MarauderAirRifle.com

[zen0s]

Hey everyone, so i finally got my chrony today and this is what i got from stock setting. Do you think i need to adjust anything or keep it the way it is? Wish I could increase the shot counts but with .25, i'm not sure that's possible unless i lose velocity which i want to keep in 850 fps range.

With first mag (8 shots), i gotten
start - 3000psi end - 2500
High - 872.6
Low - 863.7
Avg - 868.3
ES - 8.97
SD - 3

When I shot 2 mags (9-16 shots) with same fill 3000psi to 2000psi
High - 868.0
Low - 803.5
Avg - 847.7
ES - 64.54
SD - 20.95

I guess with .25 it's better to shoot 8 rounds and refill to 3000 psi?

Any tips to tuning .25 would be appreciated, Thank you again.



p.s. Thank you for the Excel sheet ssscottg

[tkerrigan]

Have you tried filling to 3200 or 3250?

[zen0s]

Have you tried filling to 3200 or 3250?

no, is it safe to do that? i don't want to mess up anything so i just follow the manual 3000 psi max

[tkerrigan]

Your shot string should start out at x fps, then about 6-8 shots later x+20 or so, then work down to x again. You need more pressure or lighten hammer spring and or decrease hammer stroke. Maybe close up transfer port a little. Do a search on bell curve. Nothing will blow up with only 2-300 lbs of extra pressure.

[tkerrigan]

Do a search on A team tuning procedure.

[zen0s]

Ah i see thank you for the tip :]

[zen0s]

Do a search on A team tuning procedure.

So reading after A-team tuning procedure, I have few questions. When following the Method 1 or 2 (all setting to starting point with meter screw 4 turns counter-clockwise) By turning Spring tension clockwise, i have reached desired velocity of 850 fps. Next step was to turn stroke, but I don't understand why stroke hammer has to be turned to adjust velocity when I already have gotten desired fps by just using Spring hammer? Also, with transfer Port opened all the way (4 turns counter-clockwise) do i need to aim higher desired velocity in method 1 or 2 and than lower the transfer port to achieve my desired velocity? Please help me understand this. >_< so confusing....

[zen0s]

after messing with the marauder for couple hours i got this... how do i know if it's good "bell curve"??

it does what it says like like Tkerrigan mentioned earlier. Exactly after 7th shot 20+ fps increase to 11th shot and dropped down to starting fps. so does this mean i have good bell curve and marauder is tuned?

High - 861.5
Low - 835.4
Avg - 848.0
ES - 26.16
SD - 7.34

transfer port - 4 ccw (fully opened)
spring - 3 1/2 cw
stroke - 12 ccw (starting point)

[unirdna]

That's not a bad curve - certainly good enough for hunting.

In the first curve (at the top of the page), the hammer was striking the valve too hard.
Now, the hammer is striking almost hard enough, but could use a little more "umph".
Increase the hammer spring tension or the striker distance a small amount and see if
that doesn't make things a bit more symmetrical. Otherwise, it's lookin' pretty good.