Dropping velocity after gun resting

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BrocStar

Member
Sep 4, 2021
88
1
California, United States
need to ask you some questions about what's been happening with my Impact. So I recently returned my gun and was shooting hole in hole at 30 yards at 886-891. Below was my spread which I thought was pretty good. Nine shots. First reg 150 second 114, macro 14 micro 3.5 and valve just below 4. This was on Saturday. I didn't shoot Sunday.

Shot count: 9

Low: 886

Hi: 891

Avg: 888

Spread: 5

STD Dev: 2.5

888

886

891

886

891

886

891

891

886

Today (Monday) I went out to hunt some doves. I shot a 50 and 70 yard shot right on center mass. Dead! I noticed the gun was unusually quiet. The pellets also didn't go through the bird like normal. So I pulled out the chrony ..To my surprise, the shot fps was at 840! Consistently through about 15 pellets So I had to increase the macro to 15 and valve to 4 to get back to 880-890. This has happened in the past as well where I lose fps after the gun sits a day or two. I shoot many shots after the tune to make sure it holds before I put it in the safe. My first reg fluctuates about 40 - sometimes 50 bar difference. I don't think I should have to Re-tune my gun every time I take it out, correct ? I am going through a ton of pellets to try and keep my gun at 880 since it keeps dropping. Second reg was at 114 but is now at 120 with a digital gauge. Didnt change it today

Thanks for any insight on this. Just wondering why I am losing FPS from one day to the next on the same tune.
 
Your regulator probably has a slow leak. This can be caused by debris in the reg or a bad seal but it's usually debris. This is making your hammer have to hit harder to get the same velocities as when you tuned the rifle. One thing you can try is taking off your bottle and dry firing until you blow out the debris. I don't actually have an fx but I do think that might work. Maybe some fx guys can chime in here. It could also be nicks in the reg caused by the washers or something like that. If your gun is under warranty and the dry fire thing doesn't help I'd send it in or if you have the skill to take your gun apart safely and not void your warranty that's cool too. I really think it's a slow reg leak. Good luck to you. 
 
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I had one of my impacts doing that for about a year. But usually it went back up, on it's own, after a few hundred shots. So, I was always adjusting it first up then down. I found the regulator rod had a wear mark in it and after I replaced it the problem went away.

Click to expand...

Regulator piston made of peek lasts much longer.

20220303_210136.1652180138.jpg

 
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hehe those tiny things do have a tendency to mess things up.

Once as a apprentice some guy came and asked me to do a few things for his private enterprise.

1: weld together two 1 mm pieces of sheet stainless steel, i burned a hole in it, cut 2 new pieces and had a old welder guy do it, and he did with a stick with a 3.25 mm core, and i was like WTF ????? i tried to do it with a 1.25 mm core and just made holes in the damn thing. And mind you i was already a pretty competent welder.

2: Was to put a 3 mm thread in a 8 mm OD pipe, that i could do even if the pipe was 150 mm long and i had to go and weld a rod to the thread bit to reach all the way thru the long pipe.

Used a drill press to get the thread going right, and then did it by hand the rest of the way.

The pipe was brass so fairly easy to work with, had it been steel i think i would have screwed that up too.
 
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