FX Fx drs classic 500mm ???

Hello there friends,
my drs which I bought last year about same time from Utah airguns,
the reg was set at 810fps using 10.3gr
this season i am noticing that my drs starts at 750fps regardless even if I use 8.4gr or in todays case 9.1 Norma gt ft pellet,
and then after 60 shots or so it creeps up to 800fps and then stays there untill I drop below 130bar which is reg pressure!!!
any idea what should I do since this rifle does not have reg gauge,
it only has tank pressure gauge.
I will be calling Utah air tomorrow to find out what is going on with it…

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Hi,
Sounds to me like it is time to replace the piston in the regulator. There is a delrin seat on the piston that can get deformed over time, or by trying to lower the reg pressure without degassing.
I am pretty sure that Sub12Airgunners has a video on the Amp 2 regulators and show that if the damage is not too bad you can polish the delrin to remove the indentation. The DRS uses a newer piston (Part 21070) which Utah Airguns doesn't carry yet. However, either of the older brass pistons work just fine in the rifle (at least mine, which is a .177). Bagnal and Kirkwood in the UK likely carries the newer piston.

Cheers,
Greg
 
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Yeah the low velocity start is probably from a good amount of reg creep. Probably needs rebuilding. At least it isn’t leaking I guess. When looking at high end guns specifically my opinion is the amp is the worst one out there.
Yeah no leaks…
I leave my drs filled up for weeks and the pressure guage stays same.
 
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When I bought my pre-owned DRS Classic 600 from Utah it didn't have reg creep like you were describing (60 shots to get back to normal velocity), but it did have too many (5-6) low velocity shots, and a really wide extreme spread of velocity values. And accuracy which wasn't up to par. Still under warranty so back it went to UA for repair. They ended up replacing the reg and the valve.

The gun returned to me MUCH improved. It seems like 1-2 low velocity shots after a fill or when the gun has sat around for a bit. But that also happens with my 500mm DRS, and I just burn a shot. Not optimal but seems common for the DRS in general. And not worth it to me to chase perfection - apparently it can be obtained but my DRS's are currently just used for fun plinking.

So UA Service took care of my issues, and I hope they do with yours as well.