Rogerborg

Oh, I totally agree. It's shooting so hot that I'd want to get it down substantially with a spring change or cut, particularly if it's going to be used in CQB.

Maybe. Short barrelled guns can experience what I'm just about to coin as "Joule leak". I get sharply dropping energy in my MP5K as I move up to heavier BBs. It's worth a try, although I still reckon it'll want the spring cut or swapped. Since we don't know what's in it, I can't recommend a replacement. I'd guess that it's got an M120, so anything in the M100-M110 range (maybe up to M115) might do it. Always remembering that there are no standards in airsoft, so one brand/production run of "M100" could be radically different from another.

I've seen a BFG painted to look like a can of Irn Bru if that counts.

Solid plan. You want to be rat-a-tatting, not BRRRRTing.

Well, am I glad I added that caveat. Phew, that's a spicy little boi and no mistake. I honestly wouldn't have expected that from such a short barrel, although CYMAs M4 and AKs do run hotter than UK limits by design, and need down-sprung for the UK market. So what I'd assume here is that you've got one with something like an M120 spring in it that should have been down-sprung by the importer or retailer. No harm in asking them if they want to sort it as a warranty issue - it isn't fit for the purpose sold. If they laugh it off, it does seem like you'll need to replace or cut the spring, and disappointingly it doesn't have a quick-change spring, so it'll be a gearbox out and open job. It can be quite intimidating the first time you do this, but it's not really that complicated. Just take it slowly and keep all the parts safe. Disassembly to the gearbox: This is a very comprehensive guide to working on a V3 gearbox. And yes, the trigger spring can be a bit of a sod during re-assembly. All you really need to do is to get it open and change the spring without touching anything else, but while you're in there you could lube and re-shim it (there are plenty of videos on that too)

Ahoy and welcome. Yes, you've found your people. Even my very modest stash of trash tier RIFs is far more than I can really use. No judgement, but do you actually play with them, or just collect?

These are amazing pieces of work: I look forward to seeing them used one and then banned at my local sites.

Nice idea, but is that that an Acetech Lighter-S in there? If so, I'd note that I've had two fail on me.

They're very rare in the UK, and I only use it very occasionally, depending on site and situation. It's not something I'd have bought, it was a freebie from TaiwanGun, back in the good old days.

Ahoy and welcome.

I use one voluntarily, particularly when sniping which tends to leave me out in the middle of nowhere with a long walk back. Stick it on the side of my boonie, pull it out when walking back to spawn. You don't know how many shots it's stopping you from taking, but it's airsoft, we cling to our traditions.

Which you'll be testing by staring directly at it before pointing it at anyone else. I'd check with your local site(s) before committing, as this seems like the sort of thing that's going to get banned as soon as some 14 year old gets dazzled and runs square into a door.

Although we've seen people being required to complete firearms declarations even for parts. But you'll still be fine, it might just take a bit more time.

I wonder if that was our old chum Stephen Glennie at it again.

Yes, generally. Of course with it being airsoft you'll get the occasional exception where a gun wants a little bit of pressure in order to get a perfect airseal, but yes, more hop = less energy for the same amount of puff. With the tendency of hops to go off, or to work differently depending on temperature, I always do it on site, just before chronoing. Sometimes I'll re-adjust at lunch, or even in game if it seems peculiar. If you're not sure, give it a little more than it needs, so you can see a definite upwards arc. It's a particular issue with MP5s, either the slide unit like that, or the non-K models with a rotating lever. In both cases, the solution is to add more friction, you'll figure it out.

That's a tricky one. Hard to find now, and prices have gone up on everything. But it's in a bit of a sad state. I'd be looking at buying that for parts so I wouldn't offer £60 for it (if I thought it was worth that, you'd already have a PM. ).

Yup, 0.2g is fine indoors, and tracers are great fun. It's just that 0.25g will likely produce a lower energy value than 0.2g due to your short barrel (with longer barrels, it tends to go the other way). I'd err on the side of over-hopping at the start of the day, because if you can see some lift on the BBs, then you can be sure that you've got at least enough hop on, and it'll bring the energy down. Our slide style hops can be prone to creeping off, if the screws aren't done up tightly. This is what your hop and barrel will look like out of the gun - there's a screw on each side holding the slide on, and if you ever have it apart, it's worth checking that they're snug (but not too snug, they're metal self tapped into plastic). The other thing you can do is to whip a small cable tie around the barrel and the end of the hop slide and pull them tightly together. You should still be able to move the slide, but it'll add some tension and help to hold it in place. Once you know exactly how you want it set up, you can put a little piece of grip-tape, a sliver of pencil eraser or something similar between the barrel and slide, then cable tie them together again to hold it very securely in place. I'd stress that none of this is necessary, it's just things that you can do if you want to have a fiddle and try to get it optimised. MP5Ks are great for CQB right out of the box, you've made a very solid choice.

Ouch, sorry for coming across as peremptory - I forgot that we've all had to figure this stuff out from the very basics at one point. You'll definitely want to get your hop dialled in before doing chronoing. When doing that, you'll want to use the BB weight that you're intending to play with on the day. 0.2g is fine for short range CQB, and especially if you're using tracers indoors. Outdoors, go as heavy as your hop can lift, and your wallet can afford. It may very well be the case that your hop unit doesn't need much pressure applied to lift 0.2g. Apologies, I don't have a dial-style hop on my MP5, I have the very short MP5K with a slide-lever unit, which is quite fussy - a tiny nudge can result in over or under hopping. Your dial may be the same, and I hear tell that they like to wind themselves off in use. What's important is to have as much range as possible to test with, so that you can see the terminal behaviour. With your 1.2J+ gun you can shoot out to a real-world 50-60m, and should be able to get a flattish trajectory for most of that. It can be tricky to see exactly how your gun is shooting when you're the one on the trigger, and having someone else standing off to the side to watch the BB trajectory can help. There are loads of opinions about ideal hop and trajectory. I personally like to see the BBs lifting just at the end of their flight so that I can be sure that I've got sufficient hop on. As in, over-hop slightly, then dial it down just a touch. Here's one I memed earlier. And as above, if you put a few hundred BBs through your gun, or leave the spring cocked for a bit, it should settle down. Chronoing with (properly hopped) 0.25g or heavier BBs should also sort you out. There's even a difference between a cold spring on its first shots of the day, and the same spring after putting a mag through it. I reckon your MP5 will be fine if you just get a little creative with it.

Looks like a Frankengun built from random uppers and lowers. But don't waste his time asking!

Yup. My MP5K with the hop set for each weight chronos at about: 0.2g = 1.05J 0.25g = 0.95J 0.28g = 0.9J

I can't see that this question was actually answered. <but-why.gif> Indoors, in CQB, fair enough. Woodland, you'll want at least 0.25g, I use 0.28g. In either case, get the hop set first, then chrono. Everybody else will be doing that, unless you have a weird site. On the bright side, this means you have a decent airseal, so rejoice. That's impressive energy out of a short barrel. I wouldn't go opening the gearbox, if only because the V3 triggers in these are a sod to get back in place. Just tap the trigger until it starts to cycle but doesn't fire, then leave it like that. If you do want to be sure about the piston position by seeing the cylinder, splitting these things isn't a huge chore. Take out the rear pins, undo the screw behind the magwell and push the pin through, take the small grub screw out of the fire selector, remove one side and pull the selector out from the other side. The receiver will then split along the dotted line. Reassembly is the opposite of removal, plus a lot of swearing as you try to get the fire selector, nozzle and hop unit lined up.

Lowered the price for this peasant-site, I see. I'd feel insulted but... well, I think he's got us pegged.

Passed on by an eagle-eyed viewer who wishes to remain anonymous. Wow, only £2000 for a wankergun shooting at 1.24J that you won't be able to use at any site (might be why he's never ever had an issue with it), and which doesn't appear to come with the one brand of magazine that it needs. [EDIT] Eddie the Eagle Eyed Viewer reckons that's £1300 worth at retail prices. I guess the extra £700 is for the peace of mind of that "never ever had an issue" cast iron guarantee about its past performance.

1000,000,0000% And magnets, magnets, magnets.

Was he on the balcony of the Iranian embassy? I ask because I reckon I've met all 60 of the blokes who were. Sure, sure, opsec, persec, nik nak paddywhack. Don't get me wrong, it's a great charity, and I hope you blow the roof off the fundraising. But anyone can (and too many do) claim to be "ex UKSF, obviously can't go into too much detail". Unless there are names and origin stores attached, eyebrows do tend to get raised after a while.