Leo Greer

I personally make protectors out of Lexan (polycarbonate), and use two layers. It’s super cheap—I cut the Lexan with tin snips and finish it off with a sanding belt.

The corner that has the chance to contact the sticker. That sharp lip on the selector window is the concern. Have you disassembled the RIF and looked at the selector plate yet since installing? You should check and make sure before doing anything.

The selector sticker is probably in the wrong spot. It can be finicky. You also want to make sure the gearbox isn’t rubbing the selector sticker. I typically file the gearbox shell down a bit so the sticker has full clearance.

I would personally do as suggested and simply increase the height of the nub with tape or glue. It’s extraordinarily easy, and may just solve your issues without an expensive hop unit. I actually did this on a friend’s RIF between games to deal with the issue. I’ll also note that Maxx units are very picky. Some models have issues with certain hop rubber or nozzles, and different models have different issues. They also won’t actually increase your performance over what the stock one can do, unless your stock has serious issues.

The Perun should be a flat drop in replacement, so assuming you can get the gearbox back together correctly (YouTube is amazing here), you’ll be doing well.

The only upgrades you really need are a Perun and maybe a hop rubber. Everything else is fine—you shouldn’t actually need to reshim or relube the gearbox. I would personally say to put the Perun in, maybe change the hop rubber if you want more consistency (only applicable if you’re using high quality BBs .25g or up), and avoid touching the shimming and lubing, especially if this is your only gun. Stock shimming and lubing does not need to be touched on most stock guns (CYMA Plats being better than most), and I can tell you from experience that as a beginner you’re more likely to mess something up than improve it on your first, second, and third tries. You can do whatever you would like with your RIF, but I would personally recommend picking up a cheap second RIF if you want to learn to tech. It’ll save your game days and headaches!

The issue with the CYMA is not a MOSFET. A MOSFET is a chip that allows the vast majority of the power to flow directly from the battery to the motor, instead of through the trigger contacts. The issue is with the trigger mechanism, which is a very small microswitch. When unprotected microswitches experience vibration, the contacts bounce, causing current to switch on and off sometimes thousands of times a second. This causes immense heat build up, and burns these units out quickly. It’s impossible to predict exactly when they will burn out. I’ve seen some burn out within a couple games, and some last for more like 3-4 game days. They will do this on any battery, as it’s not the voltage but the current doing the damage due to CYMA’s design flaw. It’s a critical issue with the series and I don’t know why people recommend them. As long as people are still buying, CYMA isn’t fixing. You can replace them flatly for an excellent Perun Hybrid ETU.

SHS gears usually match up well with SHS pinions—what’s your motor? A lot of guns actually have good shimming jobs from the factory nowadays. Truly bad shimming is relatively rare.

Curved barrels, or LRBs (Long Range Barrels) were a thing before hop up existed. Enthusiastic players would bend the last third of the barrel a few degrees in order to impart some kind of backspin. People have been debating where the BB flies in the barrel for years at this point. Over on the American forums, we actually have members working on a glass barrel project. On examination of the fluid dynamics, it seems that no proper quality airsoft BBs contact the top of the barrel or rattle around, but instead float through the barrel, closer to the top but not touching. Bore size is practically irrelevant. The people who say the BB rattles around in some bores and skids or floats in others are completely ignorant of how little the difference actually is between these barrel bores we care so much about. I will also cite that BBs rattling or skidding down a barrel produces a very distinct, noticeable sound that is lacking when you shoot your airsoft gun, even upside down. Naturally, air will push and flow around the BB due to its spherical shape. The proponents of the skid theory, where the BB rides along the top, propose that the Magnus effect forces the BB to “hop” off the hop patch and cling to the top of the barrel. However, this does not make any sense, as the Magnus effect does not become stronger than the forward velocity of the BB until long after it has left the barrel (overhop), even using extremely short barrels, which should theoretically prove this. I am not a physicist either, but having spent time both talking to people smarter than I, and researching fluid dynamics, I believe the most logical explanation is that the BB does ride closer to the top of the barrel, because of a negative pressure cushion created by the backspin (Magnus effect), but does not touch, because of air naturally flowing between the BB and the barrel and causing an opposing cushion. For some excellent practical evidence, Google Tanio Koba Twist barrels. They were airsoft barrels with rifling, tuned for 1J, that spin the air around the BB. Because they have cut grooves along the top, yet shoot normally, they prove that the BB does not ride along the top or rattle around,

HSS gears? Never heard of them... Where'd you get them from? Different pinion gears absolutely effect sound and fitment--you can switch pinions with a pinion puller relatively easily as long as your motor has an o-type shaft.

Take the motor and bevel in hand, and spin them together to find the optimal motor height--the easiest most proper fitment will feel right. You then need to fully close up your gearbox with the bevel in it and screw the motor grip on. From there, adjust the motor height until it reaches the height your hand test showed. Next, add very small shims beneath the bevel until there is about 0.1-0.3mm of play in the bevel gear. It's important to do all testing with the gearbox tightly screwed shut. Full contact is good. You want the bevel gear to have a hair of play between it and the pinion, but it looks like your bevel is rather low to my eyes. After you shim the bevel to pinion, you can add shims to the top until you hopefully end up with just a hair of play. The way I personally measure if I've done it right is by tilting the gearbox side to side, when screwed fully shut. If the bevel gear rotates on its own, yet has maybe 0.1mm of up and down play, I know it's right.

I would recommend a 7.4v LiPo, personally, as LiPo is currently the best chemistry for airsoft due to the combination of burst amps, stability, power to weight, and price. LiFe are fine, but will be larger, with less burst discharge (what you need for airsoft electrical draw). You don’t have to do anything to “convert” it to 11.1v. It’ll run on 11.1v right now. The caveats are the consequences. Depending on the quality of your trigger contacts, an 11.1v may burn them out. Good contacts will easily last 150K+ cycles, but we all know how allergic airsoft and quality are to each other. This can be fixed with some basic dielectric grease on the trigger contacts, or by a MOSFET chip wired into the contacts. Those units you plug in don’t actually protect anything, Secondly, an 11.1v may give you PME, which is where your gears are moving too fast for your piston, causing heavy wear or critical failure. To test, listen for hitching in the cycle when using 11.1v, and chrono test for any drops in FPS using full auto. This can be fixed by, as you mentioned, a stronger spring. You can then shorten the barrel or short stroke to reduce FPS to correct levels.

What BBs are you using?

Evike is crap. OP—hope you enjoy San Fran while you’re there! You can get some killer eats if you’re in the mood.

Is there an issue with the current hop unit? Broken?

the motor can have more resistance, and thus draw more current, but that’s dependent on the motor and the setup. There are numerous resources and electrical engineers online that disprove the idea that a motor can draw more amps than it needs.

I'd love to take a look at that test--the only reasonable way to get those results would be if some of the batteries were too weak or having issues. Otherwise, the motor only pulls the amp draw it needs and no more. To the motor, amp draw is literally all that matters, so if both the LiFe and the LiPo, at the same voltage, perform differently, it means there's an issue. The possibility I see here is that Negative was using LiPos with too little discharge, and thus the batteries were being overdrawn, causing an apparent disparity in performance between chemistries, when in reality output amps are to blame.

Lemme ask around and see if I know anyone who's used ML rubbers with PDI barrels--I know the shape of the window is a little weird, but I haven't tried it out myself, so no hard statements.

For amp consumption and sound: HERE Upon watching the video again, the YouTuber noticed that, while very very similar in amp draw, the T238 was much more consistent in draw and sounded better. The good stuff starts at 6 minutes in. On the QC issues, I had a professional tech mention it to me in THIS thread at post #8. If you'd like, I'm happy to ask him more about it, try to get some references.

Your math looks correct to me. There's basically no chance of it striking the outer barrel... unless something goes seriously wrong. Your choices on barrel all look suitable to me. I would be wary of PPS, since I've heard that some bad things about their barrels in the past, but it's the cheapest of the bunch so that gives it some "try and see" merit in my eyes. You may also have trouble getting the ML rubber to work with the PDI hop windows, but you could always go flathop, or use a Macaron and make it work easily. One question I do have; have you done any research on the durability of the stock gearbox shell? Most are okay, but when boosting power up this high it's always something to consider.

Cheapest and easiest? GATE Pulsar and chop the nozzle.

Hop over to THIS thread for a more detailed discussion on what BB weight goes with what barrel length. The stabilization method still works fine. "Bore up" is an unspecific term. Without knowing the diameter increase and being able to calculate the true increase in air volume, it's impossible to know. It's also related to BB weight--heavier BBs require more energy to accelerate and accelerate more slowly, thus requiring more air volume. You could use a bore up kit for a 350mm barrel shooting .48g and be correctly volumed. The full cylinder is suitable for a 450mm barrel... but only when using light weight BBs. Keep in mind that a lot of this advertising is written by people who don't know much about it--660mm is crazy long, and you're losing power even on .20g with that long of a barrel. As a note, voluming rules can be played by loosely. There are so many factors here, and the exactitudes don't matter as much as being in the general vicinity.

In general for "SP" springs, they're about the equivalent of the "M" rating + 20. So an SP100 = M120. Vaguely. I would personally go SP120 and see where you land before spending more, but it's nice to have extra springs onhand anyways. In your case, it may be worth using a shorter-than-stock barrel, depending on how heavy of ammo you're wanting to fire. For the spring strength you're looking at, I'm assuming you'll be shooting .36g or higher, which would seriously undermine your power if you use such a long barrel.

Your list looks pretty good to my eyes. There's probably no need for a delayer chip, but I've been wrong before... I would personally recommend a Guarder spring, as I know AK2M4 has them, and they're incredibly consistent. I've easily gotten ~1 FPS variance out of AEGs using Guarder. For the inner barrel, I would recommend polishing the stock barrel first and testing performance before you spend money, as stock barrels can be just fine a lot of times. Barrels are a lot of money for very little improvement over polished stock. In terms of what aftermarket barrel to go with and what inner diameter, you can build extremely accurate builds out of either end of the spectrum. I would personally recommend hunting down a Lambda SMART 6.08mm as the best balance of cost, performance, and forgiving inner diameter. For reference, Lambda are people who left PDI, so it's PDI performance at far cheaper prices, and with better hop windows. I should note, you seem to be looking at very long barrels, which most likely won't be suitable for DMR BB weights. For reference, at those lengths, you have enough air volume for .2g or .25 if your setup is very efficient. You'll be wasting power and accuracy shooting DMR weights. And finally, in my experience, the vast majority of your accuracy gain comes not from spring power, hop rubber, or barrel, but from stabilizing the inner barrel and hop unit inside the upper receiver, as well as making sure you have no nozzle wobble, and your hop arm is stabile as well. I did a full write up on airsoft accuracy and accurizing a while back HERE for a more in-depth discussion.

Is the Warhead cheaper in the UK? Here in the USA, the Warhead base usually costs about $120 (aside from shipping), and the T238 is $100 shipped from their website.