Tuning FX Impact mk2 .22 cal tuning settings

[rodevans]

I'm starting to tune my new FX impact .22 cal 700mm barrel. For those of you that have a similar set-up what are your reg pressure and hammer spring measurements. I'm shooting 18.1 grain pellets at about 840FPS. While that setting is very accurate, I'd like to bump the velocity up to 900-915 FPS without losing the accuracy. My current reg pressure is 120 and my hammer spring is at .329

Thanks for your replies

 

[Vetmx]

Just tune your gun around 900-915fps. I don’t know what videos you watched or things you read that convinced you to buy an Impact but now it’s time to watch tuning videos. You should also know that Bills or Fred’s tune has no bearing on your gun. I will say that a “new” Impact with a 700mm barrel shouldn’t need a 120b reg setting to be shooting a 18 at 840fps. Better watch some Ernest videos and get that gun right.

 

[Long_Gun_Dallas]

I'll second that. Your gun while using the same parts is not going to read or act identical to the next. Gota tune it from scratch for the best results.

 

[jbravo103]

I’m getting 900 fps (18.13’s) out if my Impact X, 600mm with RP set a hair over 80 bars. This is with the 23 mm plenum, not PP.

As others have mentioned, watch the various YouTube vids from FX on tuning. Ted Bier also posted one recently on tuning.

 

[jcote258]

As the others have said, there is no magic formula for tuning outside of the time, lead, and air required to get your desired outcome. Here are a few tips:

- Watch some tuning videos and start to understand the concepts surrounding the product that you purchase. Understand that there are really four different areas that will dictate your outcome: valve adjust, hammer spring preload, power wheel, and reg pressure.

- From an initial start, at least from my experience, I started by putting the power wheel on max and started to increase the hammer screw until my speed wasn't increasing anymore. Make sure your valve adjust is fully open on line four. Once you have reached the point where you don't gain any more speed from adjusting the hammer preload, back your hammer screw out a half-turn or so. At this particular moment, your hammer and reg are in sync. If the speed you are trying to achieve is too slow for you still, you will now need to increase the reg pressure maybe 5-10 bar. Retune your hammer preload with the reg pressure to be in sync once again. Make sure to take at least 2-3 shots after making a hammer preload adjustment to "settle the gun in". Aim for about 10-15 FPS over your target. This would be a perfect scenario as you can now turn in your valve adjust knob right until the speed starts to drop. At this point, you are essentially experiencing an efficient tune based on the reg, hammer, and closing of the valve.

Pro Tip - If you decide to dial your hammer preload all the way into max hammer, there may be a phenomenon that you will experience where you shoot a pellet/slug on max and when you turn your hammer wheel from max to 5 or 4, your speed will actually increase. This phenomenon is due to giving too much hammer and is out of sync with your reg pressure, and you need to back out the hammer screw.

This is not an exhaustive tips list by any means but should get you going in the right direction. Also, your reg pressure sounds like it's a bit high for 22cal/18.1 grain. You might find that you will actually want to drop your reg pressure about 5-10 bar. Before you do that, increase the hammer pre-load, you will probably find that you will get over 900 fps pretty quick, then adjust your valve down until you get your target FPS. You probably have plenty on the reg as is. 

 

[cmatera]

Well said.

 

[rodevans]

Thanks to all for your advise. So I will start work on the optimum tune using my 18 grains. I would like to also shoot 23 grains, my rimfire experience tells me that going to a heavier pellet would require retuning, is that your experience as well?

 

[jcote258]

Not necessarily, If 18 grains is going to be the lightest pellet you will shoot, tune your rifle to shoot fast, like 980 or more on max hammer wheel so when you turn your hammer wheel down to 1 or min, it hits at the desired speed. That way, you have plenty of headroom to use heavier projectiles.