GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: oldpro on December 21, 2018, 01:51:05 PM
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I’m making a custom F&T gun for a customer we’re starting with the Crosman.177 Field and Target gun. I ran into and issue where I couldn’t push the 10.34 grain H&N past 900 FPS so I broke the gun down to have a look(was going to anyway) Inside is a nice large volume Gauge port and a really nice adjustable regulator what was not nice is how they laid it out. They stuck the regulator right up against the valve so I have no plenum to work with and this beautiful high flow gauge port Infront of the Regulator?????!!!!! Another hey! Crosman. Now you could just put the Regulator in front of the gauge block except they drilled the vent hole back where the regulator is so now we have to replace the air tube move the regulator back on top of the high flow gauge block and drill the new vent hole.... Someone please talk to the people at Crosman Pleaee!!!!
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Great info .... at last we start seeing some of whats inside the F&T m-rod !!
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Here’s a couple more pics. Crosman is using the standard steel Mrod hammer🤮 and the F&T tube is 2 inches longer and the gauge hole has been moved forward so the regulator can sit on the valve🤯
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Travis ...
Does the valve in the F&T still have the transfer choke screw ?
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I’m making a custom F&T gun for a customer we’re starting with the Crosman.177 Field and Target gun. I ran into and issue where I couldn’t push the 10.34 grain H&N past 900 FPS so I broke the gun down to have a look(was going to anyway) Inside is a nice large volume Gauge port and a really nice adjustable regulator what was not nice is how they laid it out. They stuck the regulator right up against the valve so I have no plenum to work with and this beautiful high flow gauge port Infront of the Regulator?????!!!!! Another hey! Crosman. Now you could just put the Regulator in front of the gauge block except they drilled the vent hole back where the regulator is so now we have to replace the air tube move the regulator back on top of the high flow gauge block and drill the new vent hole.... Someone please talk to the people at Crosman Pleaee!!!!
It seems someone at Crosman sayed : dude,just slam a regulator in there ;D
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Crosman REALLY need to start reading the Forums so that they can begin to have at least a VAGUE understanding of how PCPs work.... ::)
Bob
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Crosman REALLY need to start reading the Forums so that they can begin to have at least a VAGUE understanding of how PCPs work.... ::)
Bob
Seriously!!!! I just swapped the tube over to the gen two Mrod and gained 50 fps without changing anything except moving the reg on top of the gauge block so now I can tune it back and run a string. Ive lost a lot of headroom swapping the tubes but I hope The python valve will get me back to at least the 50 shots or more from the stock tune. Let you know in a bit.
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Travis ...
Does the valve in the F&T still have the transfer choke screw ?
Yes they are running the .25 cal mrod valve. It wont have the screw in my Python test valve though.
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Crosman REALLY need to start reading the Forums so that they can begin to have at least a VAGUE understanding of how PCPs work.... ::)
Bob
+1 it kinda makes you wonder where the engineers heads are at when they design these ???
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This entire endeavor by Crosman is nothing more than groups of engineers each being assigned a development task without really understanding the complete relationships (spacially at mechanically) between subsystem. Systems Engineers are pretty much a worthless crop of inbred morons if they don't do their job- keeping individual engineers mindful of what goes where and how they interface.
Similar example: common failure-point item in cars (the alternator) requiring removal of the entire right-side axle assembly just to service/replace. IE: 10 minute job becomes a 4 hour job.
SMH
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Im at a loss how they can continue to do this over and over and over.....Thank god I have a bunch of these steel tubes laying around to replace the F&T tube, Im just going to give it to my customer free.
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It is my experience that when a company does something truly stupid from a technical viewpoint, you can bet it was driven first by lawyers, and then if more damage is needed by accountants as backup (accountants can rarely do it on their own) . . . .
While those of us that understand our regulated airguns are happy with having one gauge on the gun, and that gauge showing regulated pressure, the lawyers probably insisted that the gauge had to read reservoir pressure (for fear of people over filling when the regulated gauge stops going up). That probably prevented them from doing what all of us would do (and Travis just did).
The accountants probably vetoed a second gauge, with help from the lawyers that probably would think it too confusing. Not sure why they did not simply put in a plenum spacer on the end of their regulator though - probably not a common part that way . . .
The F&T seems to simply show what we already know - "if you want it done right, do it yourself."
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With the F&T they went through the trouble to change the air tube and the stock, they could of increased the plenum regardless of what side they put the gauge on. Are you changing the stock or making the F&T fit the standard tube?
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Another indicator that Crosman, as of late, doesn't know what they're doing.
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Travis, I would be interested in which barrel is in this F&T (LW or new crosman) and your thoughts on accuracy.
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LW and very accurate
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Is it possible to increase the pressure of the Crosman regulator? The .177 FT has enough power to get JSB heavy 10.34gn to 880 for 17.7 fpe. I turned it down to 860 and with the Crosman barrel it is almost accurate at 25 yards with .4 inches ctc.
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The .22 FT Lothar Walther can only get the H&N 14.66 to 815 fps. I turned it down to where the striker length was coming under control at 810 for 21.5 fpe. And it is not accurate. I didn't have any JSB's at the time but I was hoping to get the Jumbo or Hades 15.89 up to 860 for 26 fpe. And I hope they shoot better. The HN groups were .7" and 1 flyer at 25 yards with a Hill barrel band installed.
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The shot string with the .22 the way I had it set didn't fall off in velocity until 1500 psi so it seems the reg is set somewhere around there. I would like to crank it up into the 2,000's. I have a bottle and compressor so I'm ok with something like 30 regulated shots if that's what it takes if I can get closer to around 26 fpe.
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For all of the griping about the implementation of the reg in the FT marauders, the one good thing I haven't seen anyone mention is that both these air rifles produce an outstanding extreme spread of 5 fps for the whole string.
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But the barrel in the .25 is apparently still much better. It is grouping at .15" at 25 yards and zero flyers with JSB 25.4 at 40 fpe. Hammer debounce device and half shroud mod.
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So again. is it possible to increase the Crosman reg pressure?
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I bought one just for Hunter field target.
The information that I have is this:
I have the177 caliber.
Regulator set point = 2050.
Transfer port same as 25 M-Rod.
Valve same as 25 M-Rod.
Velocity metering screw all the way out, 4 to 5 turns.
Hammer spring cranked down pretty hard, I'll try to find the settings.
Plenum is just the volume of the valve.
There's a thread about opening the inlet of the valve (unrelated to the FT-Rod) that would give more FPE.
https://airgunguild.com/pcp-c02-and-helium-powered-airguns/mrod-valve-mods/
If your falling off the reg at 1500 then it's not factory set. It should be 2050 psi.
Hunter
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My .177 Marauder FT seems to begin to drop in velocity after about 1900. It is possible for a regulated pcp to continue flat, or even rise, after it falls below the reg. But I doubt that is the case with my rifles since I have the energy cranked to just under the max on both of them. Transfer port -5. Spring 1 turn back into the threads after falling out the end of travel. And striker in about 4-5 before it even started to come down into control.
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The .22 was obviously designed to get the maximum shot count with a max energy of 20 fpe. For FTT.
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That regulator looks like it is adjustable, similar to the Fortitude. CCW should be increasing pressure, CW decreasing. Mark your current position so you could get back. I'd look to make 1/8 turn adjustments and test.
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COME ON GUYS...
This is the sue happy U.S. ... Crosman almost has to cripple them to reduce liability... Do not like it but do understand it...
So bridge the vent hole and move the reg... then they can say was not our doing... we designed them to be used only at such and such fpe...
Mass Market rifles at $-$$, Not $$$ or $$$$$...
I think they try to walk the safest path down the current legal environment for most part...in order to stay in Biz...
at least here we can send stuff faster than 450 fps and at more than 5-12/ +++ & +++++++ fpe.. ;)
Crosman just builds some decently solid bones... We take on the liability of making it into ours.. ;)
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What I have figured out about the Rods, pistol and rifle, is that the more you replace the better the outcome.
My idea of a nearly perfect .177 M-rod is to cut the choke from the barrel and recrown, R & R the the pressure tube with a aluminum JSAR tube. R & R the hammer, again JSAR, R & R the breech with a Exclusive side lever breech and tighten if needed, remove the lawyer spring. Keep the wood stock.
Then buy a good .177 Bullet mold, and NOE sizer.
On the P-rod, breech, barrel, shroud, trigger group, grips, forearm, pressure tube, stock, which is what I did with mine.
I don’t push my Prod, 480 fps, and the Mrod l77 is powerful enough for slugs so the oem valve with maybe a B Staley mod and larger tp for both.
So basically replace or modify just about everything on the two guns. Put the cast-off parts in a drawer until you need the space then throw the parts in the trash.
Regards,
Roachcreek
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Roach,
I'm not so sure the stock valve even with a larger transfer port is up to the task of slugs ? ... well at least FAST slugs 850 & greater ....
I've build a boat load of modified Marauders over the years in .177 finding you need a pretty substantial valve that opens really easy and flow mass volume in a short dwell period. * balanced valves Cothran or JSAR or homemade.
Good luck on your .177 slug project ... there worth it and can shoot fantasic once the right parts are in place. Just built a .177 slugger myself so am speaking with some knowledge learned ;)
Scott
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That is good to know. Don’t know thar I would build one though.
Thanks,
Roachcreek