GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: dpittman on February 24, 2018, 09:52:53 PM
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I have a stock .25 mrod and have a question about the Huma regs. With or without the gauge block hole. With the built in gauge hole does it have enuff plenum for decent power. What kind of power and shot count can be had with the proper valves and hammer springs and hammers. How do some get high power with a very low cocking force.
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Remember, if you go with the guage block system, you are not going to be venting the reg to the atmosphere. So drilling the tube is needed.
I went with no gauge, and the gauge hole is used for the vent. 8)
Besides, I only trust the gauge on the fill bottle. AG guages are notorious for being off by several hundred pounds.
Knife
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Remember, if you go with the gauge block system, you are not going to be venting the reg to the atmosphere. So drilling the tube is needed.
I went with no gauge, and the gauge hole is sued for the vent. 8)
Besides, I only trust the gauge on the fill bottle. AG gauges are notorious for being off by several hundred pounds.
Knife
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I was think g of the huma because I thought it was no drill? I tried looking at the installation instructions but don’t see anything? I’m a newbie so may have missed?
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The one with the gauge port is actually vented to the atmosphere. You can still get plenty of power out of one as well. I prefer the ones with the gauge port built in. Much easier to work with and don't hafta worry about the other one sealing well.
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I'm a newbie also, and just installed a Huma regulator with the gauge port in my .25 Marauder. I did not have to drill a vent hole. Since I really don't know what I'm doing, I'm at a point where I'm not sure what to do next. The gauge is showing a regulated pressure of 2300 psi. I have the MDS hammer and TSS installed, but I can only get and average of 727 fps for an average of 29.78 fpe using JSB 25.39 gr pellets. This is over a 40 shot string, but only 28 of those are above regulated pressure.
My .22 Marauder has the Audrius regulator, the regulated pressure is 2000 psi and I get an average of 862 fps for an average of 26.23 fpe using JSB 15.89 gr pellets. Again, this is over a 40 shot string with 33 shots at the regulated pressure. This rifle has the stock hammer and hammer spring.
I guess what is so confusing to me is my Gauntlet has a regulated output of only 1300 psi, yet I'm averaging 896 fps for an average of 25.42 fpe using CPHP 14.3 gr pellets. Over the 40 shot string all 40 shots are at the regulated pressure.
I understand the Gauntlet has a lot more air volume, but why can I get higher fps/fpe with less regulated pressure than I am with the Marauder?
I would love to know if it's even possible to get 850 psi out of the .25 Marauder at a regulated pressure of 2000 psi or under with the set up I currently have?
Likewise, I'd love to know if I could get 900 fps out of the .22 Marauder at a regulated output of around 1500 psi using the setup I currently have?
I'll admit, I don't really understand the inner workings of these rifles, but I am trying to learn. Now that YouTube is pulling all the air gun videos, it's getting tough to find clear, concise explanations and instructions that someone who is just starting out can understand and follow...
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Paul does the .25 Mrod have stock valve and ports?
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Paul does the .25 Mrod have stock valve and ports?
Yes, it's all stock with the exception to the regulator, hammer and hammer spring. I'm trying to do the best I can and stay within a budget, that I've already exceeded! LOL!
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Mrod Huma reg w/gauge port: vents out gauge hole, fixed sized plenum
Mrod Huma reg wo/gauge port: vents out gauge hole, can be used with or without gauge block, so two plenum sizes to choose from. Same as audrius reg
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Yes, it's all stock with the exception to the regulator, hammer and hammer spring. I'm trying to do the best I can and stay within a budget, that I've already exceeded! LOL!
If you just install a reg but keep same ports, it will be lower power at a given reg pressure. Think of it this way, you kept everything else the same but gave it just a tiny air tube (plenum) at a lower pressure than probably what you used for conventional tune. You open the ports to get more power at that smaller plenum and lower pressure.
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Yes, it's all stock with the exception to the regulator, hammer and hammer spring. I'm trying to do the best I can and stay within a budget, that I've already exceeded! LOL!
If you just install a reg but keep same ports, it will be lower power at a given reg pressure. Think of it this way, you kept everything else the same but gave it just a tiny air tube (plenum) at a lower pressure than probably what you used for conventional tune. You open the ports to get more power at that smaller plenum and lower pressure.
When you refer to opening the port are you referring to the adjustment that can be made by removing the grub screw your n the side of the rifle? Or does it mean replacing more parts?
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When you refer to opening the port are you referring to the adjustment that can be made by removing the grub screw your n the side of the rifle? Or does it mean replacing more parts?
At a minimum, modifying existing parts. For "typical" Mrod regulation, the following TP, valve exhaust and barrel port should be around:
177: 0.140"
22: 0.160"
25: 0.180"
The valve velocity setting on all, should be "wide open".
I think the oem standard TP is 0.110-0.120 for both 177 and 22, and 0.140" for 25 cal.
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When you refer to opening the port are you referring to the adjustment that can be made by removing the grub screw your n the side of the rifle? Or does it mean replacing more parts?
At a minimum, modifying existing parts. For "typical" Mrod regulation, the following TP, valve exhaust and barrel port should be around:
177: 0.140"
22: 0.160"
25: 0.180"
The valve velocity setting on all, should be "wide open".
I think the oem standard TP is 0.110-0.120 for both 177 and 22, and 0.140" for 25 cal.
Okay, thank you! I'm assuming the cost of a TP should be minimal compared to the regulator and other parts. Is this a part that can be purchased at those sizes, or do I need to just purchase a stock TP and modify it myself? Sounds like this may be the key piece I'm missing! Thanks...
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Okay, thank you! I'm assuming the cost of a TP should be minimal compared to the regulator and other parts. Is this a part that can be purchased at those sizes, or do I need to just purchase a stock TP and modify it myself? Sounds like this may be the key piece I'm missing! Thanks...
To modify a stock TP to 0.180" makes it too thin and crushes very easily. I use poly tubing. The exhaust port on the valve will needs to be drilled out along with the barrel port to match. If you mess up a valve, it is only around $25. or you can buy a drop-in from Hill and others.
You mentioned going to a LW hammer. How light did you go? If still using the oem valve spring, that can be part of the issue, as well.
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I'm not comfortable enough, nor do I have the self confidence to start modifying the stock parts! I have no idea the weight of the Hammer. I got it from Rocker1 right after I bought the rifle because I was told it was a must have! LOL! The more I read different posts about tuning, the more confused I become. I want to learn, but it sure would be nice if there was an instruction manual that gave some common settings to try first and then adjust from there...
This is where I'm at now... I closed the Velocity Port on both rifles and then opened them a full 5 turns. On the .22 I brought the striker all the way back next to the body of the hammer and backed the hammer spring all the way out and then went to shooting and adjusting over the chrony. I have that one sitting right at 900 fps using JSB 15.98 gr pellets, so I'm happy with it. I't bone stock except for the regulator that is set at 2000 psi.
The .25 is another story. Did the same thing but the best I can get is 725 fps with JSB 25.39 gr pellets. I'm kind of disappointed in the results and am thinking of removing the MDS Hammer and the TSS and going back to stock and see what happens.
I don't know if I fully understand the function of the TSS, but it's almost as if the adjusting screw should be twice as long as it is. Twice I adjusted it to the point it went right through and then I had to disassemble the rifle to get it threaded back into the back piece. I thought the idea was having two springs that could be adjusted independent of one another, but it appears the adjuster pushes both springs equally. Or at least they do when I'm at a point where the rifle is making more than 500 fps! If the adjuster is just moving the inner spring, the rifle is producing less than 500 fps... I'm not sure if it will work, but maybe I'll try replacing the outer spring with the stock spring and see what happens...
My goal was to get between 800-850 fps, but as it sits it doesn't appear to be capable of producing that output...
UPDATE: I swapped hammer springs and put the stock hammer spring in the TSS and have been able to get a pretty consistent 800 fps from my .25 Mrod. Still thinking I need to do something different, but for now, it is workable...
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With the reg with gauge hole how much power should I expect. My gun likes the 34 gr jsb better than the 25.39 pellets. It is shooting them around 725 fps and the kings around 830. But I only get about 16-20 shots. Is it possible to get the 34 gr up to 800 fps and have 25-30 shots with a regged gun. I am liking all the Jefferson State toys that can be put in one of these mrods.
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With the reg with gauge hole how much power should I expect. My gun likes the 34 gr jsb better than the 25.39 pellets. It is shooting them around 725 fps and the kings around 830. But I only get about 16-20 shots. Is it possible to get the 34 gr up to 800 fps and have 25-30 shots with a regged gun. I am liking all the Jefferson State toys that can be put in one of these mrods.
Keith (TriggerTreat) and Dillon (Dairyboy), I believe did some tuning with a reg for the heavier JSB. They might have used a larger plenum Huma, designed for 30 cal, vs 25. They would also have porting info or what aftermarket valve they used.
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I'm not comfortable enough, nor do I have the self confidence to start modifying the stock parts!
Paul,
If you mess up the stock parts, they are available from crosman at reasonable prices. Getting the ports to even 0.160" will help you.
A number of people have documented Mrod 25 cal regulation projects on the GTA. They either modify the existing valve and ports or use an aftermarket valve.
If you are unable to do the porting, bump up the reg psi another 100-200. That will get you some more power, but reduce the number of shots on regulation.
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I'm not comfortable enough, nor do I have the self confidence to start modifying the stock parts!
Paul,
If you mess up the stock parts, they are available from crosman at reasonable prices. Getting the ports to even 0.160" will help you.
A number of people have documented Mrod 25 cal regulation projects on the GTA. They either modify the existing valve and ports or use an aftermarket valve.
If you are unable to do the porting, bump up the reg psi another 100-200. That will get you some more power, but reduce the number of shots on regulation.
John,
Thank you for all your help. I replaced the outer TSS spring with the stock spring yesterday evening and was able to get it at 800 psi using 25.39 gr pellets. Daylight was fading so the chrony was starting tor port errors and I had to quit. Later I replaced the TP with a piece of refrigerator tube. I have no idea if this will work in the Marauder or not, but it did fit in the port opening and I cut it the same size as the stock port with the two bushings attached. If I get a break in the weather today, I'll give it another go and see what happens. I really appreciate you patience and suggestions!
dpittman, what set up/aftermarket parts do you have installed in your Marauder? I don't seem to be able to get past 800 psi using the 25.39 pellets with my current configuration. Thanks...
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This is a great thread...I've been reading along and have read a ton in the past 6 months, but like Paul and some of the other guys...sometimes a lot of what gets written here does so with a bit of assumed knowledge on the part of the readers or, rather, the writer is just speaking from their head. I think after 6 months I finally know what a poppet valve is... ;D
I just purchased a modded .22 and .25 to replace my stock .25. Since I didn't do the work myself, unless I plan on sending them out, I'm going to have to start twiddling. My .22 is reg'ed @ 140 bar and ported to .140 valve, TP, and barrel. I just got it so I haven't chronied it yet, but the seller sent it with specs that show 50 reg'ed shots at about 900 average. The .25 is not regulated, but ported to .170 and averages 892 over 20 shots, according to the sheets that came with it. This is with a TSS and MDS hammer.....22 has SSG installed.
So, close to 900 with an unregulated using 25.49 gr. with just porting, lighter hammer, and spring system as others have done is achievable with trial and error. I watched Haji's video, which with the Youtube thing, was a great tear down resource.
If I can interject a question...when you take down that way, and take the breech off and the hammer and springs off, I'm assuming since you/Haji didn't mess with the spring system adjustment via the screw/hole that's at the rear cap there's really nothing to set back up when you reassemble, correct? I mean, the spring settings for the hammer should all be the same, right...you just put the springs in and the cap back on behind where the bolt goes and whatever your original settings were should still be there, correct?
I only ask because the seller said the TSS for the .25 was a bit of a bear to set up, and right now there is a slight leak in the air tube. I want to know in case I have to disassemble to replace o-rings, etc. Thanks!
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I believe the TSS has a nylon tipped set-screw for locking down the adjustment, so you should be fine.
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This is a pretty good read here about how the 40/40 tune or more can be achieved on your 25 cal.
https://www.gatewaytoairguns.org/GTA/index.php?topic=116706.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=116706.0)
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Paul, I have no mods at all. I think my settings are hammer spring 3 turns clockwise and striker all the way ccw. I think my vms is open all the way. Hope this helps you some. The king heavy pellets at only 725 are a little too loopy that is why I want to boost the speed s little.
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I'm not comfortable enough, nor do I have the self confidence to start modifying the stock parts! I have no idea the weight of the Hammer. I got it from Rocker1 right after I bought the rifle because I was told it was a must have! LOL! The more I read different posts about tuning, the more confused I become. I want to learn, but it sure would be nice if there was an instruction manual that gave some common settings to try first and then adjust from there...
This is where I'm at now... I closed the Velocity Port on both rifles and then opened them a full 5 turns. On the .22 I brought the striker all the way back next to the body of the hammer and backed the hammer spring all the way out and then went to shooting and adjusting over the chrony. I have that one sitting right at 900 fps using JSB 15.98 gr pellets, so I'm happy with it. I't bone stock except for the regulator that is set at 2000 psi.
The .25 is another story. Did the same thing but the best I can get is 725 fps with JSB 25.39 gr pellets. I'm kind of disappointed in the results and am thinking of removing the MDS Hammer and the TSS and going back to stock and see what happens.
I don't know if I fully understand the function of the TSS, but it's almost as if the adjusting screw should be twice as long as it is. Twice I adjusted it to the point it went right through and then I had to disassemble the rifle to get it threaded back into the back piece. I thought the idea was having two springs that could be adjusted independent of one another, but it appears the adjuster pushes both springs equally. Or at least they do when I'm at a point where the rifle is making more than 500 fps! If the adjuster is just moving the inner spring, the rifle is producing less than 500 fps... I'm not sure if it will work, but maybe I'll try replacing the outer spring with the stock spring and see what happens...
My goal was to get between 800-850 fps, but as it sits it doesn't appear to be capable of producing that output...
UPDATE: I swapped hammer springs and put the stock hammer spring in the TSS and have been able to get a pretty consistent 800 fps from my .25 Mrod. Still thinking I need to do something different, but for now, it is workable...
Hi Well my 2 cents worth. You got the Hammer from Rocker1 and he is in Florida, so I would go back to him and have him tune it for you. He has all the tools to what you need for your rifle. Open up the Barrel TP and make you a .187 TP you'll be in the 800 with the TSS and the light weight hammer. 40 / 40 is readily available on the MRod's.
Michael :- )
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Well, I put it back to stock with the exception of the regulator and am getting 820 fps using 15.89 gr pellets. Seems the TSS and MDS Hammer are more for lower power higher shot count applications.
If I lived closer to David, I'd definitely drop it off and have him work his magic, but I'm not a big fan of the Postal System, UPS or FedEx, and don't want to chance it getting mangled while in transit...
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I have Huma regulators in both a .22 and .25 Marauder. I have the .22 and .25 plenums with the built in gauge port, as well as the XXL tuning plenum that is used with the existing gauge port.
The plenums with the gauge port can be modified with a Dremel to hog out unneeded aluminum, as the material for the gauge port forms a full “ring” inside the plenum for easy manufacturing. Doing this will add about 6ccs of plenum space. See the picture to understand what I am referring to here (and no comments about how ugly I made the part – it is functional ;) ).
The plenums have the following lengths and volumes (as measured by the water that they hold, measured up to the threads that the regulator mounts to, in a graduated cylinder):
.22 plenum: ~11 ccs, ~17 after mods, 56mm long (not counting regulator)
.25 plenum: ~16 ccs, ~22 after mods, 70 mm long
XXL plenum: ~28 ccs, 85 mm long
Gauge port: ~2.5ccs, ~8 after mods, ~35mm long (if I recall correctly, as it is in the gun now)
Most valves probably have around 5 ccs of volume within them, thus – assuming we mod for more plenum space – we have the following approximate plenum sizes in the different set ups:
.22 regulator: ~23ccs
.25 Regulator: ~27 ccs
XXL by itself: ~33 ccs
XXL with gauge port: ~42 ccs
There is probably another cc or two that comes when the regulator is threaded into the plenum, but all these values are good for comparisons to each other.
As for performance, you can definitely get where you want to go, but you may need to install one of JSAs new SS valves. Prior to switching to this valve, I ran a modified stock valve and the .25 cal modified plenum, and with the regulator set at 2100 psi the best I could shoot the 34 grain pellets was about 775. With the SS valve and that same plenum / regulator setting I could hit about 820 fps for 20 shots with an ES of 2%.
I switched to the larger plenum, and even though it ate up 2” more of my HP reservoir space (I figure I am at ~150 ccs now and was at ~180 before), I found I now get 20 shots at about 850 fps with the same 2% ES (just 1.2% ES if I limit it to 16 shots or two full mags). It turns out that it actually uses less air per shot with the large plenum shooting at 54 FPE than it does with the smaller plenum shooting at 51 FPE – that is the level of efficiency gain that comes from the larger plenum. I won’t know how I end up tuning mine until I can get to testing the accuracy at longer ranges (plus I have a longer lightweight tube on order that will more than recover the volume lost in the reservoir from the larger plenum).
I think if I dial back the speed to 800 fps with the 34 grain pellets, I could get to 25 shots, but I doubt 30 at that power (at least not without the longer air tube).So you can get where pretty much where you want to go, and the best path there for that high power set up would be with the XXL plenum and a hogged out gauge port (or Hill high flow one) and a new SS valve with the right flow path (I run a 0.190” transfer sleeve and barrel port). . . .
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So assuming no machining on stuff which setup has more plenum. Huma reg with gauge port or standard Huma reg and Hill gauge port.. I don't want to be tearing down my gun every day to "try" stuff. Wanna get it right the first or second time.
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Well, I put it back to stock with the exception of the regulator and am getting 820 fps using 15.89 gr pellets. Seems the TSS and MDS Hammer are more for lower power higher shot count applications.
If I lived closer to David, I'd definitely drop it off and have him work his magic, but I'm not a big fan of the Postal System, UPS or FedEx, and don't want to chance it getting mangled while in transit...
I have shipped a box(same box)with Mrod action to 0utlook Washington from 0hio 7-8 times with zero damage.protect the trigger and pack box correctly and you will not have a problem.i always insure package and have it marked fragile...as a matter of fact I getting ready to send another Mrod action that way for light air tube and regulator.
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So assuming no machining on stuff which setup has more plenum. Huma reg with gauge port or standard Huma reg and Hill gauge port.. I don't want to be tearing down my gun every day to "try" stuff. Wanna get it right the first or second time.
LOL! Good luck with that! I have the Huma Regulator with the Gauge port, so it seems I would need to enlarge the inside to get more volume. I'm not comfortable with that, so I'm kinda stuck right now. The Hill Gauge Port would give you more volume after the regulator, but I believe that would come with a loss of stored air volume in the tube since you are introducing another component that takes up space.
I just ordered a lighter valve spring and a .161 TP from Hill to see if that will help. I removed the TSS and MDS Hammer yesterday and put the stock parts back in. I can now get 820 fps out of the 25.39 gr pellets but for only about 15 shots on the regulator. I'm hoping the lighter valve spring will work better with the MDS hammer.
I'm not so sure about the TSS. To make any sort of power with it installed, I had to increase tension on the hammer spring to the point where the adjustment screw went completely beyond the threads, which resulted in tearing into the rifle once again to hand thread it back together so I didn't cross thread it trying to back it out. I might look for a longer adjustment screw and try it again.
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Well, I put it back to stock with the exception of the regulator and am getting 820 fps using 15.89 gr pellets. Seems the TSS and MDS Hammer are more for lower power higher shot count applications.
If I lived closer to David, I'd definitely drop it off and have him work his magic, but I'm not a big fan of the Postal System, UPS or FedEx, and don't want to chance it getting mangled while in transit...
I have shipped a box(same box)with Mrod action to 0utlook Washington from 0hio 7-8 times with zero damage.protect the trigger and pack box correctly and you will not have a problem.i always insure package and have it marked fragile...as a matter of fact I getting ready to send another Mrod action that way for light air tube and regulator.
I'd definitely insure it! Do you ship the entire rifle, or do you remove it from the stock and just ship it without the stock? That seems like it could help reduce shipping costs some.
My other issue is the want to learn. If I ship it to someone else, I don't have the opportunity to learn how to do it myself. To me that's part of the fun of owning an air gun. It can also be a frustrating part, but by doing it myself, I hope to gain the confidence to try new things later on.
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FWIW, my standard .25 Huma, Hill gauge port and SS valve gives me 34ccs all together. I ran multiple fluid test to verify this. This is without any kind of mods to them.
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dpittman,
I really don't know the volume of the .25 cal tuning plenum - by the pictures, it clearly looks shorter than than the one with the gauge port so they probably are trying to equalize the available plenum volume between the two. However, we can't tell if they are equalizing the volume without the gauge port or with the gauge port (most likely with the stock gauge port).
My guess would be that you will get the most plenum volume from the tuning plenum and a hogged out or Hill gauge port, but if you really want to know you can ask them from their contact page on their website - they are good about answering questions.
As Paul said, the tuning plenum and gauge port together will take up more of your reservoir space, reducing the high pressure air available to fill the regulated air space. All things being equal that would reduce the shot count, but when shooting at high power you need more plenum space to shoot efficiently. I have found that the efficiency gains more than offset the lost reservoir space - but you have to gain the plenum volume for that to work. If you lose resevoir volume without gaining plenum space that would just be bad. In my specific case I gained about 15 ccs of plenum with the XXL tuning plenum at the cost of about 30ccs of reservoir space but still came out ahead in terms of shot count at power through the efficiency gains.
Paul,
I have had no issues with getting power with the TSS - set up right, it can actually increase hammer strike energy simply because it has two springs in it. I love mine, and I actually use it as a simple two power level adjuster in mine (full out to full in on the inner spring). I suggest trying different springs in it if you can't get enough power.
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That is the perfect bit of missing info Keith!
So it looks like ~41 ccs with the XXL tuning plenum and a Hill gauge port, and ~34ccs with the .25 tuning plenum and the Hill gauge port. Neither of us have tried both, but they both will work for what you want. Worst case, Huma does sell the plenums separately for about 35 euros if you ever want to change things up.
There really are no mods that you can do with the tuning plenums as they are already maxed out on volume for their length. The mods really only apply to the plenums with a gauge port, and to the stock gauge port if you don't want to buy the Hill one. I have one similar to the Hill port (I think it came from Addicted to Airguns many years ago, and I modded the other myself (it is easy with a Dremel and a metal cutting bit - just carve out the excess).
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Alan and Keith,
Thx for posting the plenum info. I was toying with the idea of a reg'ed Mrod at 55FPE with the 34g JSBs. Looks like that would drive a larger plenum than I have and probably not achievable with a mod'ed oem valve.
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John,
You can get there with the JSA SS valve - that thing is amazing. I tested it without the regulator and I had no problem pushing the 34 grain pellets over 1000 fps. I did not leave it there as the accuracy is probably lousy, but someday in the summer I may pull the reg and test it at those speeds at distance just to see what it does.
At the other end, I was able to tune for a decent string with the 25.4s at around 850 fps. It is amazingly versatile . . . . but a little complicated to get your head around with the jet changes too.
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Alan and Keith,
Thx for posting the plenum info. I was toying with the idea of a reg'ed Mrod at 55FPE with the 34g JSBs. Looks like that would drive a larger plenum than I have and probably not achievable with a mod'ed oem valve.
I don't know, if you can get all the ports to 3/16" and enough flow through the valve you just might hit that power level. I think the only difference might be the reg set point and possibly the cocking effort.
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This is what your expectations should be in 25 cal. Stock modified valve with standard Huma with gauge port and ultra modified valve with modified gauge port huma reg. Stock hammer,stock barrel length.
This is not for bragging or anything like that. This is what you should expect if not better from purchasing parts since mine were all done in the garage.
Reg setting is at 2050 psi
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Well, I put it back to stock with the exception of the regulator and am getting 820 fps using 15.89 gr pellets. Seems the TSS and MDS Hammer are more for lower power higher shot count applications.
If I lived closer to David, I'd definitely drop it off and have him work his magic, but I'm not a big fan of the Postal System, UPS or FedEx, and don't want to chance it getting mangled while in transit...
I have shipped a box(same box)with Mrod action to 0utlook Washington from 0hio 7-8 times with zero damage.protect the trigger and pack box correctly and you will not have a problem.i always insure package and have it marked fragile...as a matter of fact I getting ready to send another Mrod action that way for light air tube and regulator.
I'd definitely insure it! Do you ship the entire rifle, or do you remove it from the stock and just ship it without the stock? That seems like it could help reduce shipping costs some.
My other issue is the want to learn. If I ship it to someone else, I don't have the opportunity to learn how to do it myself. To me that's part of the fun of owning an air gun. It can also be a frustrating part, but by doing it myself, I hope to gain the confidence to try new things later on.
send just the action.i have a couple of air rifles that way I can work on one and still have some to shoot...
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This may sound like stupid question. Can you have too much plenum in a regulated gun. I see Huma has a .30 XXL plenum. If I was desiring about 50 fpe with jsb 33.95 mkII in my mrod would it be necessary to have this or stick with standard .25 reg. With the larger plenum could you have a lower set point to get higher power.
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This may sound like stupid question. Can you have too much plenum in a regulated gun. I see Huma has a .30 XXL plenum. If I was desiring about 50 fpe with jsb 33.95 mkII in my mrod would it be necessary to have this or stick with standard .25 reg. With the larger plenum could you have a lower set point to get higher power.
You can easily hit 50 FPE with the standard .25 version as long as the ports are opened up and you have the correct set point. The larger 30 cal plenum will just make it a little easier to do with the added volume.
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You can't have too much plenum. All it can hurt is the total cc of hpa you can carry. I have something like 120-130cc plenum in my .25 bottlepup and it makes 55-57fpe (33.95's) with .2 porting at 1650psi regulated pressure. It makes about the same fpe with modified stock, Cothran or WAR cobra valve. Now I'm buying a lathe and mill to make my own valves and first goal is to make 55fpe at or less than 1400psi with cobra style valve tech.