There certainly could be some bullets/loads available out there that could provide frangibility, lower report, and low flash. What are they?
Me, I don't know. It's just too easy to use a pump shotgun with a buttstock bandoleer to get the job done. For a battle rifle, I go with the .30 calibers, because in those situations I WANT to shoot through ANYTHING that the other guy (who is trying to kill me) is attempting to use as cover, i.e. a tree, a telephone pole, a truck, a building wall, whatever, ... . In that world, I will
need over-penetration big time. Indoors however, I need a massive dump of energy
right then-'n-there. Next, I want my weapon's projectiles to stop their forward momentum instantly or as quickly as possible.
If I lived alone and had an AR-15, I'd go with that rifle for home defense. I've no problems with that weapon. But, we have a disabled adult son. When my wife and I were young, we had three children sleeping in two other rooms. MANY people have a bunch of family members in their homes. If one can guarantee that all of those people can get into a safe room before it hits the fan, then Hurrah!, go with a battle rifle.
"Choosing 5.56 NATO Ammo for Home-Defense Use"
https://www.shootingillustrated.com/content/choosing-5-56-nato-ammo-for-home-defense-use/
... "But before selecting 5.56 NATO ammo, you have to consider your unique environment. A house full of family members requires different planning than an empty-nester pad. Rural dwellers have more flexibility than those who share common walls with neighbors. Residential interior construction is not well-suited to stop bullets. We have to assume that any shot that misses or passes through its intended target with little upset can harm someone or something we want to protect. This is a good time to point out that proper shot placement is as critical here as it is for any distant shooting pursuit. The fact is that even well-placed shots can penetrate through the human body in spite of our best efforts to prevent it.
"Today’s frangible-ammo options are much better and tend to stay together until they make impact. Unfortunately, I know a couple guys that learned the hard way how even frangible ammunition can penetrate thin, interior walls and hurt good people on the other side. Like any other new ammunition you try, you should ensure frangible ammunition functions correctly in your rifle and that projectiles go where you aim them before relying on them for defense purposes.
"Bullet performance is not the only indoor concern. Muzzle flash is a huge problem during the hours of darkness. Not only does it make your location clear to anyone not dispatched by the flash’s source, it tends to temporarily make things difficult for your own eyes. In a life-or-death situation, you need to be focused on assessing threats, not a huge bright spot imprinted on your retinas.
I build guns for other people for a living. [emphasis Old Hobo] Most of those gun owners intend to use their arms for self-defense shooting, among other pursuits.
"The heavily increased demand for short-barrel rifles (SBRs) and rifle-caliber, semi-auto pistols tells me this is a trend that is not going away. Short barrels are notorious for belching bright balls of flame, or secondary muzzle flash, as hot gasses and unburnt powder crash into the atmosphere outside a gun’s muzzle. Thankfully, today we can all benefit from low-flash propellant technology that was once reserved for specialized military and law-enforcement elements.
"The concussion that is produced by firing full-power 5.56 NATO ammunition in tight confines can be deafening and disorienting to unprotected ears. Unless you sleep with ear protection in place, there is a fair chance you are going to have to deal with immediate threats with ears wide open. I recommend trying to reduce the blast you have to deal with indoors. Conventional muzzle-brake equipped rifles or carbines amplify the problem through side ports and baffles. Directional muzzle brakes help to a small degree by pushing everything out to the front. But a good, prong-style flash hider is better in this environment. Sound suppressors deal with both muzzle blast and flash and although they add length in most common rifle configurations, are great tools for indoor use. I used a sound suppressor for CQB operations whenever possible while in the Army and was always very happy to have them indoors and out."
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