FX Impact problem - FPS dropped

Jump to latest Follow Reply
nonsheep

nonsheep

Member
Jun 17, 2018
22
7
CA, United States
Hello, I'm seeking some help & advice on my FX Impact Gen-1 .25. My typical M.O. is "something is wrong, lets gut it all and see what the problem is", but I'm hoping that someone out there has had the same problem as me, and may know a simpler fix for this airgun. About 2-3 years ago I tuned this Impact to around 920fps (25gr JSB), the gun has less then 300 pellets total lifetime. I shot it a few days ago and it seemed very weak so I chrony'd it and it was shooting in the 400's, so what changed from sitting, and what is the easiest fix? (Currently 200BAR on the gauge, 140BAR on the back gauge, "MAX" on the side adjuster). Is the regulator failing, or? Any intelegent thoughts or advice?
 
Thank you all for your good suggestions. The C3 sure seemed like it may have been the problem from what I read, but it wasn't the issue in my case. I just opened it all up and my O-ring is in pristine condition.

FX-Impact-C3oring_20220911_01.jpg
 
Upvote 0
I opened the regulator to check it and all the o-rings seemed hard & squared, so I replaced all o-rings and re-adjusted it as I had it previously. It made no difference. Currently with a 200 bar fill, and 130 bar adjustment on the back gauge, I am getting 589fps on a 25gr JSB. So.... nothing so far has addressed my initial issue/question here. When I fire it, it feels like the hammer is striking some kind of dampener like the old Bstaley Mrod mod.
 
Upvote 0
Have you checked the valve assembly itself out or replaced the oring on it? The wrong size oring can increase stiction.

Are the micro and macro dials where they were previously when you shot your original speeds?

Are the breech orings in place and sealing?

Is your valve adjuster screwed in too much? May explain the feels like it is striking a dampener comment.

Do you feel or hear any air coming out near your cheek when firing?

What does your hammer assembly look like?

Losing half your velocity is pretty substantial. There isn't that much to it really. If the plenum fills to 130 bar, then 130 bar should be sent into the breech when the hammer strikes the c1. I can't imagine the hammer spring losing that much compression unless it broke completely, but who knows.
 
Upvote 0
Somethings not adding up. All the advice given was great as doing one of those things forces one to check on other things. 99.9% of the time when something suddenly happens with my impacts anyway, it’s because of something I did, and it’s usually the last thing I did. If I used a liquid lube say around the cocking block area and all of a sudden my shot strings go wonky, it’s because that wet lube drizzled down onto the valve rod by the spring and hammer area which is a no no.

The OP has to trace back steps as to what was done to the gun, the last time he used it. If it was loaned out to anyone that also counts as something done to the gun(and it’s because no one will take care of something as good as the owner does- human nature. Sad, but true)
 
Upvote 0
All good advice, thank you. Twice I thoroughly checked the valve rod & hammer WITHOUT removing them, but they all "seemed" to function perfectly. I suppose I really do need to remove the hammer spring to check it, I was hoping to avoid the full tear down. No oil/lube was introduced to this gun, no loaning of this gun, no adjustments made, no o-ring replacement until after I started this thread. This gun functioned perfect at around 920fps, and it sat for months, and then the fps dropped to 400's/500's all on it's own. I'll update after I remove the valve rod & hammer. Thank you guys.
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu