A new 13xx feels sooo wonderful to pump when new. You feel every bit of pressure build as you pump. The pumpcup wears in and pumping smooths out abit. Dont know whatsup with guys that are happy with hardly ever putting oil on in thier AG.? After enough shots a different feel shows up, a different feel when pumping, This tells me the AG pumpcup needs oil. Sometimes its as low as 20-30 shots< 200-300 pumps before i feel they need oil 1 drop on the piston cup. With enough use, 1377 and 1322 will start to lose some pump pressure and with that a loss in some fps/fpe. To bring back some pump pressure and FPS/FPE ,I shim the pump cup using a 7" piece of threadtape, folded 2x to create a 3 layer strip. This is enough to make 5 rounds between the pumpcup and piston, doing this moves the pumpcup up, as the pump is reinserted into the tube the tape will compress abit and push out on the pumpcup creating a better seal during pumping. I did this twice, both times an increase in pump pressure made an increase in Muzzle Velocity. As i continue to shoot these, when they start to show a drop in pump pressure, i have my fix, soon im sure each of the 13xxs i have will also get shimmed pump cups. A new pumpcup doesnt cost alot,,, starting to think a new 13xx w shimmed Pumpcup would be great.NVak
2A Georgia, With 10 pumps and 14.3gr you should be getting 450-470 FPS, sound like your valve is not holding air good,, or your TP is leaking a bunch.. either replace your valve seals or findout if yourTP is leaking during the shot..checkout the Svitvu 3-9x32mm Half mildot. Parallax Needs to be manually changed for AG use. Have 4 all with parallax set to 30- 40 yards.thats a lot of fences to hurdle through buddy. goodluckRick67, Man those are pretty, what you put together. Excellentwork.threesuns, A 78' 1377,,,,,, wow. Excellentwork,---Ill have an update for you later or tmrw.NVak
2A Georgia, Thats good your AGs can shoot the .22 CPHPs, most of my airguns do good with them, except for a few that need heavier or wider head pellets. 11+ Pumps. Your 1322 doing 472 FPS @ 10 pumps is good, pumping past 10,, I am not One to pump past 10 mainly because pumping to 10 takes long enough, also im sure overpumping brings about sooner wear to the Pumpcup and Pumplink/Pumparm. ------- -------C2289x14.6"2 years old from Manufacture Date. Ive Had this nearly a year now since last fall. This AG has always been accurate with CPHP and CPUM 14.4gr and a few other pellet types ive run through this. For quite sometime this wore a Aluminum Breech < had to be modified to fit> and scoped on and off along with a BRLDC. Last Month i moved parts around to where this was apart for a couple weeks,,, until i found a TransferPort that had been missing. XD I removed the grips and stock pump arm, removed Pump arm Pin using a Punch Set and a light hammer. Before removing the pump piston from the tube, the holes for the PumpPin are sanded to remove the burrs that likely will scratch the piston and pumpcup unless smoothed out. I added 6 rounds of HalfCut threadtape under the cup between the piston. This keeps the pumpcup shimmed up and out. A renewed resistance is felt after shimming the pump cup. Reassemble using the Stock breech and open sight with an Extended Probe Bolt and a 760 Front sight, 1399 Stock On and Off when i feel like it. Good VeryGood. ------- ------- 2289x14.6" 821-532Modflow BoltOpened Transfer PortShimmed Hammerspring10 PumpsCPHP 14.4grAvg 506 FPSFPE 8.2---EHD 14.6Avg 493 FPS 7.9 FPE---HNHP 20.1gr 5.53mm SlugAvg 418 FPS 7.8 FPE-------- -------C2289x14.6" 821-532Extended Probe BoltOpened Transfer PortShimmed HammerspringShimmed PumpcupCPHP 14.4gr3 Pumps < 333 FPS4 Pumps < 379 FPS5 Pumps1. 4122. 4153. 412Avg 413 FPS 5.5 FPE---10PumpsCPHP 14.4gr1. 5252. 5213. 5224. 5165. 522Spread< 9 FPSAvg 521 FPS 8.7 FPE-------HNHP 20.1gr10 Pumps1. 4482. 4463. 4454. 4445. 440Spread < 8 FPSAvg 445 FPS 8.8 FPE------- Having exchanged the Modflow bolt for a Extended Probe bolt and shimming the Pumpcup produced a gain of 15 FPS and 0.5 FPE when using CPHP 14.4gr. A gain of 27 FPS and 1.0 FPE when using HNHP 20.1gr Slugs. NVak