Tuning What am I doing wrong? M3 .25

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I could be wrong but it kinda sounds like you're right back where you started. High speeds, low reg and hammer settings. Did you step up through the macro to find where the speed stops going up? If you set macro 8 and micro 3 at the start and left the micro alone you'd be on macro 5 or 6 with a micro of 2.7. My guess is you won't see any speed increase past maybe 8 or 10 at the current tune. Is it still loud?

Low reg pressure, wide open valve, and light hammer strikes are not conducive to tight spreads and low std dev. I really think you need to try going to at least 120bar or whatever pressure gives you a speed increase each step up to 16. If you end up over 1000fps that's fine. Just drop back a couple clicks on the macro and use the valve to take 20-40fps off. That is the time to use the micro to add or subtract a few fps if needed.
 
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Yea I wasn’t getting anymore speed increase past 6 with a max of 960 so I just stopped there with the reg and went down on the hammer and I closed the valve .5 turns then I brought the speed back up till it maxed out with the hammer around 935. Then I brought the macro down a few clicks and just adjusted the micro till it was around 910 fps. That’s where I stopped for now As I figured I would read up on getting the std dev closer before I continued. And yes the gun is a lot quieter than it was before which is kind of nice. When I go out next I’ll try playing with the reg and see if bribing it up a bit more will tighten the std dev a bit. Should I play with the valve at all or should it be good around 5 and just tune with the reg and hammer mostly? 
 
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I would leave the valve open till you find the reg pressure that gives you an increase of speed each step up to 16. Do you have a valve adjuster with 6 lines or are you guesstimating past the 4th line? I've read about a mythical 6 line adjuster but never seen one. 

Once you have a full range of speed increments from 1 to 16, then pick the macro setting about 50fps above what you want and start closing the valve a little at a time till it brings the speed down to, or a little less than, what you want. Now use the micro to dial in the exact speed. That should produce significantly better spread and std dev. The gun will need time and shots fired for it to 'settle' as Earnest likes to say.
 
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The flexibility of regulated PCPs is a double edged sword to the new user. Different methods can be used to end up at the same exact tune, and also completely different tunes can have the same accuracy. This is significant on the M3 with the Macro and Micro wheels both moving the hammer spring, the addition of a valve preload knob, as well as the platform overall being very tune forgiving.

Looking at tunes of top 100yd benchrest shooters in recent years - Ted runs tunes around 97% (maybe even higher!), Justin Welch around 90% last year, and Keith Kibson was in the middle around 95%. Now they are all shooting pellets which are the most forgiving projectile, but that still tells us that the Impact can be accurate and competitive with a variety of tunes.

Everyone has their own preference and style, and this is where it is easy to get swamped with different people recommending different strategies and tune points that could be equally accurate. I still think the best strategy is to start at a 95% tune since the mechanics give that point best chance for low standard deviation and decent accuracy. You should be able to get the gun shooting good at this point and it gives you a baseline. With that established, and if you want to burn way more projectiles than you spent getting the 95% tune, then you can experiment with the valve knob, and try different tune points outside of 95%. The Canada angle (no suppressor) makes 90% look very attractive if accuracy can be obtained there.
 
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I just re-read the thread and didn't see it mentioned anywhere, what length barrel are we working with? It doesn't really change anything discussed so far but it will tend to effect the final reg pressure you end up with. I run my Mk3 .22/700mm at 105bar and can push 18gr H+N barracudas from about 830fps on macro 1 to 1070fps on 16. 25gr JSB knockouts go 950fps on 16. But on my compact Mk2 .177/500mm I run 125bar with H+N 10.6gr pellets and get 700fps on min power wheel to 970 on max. That's just to say you should be able to obtain a usable full range of speeds from the power wheel once you find the right reg pressure.
 
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The more you understand the gun, it opens other avenues on how to arrive at a good efficient balance point. We can use shortcuts because we understand the gun. I believe newbies need to start at the bottom with all adjustments except the valve. The valve is the icing on the cake, but you have to bake the cake first. Your reg is the engine and your micro/hammer screw is the gas pedal. Your power wheel is the brakes and I leave it on 16 for all initial tuning until I need to start applying the brakes. As you add hp to your engine (reg), you have to step on the gas more (micro) to see what your new max speed is. When you finally get let’s say 5% over your desired speed it’s time to step on the brakes and back it down with the power wheel. By backing the wheel down from 16 to maybe 12, you have the ability to add a little or subtract a little if tuning a picky projectile without touching your reg.
 
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NYmike I’m using a 700mm barrel sorry didn’t mention that before. And TDK I like the “Canada angle” at 90% if it keeps the gun quiet then that’s what I’m going to aim for and see how it works out. Im hoping to get out tomorrow to keep working at it but we’ll see when I get finished up at work If I have time or not. I’m really hoping when it’s tuned for slugs it shoots the pellets nice too so that I can shoot pellets at the range and not spend so much money on slugs haha save those for hunting.
 
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Set your reg to 150 bars and follow the videos:





https://youtu.be/VjqD-eQwyHo









https://youtu.be/a7F_-FTwx0o



Click to expand...

Worst advice anyone ever gave me. Thx but no thx.
Click to expand...




LOL! Have fun then since you got everything figured out already. I’ll just keep the worse advice to myself and enjoy my terrible tune that gets me sub MOA at 100 yards all day, everyday. 
 
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Well I got out to test it some more and I was between 1.5 and 3 inch groups at 50 yards couldn’t get any better. So I figured I’ll try tune the 33.95 pellets instead, I played around and got the std dev down to 3.4 over 44 shots. It pretty much shoots 1/2” or better at 50 and I had a few 1” groups at 100 yards when the wind stays constant or none. I really don’t know if I’m going to bother chasing the slugs anymore after those results. The pellets seem to do pretty damn good out to 100 so far. Next i want to try 150 yards and I’ll decide if I’m going to stick to the 33.95 grain pellets or keep trying to chase that tune for the 26. grain slugs. But really the pellets were fast and easy, like 3 or 4 mags and it was good to 100. I’m going to use up the last of my slugs trying to tune this new way and see if I can get a good grouping tune. But if I don’t figure it out I think I’ll just keep shooting the pellets for how easy it was to set up and then I can learn to fine tune the gun, maybe after that revisit the slugs again.
 
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Well I got out again finally, supposed to rain 60mm this weekend so glad I did. I got it down to both the slugs and pellets doing 1/2 inch groups at 50 yards. I had to up the reg 10 bar higher to 114bar and just played with the micro adjuster and shooting at 920 FPS it was back to those nicer groups. Not quite as good as before but it was pretty windy today. The 33.95 JSB pellets are shooting a little slower at 842 FPS but are still very accurate at 50. I then moved over to 100 yards and both the slugs and pellets were staying in a 3 inch 10 shot group with the wind changing directions. I got 3 shots in under an inch with both but the wind would change directions and open up the groups. I’d still say the pellets are more accurate BUT it’s about double the wind hold from the 26.8gr NSA. I also notice the NSA slugs aren’t in the best shape, a lot of imperfections on the end of the slugs. Maybe next time I’ll try to sort them and see if it helps my groups. There still the cheaper slugs I can find so I don’t wanna give up on them just for a little inconsistency here and there. 
 
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