Marauder Pistol/1720T/1701P Lightweight Hammer - Machined OEM Part Results

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HPA_Hunter

HPA_Hunter

Member
Mar 8, 2019
36
2
WA, United States
*Updated with chronograph/efficiency data on 09/06/2021 - See below

Hey folks,

Hadn't seen a lightweight hammer for the Marauder Pistol that was available for regular sale. So I decided to CAD one up and estimate what it would take to "lightweight" the OEM part in a simple, reasonable manner. Long story short, after some iterations in Solidworks, the estimate hovered just under 50% reduction in weight (55g in OEM form, 27g machined). Since the result looked decent, and an OEM part is ~$18 to your door, I ordered one to cut up on the mini mill.

Final result of machining: OEM part weight - 54g; Machined - 25g; ~54% weight reduction. Retains all OEM functionality and interface geometry.

For comparison, a 6061 Aluminum version of the OEM hammer geometry would weigh ~19g, compared to 54g for the steel part.

Wanted to try this to see if I could net the highest shot-count, lower power tune when regulated. Plan to update this when I've done some Chrony testing.

Figured others may find the info helpful in their tuning efforts. A similar result could be achieved with a hand drill, a set of metal files, and a steady hand (angle grinder too, if you're feeling fancy). Took about 3 hours with the mini-mill all said and done but I don't claim to be remotely close to a competent machinist with adequate tools... Thankfully the steel is not hardened, and cuts well with HSS tools.

Thanks for reading!

OEM: Machined:

MP_HammerOEM - Copy.1625260404.PNG
MP_HammerLW - Copy.1625260403.PNG


DSCF1279 - Copy.1625261056.JPG
DSCF1281 - Copy.1625261056.JPG


DSCF1283 - Copy.1625261057.JPG

 
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Regulated should work very well ... Not regged ? likely too light to work with 2-3k pressure range.

Did a BUNCH of R&D on my 1701 back a few years ago. See: https://www.gatewaytoairguns.org/GTA/index.php?topic=69914.msg665440#msg665440



Click to expand...


What he said! That hammer is likely way too light to even open the valve at 3000PSI, probably still too light for 2000PSI. Have you tried it? Very curious on your shot string. Then you can stick a regulator in there without completely killing the shot count……ask me how I know! LOL 



after messing around with it for ever I’ve come to the conclusion that the factory tune is the best. Doh! 
 
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@UCChris - Thanks for the kind words!

@Motorhead - Sorry, I should have clarified that there wasn't a ready-made LWH option for sale (post now edited). I used all your experiments with the 17-series guns to compile strategy and info well before and during this process, and I greatly appreciate the knowledge freely given to help everyone out! I hope to do the same.

@Motorhead, @Qball - Yep, only intended for a regulated gun. I had done a bunch of testing with the OEM hammer/spring, Huma reg, and a wide-open valve at setpoints from 70-110 bar. Got good efficiency with minimal bounce at the higher pressures, but way over my power goals (was getting 13-15 FPE, vs. the 8-11.5 I wanted). At those levels, it tanked the shot count like you said @Qball. I was able to hit the goal of 50 shots at 10FPE with the OEM valve and the reg, but knew I was likely leaving power/shots "on the table" so to speak, given the restricted ports, higher pressure, and whacky hammer throw length/HST adjustments.

I am excited to see what all this nets, but the only problem is carving out the time to execute the testing in a rigorous manner.

I agree that the factory tune is pretty darn good... Got some 1701P and 1720T transfer ports to play with when un-regulated as well. Hell, half the fun is re-configuring things and seeing if the hypothesis was right!

Thanks for the interest, folks!
 
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The fun definitely is the tinkering part! You certainly have the skills and tools to do it. I spent many hours with TP and regulator but finally gave up and went back to factory on my 1701P which also took a while to figure out. 


my 1720T has a regulator with HS on the lowest setting and the hammer throw choke down the speed to about 700FPS or around 10.5 FPE and it’s a laser and deadly on squirrel. Quite a few shots and a few pump from the hand pump and I’m good again. 


good luck on the fun project, these are fantastic little guns. 
 
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Hey folks,

Big delay, I know, but I’ve finally got some (almost) apples-to-apples data on the “lightweighted” OEM hammer.

Parameters for “OEM Hammer” setup:

-Hill Max Power Valve, .140” transfer port, higher-rate valve return spring

-Un-drilled barrel port (~.128”)

-OEM Hammer, striker, hammer spring

Parameters for “Lightweight OEM Hammer” setup (same as above, except for):

-Drilled barrel port (~.140”)

-“Lightweight” OEM hammer (25g vs 54g for OEM)



First, I looked at the regulated application, and what each turn of the hammer spring netted in terms of velocity and “plateau” (see Rsterne/HAM articles on regulated tuning). Of note – “Regulator Simulation” was tethering the gun to a SCUBA tank at 1700PSI.

OEM_Reg.1630975799.PNG


LWH_Reg.1630975799.PNG


HSTvsVelocity_Regged.1630975799.PNG




The highlighted values represent the beginning of the “plateau,” the balance point of max power vs. efficiency when regulated. Showing roughly a 20 FPS difference between lightweight and OEM. Also notice that at 0 turns HST, the lightweight hammer nets 45 FPS fewer than OEM.

At the end of the day, this was what I was looking for – a reduction in the starting and “plateau” velocities. Now, it’ll be different with each reg pressure/pellet combo, but the lower velocity at 0 turns may be indicative of what’s possible with a lower regulator setpoint.



Next, I wanted to look at where the unregulated shot string sat with the upgraded valve components and OEM/Lightweight hammers. From experience, I knew the lightweight hammer would need a lower starting pressure to operate than OEM, and this was borne out in testing; though not as much as one might think (~250PSI lower).

ShotString_Unregged.1630975885.PNG


Long story short, going from the OEM hammer to the lightweight unit reduces the peak velocity, but not necessarily the pressure at which it occurs. Looking at the data, the efficiency is roughly the same (~10.5 bar-cc/FPE), but the power output is about 82% of the OEM hammer.

As a point of reference, with a completely OEM setup (valve, hammer, port, etc.), 24 shots at 10FPE (0 turns HST) occurs from 2100-1300PSI, with an efficiency of 14.4 Bar-cc/FPE (compared with ~10.5 bar-cc/FPE with upgraded components above). As expected, more open valving nets better efficiency for a given power level…



As far as drawing an overarching conclusion from all this, “lightweighting” the OEM hammer does have benefit if you are looking to reduce power output without constricting the valving. I would also imagine that it would reduce hammer bounce in regulated applications.

As others have shown, it’s all one big balancing act based on one’s desired application (fill pressure range, shot count, power, regulated vs. unregulated, etc. etc.). Hopefully this data helps other folks in their tuning pursuits!

Will update if/when I decide to throw the regulator back in. However, I am coming 'round to the idea that the Marauder pistol should really be viewed for what it is - compact, lightweight, and simple. 24 shots between 10 and 15 FPE, depending on fill pressure and hammer spring.

Crosman knew what they were doing when they set it up, and it's taken me a good bit of time and effort to prove that to myself, but hey, fixin' stuff that ain't broken is what I do :grin:.

Acronym List:

HST - Hammer Spring Tension

CP 14.3gr - Crosman Premier .22, 14.3 grains

OEM - Original Equipment Manufacturer (in this case Crosman)

HAM - Hard Air Magazine

Bar-cc/FPE - Pressure (Bar) consumed times tank volume in cubic centimeters, per foot-pound of energy output. Gives a baseline for comparing efficiency of different setups. That efficiency is a measure of the compressed air volume consumed to produce one foot-pound of energy.
 
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