ftp 900 velocity adjustment

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Hunkaluv
Posts: 65
Joined: Thu Jun 18, 2015 10:14 am

ftp 900 velocity adjustment

Post by Hunkaluv » Thu Aug 18, 2016 9:06 pm

Hi there,

I'm wondering if anyone knows how to properly adjust the velocity on the FTP 900. I got some JSB 7.87's sent to me by accident, but they actually group really well, so i wanted to adjust the power up a touch to be closer to 12fpe for FT. I know on my old s400 MPR, there was a "secret screw" to open up the transfer port to increase the velocity, and it worked no problem. On the FTP 900, apparently there's an export model and a UK model. The UK model only has a screw on the right side of the rifle (as you're looking down the barrel) which is only meant to LOWER velocity. The export model has a screw on both sides of the rifle. As expected, when i tried opening up the transfer port from the right side, velocity did not increase. From the left side, i was able to dial the velocity up to 825fps, which would gave me 11.89fpe. I shot about 100 shots through it, then checked it again, but the velocity had increased up to 846fps at that point. I can't find a lot of info out there to see if the left and right screws are meant to work in conjunction with each other or if there's something wrong with the left side screw (loose or something) that is letting it move further out with vibration.

CHrony is a Caldwell, i use it to tune all my rifles and i believe it to be consistent. I shoot through the chrony using the scope at a point on a target 10 yards away, so i believe that to be consistent as well. THe pellets are all from the same tin, washed and lubed with Lupus oil, and pellet gage has them all pretty consistent. 

ANy help would be appreciated.

Thanks!

RYan

Hunkaluv
Posts: 65
Joined: Thu Jun 18, 2015 10:14 am

Re: ftp 900 velocity adjustment

Post by Hunkaluv » Sat Aug 20, 2016 6:53 am

In the end, the problem was the loose screws on either side of the transfer port - they were a little bit too sloppy after i had "broken" the loctite which was factory applied. I re-loctited them and set the velocity where i wanted it, and now everything holds at 825fps where i wanted it.

Here's the instructions i got from AA:

"Yes use the two adjusters on the FTP, one each side of the transfer port. Both of these can be adjusted out to increase the power slightly.
I say slightly because each rifle is different. If the chap needs more adjustment he can wind the rear adjust in a small amount to increase spring tension.
This has to be done in small amounts as it will be possible to coil bind the main spring using this adjuster. With the stock removed you can adjust the hammer spring in but may need a special tool. They are not usually too tight and a set of of split ring pliers should work fine."

Dennis Eden might be interested in this, but i don't know if he patrols the forums.

Ryan

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FTguy
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Posts: 438
Joined: Sat Jun 16, 2012 4:57 pm

Re: ftp 900 velocity adjustment

Post by FTguy » Sat Aug 20, 2016 10:16 am

Glad to see you got that sorted out Ryan.. That new rig will be interesting to see in action..
Shoot Safely, Shoot Often & Share Your Sport!

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