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I saw that Genesis Arms is now offering the Gen-12 with some really short barrels. 10.5" and 7".
Is there a point where the shortness of barrel would negatively impact 12 gauge performance?
I guess, basically asking if there's such a thing as "Too short" of a shotgun barrel.
Below 12" I have never seen any numbers myself, but I recall seeing someone chrono a bunch of buck starting at 12" and between 12 and, I think, 30 inches, it picked up around 150fps, total.
I don't know at what point it really starts to drop off but just thinking about the mechanics of shotshells I bet they don't do a great job of really containing pressure. I'm not really a shotgun guy so I'm just thinking out loud here but I would guess this is part of why shotgun pressures are so low: 12 gauge MAP is what, like <12,000 PSI compared to 5.56's >50,000?
As such I'm betting that shotguns are highly resistant to barrel length reduction as far as velocity goes. You probably reach full speed really early on compared to rifles.
That said I bet below 12ish inches it gets a lot worse per inch.
THAT said... whenever I think about shotgun defensive ammo, I think...the problem isn't really lethality, is it? Isn't it pattern?
So again I am just thinking out loud here, but I would personally probably not be worried about whether 00 buck will do adequate damage out of anything but maybe the absolute shortest shotguns - we see some 8s around here and I'm still pretty confident in those - but what does the pattern look like at my max in-house distance from the change table near my kid's room, down the hall to the living room: about forty feet.
I bet that pattern is already going to be unreliable.
Final disclaimer: I am not speaking from a position of authority here at all.
Okay this really got me thinking though, so I looked around to see if I could find anyone who's done super short 12g testing recently.
Here's what I found: Small Arms Review tried it, minimum length, 6 7/8".
Muzzle velocity: 1,117 fps.
From 30" down to 6 7/8" they lost a little under 500 fps. Well, peak speed wasn't at 30 so it depends a bit on how you want to describe everything in plain English; recently I had an argument with some engineers because I casually commented that smaller structures are typically more rigid than larger ones and I quickly realized that the amount of interest they had in exporting mathematical precision to conceptual conversation radically exceeded my own. So take the numbers how you will.
Bottom line: from 30" down to 12 they only lost about 200fps. Over the next 5", they lost about 250fps.
Spread was smallest out of the 18" barrel : Remington 9 pellet 00 had a 8.5" spread at 15y.
The super Shorty was 17" at that same distance which is actually better than I would have guessed. Still too big IMO but I thought it would be worse.
https://smallarmsreview.com/display....idarticles=111
Thanks for that article (and kicking around ideas in general). Really good read.Quote:
Originally Posted by Maple Syrup Actual
I think your point re: lethality in the context here is probably right. Spread might be interesting, but you could always choke up. Or switch to flight control.
Low recoil flite control is the way. Using it, I clock a loss of about 37fps from 18.5 to 14".
Not that this needs to be said, especially three months later, but I think shotgun lethality comes from multiple projectiles hitting the same general area at the same general time, overwhelming the tissue's ability to stretch, and creating devastating wound cavities. As opposed to 5.56 or other rifle calibers, which are highly dependent on velocity in order to yaw and/or fragment. The mindset of barrel length being very important, and velocity equaling lethality, is a holdover from rifles. I think as long as shotgun projectiles have enough velocity to penetrate to vitals, the rest probably doesn't matter. Therefore, it might be a better exercise to think of shotgun barrels the way we think of handguns, as counter-intuitive as that may be. We don't care about handgun velocity beyond its impact on penetration, because handgun bullets don't reach a high enough velocity to do what rifles do.
What is "enough" shotgun velocity to penetrate sufficiently is what we need info on. Ballistic gelatin tests with different barrel lengths would probably be the best source of info. Annoying and expensive to do though, since you can't really re-use a block for more than one shot :)
I agree that short shotguns probably lose little if any lethality. I think they become really unpleasant to shoot long before they become ineffective. The biggest factor is probably actually magazine capacity without the tube hanging way over the barrel.