^^^^^^Exactly this^^^^^^^
I have fixed the regulator creep issues with better regulator pistons. Also fixed the issue of 1st slow fps shot by making a modified front part of the plenum. In OEM plenum, there is the issue of O ring extrusion that the revised design successfully fixed.^^^^^^Exactly this^^^^^^^
From memory, the barrel passes through the front block ( which is where the scope is mounted) and is only held concentric with a couple of o rings, then is attached to the rear butt block by a thumbscrew. The only connection between the front and rear blocks are the top rail made from a flat section of aluminium (approximately 25mm x 5mm) which adds little to torsional stiffness. Then there is the plenum, however only one end has a firm connection to the block, the other end is a push fit with an o ring for the seal and a grubscrew to hold it in place.
By holding the front pistol grip and the rear butt grip it is not difficult to twist and flex the gun, only a guess but I would say that’s probably not a good thing for consistent poi placement.
There was two other issue that I could never resolve, reg creep, this was only slight but leave the gun for a hour or so and the pressure would rise. The other was valve sticking, again after the gun had been left for a while. The effect of both of these was the first pellet would always travel slower than the rest. Dry firing one shot stopped this happening but none of my other guns have a problem even if unused for weeks or even months.
IMO the impact is a great concept (which is why there are many copies) poorly executed.
Can you post a pic of your build? I would love to see your upgrades, I enjoy custom tinkering.
Yes but don’t forget I’m only 12fpe which means there is very little spring load required to knock the valve open. Any sticking of the valve stem o ring leads to a massive power drop. The longer the gun was left, the greater the velocity difference, Target shooting was never really an issue but while hunting it may be up to an hour between shots, so this valve stem issue (and to continual poi shift) made the gun unfit for purpose.
I'm sure in some cases you may be correct, but I assure you there are far too many instances having been reported by too many very experienced shooters and engineers to disregard this very real issue. I was going to purchase an M3 last year and changed my mind because FX is NOT dealing with this issue.
After following modification, my Impact doesn't give low fps even on the very 1st shot at 12 ftlb.Yes but don’t forget I’m only 12fpe which means there is very little spring load required to knock the valve open. Any sticking of the valve stem o ring leads to a massive power drop. The longer the gun was left, the greater the velocity difference, Target shooting was never really an issue but while hunting it may be up to an hour between shots, so this valve stem issue (and to continual poi shift) made the gun unfit for purpose.
Keep up the good work
Bb
Agree. You can make the problem worse by assembling an Impact on a bind but what about the Crown, Maverick, Wildcat and Dreamline guys? My Dreamtac Compact put every Impact I ever owned to shame when it came to POI problems. Not accuracy problems, it was accurate but my scope got a workout. The gun is simple, not a bunch of pressurized sections fighting with each other. I wasn’t on hallucinogens. Never hamfisted anything on the gun. That thing never shot in the same spot day to day. Machined a solid barrel for it, haven’t touched the scope since. There is something going on. If customers demand modular guns with a bunch of cheap options to switch calibers and projectiles, this just might be a side effect.
