I have a problem.

I can’t stop thinking about the poor, innocent U.S. Army soldier who in September asked Reddit for help identifying the training rounds he found at the Hohenfels Training Area in Germany. And I can’t stop thinking about the consistent piece of advice he received from dozens of fellow U.S. service members: put ’em straight up your butt.

As a civilian (albeit a nasty one), I can’t seem to wrap my mind around this. Why does ammo belong in the butt? Why are U.S. service members so obsessed with ammo belonging in the butt? And, more importantly, what’s the best ammo to jam up one’s uniformed butt?

These are most pressing questions of the time, and they deserve answers. To wit, I present a brief list of ammo you should strongly consider jamming up your butt. For country. For freedom. For science.

I regret nothing:

The 5.56x45mm NATO round

Lightweight but high-impact, the 5.56x45mm round that’s standard issue among North Atlantic Treaty Organization forces is designed to tumble as it travels for maximum damage to that pathetic tush of yours

The 5.56mm M855A1 Enhanced Performance Round

Munitions photo

The 5.56mm M855A1 Enhanced Performance Round, engineered by the Army to deal with the proliferation of body armor downrange, comes with a copper-jacketed steel core that’s proven more effective against, uh hard targets

The 6.8mm intermediate round

Munitions photo

Developed specifically for the Army’s Next Generation Squad Weapon program and officially selected by the service in September, the 6.8mm round is also intended to counter the proliferation of booty-armor among America’s enemies

The .300 AAC Blackout round

Munitions photo

Formally known as the 7.62×35mm round, the .300 AAC Blackout is known as such because it’s normally what appears in your butt after you when you wake up in the barracks after a night of drinking

The 7.62x51mm NATO round

Munitions photo

Not to be confused with the Russian 7.62×54mmR cartridge, the 7.62x51mm NATO round is mostly issued to sniper rifles and machine guns for precision, long-range booty fires

The 9mm M1152 & M1153 Special Purpose rounds

Munitions photo

Developed for the Sig Sauer P320 that the Army adopted as the M17/M18 under its Modular Handgun System program in late 2017, legendary gunmaker Winchester’s 9mm M1152 and M1153 Special Purpose rounds are designed for the next generation of butt stuff

The .45 ACP round

The standard round for Colt’s beloved M1911 pistol, this round has been perforating buttholes for more than a century

BONUS: The 155mm M107 howitzer shell

Not technically “ammo.” Still technically hilarious. I regret nothing.