I was fooling with the hammer spring adjuster on my .177 marauder field and target yesterday to reduce the velocity which has crept up since I got the rifle over a year ago. Out of the box it was shooting AA 10.3's at 895 fps and more recently it was shooting at 915 fps. I reduced the hammer spring preload yesterday to zero and was getting 865 fps and my groups seemed to tighten up, although I was fighting a 10 mph wind. I shot again today and the velocity was back up to 895 with the hammer spring still at zero turns in. If it is going to stay at 895 regardless of where the hammer spring is adjusted would there be any advantage or disadvantage to leaving it at zero preload? I also shot some 8.4's yesterday and their velocity only dropped from 965 to 940 when the hammer spring was reduced to zero turns.
marauder f & t hammer spring adjustment?
- Thread starter rong1966
- Start date
With the stock length hammer spring there is still a little preload on the hammer at zero turns in. I see no disadvantage to this and the advantage is a easier (lighter) cocking gun.
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The new FT .177 Marauders are Powerful. I turned mine up to full power just because before I started tuning it to see what it would do and it was throwing the JSB heavies at 930. Which is really fast for being regulated for 80 shots out of 215cc tube. 19.5 fpe. Crosman did an amazing job designing the regulator and valve for this version. I started turning the hammer spring down little by little and ended up all the way backed out before it really began to slow down any at all. It was still shooting 880 fps but I wanted to see what groups might result from settings at 860 and 830. I have my hammer spring at zero and tight so it can't ever creep. You have one more means of adjustment. Marauders have a striker adjustment that you reach all the way through the hammer with a smaller allen wrench to adjust. Turning the striker in shortens the stroke distance that the hammer has with which to accelerate and reduces the velocity. Back it all the way out until it touches and then count the turns on the way in. I ended up going in 8.5 turns before it came down to 860. It looks like 12 turns is the most striker adjustment that is available. To go much slower I might have to try reducing the transfer port. But I don't like to mess with that since it is hard to make it stay where you want it while you lock it down. I'll have to figure out a way. Unregulated Marauders benefit from using some restriction in the port to flatten the peak of the power curve and to minimize max spread deviations. I haven't touched it on the .177 and ended up just removing the port pintle and putting the locking cap back on with locktight for my .25 since that is tuned for nearly max power and the pintle kept screwing all the way in as I tried to tighten the locking cap.
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Next time I order I will try some of the "new" JSB Monsters in .177 to see how they group. Should be able to go back up to the max on the rifle and get them to 810 and they should have an even better BC than the 10.3 gn heavies. Which are already fantastic for .177 at .031.
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The reg and valve work great together with a max spread of just 6 fps over 40 shots and it was still on the reg at 2,000 psi. I've yet to shoot a full shot string to see where the reg is set.
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Check out this excellent work someone did to chart the result of every combination of possible spring vs stroke with their .25.
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https://www.airgunnation.com/topic/interesting-graphs-of-marauder-strikerspring-adjustment-relationship/
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Next time I order I will try some of the "new" JSB Monsters in .177 to see how they group. Should be able to go back up to the max on the rifle and get them to 810 and they should have an even better BC than the 10.3 gn heavies. Which are already fantastic for .177 at .031.
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The reg and valve work great together with a max spread of just 6 fps over 40 shots and it was still on the reg at 2,000 psi. I've yet to shoot a full shot string to see where the reg is set.
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Check out this excellent work someone did to chart the result of every combination of possible spring vs stroke with their .25.
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https://www.airgunnation.com/topic/interesting-graphs-of-marauder-strikerspring-adjustment-relationship/
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I believe that the hammer spring comes maxed out from Crosman and the hammer throw is all the way out giving it the shortest stroke. It just seems that adjusting the hammer spring doesn't do a whole lot . I got it down to 865, but the next day it was back up to 895 by itself. I guess the only way to reduce the velocity would be to choke the valve port like you mentioned. BTW, I have the Crosman barrel and unfortunately it doesn't like the original jsb monsters.
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My FT Marauder .177 came with the striker way in. I didn't count the turns since the first thing I did was crank the rifle up to max to see what it had. Turning the spring all the way back took it from 930 with the heavies to 880. It then took 8.5 turns in with the striker to start having any further effect to get it down to 860. The transfer port will definitely reduce the power anywhere from there but it is a pain to hold still to get the locking cap back on without the adjustment moving. My .25 was going from 830 to 600 with the pintle all the way in.
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I slotted the stock to allow access to the port adjuster without removing it. It is silly that Crosman didn't do this in the first place. And I may try slightly deforming the threads on the pintle to get some drag while turning so it will stay steady while the locking cap is tightened.
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I did a half shroud mod to both Marauders so that the shroud can no longer push the barrel around from bind on the rear threads shifting. This also allows removal of 2 of the 7 baffles to shorten the overall length.
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https://www.airgunnation.com/topic/half-shroud-on-a-marauder-for-better-accuracy/
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I hadn't yet removed the "lawyer spring" from the 177 when I shot these 5 shot groups at my indoor 12 yard range. . It is hard to tell at just 12 yards on cheap paper but I think the .25 shooting JSB 25 gn Kings at 830 is slightly more accurate in that test.
.177 top and .25 bottom.
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I slotted the stock to allow access to the port adjuster without removing it. It is silly that Crosman didn't do this in the first place. And I may try slightly deforming the threads on the pintle to get some drag while turning so it will stay steady while the locking cap is tightened.
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I did a half shroud mod to both Marauders so that the shroud can no longer push the barrel around from bind on the rear threads shifting. This also allows removal of 2 of the 7 baffles to shorten the overall length.
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https://www.airgunnation.com/topic/half-shroud-on-a-marauder-for-better-accuracy/
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I hadn't yet removed the "lawyer spring" from the 177 when I shot these 5 shot groups at my indoor 12 yard range. . It is hard to tell at just 12 yards on cheap paper but I think the .25 shooting JSB 25 gn Kings at 830 is slightly more accurate in that test.
.177 top and .25 bottom.
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I might try to get some Vibratight to try on the transfer port pintle to hold it while tightening the locking cap.
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https://www.vibra-tite.com/products/threadlockers/vibra-tite-vc-3-threadmate/
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https://www.vibra-tite.com/products/threadlockers/vibra-tite-vc-3-threadmate/
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Do you have the Crosman barrel and how does yours group at 30 yards and 50? Mine groups at a half inch at 30 and just under an inch at 50 with the AA 10.3's--good but it doesn't exactly stack pellets even at closer ranges.
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I have the regular Crosman barrel. It's been too cold and snowy in NY state to get outside at the range yet. I live in the city so can't shoot in my yard.
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