Lozart

All the issues you have highlighted are nowhere near as bad or as common as they used to be though. You are correct that a well built gearbox will reduce stress on the standard parts but look at it like this - once you've taken out all the parts likely to contribute to poor performance, you've removed any of the stock parts liable to stress failure anyway so that becomes a moot point. If you're chasing performance then absolutely a well set up gearbox is important but performance isn't always compatible with reliability. It's absolutely worth having a gun serviced if only to clean out the earwax that some manufacturers use for grease, but that's not the same thing as sending it straight off for "upgrades", and it really should be something that owners ought to be able to do themselves.

And yet the Hera Arms abominations are everywhere

I'm going to resist the immediate temptation to reply "get fucked" and ask why you think anyone "should" stop playing?

I have a couple of CA MP5s, so far the Nuprol NP5 mags have been pretty good. Cyma ones feed but need a good slap to get them to latch into the mag catch. Same for the Mag ones. If you can get some Classic Army ones they would probably be the best bet.

That's what he's already got. It still uses a standard length cylinder instead of the elongated one in pretty much everyone elses SR25 models.

https://www.airsoftwholesaleuk.com/Wholesale-blog/li-ion-airsoft-batteries-showdown-oper8-vs-titan-power/ I'll just leave this here. It does state that the cells used in these Li-Ion airsoft packs are capable of up to 95A burst. The simple fact of the matter though is that there is plenty of people out there using these batteries that don't seem to be having any issues. Don't get me wrong, if mine all die in 6 months time I'll be happy to come forward and let everyone know but they certainly don't seem to be showing any adverse signs so far. I've definitely had LiPo packs puff up in less time!

I don't think there is on account of the trunion mounting on the Zenitco stocks. Literally trying to get a square peg into a round hole. You might be able to Macgyver something together with this though: https://www.ant-supplies.uk/rifle-accessories/ar-folding-stock-adapters.html If you can modify the hinge pin on the Zenitco maybe?

Have a Google for BCM Gunfighter Mlok. The real steel one is only about £25

What style of AK stock?

Yeah, 13.4 is pretty poor (it should be a minimum of 13.7 really). You could just swap out the outer barrel for a better one (Cyma do some good ones that don't cost much).

There's the ASG one too.

Do you have the box? As mentioned above, RPB make the real one. We would need to know who the airsoft one you have is made by

Something doesn't add up here. Bolt outer barrels are 14mm CCW threaded so if yours is smaller than that there's fuckery at play. Do you have a picture?

Every battery comes with risks. Thing is, be sensible. If you puncture or short ANY battery you can have a fire or an explosion. Can you rescue a deep discharged LiPo pack? Yes. Should you try and rescue a deep discharged LiPo pack? Probably not. Is a metal cased battery inherently less prone to mechanical damage than a soft pack? Yes, but it isn't impervious. If the outer metal casing of the cells is exposed you do run additional risk of shorts but if your battery is so badly handled as to expose that metal casing then you should be more careful with your batteries. Plus you can easily whack some electrical tape or heat shrink over it and you're back to square one. If you manage to peel back the outer sheath on a soft LiPo then you're in for a bad time. As for the whole "Li-Ion batteries only work in standard guns" thing? Yeah, that's bollocks. I run one in my MK12 DMR which has an M120 spring and an Infinity U22000K motor in it and it's absolutely fine. Will it work as well in an SSG1 with 45RPS? I don't know, I don't wear lycra, but the point is that not all batteries are the same. Pick the one that suits your application and get on with your life.

You need to bear in mind that the gearbox positions the hop unit in the right place to mate with the magazine. That gun is designed to work with the style of gearbox it cane with. Be that either a v2.5 (like all the other SR25s on the market) or a standard v2 with a proprietary hop unit and ridiculously long nozzle (like the G&G). Ares make an e2 M110 by the way. Except it's ludicrously expensive and, well...it's an Ares.

That's exactly the battery I use in my M4. Unless you have a spectacularly short battery lead, it should be plenty long enough to get the battery in and have the connectors at the back end.

I charge my Titan Li-Ion batteries with the same charger I use for my LiPos (Accucell S60). They're all basically the same chemistry at the end of the day, the bit that is a touch confusing is that when you get a Titan battery it has "CHARGE ONLY" on a label on the balance lead and "DISCHARGE ONLY" on a label on the main power connector. Thing is that my charger won't balance charge unless BOTH are connected. Hasn't burnt the house down yet though.

V3 won't fit in there.

As mentioned, ideally they should be put to a storage level but it isn't absolutely necessary. If you don't have a decent charger, get one.

Might be worth having a watch of this before you go headlong into your DMR build

If they're the Warrior pouches with the black, textured vinyl type lining, just ditch the bungee loops and run them as is. They'll be fine. Alternatively, get yourself some kydex inserts and shove them in your pouches. Job done.

These are worth a look https://www.wtfidea.com/air-tank-pouches/ In case you don't know them, WTF grew out of the paintball world into general tactical gear via airsoft so they know what they're doing. It's good gear, shipping from the US is pretty quick and not too expensive. Tactical Kit stock some of the more tacticool pieces they do but not the paintball/airsoft stuff.

I like M4s too (I have three). I just like baiting people that get upset when you dare suggest that their L119A2 is just an M4 in a fancy frock. Yours is very nice though (but if you do have a Bazooka that would be SO MUCH COOLER!!!!!)

Except you can't, because the Magnus effect in the case of airsoft BB's provides lift. It also produces increased turbulence in the BB's wake which contributes to drag which affects the terminal energy. Axial spin in rifled barrels increases range by the conservation of angular momentum which is a whole different kettle of ballistic fish.