You may get some insight here: https://www.gatewaytoairguns.org/GTA/index.php?topic=80474.0 or you can try You Tube.
I'm confused here, what does the barrel length have to do with the piston? Any extra length sticks out the front of the gun. Regards, Tom
Did you find this thread? https://www.gatewaytoairguns.org/GTA/index.php?topic=49115.msg639814#msg639814You can also do the backdraft mod, and change it at will.If you simply drill a hole into the face of the piston, it will de-comp. If you go too deep, a bit of epoxy will refill to a depth that works for you.I highly recommend backdrafting with a 117 ring. The rings last, and the ESs drop to amazing levels.Good job TomRob! LOL... Tom is right... slug it often as you sneak up on your choke... you'll feel when you are close. Try shooting it before you go the last little bit, you may already be where you need it.
I have a 13.5" barrel on my Alecto and it works just fine. +50fps. Regards, Tom
Quote from: mr007s on February 15, 2019, 07:59:22 PMDid you find this thread? https://www.gatewaytoairguns.org/GTA/index.php?topic=49115.msg639814#msg639814You can also do the backdraft mod, and change it at will.If you simply drill a hole into the face of the piston, it will de-comp. If you go too deep, a bit of epoxy will refill to a depth that works for you.I highly recommend backdrafting with a 117 ring. The rings last, and the ESs drop to amazing levels.Good job TomRob! LOL... Tom is right... slug it often as you sneak up on your choke... you'll feel when you are close. Try shooting it before you go the last little bit, you may already be where you need it.Well Eric, I saw that thread as well. Just didn't feel like reading through 28 pages of tit-for-tat to try to find the real answer, if it even lies within that thread. The page that your link goes to directly talks about de-comping, which is not what I want to do, so dishing the piston face does not apply to my question.I'll read that thread in full I guess, right after I re-read the Bible.Funny thing though about your #117 o-ring comment. I happen to be right now doing just that. I just got in a bag of 50 pcs. #117 o-rings (anybody need one?) and now I'm putting a Band-Aid on my knuckle from pulling out the piston and hitting the upper shroud.Am I the only one who cuts themselves EVERY TIME I open up a gun?
Eric, I wasn't making a slam on your very thorough thread. It's just that I still couldn't find the answer to my question.I'm beginning to think that the backdraft thing does not exist, and that the only way that silent_airman got that setup to shoot is to remove and replace the TKO in between shots (which I did read somewhere in all my searching).Still a nice article though. Wish I had all that access to machining. Nice job!!
If the pistol is still holding a vacuum when nearly fully opened, your valve spring is too strong
Replace the pin (to cover the hole).
"knurl" one end of the pin, with wire cutters, and it will stay put.