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CatgutViolin

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About CatgutViolin

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  1. CatgutViolin

    GHK AUG H-Bar LMG w/ GBBR hicap

    After a couple weeks of waiting, the gun itself is done. I also added an RMR mount from Shapeways, so as to have a backup red dot for quicker acquisition at short range. The Haephaestus steel barrel is very nicely made. It didn't fit the barrel quite as tightly, so I had to shim it a bit, but otherwise it was easy to fit the gas block and get it all reassembled. Not really much more to say. The gun works and the barrels interchange. With the steel gas block and barrel, the gun actually is only half a pound lighter than the real thing, and the balance is identical. I'm looking forward to putting this through its paces.
  2. CatgutViolin

    HK21 Build

    Man, that's really awesome. Great fabrication work on all of it- very different skills involved in laminating ABS and cutting tubing, but you've really made it look the part. I have no particular input on drum vs belt; the belt-fed variant would certainly be more unique, but having the result not live up to expectations can be really frustrating. Would it be practical to get a real feed tray from another platform?
  3. CatgutViolin

    GHK AUG H-Bar LMG w/ GBBR hicap

    Minor update: The PDI W-hold bucking, using the PDI barrel without the R-hop patch, works surprisingly well. The W-hold gimmick actually seems to work for keeping the BB in place and producing a consistent hop effect, and after a minor initial break-in period I am getting great consistency, both horizontally and vertically, producing a ~6" group across five shots using HPA 0.32g BBs at 100ft. I think this might now actually be the most accurate airsoft gun I own inside of 100ft, although I'm not sure how it will perform at longer range. Now I'm just waiting on the steel barrel, and extra TM mags so I can convert more hicaps, and then this rifle/LMG is good to go.
  4. CatgutViolin

    GHK AUG H-Bar LMG w/ GBBR hicap

    Adjusting the recoil spring is a possibility. Unfortunately, the recoil springs are contained within telescoping guide rods inside the stock, so adjusting them is a bit of a pain, and they're already light enough that it generally won't go into battery with less than half of its stroke. Definitely agreed regarding barrel rigidity. While I bought the steel gas block for the rifle barrel, on the LMG one I'd much prefer for the gas block to give out rather than break the barrel if something gets smacked. The Ratworx bipod is actually quite light (it's aluminum), but I do worry a bit about it catching on something. My issue is that, as far as I can tell, nobody makes a steel AUG barrel, and I'm not sure whether a barrel from an AR or something could be retrofitted to work. In theory, I suppose as long as I can secure the gas block in place, that should allow it to lock into the receiver; then it's just a matter of fitting the hop unit. Edit: Well I'll be damned, Hephaestus makes a steel barrel! Got one ordered; I'll combine it with the steel gas block to make a 'main' barrel and swap LMG extension / rifle flash hider as needed, and then I can use the aluminum combo as a backup.
  5. CatgutViolin

    GHK AUG H-Bar LMG w/ GBBR hicap

    Work continues, so now I'm going to document it as I go. While the H-Bar functionality is complete, I am still experimenting with hopup. The GHK AUG is peculiar in that its stock hopup unit is designed to accept AEG-type buckings and barrels, rather than the VSR-type as is common with GBBs. However, the T-NT aftermarket hop unit is a more conventional GBB type. Since I ordered a spare barrel to make the 24", I have two stock hop-up setups, so I could mess with one and leave the other alone. So, I've done a bit of experimenting thus far and found some very peculiar results. Stock hop-up setup: Reasonably consistent hop, decent accuracy, occasional horizontal deviation. T-NT setup (w/ T-NT barrel and bucking): More consistent than the stock setup, both vertically and horizontally, but not a huge difference. Stock hop-up unit, R-hopped 6.05mm PDI barrel from a reputable source, flat-hopped Lonex bucking, pink eraser nub: Very consistent horizontal dispersion, but completely inconsistent amount of hop applied. Weird, right? Well, with some experimentation I think I've found the culprit- a while back I remember reading about similar behavior with Polarstar guns, specifically caused by the very rapid action of the solenoid-driven nozzle. Essentially, the nozzle was propelling the BB into the hop unit with such force that it was seating the BB inconsistently on the hop-up. This inconsistency led to underhopping, overhopping, hooking, and generally accuracy. It seems reasonable that this behavior would apply to GBBs as well. I calibrated each hop-up to the .32s I use, then removed them from the barrels and tried manually pushing a BB through each. The stock setup and T-NT setup both required some force to get past the contact patch in the bucking. The R-hopped barrel, on the other hand, offered less resistance, but across a longer distance. As well, the Lonex bucking is considerably softer than the stock GHK bucking, and the T-NT one (the GBB type) is the stiffest. So, it seems like the GHK and T-NT hops have enough resistance to stop the BB in a consistent location, while the R-hop is allowing the BB to seat at varying 'depths' and thus cause problems. However, the flat shape of the R-hop provides better horizontal consistency than the traditional contact patch on the GHK and T-NT buckings, so the R-hop still has better horizontal consistency. I think this explains why we haven't seen much in the way of R-hop or flat hop type buckings for GBBs. Interestingly, with Polarstars the recommended solution is to tighten the bucking lips, but I found no noticeable difference when trying this on either the GHK or T-NT setups. In fact, the GHK and T-NT bucking lips are very loose and provide no resistance to the BB at all (not a problem for sealing, since the nozzle doesn't actually seal on the bucking, but rather the entire hop unit), while the Lonex in the R-hopped setup does provide resistance at the bucking lips. With all that noted, my next step is to order a PDI W-hold bucking- which I've anecdotally heard works well in the GHKs- and give that a go with the PDI barrel sans R-hop patch.
  6. I didn't make a build log before completing it as I had no idea whether it was actually going to work out, but here's a conversion of the GHK AUG to replicate the real AUG LMG variant used by the Austrian military and... nobody else, as far as I can tell. The real LMG consisted of basically just a normal AUG, but with two changes: A 24" barrel with integral bipod, and (doctrinally) 42rd magazines rather than the normal 30. There was a drop-in trigger pack that converted the gun to fire from an open bolt, but for all intents and purposes, the AUG LMG is basically just a different barrel and a permission slip to use extended mags and full auto. So, there were really two parts to this: Building the 24" barrel setup, and building a hicap magazine so that it could actually be used in an LMG role for airsoft purposes. First, the barrel: Unfortunately, I could not find an airsoft replica of the original H-Bar bipod, and I wasn't going to sacrifice a real one for this, so I settled on a modern Ratworx bipod. This is an original design based on a combination of the AUG bipod and the Steyr SSG 08 bipod, and while not completely accurate to the original, I think it still looks the part (and works quite well, too). To get the 24" barrel length, I used a combination of barrel extensions. In the process, I discovered that GHK's 20" barrel is actually a bit short. Since I have a real AUG to refer to, this was rather puzzling, since they both appear to have the same length- I eventually realized that on the GHK ones, the locking nut that secures the flash hider is actually cast as part of the flash hider, so the barrel is a bit shorter to compensate. So, I ended up using about 5" of barrel extension. From front to back: -Angel Custom AUG H-Bar flash hider (intended for AEGs, but it's standard 14mm negative, so works fine) -Ratworx bipod locking nut and Ratworx bipod, over a 2" barrel extension with the outer diameter reduced from ~18mm to 17mm. I don't have a lathe, so this was a royal pain in the *albatross*. Once I reduced the diameter sufficiently for the bipod and locking nut to fit, I drilled into the barrel extension and tapped the hole for a small grub screw, which hits a shelf on the bipod about in the middle and stops it from sliding back further. -1" barrel extension -2" barrel extension, with another grub screw at the rear. The grub screw is there because of an issue I found with the bipod- the locking nut incorporates a grub screw that acts as a travel stop, so that the bipod only has about 45 degrees of rotation to either side. When the gun is set on the ground, it falls over, the travel stop hits the bipod, and the remaining momentum (or even just weight) was sufficient to start unscrewing any part of the barrel or barrel extension that relied on a friction fit. So, all the barrel extension parts are epoxied together, and then the combined extension unit is secured to the barrel threads with that grub screw, in the same manner as the cheesy plastic flash hiders that come pinned to most AEGs. So, that's the bipod. Relatively straightforward. Now the magazine. This is a hybrid of the top 2/3 of a GHK mag mated to the lower 2/3 of a TM mag, with an ugly seam where I had to resculpt part of the joint due to a chop saw-induced mishap. It's easier to understand what's going on if I overlay the internals over the shell: So, at the top, the GHK magazine internals have been cut very short. The original gas reservoirs had threaded caps on the bottom, so I had the brilliant idea to measure the threading, order an appropriate tap, and tap the remaining stub of the front reservoir to insert the original plug. Unfortunately, while the threads are definitely 17mm diameter and 1mm thread pitch, the threading cut by an M17x1 tap was too shallow, and inserting the plug ground off its threads. So, it was epoxied in place, and a grub screw was inserted from either side to provide additional support and then ground flush. I then drilled through the middle of the plug, tapped it for 1/8" NPT, and inserted a 45 degree elbow followed by a 6mm push-connect adapter. Only the front gas reservoir actually leads to the valve, so that was the gas system sorted, but I still had to make more changes to the GHK part of the mag. For starters, I needed to secure the mag to the shell, since normally GHK mag internals are held on at the baseplate. This was easy; I just drilled a hole for a cross pin, cut a nail to length, and peened the end slightly to get a good friction fit in the shell. The other issue was reloading, since obviously a hicap normally fills from the top. This was my solution: I drilled out the fill valve threading to 6mm, countersunk a larger hole, and inserted a 6mm ID O-ring which stays via a friction fit. The hole on the back of the shell is sized for a speedloader, so the mag is reloaded by inserting a speedloader and then just shoving BBs through the O-ring. They drop into what used to be the rear gas reservoir, which opens into the body of the magazine. Simple. At the bottom of the mag, I cut down the TM hicap internals as pictured, and epoxied a length of spring tubing to the hicap's feed track. The hicap internals secure to the baseplate: So, no further modification was needed. To get the spring tubing to fit through the feed track on the GHK side, however, I had to run a 8mm drill bit up from the bottom and down through the top. This was a bit nerve-wracking as it would have been very easy to chew through the front of the mag.After all the internal work was done, I cut a pair of 1" x 4" plates from some 1/8" steel sheet, and epoxied them in place to connect the two mags. Unfortunately, I had accidentally mangled the top of the TM mag when cutting it on my chop saw, as the plastic used on it was much more brittle than the GHK mag and it chipped. So, I had to do a bit of reconstructive surgery at the joint, which I did using a mixture of steel-reinforced JB Weld epoxy putty (for strength) and Kneadatite hobby epoxy (for sculptability) in about a 2:1 ratio. After that was fixed and all the test fitting went well, I spray painted the whole thing. The join is noticeable up close, but I was more concerned about durability, so I think it worked out alright in the end. The final hicap holds about 450 BBs, and can feed 250-300 on a single full wind, so should be usable for an LMG role. Because the barrels are quick-swappable, and the HPA conversion was done to the magazine, I can swap from gas-in-mag rifle to HPA light machine gun in just a few seconds: Next on the agenda is making at least one more hicap, and modifying an Odin speedloader to work with these. With a competent A-gunner, I'm thinking even two magazines should be enough to maintain constant fire, with the A-gunner reloading and rewinding one mag while I shoot the other.
  7. CatgutViolin

    HK21 Build

    Saw your posts on Reddit; this is an ambitious project and I'm interested to see where it goes. I'm not sure if this is what you meant you were going with, but with the 6mm ID spring tubing used for machine guns you should be able to splice the box mag into the regular magazine's feed track internally, allowing it to feed like a normal AEG.
  8. CatgutViolin

    Northeast Mini and full sized Uzi GBB

    The wood stock was actually the original configuration of the Uzi. It isn't as well-known as the underfolder, and obviously isn't as compact (although it can be removed for transport), but it's a better (shorter) LOP and MUCH better cheek weld. 16" would be a civilian-only thing though. I built an Uzi SBR from a parts kit and receiver flat so I'm pretty much obligated to buy the Northeast version when it comes out. I've only heard good things about the Sten.
  9. CatgutViolin

    SMG Picture Thread

    I was inspired by an item in the Imperial War Museum catalog to try bodging a FAL foregrip onto the slimline handguard. I have no idea what the historical origin of the IWM piece is- the entry provides no information and their FAQ basically says 'if the page doesn't answer your question, we don't know', so I can only speculate. On the IWM one, the foregrip was epoxied on, while I've taken the approach of securing mine with a screw and nut. So aside from the hole in the bottom of the handguard it's reversible, and I can ignorantly assume I've replicated some field-expedient SAS mod and not just a bubba job from some random dude 😛
  10. CatgutViolin

    SMG Picture Thread

    I resurrect this thread to post a WE Apache, to which I fit a surplus German SEF trigger housing and original slimline handguard with no modification to the airsoft parts and a lot of swearing and Dremeling to that trigger housing. I even had to redesign how the selector switch locks into the trigger pack, because the normal catch on the selector pin was hitting the stop catch in the trigger pack before it could reach the FA position. Anyways, now it works, and since the airsoft guts were unaffected it's 100% reversible if I want the Navy pack back. I also scored an original Surefire grip at a local gun show so I'm on my way to a Stargate build or something.
  11. CatgutViolin

    wot am best SUSAT?

    Honestly not sure, I hadn't looked too much into winter games (driving from NOVA can be a bit of a problem if there's snow). If you want it ASAP, I'd be happy to ship it to you instead if you don't mind covering shipping.
  12. CatgutViolin

    Airsoft Glock Flux Brace clone, stop the presses!

    All the lawyer-friendly not-Glocks are sufficiently different from the Glock design that I highly doubt any Flux will fit, knockoff or not. It'll only work on the definitely-not-lawyer-friendly unlicensed Glocks that WE, TM, and others have been making for years. And on the licensed gen 3 VFCs.
  13. CatgutViolin

    wot am best SUSAT?

    A couple of years ago I wanted to find a decent SUSAT for use on a STALKER LR300 build. I could not for the life of me find any that were positively reviewed, and the one I ultimately went with ('Matrix') has decent glass, decent zoom, a clear reticle- and an inch, generously, of eye relief, making it unusable on an AR. I did a bit more research and found that that was about the best I'd get. Honestly, if you want it, I'd be happy to just give it to you next time I come down to Ballahack.
  14. CatgutViolin

    Airsoft Glock Flux Brace clone, stop the presses!

    Having converted a Flux to airsoft use, and having used various carbine kits over the years, I really gotta disagree. My main issue with carbine kits has that they turn your pistol into, well, a carbine. They become a lot harder to holster, and basically impossible to use as a pistol. They become a primary, which obviously is the point, but somewhat limits flexibility. With the Flux brace, you can manipulate the pistol just fine with the brace collapsed, allowing you to use the pistol as a pistol (one handed, in close quarters, etc). It also barely changes the overall profile of the gun, so it still fits fine in soft holsters (although obviously not Serpas or molded holsters). The Flux is, IMO, exactly what a pistol carbine should be- it's just a stock extension for a pistol, not a compact rifle frame swallowing up a pistol. It follows the legacy of the Hi-Power and C96 stocked pistols from a century ago, with the convenience of always being available on the gun. Regarding this clone, I would like to point out two things. It is designed for a gen 3 Glock, not a gen 4 like the real Flux. This is good since airsoft gen 3s are much easier to come by. Flux does not, and has no apparent intentions to, manufacture the bog-standard Flux brace intended for airsoft use. Their 'Milsim Flux Brace' is larger (with an integral rail on the frame) and IMO starts to creep away from what makes the bog-standard Flux good. It also is ONLY compatible with the Umarex-branded gen 4 G17- while it might be made to fit a WE or TM gen 4, it certainly won't fit a gen 3 without heavy modification. Knock-offs of real-steel products have been around since the start of this sport so I'm surprised to see a debate here on buying the clone vs buying the original- follow your own conscience. But I have to say, the clone looks to be more consumer-friendly than the real thing. If Flux just sold a bog-standard brace intended for the airsoft gen 3s it might be a different story. By the way, Octagon Airsoft is selling this clone plus a Kydex holster: https://www.octagonairsoft.com/product-page/flux-collapsible-stock-for-marui-umarex-vfc-glocks-with-holster-set-的副本
  15. CatgutViolin

    WE Desert Eagle (Licensed by Cybergun)

    Little bit of an update. I bought a second Desert Eagle, this time in black, and swapped a few parts around. I also used a bit of Tung oil finish to liven up the wood grips I previously had. So, here are a few things I've noticed, having two guns to compare: -The magazine catch profile I mentioned at the end of the previous page is a design flaw. Fixing it is straightforward, just use a steel file to make the angle at which it engages the incoming magazine a bit shallower, then polish with sandpaper. Leaving it stock means it will take significant effort to slap the magazine past the catch, which will cause peening to both the magazine and catch over time. -On both guns, the hop adjustment screw felt like it was bottoming out before I was getting any hop. This is, again, an engagement angle problem. It hits the hop arm at a very steep angle, so instead of pushing it down, it just gets stuck. I removed the grub screw from the hop unit, filed the end of it to a shallower profile, and again used sandpaper to polish. Upon reinsertion, it got to the point where it felt like it was bottoming out (when the screw contacts the arm), but after another full turn it engaged properly and deflected the hop arm. -The hop bucking has been mediocre on both. Get the Maple Leaf, and might as well get a new barrel while you're at it. The Maple Leaf Autobot (60-deg) bucking and Crazy Jet 6.04 (138mm) are perfect, and cost me all of $43 shipped from WGCShop. Whether you keep the stock barrel or get a new one, shim it with electrical tape so that it's snug- there's a bit of play by default. -Buying a low-power nozzle from KY Airsoft was a waste of time; they sent me another full-power one. To reduce the FPS, glue a piece of tubing into the front of the rocket valve to reduce its inner diameter. This restricts the flow without causing backpressure like the restricter disks, so you get better gas efficiency and a slightly quicker/harder cycle. -The thinner Alumagrips (left) make the gun easier to carry and fire one-handed, but the contours of the KSD Grips wood grips (right) make supporting the weight of the red dot sight easier. The KimPOIShop grips fit well, but they look a little toy-like compared to the KSD ones and haven't stood up well to use. If you're looking for better grips and willing to do a minor bit of work (just a bit of filing), I highly recommend the Alumagrips. That's all for now.
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