GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: AlanMcD on May 06, 2021, 06:13:05 PM
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I now have “completed” a .22 caliber Bottle Rod that I am thinking of keeping as is, at least for a little while . . . ;)
This gun is really a collection of spare parts, some of which I had, and some of which I had to go out and acquire to complete the gun – many of those purchased parts were acquired before the decision to make it a bottle gun even was considered. The first major “spare part” was a 0.63” LW Poly barrel that shot very well, but made the gun much louder (the barrel basically fills the shroud) - plus it added over a pound to an already heavy gun. Once I decided to let my father have that gun, I ended up swapping to a lighter hammer forged barrel for him - leaving the Poly with no home. Add in an available stock from an eventual swap to a Boyd’s stock, and an available spare air tube from a swap to a JSAR aluminum tube for my father’s gun, and those parts just kept asking me to build them into another gun.
So the vision of a dedicated bench Marauder took hold, and the first incarnation started to take shape about three years ago. It was done with one of the Russian side lever breeches (I could not find another spare Gen I breech anywhere – if anyone reading this has any they are willing to part with, do PM me as I still want to build other top ends for this thing), and the factory tube got a WAR valve and a regulator. But since this barrel only liked high speeds, and seemed to shoot the heavier stuff better, that left me with very few shots per fill. And then not long after that, I separately decided to swap out the heavy aluminum 500cc bottle on my Daystate Air Ranger - and what do I start to hear but that bottle saying it would love to be part of that bench build Marauder project!
So that led to sourcing a drop block from New England Airguns, and GTA member makeral5 was able to offer up the other “half” of a Gen I bottle tube from his build project, while YEMX was the source for a JSAR adjustable regulator and spare stock that was in the right condition to molest into a bottle gun stock.
I have spent about 2 months or so kicking around with it in that form (externally regulated feeding an ~75cc plenum space ahead of the WAR valve, and a DonnyFL Tatsu to tame the bark - since the shroud is filled with the fat barrel), which of course let me try lots of the heavy stuff at high power. I ran it at multiple power levels up to a little over 60 FPE (JSB Beasts at ~900 fps) and tested lots of different slugs – with OK but not stellar results (the barrel is choked, and I am not about to cut it off any time soon). But in the end, with all the various options tried, the best results from this barrel are from JSB Redesigned Monsters at up to 900 fps (they even did very well even at 1000 fps, but there is no point in that as they would do worse in the wind than at slower speeds). I even swapped to my .25 cal marauder top end for some high power fun (hit 75 FPE pretty easily) but the accuracy was not as good as the .22 Redesigned, and I really have no use for that power level anyways (at least not without it giving me equal or better accuracy).
So after some thought, the gun came apart again and I popped a Huma regulator in the tube, so it is now a “double regulated” gun. I have the Huma set at 2200 psi, and the JSAR adjustable reg set at about 2400 psi (I’ll still play with that some as time goes on as it is so easy to do). Right now it is shooting the Monsters at 885 FPS (44 FPE) with an ES of about 7 fps over more shots than I am willing to shoot in a string right now (don’t have that many Resigned Monsters to burn right now). If I fill the bottle to its 3500 psi limit, I’ll get ~65. If I swap the bottle to CF, I’ll likely get over 100. I used to get about 15 shots on the regulator at this speed before I bottled it.
Obviously the thing is a beast with all the steel and the heavy aluminum tank. To make it even more beastly, (per its use a dedicated bench gun) it has an appropriately heavy Athlon 8-34x56 scope on it, and together the thing weighs in at just over 13 pounds (like a said, a beast). But so far it is stacking pellets in my indoor 21 yard testing – I need to get out as stretch it out some to see how it does, but I know this barrel is capable of MOA 10 shot groups at 50 yards. If I want to, I can easily shed a couple of pounds with a CF bottle and a more svelte scope, but I am OK with it as is for now. After all, it was built as a dedicated bench gun . . . .
Anyways, here it is, at least for now. I might use or modify it in another form going forward (especially if I find another breech for a yet another top end). I tend to treat my Marauders (all Gen I) sort of as an adult “Mr. Potato head” toy set anyways . . . . I think I enjoy swapping and testing stuff on them almost more than shooting them ;) .
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Well done Alan. 8)
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Great job, it came together very nicely. All that's left is to shoot, shoot, and shoot some more.
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Great job ... and using spare / misc parts too boot !!
That stock looks fantastic as well.
So vaguely familiar some how ;D
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So vaguely familiar some how ;D
I agree! I remember seeing yours as mine was shaping up, and I have to say that the color was decided when I saw yours. I had the can of spray paint in my collection and was thinking about it, but was not sure it would look OK - and I liked yours enough to go ahead and do it (although mine is flat in that color and not the stone type). But I also might try it in Army Green too, as I have a can of that too - I am thinking of reshaping the bottom of the stock to be more amenable to a BR rest, and it would have to be repainted again after that.
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Alan, very nice build sir!
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So after some thought, the gun came apart again and I popped a Huma regulator in the tube, so it is now a “double regulated” gun. I have the Huma set at 2200 psi, and the JSAR adjustable reg set at about 2400 psi (I’ll still play with that some as time goes on as it is so easy to do).
I'm curious about your decision to put the HUMA in. I get the concept of two regs, to take the strain off, and possibly also to minimize creep. Good stuff. - But here are negatives. First, obviously, you no longer have an external adjust for the final pressure. Second, you've made the plenum much smaller.
The first issue isn't huge, if it's a 1-purpose gun, but (assuming you previously had the JSAR set to 2200) did you notice any performance decrease after the HUMA install?
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What a nice project, congrats.
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Great looking gun Alan. And one heck of a tune! I have a b-rod that I would like to dual reg as well. Very nice, thanks for sharing.
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A very well done project !
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Fantastic! I got my 580c cf bottle, but waiting on the reg.
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I'm curious about your decision to put the HUMA in. I get the concept of two regs, to take the strain off, and possibly also to minimize creep. Good stuff. - But here are negatives. First, obviously, you no longer have an external adjust for the final pressure. Second, you've made the plenum much smaller.
The first issue isn't huge, if it's a 1-purpose gun, but (assuming you previously had the JSAR set to 2200) did you notice any performance decrease after the HUMA install?
That’s a good question . . .
I’ll say first that I already had experience with this “upper” running with the Huma in a tube, so I pretty much knew what I would get. That said, I put the Huma in with a hogged out gauge port and a .25 cal tuning plenum, as it fit in this tube (the XXL plenum with a gauge port would not fit, but it would on its own). So I have about 30ccs of plenum in this set up (the XXL on it’s own would give me 3 or 4 more ccs), and I set the reg at 2200 psi.
Basically, I gave up about 15 fps and a bit of efficiency, as I am using the same amount of air per shot as I did with the full tube plenum space (about 75 ccs or so) at approximately the same pressure setting as the JSAR regulator was at on its own. Note: this reinforces something that I have consistently observed – when tuning for higher power levels, more plenum has always led to more shots at an equivalent energy level due to gains in efficiency from the larger plenum. People keep thinking that using a larger plenum on their regulator in tube guns will cost them shots due to the lost space for high pressure air, but that is the opposite of my actual experience: more plenum has always led to more shots (this probably would not hold for sub 12 FPE guns, but I have not tried it).
Anyways, when I went down the bottle path, I was hoping that I would be able to leverage the higher amount of available air and the larger plenum to find more accuracy with either something like the 34 grain JSB Beasts or some slugs at reasonable speeds – as this would lead to less wind sensitivity. Unfortunately we don’t get what we want – we get what we get (although sometimes we do get lucky and get what we want ;) ). But in this case, the best shooting ammo after lots of testing (made easier with the externally adjustable regulator) was still the JSB Redesigned Monsters at around 900 fps (and for wind drift, lower than that is probably even better).
That, coupled with the fact that I was getting a higher ES running on the JSAR regulator than I had seen in the past with the Huma (the variability of the JSAR/Ninja regulator has been discussed in other threads), made it a pretty easy decision to try it with the Huma back in the tube. With just the JSAR regulator I was seeing an ES of about 20 fps even when on the knee – while that sounds good, I knew that this WAR valve was capable of rock steady results if fed a constant pressure. And now with the Huma back in it, the ES is down to single digits. In fact, the chrony often shows three or four identical numbers in a row and if I did not know better, I would suspect it was missing shots.
So unless I find another type of ammo to try at higher energy levels, or want to put a different top end on it, I will leave it as is for a while (although none of my Marauders stay the same for very long though). And if I do need a little more energy for any reason, I can always raise the Huma set point some, while keeping that great low ES from this valve. And if I ever need to go much higher in power, I will probably have to rebuild the JSAR regulator to get more consistent pressure out of it, per Scott’s recommendations in other threads.
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Yes indeed. Replacing that soft ball seat with a PEEK one really stabilizes the output.
Finding out in my build that uses a custom "Balanced" valve .. ANY CHANGES in plenum pressure created changes in speed, NOT GOOD !!
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Very, very nice! SSG and all the works plus.
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Very nice build, Alan. 8)
Thx for some info on the dual reg set-up and results. I have been thinking of doing the same.
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Very nice build, Alan. 8)
Thx for some info on the dual reg set-up and results. I have been thinking of doing the same.
The in-tube reg makes perfect sense for Brods where the energy goals are approximately 60-70fpe or less.
I like the in tube regulator if only to reduce weight/length of the Brod.
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Yes indeed. Replacing that soft ball seat with a PEEK one really stabilizes the output.
I'm surprised that Ninja still used that soft ball seat in the flex, given the higher set-points. While not peek, I will replace it with one of Jason's delrin ball seats.