VALERIY: Guy had it coming. Soldiers fight even on the homefront.
Just wanted to remind people in case that Kei has taken his recruit section outfield for the duration of this week(returning on Sunday 9th) to train field exercises like field craft, first aid and other intense activities. He says that some people "peek in my thread every now and then without saying anything, they're most likely the ones who want to know."
Anyway, interesting stuff here. Guys at the Defence Distributed who are designing AR-15 lowers are making some unique designs, specifically one user 'WarFairy' who designed a P90-esque lower receiver for the AR platform. One model features an adjustable stock(nice) that extends it's length by nearly 8 cm more when fully extended, another is a pistol lower(no stock, just a grip) with either buffer tube or non-buffer tube variations. Obviously with the non-buffer tube version, you'll need an upper AR-15 receiver that likewise does not use a buffer tube(e.g. RRA LAR-PDS upper or Faxon Arms ARAK-21)
Note also that WarFairy's lower receivers also feature a finger hook at the bottom of the magwell, I assume that is to help with recoil when handling the weapon in the 'magwell' firing form.
Also interesting is a shot from an ex-Army Ranger Sniper Team Leader, Ryan Cleckner, who hit a target 1000 yards away with the Barrett M107 .50 cal AMR standing up. Amazing considering that thing weighs 16 kilos and recoil from a .50 BMG, even with the M107's compensator, is a bitch.
TL;DR Version
Kei is away at his job for a week.
WarFairy is making 3D models of a custom P90-like AR-15 lower receiver that is printable.
Ryan Cleckner is a badass with an M107.
Pictures and videos in the spoilers.