No reason to use more than 1 O-ring.... Keep it as close to the end of the F-T-P as possible, and machine the end of the valve off as close to the O-ring groove as possible, to minimize the headspace.... Bob
Quote from: rsterne on April 18, 2017, 01:27:25 AMNo reason to use more than 1 O-ring.... Keep it as close to the end of the F-T-P as possible, and machine the end of the valve off as close to the O-ring groove as possible, to minimize the headspace.... BobI did ,but I wanted more power & my chrono dont lie guess thats why they Put two compression rings on car pistons with an oil ring. I guess the whole carIndrustry is gonna sue me for copying their design. Oh well they wont get anythingBecause Im broke as a convict.😂
i was surprised when my stock 1377 was actually shooting a few fps over 600 with the crosman pointed. like you i assumed the advertised numbers were with lighter pellets.the general rule of thumb is just that. you will pick up more fps per inch going from 10" to 14.5 then you will going from 20 to 24.5 "
Thanks! I saw the rating but thought it was overstated like many of the factory specs. I saw on Airgun reporter and the Pyramidair blog where the average from tests was 500fps with 10 pumps, so I wanted to make sure my chrony (first time using it) wasn't giving me some funny numbers!
Quote from: hank hill on April 16, 2017, 11:40:52 PMi was surprised when my stock 1377 was actually shooting a few fps over 600 with the crosman pointed. like you i assumed the advertised numbers were with lighter pellets.the general rule of thumb is just that. you will pick up more fps per inch going from 10" to 14.5 then you will going from 20 to 24.5 "I hope that all newer 1377 (those with new-style plastic grips and pump arm and improved piston design) shoot around advertised velocity, since I'm an owner of one......but have no chrony to test it . I only started to look for info on improvements of velocity of stock 1377 after I noticed it hit the targets waay too hard for 500 fps. At the moment I have found only one video of post-2015 production 1377 shooting (and it got around 570 fps with crosman pointed at 10 pumps), and 2-3 posts on various forums stating that they are getting numbers around 600 without any mods. Did you get these numbers on 10 pumps? I hope more people will post in this thread - if the results are consistent, I won't have to bother with FTP mod and go straight for longer barrel. Alternative is finding somebody who owns a chrony around my place, but I guess I'm too lazy to actively search for those
Quote from: Pantokrator on April 25, 2017, 04:17:57 PMQuote from: hank hill on April 16, 2017, 11:40:52 PMi was surprised when my stock 1377 was actually shooting a few fps over 600 with the crosman pointed. like you i assumed the advertised numbers were with lighter pellets.the general rule of thumb is just that. you will pick up more fps per inch going from 10" to 14.5 then you will going from 20 to 24.5 "I hope that all newer 1377 (those with new-style plastic grips and pump arm and improved piston design) shoot around advertised velocity, since I'm an owner of one......but have no chrony to test it . I only started to look for info on improvements of velocity of stock 1377 after I noticed it hit the targets waay too hard for 500 fps. At the moment I have found only one video of post-2015 production 1377 shooting (and it got around 570 fps with crosman pointed at 10 pumps), and 2-3 posts on various forums stating that they are getting numbers around 600 without any mods. Did you get these numbers on 10 pumps? I hope more people will post in this thread - if the results are consistent, I won't have to bother with FTP mod and go straight for longer barrel. Alternative is finding somebody who owns a chrony around my place, but I guess I'm too lazy to actively search for those I bought 2 at the same time when Amazon had a sale, one of them shot almost equal to a ft piston, and started retaining air at 15 pumps or less, I can't remember for sure. The other would never pump up high enough to retain air.