Tuning Impact M2k shooting hot after topping off

[Tnp]

I'm in the process of tuning my Mk2 with a power plenum and a power slug kit installed. This is my first time tuning an impact so I watched a videos to help the process.

-Shooting JSB 25.39 in .25

-FPS goal of 950fps after tune

I set the regulator to 110, max on power wheel and max out hammer screw

First 10 shots where between 971 and 961fps.

The more I backed out the hammer screw, the better the consistency of my shot string.

I go to top off my gun and the next few shots are hot. Around 978 fps for around 8-10 shots before it gets back to the fps I left off before topping.

***What's going on here?

 

[Glem.Chally]

You don't need all that hammer spring preload for 110 bar. Save that for 150+

 

[Tnp]

Yeah it does seem excessive. Do you have a topic post or YouTube video you'd recommend for tuning. Seems as though every video I've seen everyone maxes out their hammer screw.

You don't need all that hammer spring preload for 110 bar. Save that for 150+

 

[Glem.Chally]

Try backing off the preload screw until the sliding part just moves between minimum and 1. You'll have to push the slider against the wheel to remove the slack to see it move. See what you get on max like that,

I usually run my impacts like this (unless going for very high power) but I like the in plenum spring like the old style. Anyways have the valve adjuster at the 4th line or so and if you want more power add some preload. Then you're working your way up and I think you'll find a happy spot easier, and can go a bit faster than you want and close the valve adjuster to get your spot.

Nicer shot cycle too.

 

[Corvid_hunter]

I think that is how Steve from AEAC recommended tuning the Impact also. He referred to it as neutral cam (or something like that).

 

[triggertreat]

Deleted.

 

[corny]

This is my experience…

At 110bar, if u have the power kit installed. (Both spacers)

You can’t back off the HS enough to balance the hammer with the valve. 
IMO, the power kit messes up the impact for lower tunes.

 

[Tnp]

This is my experience…

At 110bar, if u have the power kit installed. (Both spacers)

You can’t back off the HS enough to balance the hammer with the valve. 
IMO, the power kit messes up the impact for lower tunes.

My fps seems pretty consistent as it sits without having to do much. Here are some of the numbers I recorded last night. The reason I created this topic was to address the fps and regulator pressure drop but we got a bit off topic with tuning lol

 

[Tnp]

So the regulator started here when the bottle pressure was at 248 bar 

After quite a few shots, the regulator ended up here and the bottle pressure was at 140bar

 

[corny]

What I’m trying to say…

I saw the gun do funky stuff when was valve was overpowered. Increase in velocity over 200bar fill

decrease under 200bar.



but yeah…if ur reg doesn’t drop settle after one shot on a refill. I would suggest rebuilding it.