Impulse

My first choices would be:
TM Hi-Capa - hicapahub.co.uk is a hell of a drug. Can build a hicapa to do basically anything and they shoot well out of the box
AAP-01 - Has a fun switch and highly customisable, but needs a few upgrades to get it good (and not eventually blow itself up)
KWA mac11 - Haha gun go brrrrrrrrrrttttttttttttt. Can get a SMG thigh holster that fits it well, or a shoulder rig.

I've always been an advocate for GBB sidearms anyway, as most of the time when I need my pistol I need the extra firepower that the squishy double action trigger of the mk23 just doesn't give; if I want to go undetected and they're within my MED, I tend to just go to ground and let them pass. When it comes to GBB sidearms, it's basically just "what TM pistol do you like best?"

If you want to keep with the NBB, the TM Bodyguard 380 or LCP2 are solid options. Get the Hadron TDC upper for it and it'll shoot with decent accuracy within your MED, plus it's nice and small. Alternatively, for mk23 mags I've had a lot more success using the clone mags with TM feed lips and Nineball routers (the clone feed lips and routers are ass). They don't leak as much and any leaks that have happened I've managed to fix fairly easily.

I haven't noticed it, but it's possible. People originally thought they were great budget pistols as they were only £90 or so, but then people realised that they need a load of fairly pricey upgrades because they eventually explode, making them more expensive than just buying a TM and being done with it. Also, full-auto gas guns can be temperamental in our lovely climate, so using the fun-switch isn't always possible. Maybe people are realising this now?

I find it amusing because I'm actually looking at completing my AAP build and potentially getting the folding stock and a vertical grip/flashlight combo and maybe some extended mags and having it be like a small SMG for a sniper sidearm  

Cyma SR-25 could be the mosfet? I know the Cyma platinums have mosfets in them that aren't exactly the greatest

@EDcase Evike Europe. I was hoping that Evike Europe wouldn't be like the US Evike, which always requires a declaration form to be filled out, but it seems that Evike Europe is the same, even though it's coming from France. It's only a stock and an m700 bolt, but it's stuff that doesn't seem to be stocked anywhere else (m40a3 kit for the m700 and a King Arms adjustable m700 bolt)

Ah, yeah, my bad. The answer is the same though, for @Lozart's reasoning. It's way too snug to fit a gun with a flashlight on it.

It doesn't. It will accept the pistols without the flashlight, but the retention locks into the trigger guard and a light definitely won't go in (as it's solid at that point).

Only pistols (without a torch, obviously) I've had difficulty fitting in mine are the 1911 and the mk23

I like .4s or higher in a DMR, but in terms of brands I like Geoffs, BLS or Longbow, depending on what's in stock and for what weight.

I tried fixing mine too and they were gas tight for a game day before they sprung a leak again, plus one of my gas tight ones also sprung a leak so I just said "screw it" and gave up on them. Fortunately I have a bunch of STTI mags that have been gas tight for years, so I just swapped the feed lips and gas routers over because the STTI feed lips are wank

@Rogerborg See, I wouldn't mind that; very much a fan of practicing what I preach, but I started airsoft in a time where we were full-auto-ing each other up close with slightly hot guns (because the chinese clone guns came out of the box too strong and nobody chrono'd back in the mid 00s). I'd even be happy to take it at 1.88J if it meant bringing the power up to that too, but that will never happen at my local site because I think one of the owners hates DMRs and is perfectly fine with literally nobody using one at Worthing.

@Shamal Yeah, and what doesn't help is that there are some repeat offender bolt action users who keep shooting under their MED. I still think 1.64J should be a 20m MED as it's not -that- much harder than 1.1J, but I think it's going to be a fool's errand anyway

@Musica The 3 screw allows you to correct if it's arcing to the side as well. It's basically just the 1 screw version with two extra screws. I use mine just like a 1 screw, but it's nice to have options just in case!

@MusicaNo, you need a VSR style barrel. Are you looking to put it into a carbine kit as a DMR? Running a barrel that long into the suppressor could easily take it over 1.14J thanks to joule creep (I know that the clone mk23s that have an inner barrel extension into their suppressors tend to be pocket DMRs)

Out of stock, but this is the kind of barrel you want:
https://www.outdoorandtactical.co.uk/product/maple-leaf-vsr-l96-open-300mm-crazy-jet-inner-barrel

I'd probably ask for a partial refund before leaving negative feedback.

In terms of upgrades, Maple Leaf autobot rubber, Hadron H-arm, Hadron TDC and a tightbore of your choice (I like Maple Leaf or Nineball) are my go-to upgrades for any mk23 build.

Cyma for m14s, mp5s and AKs. £150ish for a really solid platform

@MusicaAAP has blowback. Typically anything non-blowback will have a mushy trigger pull.

A lot of people like HPA-ing their AAPs. With the right mods you can get great range, a snappy trigger and a horrendously evil brrrrrrrrt that won't explode itself

That's their website, yeah. It's not amazingly set up, but you can see their events at their sites (Book here at the top right)

I really love Gunman for historical and filmsim stuff. Josh runs some really great games!

Honestly, part of the reason for the consideration is because my HPA m14 has been a disappointment. It likes to jam itself open when I take the mag out and fire it to clear it which is a pain in the arse. I have a 2nd m14 and already had most of what I needed for a good build with it, so figured I may as well.

@Adolf Hamsterit's more for the noise reduction and less for aoe (though that is part of it), and I'd rather not be covering the vents on my piston head if possible.