Tuning FX DreamTac Compact FPS for JSB 15.89 and 18.13 Pellets

I bought a .22 FX DreamTact Compact here at AGN several months ago. Just got around to mess with it a couple weeks ago. The gun came without any mods. I added a Dreamline plenum and changed the tube to CF bottle. My first effort at tuning it got close to 800 FPS for JSB 15.89gr and the 18 gr lower. The reg pressure is at over 100 but maybe less than 110 bar. TP at "med" and hammer spring at 3 with the fine adjustment bottoming out at MAX. Tried a few higher settings without significant improvement. I didn't write them down but I believe I got as high as 160 bar and the velocity was not over 850 FPS. I think 800 FPS at 110 bar is a good balance but keep wondering whether the gun can reach 870-880 FPS with the 18 gr pellet. Of course, I'm saying this with the stock 320mm barrel. It would not be a "compact" anymore if a longer barrel is installed.

Does any of you have a DreamTact Compact (320mm barrel) tuned to run over 850 FPS with JSB 18 gr or 16 gr?

Thank you!
 
As douger said. Open your transfer port to max. My micro adjuster is almost all the way backed out, I have factory plenum, and at power adjuster on high I’m getting 880 with hades pellets with reg at 120b. I lowered it down to shoot low power and at same reg pressure at power wheel 2 and transfer port on medium I can shoot hades at 700fps.
 
I have owned one since they came out. FX never marketed the gun as a powerful gun. If you want a .22 to shoot 18.1’s 870-880fps, buy a different platform or install a longer barrel. If you somehow manage to get it to spit 18’s around 850fps, I did, you are wasting so much air and the gun sounds bad. I wound up building a slightly longer barrel that easily lets me shoot 18’s around 900fps. My gun is not big now but it also isn’t as compact as it was with the original 320mm.
 
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Just listen to the gun as you tune it. I will tell you two things that are going to happen. One, as you turn the speed down you will hear when the gun sounds like a $1k+ gun should sound like. When you check it over the chronograph, you will be disappointed. If you plan to shoot Hades and get them shooting 850+, turn your hammer wheel down until the gun sounds real nice. Be prepared to not even see 800fps on the chronograph.
 
After seeing further comment by @douger and @Vetmx, I think I will let it be. The gun is happy now at 790-800 FPS and it sounds really good. I enjoy tinkering so I may one day crack it up just to see how it behaves at 850+. I guess one of the reasons we have multiple guns is to have them serve different purposes. I have decided to use DreamTact Compacts for .177 and .22 for backyard plinking and occasional pesting. I should stick with it. My 600mm Maverick shot 18 gr at 890 FPS with less than 80 bar. A newer gun with a much longer barrel, it of course can do it easily. That gun will now be .30 only.

Thank you all for your comments and guidance!
 
yeah the 320 barrel is not a power gun but its damn accurate at those speeds, i shoot the 13.43 jsb with it or the 14.? jsb they shoot little faster and are very accurate cheap pelets try they might shoot well also 14.3 cpd
I have a few tins of CPHP. Doesn’t hurt to try them. Don’t have any CPDs, heard they are better than HP. JSB/AA/FX pellets are consistently more accurate than CPHPs for all my guns. But CPHP actually worked fine for pesting. In fact, it is the pellet I use for my .22 Avenger.
 
I appreciate your advice and insight. Many thanks to @douger @madeintheuk @Vetmx @Bravo1956 @wildcj5 !

What I have learned:
1) .22 Dreamline Compact has the ability to make 850+ FPS with JSB 18 or 16 gr pellets.
2) Given the short barrel, it is not efficient at such a high speed for heavy pellets. Shot count suffers and it is loud if the gun gets pushed that hard.
3) My tune appears to be at the high end of the speed for the gun to be naturally happy.
4) JSB 14 gr pellets might be a better choice than 18 or 16 gr.
5) Crosman Premier 14.3 gr domed or hollow-point pellets may be a good enough economical selection.

I tried about 50 shots CPHP without changing the tune at 25 yards today. The results are consistent with my other guns. The groups are not as good as JSB pellets and there were 3 fliers. Didn't have time to compare with my Avenger. I felt the groups are slightly tighter than Avenger shooting CPHP. Since I have several tins of CPHP, I will use them on this gun for backyard plinking and pesting. If I like it, I'll continue. If not, I'll use 15.89 gr JSBs.