looking for a solid StdDev I ended up at HS of 1.25. This gave me an avg speed of 910.
4. Finally I tested shot count. I ran 3 fills of the onboard tube reservoir (210cc). Shot from 4350 to 2000 psi and/or until pellet fps dropped to 899. I easily got 85-90 shots for each fill.
I attached my target boards for the day. The first three were shot at 32 yards and the last at 50.
Fun with air rifles!
Notes:
1. The 50 yard card is likely due to me. I still have a hard time getting centered behind the eyebox. My eyes are old and it's a work in progress, thus the bigger, higher magnification scope.
2. I erroneously wrote 2000psi on the target cards. It really is about 1800.
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