It's because its blocky shape makes it easier to embrace than other guns.

I guess this is a follow up to my recent post, "In praise of the oldest star in Gunslinger Girl." There, I linked to a couple pictures of anime characters hugging their FN P90 submachine guns (Iriya from Iriya no Sora, UFO no Natsu, and LLENN from Sword Art Online Alternative: Gun Gale Online). Naturally, Henrietta also does this in the first episode of Gunslinger Girl, as depicted above, after going aggro with it against some chumps who totally had it coming, probably.

Rounds in the translucent magazine make a 90-degree turn before entering the chamber.

I believe Henrietta's P90 is the most modern firearm to appear in Gunslinger Girl. It was only about 10 years old when the manga began in 2002, and is quite a contrast to Triela's 19th-century shotgun. Its distinctive appearance probably also accounts for its popularity in various anime, Sword Art Online Alternative Gun Gale Online being a notable example. I can't rule out the possibility that some LLENN fan bought herself an FN PS90, cut down the barrel after getting an NFA tax stamp, and painted it pink for questionable cosplay purposes.

This was a pretty good deal for both parties.

Incidentally, I was somewhat surprised a minor character in SAO GGO carried an AR57, which is basically an AR-15 upper designed to accept P90 magazines on top and eject out what is usually the magazine well of the lower receiver. But I'm most impressed that Kirito never showed up in GGO for some bullshit ammo exchange contrivance, since Kirito's FN Five-seveN is pretty much the only other firearm that shares ammo with LLENN's dear P-chan. Kirito's total absence definitely improved Gun Gale Online as an anime.

I'm impressed Triela didn't get any blood on her.

I've written a fair amount about Gunslinger Girl, but haven't mentioned much about the firearms themselves. The first gun to appear in the show (outside of the OP) is Triela's shotgun, a Winchester Model 1897 Trench Gun with its big ass 17-inch M1917 bayonet fixed. I believe this is also the oldest firearm to appear in the anime. As its name suggests, this is literally a 19th-century design which Winchester started selling in 1897 (although it remained in production until 1957). In contrast, the primary weapon of the show's ostensible lead, Henrietta, is an ever popular FN P90, which was barely more than 10 years old when the manga began publication in 2002. Triela's M1897 is also the only shotgun in the first cours, but I don't remember it featuring in particularly many scenes. The old Winchester gets a lot more attention in the sequel, Gunslinger Girl -Il Teatrino-. (And occasionally appears in fanart.)

The action can git ya if you're careless while racking the slide back.

Prices of the World War I-era M1897 Trench Guns have risen quite a bit as of late, probably at least partially because of The Great War's centennial and maybe because of the shotgun's inclusion in popular media such as Gunslinger Girl itself and the Battlefield video games. For example, a "very fine" Model 1897 sold for $8625 in December 2018. I am somewhat amused that Gunslinger Girl features a firearm from the 19th century when basically every other gun in the series is from the Cold War or newer. I have to assume the original mangaka, Aida Yu, just really liked it. That's totally understandable, at least.

I've added a couple more seiyuu blogs to Wakusei. The wacky adventures of Kana Ueda (the voice of Yumi from Marimite) and Yuuka Nanri (Nao from My-HiME and Mai-Otome) are on the march.

Still waiting for Saeko Chiba and Tanaka Rie to add RSS or Atom feeds to their blogs....