FX FX DRS with low velocity first shot! What should I check?

This is exactly what I'm talking about. First shot after sitting over night in the air conditioned comfort of my mancave! Regulator crept from 130 BAR up to 135 BAR.

POI Drop.jpg


First shot didn't even register on my FX Chrony, so I have no idea how low the velocity was. The second shot is 970 FPS! The first shot is almost ⅞ of an inch below the second shot at 35 yards. I typically shoot rats at around 50 yards, so the drop would easily put POI at over and inch below POA.

I'm going to continue to throw lead down range, but as far as this being a dedicated pesting airgun, it's not going to be the first one I grab unless this improves over time.
 
I had already beaten this with a stick with the increase after topping off. I had reached out to HUMA, and this was their reply.

Due to the small piston construction of the fx regulators a little primary pressure dependency is unfortunately not completely avoidable. 3 bar is what can be expected. When well tuned it will not influence muzzle velocity measurable.
 
Interesting. Well, mine is a 5 BAR creep and apparently it has a pretty significant impact on velocity since it’s too low to even register on the high power setting of the FX Chrony.

I probably should choose a different profile for the first shot to see if it will even capture the velocity of the first shot.

And, apparently it’s not “well tuned” either! o_O

I’m timing how long it takes to creep up to 135 BAR also.
 
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Temperature doesn’t really play a factor for me, my Airgun is sitting in a DeathGrip tripod inside my air conditioned house. The temp is a steady 73 degrees all day and night. I have an alarm set up where the rats are present, and a surveillance camera. So, when the alarm goes off, I check the camera to confirm it’s a rat and then just open the window long enough to get on target and pull the trigger. This is typically under a minute, so not enough time for the temperature in the house to change. I feel this is strictly internal to the air gun. I can fill it after shooting and the regulator shows a solid 130 BAR from there it will slowly creep up to 135 BAR where it finally stays until the Airgun is shot again. Filling and resting is all in the same air conditioned environment.

The Dreamline has the regulator in the air cylinder and uses what I refer to as the old style regulator that slides into the air tube. The Crown and DRS use the newer small regulators. I’m not sure if there is any significant difference, but I know my Dreamline, and Marauder, which both have the same type of regulator, don’t exhibit the same low velocity first shots.
I have replaced all my AMPS with a Huma, when storing in the same temperature room they don't creep(got a Sekhmet digital gauge to confirm).

The AMP regulators I had always tend to creep afther certain time. I tried rebuilding them, polishing and even inserting the new brass piston.

This is my personal experience with them, others can differ from mine.
 
I went over my regs in my dreamlines because of reg creep. There are some videos on here showing you what to polish and smooth out for a much more stable reg. I only hand a hand drill for my shade tree machinist lathe. Now my 2 dreamlines are rock solid. Just buy the small little orings in bulk because you will break or shoot some across the room.
 
We went out last night and didn't get home till late and I forgot to check it before going to bed, but the second shot over the chrony was at 10:23 am yesterday morning. The regulator pressure was a solid 130 BAR after that shot. Before leaving the house at 2:30 pm yesterday, the regulator had crept up to around 131/132 BAR. This morning it's back at 135 BAR...
 
We went out last night and didn't get home till late and I forgot to check it before going to bed, but the second shot over the chrony was at 10:23 am yesterday morning. The regulator pressure was a solid 130 BAR after that shot. Before leaving the house at 2:30 pm yesterday, the regulator had crept up to around 131/132 BAR. This morning it's back at 135 BAR...
5b of reg creep should not spell disaster for a first shot velocity wise. At least it didn’t when we were tuning guns with heavier hammers in the 3-5% range. We could always compensate for a little creep with a touch more hammer spring adjustment. My gun is already set at 2% below so I don’t have a ton of wiggle room. But I will try going almost full beans and see what happens to my shot string across the fill range. And see if I can overcome the slow first shot without screwing up the nice numbers the gun produces.
 
Seems more makers are switching to balanced valves which if this is a side effect of them, hunters will not be as keen to buy guns with the new valve.

Best thing I found in the thread was that it uses a balanced valve, no thanks.
I'm my experience with using them once you finally get it to work, it's very short lived victory..
 
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I wasn’t aware the DRS had a true balance valve. I never took it apart. I’ve heard people refer to this FX or that having a balance valve, but people don’t always refer to stuff accurately. My P2 has a balance valve and it definitely doesn’t suffer from slow first shots. I turned the HS up a quarter turn today and my first shot was still way too slow and off its mark. As I sat there I wondered if anyone ever had a fast first shot with a DRS. If not, then it might not be fixable and I’m chasing my tail. Now that I have an idea what’s going on, I’m going to try to smack that valve hard enough to overcome its shortcomings. If it works, then I’ll check and see how my shot string looks.

I really like the gun but I can’t be in the woods with the timer on my watch set for every 30 minutes to dump a shot. A little baffled about a gun that was designed cosmetically to look like a hunting gun but it’s not. I would actually like to hear FX’s explanation on producing guns with assumption that guys think it’s acceptable to warm the gun up before they shoot. Like an old freakin farm tractor.
 
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I have a DRS classic .177 500mm wood stock on order so I'm very interested in this thread. As I have followed this discussion, I have had a hard time believing this is a regulator problem. Regulator drifts high by about 4% and first shoot is low? It seems more like a valve/hammer issue. I'll be really interested in what the actual issue is.
 
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