Tuning Dreamline compact shot strings

[ukgunner79]

Hey All,

I am tuning my friends dreamline compact for pesting on his farm, but the shot strings seems a bit up and down, I cant seem to get a really consistent string, over a full 18 round mag .22 im getting hi of 756 low 726 fps with std dev of 8.6, reg is set a tad over 100 bar hammer spring on max but with about 1 to 3/4 left.

turning reg up to 110/120 doesnt seem to gain any more fps, maxing hammer spring same doesnt seem to gain fps, if anything adjusting both doesnt give any higher fps so I assume its at max for the gun.

mods done: plenum - TP 4mm - heavier spring

any advise and suggestions please.

Al

Edit: forgot to mention the valve wheel doesnt change from med to high, taking it apart the holes are 4.5mm on med and the internal part is 4mm so going to high doesnt affect it hense taking TP to 4mm

 

[qball]

You most likely need to bump the regulator up to 130-140, because of the short barrel you need more burst of energy to get up to speed. Also a tip from Ted holdover is to listen to the gun, as you turn up the speed if you hear the sound change from a pop to pop and psss or air gushing out then go back to the last setting because that’s the was your sweet spot. More air doesn’t get you much more speed and waste a lot of air and negatively affect your accuracy. 


I don’t know about 22 but in my 25 compact the sweet spot is 760 and anything faster it is just wasting air. It is possible that mid 700FPS or right at 800FPS is the sweet spot for 22, there is still plenty of power at the lower speed and if you need more knock down power just go heavier pellets. 


edit: your hammer spring doesn’t have any effect which means you already got too much hammer spring and most likely culprit of inconsistent shot string. The action which includes hammer and valve already has more than enough power to push a 22 pellet since it is the same for even the Dreamline 30 cal so I would suggest reset the HS back to factory setting. Your power/speed limitation is the barrel not the gun’s action. If you more power then get a 500 or 600mm barrel.

 

[ukgunner79]

Thanks for the advise, I just watched teds video thats brilliant how he listens not just look at numbers, I shall try going upto 130/140 but originally kept it low for shot count.

I will up reg to 130/140 to see what it does, if nothing then set it back and fine tune the hammer spring till it levels out.

find the balance between reg and hammer spring and shot count is a fun game that makes you crazy!

 

[FelixS]

https://www.youtube.com/watch?v=7PKwuw11DEo

 

[qball]

Thanks for the advise, I just watched teds video thats brilliant how he listens not just look at numbers, I shall try going upto 130/140 but originally kept it low for shot count.

I will up reg to 130/140 to see what it does, if nothing then set it back and fine tune the hammer spring till it levels out.

find the balance between reg and hammer spring and shot count is a fun game that makes you crazy!

it’s actually pretty easy especially on FX with all the dials. Basically you choose a regulator setting and leave the dial on max and increase the HS until it doesn’t increase speed any more and back down half a turn and that’s your max speed for your regulator pressure. Then dial down the power wheel one setting at a time and listen for the Pssss to turn into just a thud and that’s the sweet spot for your barrel. Once the reach the sweet spot you should notice every lower setting there is a significant speed drop and every settings higher than the sweet spot there isn’t a significant speed increase, so you have 2 ways to verify your sweet spot for hour ammo and barrel.


once you found your sweet spot speed for the ammo you can then play around with the regulator pressure for efficiency. If regulator is at 150 and power wheel is at 3 then lower the regulator and find the sweet spot again and it’s probably 1-2 settings higher or 5.


You should be able to get your Dreamline tuned in 15 minutes, it’s that easy to tune because the barrel is so short it will bark at you right away if it doesn’t like it. 



Edit: I would suggest you put factory spring in, the action has more than enough power to over power the barrel as it is and having heavier spring will only throw the balance off and create problems like the inconsistency you are seeing.