What’s Your Preferred Barrel Length

Them motor scooters are loud!

Generally I don’t look to Garand Thumb for much more than hair grooming advice.

Having said that, main AR has a 14.5″ mid length gas system to help with getting out to 5-600, which I have to contend with in my area and it’s still compact enough when it needs to be. So that’s the patrol rifle.
SBR is 11.5″ with mid-length gas system for slightly less violent recoil impulse. This is my “grab it right now there’s bastards in the yard” rifle. It has a “grab it right now” compact throw over shoulder bando rig with extra mags, smoke grenade, radio & trauma kit. (this is not a chest rig nor a belt rig). It’s a rig specifically for this purpose.
Additionally, if it happens so fast as to not even be able to grab the bando it’s loaded with Magpul mag coupler for quick reload / extra rounds. This is a 250-300 yard gun and plenty for my out the door now needs.

Garand Thumb mentions recoil impulse and dwell time which he’s correct, but (unless I missed it), he doesn’t mention gas system length. I stay away from carbine length wherever possible for compatibility with other rifles but also less wear on internals.

I was using a 10.5″ GAU 5 vietnam era left-over in 1990 as a cop. I love how this is all new and “special”. When I transferred to SOF i ran a 10.5″ cqb M4 version we made from converted A-1 lowers and uppers. THat was way prior to the 14.5″ M-4 flat tops coming out, 14.5″ was fine but 10.5′ was my preferred length especially for cqb. As a home defense gun, I go with a 7.5″ with a short mini-k can, and a whole lot of extras i wont get into, running 40g v-max, theyre like mini-hand grenades in soft tissue, no collateral damage, come apart in dry wall, with a backup mag of tap barrier or green tip for those special “anti-material situations.
What i would take into a room to clear it? depends on what the goal is. If it is to just clear the room, no holds bar, ill take grenades, or a JDAM while i lase the target from the ridge, in their absence, ill take a 12g with 3″ #4 buck, with 30 pellets per, at 7 rds, thats basically a combat load dumped in less than 2 seconds full run from a semi, indiscriminate, check. Room cleared, check. If its surgical, long gun with a can, hence the 10.5”. I would never chose to clear a room with a pistol unless my long gun malfunctioned, was hard broke and had to transition, or I had only that to use, in which i would rethink clearing the room, and look at option B, or C, like not be there preferably. Now, a special,movie-like situation needing a a pistol, suppressed, preferably 45 acp, yeah but that is getting out in not-likely land territory. Whole different discussion. But again, if it was that special,Id like a long gun, maybe a 10.5′, suppressed 300 BO with 190 sub-x subsonic ammo, and supersonic mags ready to go, again movie-type stuff, CAG, 1st GRP, colored teams, SMU stuff. So, not our reality anymore. Ill stick with what Im running and leave the shenanigans to the movie makers.