Tuning my Marauder .25

[bill_dd97]

Tuned my Marauder .25 today.
?1
Here are the settings I used
Metering Screw: Clockwise to stop then 5 turns Counter Clockwise to fully open it.
Hammer Spring Preload: Counter Clockwise to stop then 3.5 turns Clockwise.
Striker: Counter Clockwise to stop then 4.5 turns Clockwise.

I used H&N Hunter Extreme 28.40gr for this tune. Started at 3000psi and shot it down to 2000psi with 24 pellets. I got a spread of 41FPS from 806-839-798 with a StDev of 11.55. Average FPS of 825 with Average FPE of 42.93.
?1
Sorry about the chart splitting. I uploaded it from my tablet and didn't notice until I went to link it.

 

[guod123]

For some more power, if you go to 4.5 turns on the hammer spring and a 3300 fill I get 10 good shots around 880(9-12 FPS spread) with 25.39 jsb's shot 11 is 860 shot 16 is just over 800

 

[bill_dd97]

I did this to get 24 shots. This rifle is for pesting ground squirrels and birds at up to ~100yards. Also, I'm not planning to go over the recommended 3000psi on this unmodified rifle, that I hand pump.

 

[ajshoots]

Very nice bill!! Great shot count and still plenty of power!! A couple small mods that might tighten the string a bit would be to highly polish the hammer and the airtube where the hammer rides. Also face drilling the hammer and maybe try 2 oring for a bstaley mod.

Your string is great and I am not trying to knock your work just providing some things that helped me tighten my strings up. Feel free to pm me if you would like further explaination.

 

[guod123]

I tried juicing it up just because I read about it. I believe it was Hill. My gun shoots more accurately with the 3.5 turns and is in the 840's. Just trying to pass on possibly useful info.

 

[bill_dd97]

Thanks for the tips ajshoots. Mine is a gen2 and the hammer isn't bouncing with these settings. I am looking at possibly adding a regulator when the cash becomes available. I'm also going to change out the depinger for one of my own design.

Whenever I get something new I try to optimize it's settings before adding in aftermarket parts and making physical changes.

 

[ajshoots]

NT

 

[N89]

I see this post is from 8/2015. I just picked up a brand new marauder .25 and would like to get 40+FPE range would this be a good place to start? Any other suggestions?

My average out of the box from a 2700 psi fill is 792 FPS that’s about 38.7 FPE I’d like to bump that up. 

 

[Crusher]

Yep. If you do this same tune on your gun, it might not be exactly what he got, but it should be close. What he has done is pretty much how I have my Gen 1 tuned.

Crusher

 

[LDP]

N89 you will also most likely need to fill to 3,000 psi to get the most out of higher power tunes.