I've edited this to fix the several spelling and grammar mistakes. I feel really dumb after reading them all.
Sorry to anyone that had to read the original post...
Hello! I'm new to the forum, but this seems like the best place to get advice. I am not new to airguns, but I am new to the FX Impact. I work on all of my guns—centerfire and air—and have never had this many issues. I'm almost ready to throw it in the trash.
I am including all of my problems, even though they might not be related.
Some Backstory:
I bought a Demo FX Impact M3 .22 600MM from Utah Airguns a few months ago and have had nothing but problems with it. It seems that every time I buy an airgun from them, there is some major problem with it. I guess I haven't learned my lesson. To start off with, my "functioning gun" came with a junk regulator (4 disks flattened and caused severe reg creep). Then I installed a new Huma regulator. It was also missing a few random parts that have been replaced. I installed a Slug Power Kit and had several issues with power consistency. I have since removed everything, but the hammer weight. I have installed a STX heavy barrel liner and a carbon fiber barrel sleeve. I have lightly glued the ends to keep the sleeve from moving. At some point the valve rod bent (not sure if it was like that when I received it or after, but it has since been straightened out within a few thou). The first stage of the trigger sometimes gets hung up and won't reset. It will then proceed to fire when on safe. I have tried adjusting it, but the issue always comes back. There have been a few other problems, but I'm sure you guys don't want to read an entire book.
I currently have about 450 slugs through this liner. I am currently shooting NSA 31.2gr @ 990fps. My tune is 1st reg @250 bar, 2nd reg @ ~173 bar, front valve adjuster @.404, macro @14, and micro @ 4.375.
Now to my current problem. Every time I take the gun out of its case (after sitting for a day), my zero/point of impact is severely off from the day before. It seems to trend down and to the right about 2" at 40yds (my zero). I have had some extremes as far as 4 inches to the right. I check my velocity every time I take it out, and it stays within 5fps of 990fps. I can refill my bottle and shoot as many rounds as I want, and it will not return to my original zero. When I put the gun away for the day, I lay it down on its side on a foam pad. There is nothing that should be tweaking the barrel. The temperature and humidity have stayed roughly the same throughout all of this. I have tried retuning my gun a few times, and it doesn't seem to improve my situation either.
So far I have done the following to try to help remedy the poi shift. 1.) Carbon Fiber Sleeve (I have never tried shooting this with the factory o-rings)
2.) Ensured that everything is torqued to spec (scope base, scope rings, backbone, pic rail, barrel clamp, set screw that attaches and holds down the barrel by the transfer port.)
3.) Put on a trusted scope that has never had any issues before.
4.) Retuned the gun and ensured that nothing was getting bumped.
5.) Checked weights and lengths of slugs to ensure I wasn't getting weird seating depth issues. Also includes making sure slugs are clearing the transfer port.
6.) Swapped to 25cal Donnyfl moderator in case it was clipping
7.) Used gauge pins to ensure slugs aren't clipping shroud.
8.) Holding the gun in many different ways (I have heard they can be hold sensitive)
9.) Removed all o-rings touching the outer sleeve of the barrel
Some potential issues that may be causing it 1.) The carbon fiber sleeve has about .010 of play inside of the outer sleeve. (Should it be a light press fit?)
2.) The scope rail does not allow for centered scope rings on the tube. The front ring has about .100 of clearance from the turret. It is currently sitting in the only place for proper eye relief.
3.) Possible bad o-ring that I can't find. (I have taken the gun apart several times and can't seem to find any that are bad.)
4.) The entire barrel system (related to the carbon fiber sleeve fitment)
I'm sorry for the rambling, but I am at my wits end with this rifle. Has anyone ever had this many issues with POI shift? How were you able to fix them? It would be nice to know why you decided to change the part(s) and how much it affected the outcome. I'm willing to try just about anything at this point. I don't mind spending money to fix it, but I am also getting really sick of dumping money into it. I haven't contacted Utah Airguns about this issue, but I will not be doing that. That's a story for another time. I have debated on putting an Airmarksman backbone on it, even though it doesn't seem to be hold sensitive. I have also considered sleeving the old liner and glueing the carbon fiber sleeve to the outer liner, installing a tensioner, or machining a solid barrel. This is a hunting rifle, so I don't want to add a bunch of weight to an already heavy gun as I walk several miles every time I go out. First shot accuracy is very important to me, and I can't trust this rifle, which is a shame as I hadn't heard of anything negative about these guns until I really started researching the issues I've had.
I've attached a picture of my scope mounting so you can see what I am talking about.
Thanks for the help!