FX Impact M3... loss of power

[oncall-50]

I shoot a FX Impact M3 600 with tuner, suppressor & shoot Nielsen 33.5gr slugs. It was sent in and tuned at the factory (under warranty) in 2/24. When it was returned, the MV was 960 fps. I have shot it a bunch and have not changed any knobs. It now shoots 740 fps. I have checked every O-ring for damage.... none. Has anyone had this problem?
oncall-50

 

[frankie]

It shoots 740 for how many shots? Reason I ask is because my FX impact M3 also shooting slugs at 915 fps, takes about 15 shots to get up to speed. It'll start out at 760ish for a few shots and then start working it's way up to the tuned velocity. Something about o-ring stiction, and a guy in Pakistan has a improvement, I just haven't contacted him yet. I'm gonna follow this thread, interested in the responses that you get.

 

[bigHUN]

If the Impact was sitting for a while, there could be any of these common scenarios:
- a Reg creep, the hammer cannot over ride the raised pressure in the plenum, it needs 5+ blank shots to balance the valve;
- check the C1, can possibly get loose. Check the Hammer set 6mm;
- check if air blows from the slug probe / mag area, maybe the brass port oring worn out and time to replace;

 

[oncall-50]

If the Impact was sitting for a while, there could be any of these common scenarios:
- a Reg creep, the hammer cannot over ride the raised pressure in the plenum, it needs 5+ blank shots to balance the valve;
- check the C1, can possibly get loose. Check the Hammer set 6mm;
- check if air blows from the slug probe / mag area, maybe the brass port oring worn out and time to replace;

I sent the M3 back to the Utah Air repair shop. They replaced several items. Once back k it shoots like new. I now shoot acorns in trees at 50 y! The guys at Utah Air really know their stuff...KUDOS!
oncall-50

 

[cmatera]

Yes, the techs at Utah Airguns do a great job. I'm glad they got you fixed up.