.22 Marauder rifle won't tune
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.22 Marauder rifle won't tune
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Topic: .22 Marauder rifle won't tune (Read 3397 times))
truck
Marksman
Posts: 341
Real Name: Barry
.22 Marauder rifle won't tune
«
on:
September 23, 2021, 02:11:51 AM »
My groups at 25 yards started getting bigger so I am trying to tune the gun using the A-Team tuning guide, technique B. This is a generation 2 Marauder. I can't get above 530 FPS with JSB Hades ammo. I adjusted the hammer throw till the speed dropped off into the 300's FPS. The valve metering screw is out 4.5 turns, the hammer spring is out 2 turns from maximum tension, and I adjusted the hammer throw .5 turn in after each shot until the speed dropped into the high 300's then started backing out till it was in the 522 to 530 range again.
I was hoping to see 800 FPS.
Where do I go from here?
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Breinigsville, Pa. USA
bear air
GTA Senior Contributor
Posts: 3386
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Real Name: Chris
Re: .22 Marauder rifle won't tune
«
Reply #1 on:
September 23, 2021, 07:22:16 AM »
Sounds like the transfer port is leaking. Have you draped a tissue across the breech and fired it. This will let you know if the transfer port isn't sealed properly.
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Sioux City IA, USA
Psalm 107:14 He brought them out of darkness and the deepest gloom and broke away their chains
FuzzyGrub
GTA Senior Contributor
Posts: 7135
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Real Name: John
Re: .22 Marauder rifle won't tune
«
Reply #2 on:
September 23, 2021, 07:58:43 AM »
What was it shooting at before you started tuning? Try returning to the original settings and see if it shooting near same.
The velocity screw does have a locking cap over the adjustment screw, which will turn in all the way but not back it out.
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Rural New York
1701P, 2201P, & 2501 Pistols,
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truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #3 on:
September 23, 2021, 09:40:40 AM »
I'll give the tissue thing a try.
It was shooting at 537 to 544 FPS over five shots. These readings were with a $30.00 chrono which I replaced with a Caldwell to get the speeds I posted. I have the locking screw removed.
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Breinigsville, Pa. USA
FuzzyGrub
GTA Senior Contributor
Posts: 7135
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Real Name: John
Re: .22 Marauder rifle won't tune
«
Reply #4 on:
September 23, 2021, 10:18:51 AM »
I’d make sure there wasn’t something else wrong before further tuning.
Leave velocity at 4.5 turns from full CW, throw at full CCW, and hammer preload at 6-7 turns from full CCW.
2.6k fill
You should be over 800 with Hades.
«
Last Edit: September 23, 2021, 10:24:41 AM by FuzzyGrub
»
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Rural New York
1701P, 2201P, & 2501 Pistols,
1720T/Prod/Fortitude based( 7 ), Mrods( 5 ), SAM,
Sumatra 25 carbine, 357 Bulldog, Walther CP88 ( 2 ),
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HunterWhite
Hunter Whitebeard
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Bishop's Castle
Real Name: Hunter
Re: .22 Marauder rifle won't tune
«
Reply #5 on:
September 23, 2021, 10:34:56 AM »
Truck, is the little o-ring in the barrel okay?
I have expelled that O-ring when I pulled the trigger without closing the bolt completely.
What is the reservoir pressure?
These M-Rods are good rifles. I had one that I never worked on in five years. Sellers remorse.
The second one was fine until I tried to improve it. Things went downhill before I got it right. It's good now.
Hunter
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Arlington Texas
JSAR Mini Raptor, 25 cal,Condor 25, 2240, Umarex Colt, 177 FaTRod😎
truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #6 on:
September 23, 2021, 01:53:27 PM »
I did the tissue test and there is no air leak at the transfer port or the breech.
When this rain stops in a day or two I'll try these settings and report here. (
Leave velocity at 4.5 turns from full CW, throw at full CCW, and hammer preload at 6-7 turns from full CCW.
2.6k fill
)
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Breinigsville, Pa. USA
bear air
GTA Senior Contributor
Posts: 3386
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Real Name: Chris
Re: .22 Marauder rifle won't tune
«
Reply #7 on:
September 23, 2021, 06:13:50 PM »
What velocity does the stock 22 cal shoot normally? I would think a standard marauder could achieve over 800 fps with the hades pellets.
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Sioux City IA, USA
Psalm 107:14 He brought them out of darkness and the deepest gloom and broke away their chains
kbstingwing
Former Rat Lobotomizer now Squirrel Lobotomizer
GTA Senior Contributor
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Real Name: Kevin (Bushido)
Re: .22 Marauder rifle won't tune
«
Reply #8 on:
September 23, 2021, 06:24:09 PM »
sounds to me like there is some kind of obstruction in the air pathway, maybe the transfer port is partially blocked, or maybe something is blocking the Hammer from full contact to the valve stem..... Just some suggestions...
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truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #9 on:
September 24, 2021, 02:25:12 AM »
I got out Thursday and chronoed it with the setup FuzzyGrub suggested, the first shot was high so I did 6 shots. The rifle is untouched from the factory and the fill pressure was 2,900#.
542
524
528
526
526
528
I did six shots with my .22 Fortitude too which shoots great at 25 yards using Hades ammo.
579
631
636
625
631
624
«
Last Edit: September 24, 2021, 02:27:17 AM by truck
»
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Breinigsville, Pa. USA
FuzzyGrub
GTA Senior Contributor
Posts: 7135
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Real Name: John
Re: .22 Marauder rifle won't tune
«
Reply #10 on:
September 24, 2021, 06:53:36 AM »
Given the chrony is good, there is something wrong with the Mrod, at less than 10FPE at near max settings. It should be >30FPE. The Fortitude is shooting low for stock settings. 14FPE vs 17-18FPE. So, some of it may be your chrony or chrony set-up.
Since you have both, does the Mrod pellet make less noise on impact than the Fortitude? Quieter on the shot noise?
The easy things have been covered, Vas screw, barrel O-ring, TP leak. There are numerous things that can be causing the power loss, but will take dis-assembly, to inspect/find. If it is under warrantee, consider calling Crosman CS for return. Otherwise, we can help with the process.
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Rural New York
1701P, 2201P, & 2501 Pistols,
1720T/Prod/Fortitude based( 7 ), Mrods( 5 ), SAM,
Sumatra 25 carbine, 357 Bulldog, Walther CP88 ( 2 ),
Akelas 22 & 25,
ATI Nova Liberty Wood 177 & 22,
P1, A4-P, & DPMS Full-Auto Fun
KevinJBrown
GTA Moderator
GTA Senior Contributor
Posts: 3242
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Real Name: Kevin
Re: .22 Marauder rifle won't tune
«
Reply #11 on:
September 24, 2021, 09:08:24 AM »
Wow, so many things that could affect pellet velocity. One thought, have you tried a different pellet to eliminate that as the source?
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USA, Mahomet, IL
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HunterWhite
Hunter Whitebeard
GTA Senior Contributor
Posts: 3692
Bishop's Castle
Real Name: Hunter
Re: .22 Marauder rifle won't tune
«
Reply #12 on:
September 24, 2021, 09:26:36 AM »
If the poppet stem is pushing into the plastic part of the poppet, then it will continue to lose power until the poppet fails. If the poppet fails, it will spontaneously degas.
The last poppet that I bought from Crosman was $1.70.
Hunter
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Arlington Texas
JSAR Mini Raptor, 25 cal,Condor 25, 2240, Umarex Colt, 177 FaTRod😎
Ribbonstone
GTA Senior Contributor
Posts: 12030
Re: .22 Marauder rifle won't tune
«
Reply #13 on:
September 24, 2021, 10:09:40 AM »
Over all, it is adjusting….it’s just not adjusting to where you want it.
That does signal something mechanical being “off”.
If it’s not spitting air at the shot, then there really are three things that can happen on a non-regulated PCP:
Something limiting the striker’s travel/strength to the valve stem.
Something limiting the valve stem/poppet’s movement.
Something limiting the flow of air from the valve to the pellet’s base.
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Louisiana
truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #14 on:
September 24, 2021, 11:12:23 AM »
The Mrod impact sound is quieter, as far as shot sound, the Mrod sounds weaker. I can see the pellet in flight real easily from the Mrod, it's eye-catching right before impact on the paper target.
The Mrod is a gen 2 that started as a .177 that I myself changed to a .22 so no more warranty I imagine, and it shot good for a long while but gradually the groups got bigger.
The rifle has about 9,000 shots through it in .22 judging by the 20,500 rounds I have a record of buying and split between two guns and I don't know how many shots in .177. All the parts have a lot of cycles on them, so is there any part that is more prone to wear than the other parts?
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Breinigsville, Pa. USA
HunterWhite
Hunter Whitebeard
GTA Senior Contributor
Posts: 3692
Bishop's Castle
Real Name: Hunter
Re: .22 Marauder rifle won't tune
«
Reply #15 on:
September 24, 2021, 11:37:27 AM »
Barry, it sounds like your M-Rod has served you well. It may be a good time to give it a new set of o-rings and a new poppet.
M-Rods are easy to work with. Order several poppets, they are cheap. You can order orings from Crosman, or Amazon, Mr O-Ring.
The poppet stem should stick out about a quarter inch, IIRC. If you remove the stock, trigger assembly, rear plug, hammer, hammer spring, then you should be able to measure poppet height. If it's less than 0.15" then that could be the problem.
My .02.
Hunter
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Arlington Texas
JSAR Mini Raptor, 25 cal,Condor 25, 2240, Umarex Colt, 177 FaTRod😎
FuzzyGrub
GTA Senior Contributor
Posts: 7135
yes
Real Name: John
Re: .22 Marauder rifle won't tune
«
Reply #16 on:
September 24, 2021, 11:57:24 AM »
IMO, it needs to be completely dis-assembled and many things checked and might as well replace all O-rings and poppet, while in there.
Logged
Rural New York
1701P, 2201P, & 2501 Pistols,
1720T/Prod/Fortitude based( 7 ), Mrods( 5 ), SAM,
Sumatra 25 carbine, 357 Bulldog, Walther CP88 ( 2 ),
Akelas 22 & 25,
ATI Nova Liberty Wood 177 & 22,
P1, A4-P, & DPMS Full-Auto Fun
truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #17 on:
September 24, 2021, 02:31:37 PM »
Thanks for all the input. I think I should try and tune the Fortitude and see where I wind up with it, if not good I'll redo both guns.
Are there any tuning values for the Fortitude like there are for the Marauder?
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Breinigsville, Pa. USA
FuzzyGrub
GTA Senior Contributor
Posts: 7135
yes
Real Name: John
Re: .22 Marauder rifle won't tune
«
Reply #18 on:
September 24, 2021, 04:52:29 PM »
The Fort only has one user adjustment for tuning. May want to read this:
https://hardairmagazine.com/reviews/fortitude-gen-2-hammer-spring-adjustment/
Logged
Rural New York
1701P, 2201P, & 2501 Pistols,
1720T/Prod/Fortitude based( 7 ), Mrods( 5 ), SAM,
Sumatra 25 carbine, 357 Bulldog, Walther CP88 ( 2 ),
Akelas 22 & 25,
ATI Nova Liberty Wood 177 & 22,
P1, A4-P, & DPMS Full-Auto Fun
truck
Marksman
Posts: 341
Real Name: Barry
Re: .22 Marauder rifle won't tune
«
Reply #19 on:
September 24, 2021, 08:29:41 PM »
Ok. So no tune on the Fort.
I just checked the hammer spring on the Fort and it is right at 4 turns in.
Logged
Breinigsville, Pa. USA
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.22 Marauder rifle won't tune