No, what I mean is that in the "Aliens" universe, both the M41 rifle and the service pistol shoot 10mm rounds. But the M41 round is longer and higher-velocity than the 10mm round fired by the pistols. I don't remember dimensions, but it might be that the M41 round is 10x30mm, while the pistol round is 10x20mm. But the point is, they're the same diameter, different lengths.

Ah, I see. I get it now. There are grenades the size of shotgun shells now, but they obviously don't make such large explosions.

The gun is suppossed to fied a 10x24mm round, which would leave it in the same range as the real-life 10mm Auto (10x24mm). What a wimpy round. And I though armor-piercing ammo was supposed to be small-calliber, so it could penetrate eaiser

Well the 5.7 that FN makes is a pretty small round and it can defeat some body armor. But I've never heard of a 9mm penetrating standard vests. Most body armor are pretty good against most types of pistol ammo.

I mean, by your logic that the smaller the bullet, it can penetrate armor, then a .22LR can go through anything since it's so tiny.