Marauder .22 String at 2600 psi, what do you think?

Marauder .22 String at 2600 psi, what do you think?

Joined: October 4th, 2009, 2:41 am

February 27th, 2010, 8:47 pm #1

I am new at this so any help will be appreciated. I want to fill to 2600 psi and get 30 shots with an acceptable velocity curve. I tinkered some this morning and here is what I am getting on my new .22 Mrod, using 14.3g Benji HPs:



Lo: 860.95 fps
Hi: 890.72
Avg: 878.17
ES: 29.77
SD: 8.66

Do you think this setting is ok or should I make more tweeks?
Thanks,
Dave P in SC
Last edited by DiaboloDave on February 27th, 2010, 8:50 pm, edited 1 time in total.
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Joined: January 10th, 2005, 4:28 pm

February 27th, 2010, 10:01 pm #2

Congrats Dave! It appears your string is preaty darn good (atleast I think so) someone else may say different but that string will be hard to improve on. I believe it were me I would leave it set there shoot a few rounds and check it again....been my expreiance with PCP that once things settle in you have to play with your fill preasure, sometimes they want a little more psi and sometimes they want less but once it has settled in thats where it will stay.
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Joined: October 4th, 2009, 2:41 am

February 27th, 2010, 10:27 pm #3

I haven't even atached the scope yet. I wanted the get the Chrony #s first while the weather permits and thank goodness I was off yesterday and today. At least we switch back to daylight saving time in a couple of weeks that will give some more time to adjust the Mrod. I feel better now that I have a curve to play with.
Dave
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Joined: December 12th, 2009, 4:14 am

February 27th, 2010, 11:22 pm #4

I am new at this so any help will be appreciated. I want to fill to 2600 psi and get 30 shots with an acceptable velocity curve. I tinkered some this morning and here is what I am getting on my new .22 Mrod, using 14.3g Benji HPs:



Lo: 860.95 fps
Hi: 890.72
Avg: 878.17
ES: 29.77
SD: 8.66

Do you think this setting is ok or should I make more tweeks?
Thanks,
Dave P in SC
Care to share your settings?
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Joined: October 4th, 2009, 2:41 am

February 28th, 2010, 2:02 am #5

there isn't much to tell. At first, I left the stock setting alone, filled it to 2500, shot a string of 30 shots. Didn't like the results. Then I upped the pressure to 2600 psi, got a curve, but still needed it to be flatter. Turned the hammer spring 1/4 to 1/3 of a turn CCW. That was it. I know what you probably asking, but I have not yet recorded all three screw settings, will be doing that if I do further adjustments, one needs to know, just didn't get there today.

Dave
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Joined: July 9th, 2001, 12:24 am

February 28th, 2010, 6:29 am #6

Thanks for the information. FWIW mine is similar but a slight bit lower in MV as it came out of the box.

Doug Owen
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Joined: October 4th, 2009, 2:41 am

February 28th, 2010, 2:15 pm #7

Like I said, I am new at this, should I want more or is this good enough for a Marauder? Would you be ok with this performance?
Thanks!
Dave
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Joined: November 17th, 2006, 3:51 am

February 28th, 2010, 3:36 pm #8

I am new at this so any help will be appreciated. I want to fill to 2600 psi and get 30 shots with an acceptable velocity curve. I tinkered some this morning and here is what I am getting on my new .22 Mrod, using 14.3g Benji HPs:



Lo: 860.95 fps
Hi: 890.72
Avg: 878.17
ES: 29.77
SD: 8.66

Do you think this setting is ok or should I make more tweeks?
Thanks,
Dave P in SC
Are getting 22-23 shots inside of 20FPS and about 27 shots inside of 25fps, and averaging something close to 24-25 foot pounds per shot. Call it 25 shots/25 FPS variation, which isn't bad at all.

Could fiddle with the adjustments and end up with a more shots at a less power and a lower starting pressure, or a few less shots at a little more power at a higher starting pressure, but what you have seems like a pretty good compromise, esp. if you hand pump fill (as filling to 2500-2600 is a lot easier than filling to 3000).

If you've got some heavier pellets the gun will shoot well, might want to run that test again just to see if the trend holds up. Have often found that heavier pellets stretch out the "sweet spot" by a shot or two.
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Joined: October 4th, 2009, 2:41 am

February 28th, 2010, 4:01 pm #9

I have some JSB 15.8 grains that I plan on testing too. Thanks for the info. Also, I think the JSBs may be have less variation in velocity too, which will smooth the curve somewhat, at least that is my theory.
Dave
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Joined: July 9th, 2001, 12:24 am

February 28th, 2010, 7:12 pm #10

Like I said, I am new at this, should I want more or is this good enough for a Marauder? Would you be ok with this performance?
Thanks!
Dave
Chairgun doesn't list that pellet but using the CP you get 6.922 inches of drop at 50 yards with 890 MV, 7.244 inches with 870. So we're talking about a quarter inch shift at *50 yards*, probably not a deal breaker?

A good number to 'shoot for' might be a 35 fps wide window. Time to start enjoying the gun seems to me.

Doug Owen
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