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Author Topic: Marauder Tuning Secret.  (Read 13698 times)
ShadowShot
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« on: September 01, 2009, 02:35:08 PM »



Its all in the velocity screw.



I am now having greater accuracy results with the MDR and CPHP 14.3.
Its long to explain but start by setting the hammer throw all the way back.
Set the preload all the way in and the velocity screw all the way out.
This has the gun at max power. Now you want to bring the velocity down
for your CPHP to around the mid 800 range, this seems to be where you
get the best accuracy for this pellet.

What I did at this point was turn the velocity all the way in and started backing
it out at 1/2 turn at a time and shoot one shot at 2500 psi fill. I keep filling it, backing it out
and shooting untill I got into the zone I wanted, Low to Mid 800's.



Now I have to make the adjustment to the preload so I am not wasting air and keeping accurate.
Start turning the preload back out .5 turn at a time from fully in and  shoot a  10shot string starting at 2500Psi.
You will find you are dumping alot of air and the velocity spread is not bad but drops the psi fast in 10 shots.
You will dump about 200 psi Out of the MDR the fist 5 shots. The next 5 will drop you about 300 psi in the MDR.



I kept adjusting the preload out until I got to 1.5 out and the velocity screw was still set at 2.5 out.
That gave me good power, accuracy and not much wast of air. I only had 1 flier in a 20 shot string.

I posted this in the Marauder Owners forum and then copy past it here below.





Quote
Thanks so much again for your info.

Armed with your settings, I went out and gave it another go with the CPHP 14.3.
Drastic improvement. My best accuracy, but not best power curve.
I only got about 10 shots between the 845 to 850 range.
The next 5 shots were between  839 and 827.
The last 5 shots were between 823 and 818.

This was all done with the following settings.
Throw       -max 100% back.
Preload     - back out 1.5 turns from being fully turned in.
Velocity     -2.5 out from fully closed.

The velocity screw was the secret.
At 20 yards, I shot a dime size group or smaller with one flier

I started at 2500 psi
1. 851.7
2. 848.5 flier=1.5 low and about same to the right
3. 850.6
4. 846.3
5. error     2400psi end

2400 PSI
6.  852.7
7.  848.9
8.  851.0
9.  845.6
10. 844.8   2300 psi end

2300 PSI
11. 838.8
12. 837.0
13. 835.8
14. 829.9
15. 826.5  2100 Psi end

2100 Psi
16. 832.4
17. 820.1
18. 819.5
19. 817.5
20. 813.5 2050 PSI at end.





Now please note that this is probably not the best it will get.
I ran out of light before completing adjustments and testing.
I should get this to where I have a much longer shot string
and closer FPS spread in that string.

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47 Cow Birds
4 Starlings
2 Crows
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daveshoot
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« Reply #1 on: September 01, 2009, 03:31:39 PM »

Thanks for the research and the update. A lot of us will find it valuable. My Marauder is temporarily off line but that will change soon.
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Leadhead
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« Reply #2 on: September 01, 2009, 03:49:12 PM »

Thanks for sharing, Paul. I shipped my Marauder back to Crosman today for some repair work, but when it comes back I'm gonna try your tuning approach.
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Benjamin Marauder .22(#004), Leapers 4-16x50AO
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Bogey
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« Reply #3 on: September 02, 2009, 12:03:32 PM »

Thanks for the instructions regarding the Marauder tuning.  I don't have a Marauder yet but I  will soon and I took the time to print off your instructions for future reference.
 I know nothing about the Marauder and info like this should be helpful inorder to get the most from the rifle.
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ShadowShot
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« Reply #4 on: September 02, 2009, 03:11:29 PM »



Now as you can see from the post,
 I was saying THANK YOU to a member (unirdna) on another forum, (marauderairrifle.com).
This is mostly all based off of his work, so creds go to him.
 It was he who keyed me into the velocity screw, which is where I was going next.
 It was the next only logical adjustment to me that made sense.
 Now, this may not be The Best way to do it but it worked for me.
 Anyone having problems with the cp 14.3 in .22cal. this could be your answer if you are going to continue trying
 to use them. They do not like to fly much over 850fps, You start getting a lot of flyers.
My goal is to get a good 20 to 30 shot string in the 820 to 850 range. (CALL ME A DREAMER)
 
 Best of luck with your adjustment.

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36 Grackles
47 Cow Birds
4 Starlings
2 Crows
1 Ground Hog
9
ShadowShot
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« Reply #5 on: September 03, 2009, 11:42:32 AM »



Tune Update.
 
 First, my settings.
  Hammer Throw: 1/2 turn in from max out setting.
  Spring Preload: 2.5 turns out from max in position.
  Velocity Screw: dead between 2.25 and 2.5 turns out from completely closed in setting.

Outside temp around 85 deg.
Shooting CPhp 14.3Gn .22cal.

 
Shot string starts at the 2500Psi fill.

2500 Psi
01. 818.9
 02. 822.9
 03. 822.1
 04. 826.2
 05. 819.6

2425 Psi
 06. 824.0
 07. 813.2
 08. 825.3
 09. 831.2
 10. 821.6

2400 Psi
 11. 828.7
 12. 827.5
 13. 828.9
 14. 822.9
 15. 821.4

2250 Psi
 16. 833.3
 17. 829.4
 18. 826.1
 19. 820.2
 20. 818.2

2200 Psi
 21. 819.1
 22. err
 23. 817.4
 24. 815.2
 25. 814.0

2175 Psi
 26. 813.7
 27. 813.1
 28. 811.3
 29. 804.8
 30. 804.7
2100 END Psi





Two pictures below.
First one is a 30 shot group, 2 fliers. Take out the fliers and all would have hit a dime.
Second is a 20 shout group , all inside a dime.
Range: 23 Yards



* 1.jpg (68.24 KB, 600x450 - viewed 219 times.)

* 2.jpg (67.02 KB, 600x450 - viewed 162 times.)
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2010 Kills

12 Tree Rats
36 Grackles
47 Cow Birds
4 Starlings
2 Crows
1 Ground Hog
9
Gene_SC
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    « Reply #6 on: September 03, 2009, 02:04:34 PM »

    Congratulations Paul, you have finally tamed your baby and all your hard work has paid off my friend. I am very happy for you buddy.
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    THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
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    Timmyj1959@yahoo.com
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    « Reply #7 on: September 03, 2009, 02:27:40 PM »

    Thanks for sharing Paul!!:D Glad Ya got her shooting dem lil light pells again!!:p Personally,,, I like dem big ole heavy Kodiaks @ 35 ft. lbs.,,,, I like em going into the same hole too!! Sorry about bustin Yer paintballs @ 40 yrds last weekend Buddy,, also,, Im sorry for putting holes in "Papa Bears" cow bells @ 50 yrds.Shocked LOL!! Just funnin wiff Ya Paul,,, was a pleasure finally meeting you in person & hanging out wiff Ya!!:) Marauder Ya say??,,,,,, I will keep mine "wide open" thank you very much!!8) I LOVE my truck,,Errr,, I mean my Marauder!!:) Timbo.
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    ShadowShot
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    « Reply #8 on: September 03, 2009, 03:00:40 PM »



    Timbo,



    The pleasure was all mine.

    I still love the looks of the Kodiak's.
    I have it marked down now, so I can convert back and forth.

    HA, the cow bell, how could I have forgotten?
    You took it from making a good clonkg, clonkg sound,
    to a thunk. I mean, it dont even ting anymore.
    Gene will be mad when he finds out who dunit.

    Glad dad will be mad at you and not me.
    What are yourger brothers for?

     

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    2010 Kills

    12 Tree Rats
    36 Grackles
    47 Cow Birds
    4 Starlings
    2 Crows
    1 Ground Hog
    9
    Rolls-Royce
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    « Reply #9 on: September 04, 2009, 12:50:50 PM »

    Wow, Paul, those're great results.  Using the bar/cc/fpe calculation some of the guys on another airgun forum use, that's 9.72 bar/cc/fpe (I used 818 in the calculations to replace your "err" shot, as this number fit into the string at that point, and leaving it out would've skewed the results since you did use air for the shot).  Those guys consider 13.5 as about average for a well set up PCP, and you beat that by about 30%!
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