Tuning Tuning FX Dream-Tac Compact .177

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chip78

Member
Feb 6, 2022
148
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Georgia, United States
I bought the gun here on AGN and started tinkering with it. To my surprise, I actually really like this little gun! It came with a power plenum. Just for grins, I added one more. It doesn't appear to really do anything. With no change in tune, the muzzle speed is about the same with or without the 2nd plenum. Well, I thought at least we have a little more air in the gun so more shots for sure. The gun is .177, not a huge amount of power needed so I thought I can run it at a lower pressure. Sure enough, with the valve adjuster set to high, I can do JSB 10.34 at 870 FPS with the reg set at 100-bar. For the same speed, the reg setting was 125-bar but the valve setting was med and the hammer spring at a higher setting. Questions:

1) Is 100 bar too low? The fill pressure is 230 max. So the max pressure differential the reg sees is 130-bar now. It was only 105 before. Is it bad for the regulator?

2) Any downside in setting the valve at "high" (older version gun was ".25/.30")

3) My last shot string of 25 shots was 877 high, 851 low, 862 avg, spread 26, STD dev 6.4. Is it good enough? I will try a slightly high hammer spring setting to get close to 870 FPS to see if the shot string is better.

Thank you,

Charles
 
Congrats, I have the same gun and it’s one of my all time favorites! my preference has always been high reg pressure especially for shorter barrels. The short barrel means less runway to get up to speed so needs more power. The highest you can go with stock hammer is right at 115-120 bars which is where I set mine. I normally shoot very low power of 9.5 FPE so I get over 100 shots. Shot count doesn’t just depend on low reg pressure, it has more to do with how efficient the tune is. 



As far as TP goes I always use medium because the high setting has a very large cavity so it takes more air to fill that area before it reaches the pellet, ideally there should be just enough space for max air transfer so the acceleration can start as soon as possible. 


the question is how does the muzzle report sound? 870 is really quick for that short little barrel. I prefer heavier pellet at slower speed which gives you better efficiency, down range power and quieter too. Try all the power settings from high to low, as soon as the gun gets into the sweet spot the muzzle report will switch from a pop to thud. 


 
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Thank you for the guidance. I will set the TP back to med and try again. You are right, at 870 FPS it does sound a little harsh. Probably below 850 is more reasonable for the 320mm barrel. I want high speed for enough energy to dispatch squirrels. JSB 10.34 is the pellet I would like to use. I believe 800 FPS of 10.34 gr is still powerful enough.
 
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I have the older version with the fat shroud, so the Power Plenum doesn't fit. I did install the Huma Air Dual Port TP and Pin Probe. My regulator is set at just below 150 BAR and it's shooting the 10.34 grain pellets at an average of 893.8 FPS. The Transfer Port is set to medium (.177/.22), hammer spring set to MAX. Prior to swapping parts to the Huma Air parts I was getting 791.6 FPS from the same pellets. I also have a DonnyFL Koi hanging off the end of the barrel that does a good job of keeping it quiet! I do love this gun also, super light weight, compact and laser accurate! I did upgrade mine to a 300cc CF Tank from Best Fittings, so that helps a lot with shot count!
 
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Thank you for the guidance. I will set the TP back to med and try again. You are right, at 870 FPS it does sound a little harsh. Probably below 850 is more reasonable for the 320mm barrel. I want high speed for enough energy to dispatch squirrels. JSB 10.34 is the pellet I would like to use. I believe 800 FPS of 10.34 gr is still powerful enough.
Click to expand...




i have no issue with taking down big fox squirrels with vital shots out to 34 yards shooting 10.3 grain hades at 680fps and still get pass through. I have a suburban yard to quietness is of highest importance. Also I get over 100 shots shorting 7.9 grain CPHP at 680 fps with same POI or zero. 


the short little 320mm barrel is best at 800 fps or lower. Usually at 760 fps it’s really quiet and efficient, you can get the 13 gain beast shooting at 760-780 fps it would be really quiet and still packs a huge punch out to 50 yards while being dead nuts accurate. 


 
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It is now fairly stable around 895FPS for 10.34 JSB with TP at med, 120-bar and hammer spring 23 (my max is 24). It is loud. I will next try around 800FPS to be my normal tune. I am also in a subdivision, noise level and safety are important. I only shoot in my backyard into the woods with a negative elevation angle meaning the pellets go down to the ground. Many times I saw squirrels up in the tree and let them live so I don’t have pellets flying too far.
 
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Messed with it a little more today. I couldn’t get a stable shot string at close to 800 FPS while the high 800 performance continued to be good. Found a spot where the gun didn’t bark as loud. Amazingly it was not much slower. The reg pressure is just a bit over 100, I’d say 105-bar. The average muzzle energy is 17.7 FPE. I decided to be happy with it for now.

Many thanks to qball and FLgunner for your words of wisdom and encouragement!

Notes: 105-bar, TP med, PW 15

Shot count: 33

Low: 863

Hi: 884

Avg: 877

Spread: 21

STD Dev: 3.9
 
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