25 Automatic
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25k PSI
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A curated collection of everything that shoots out of a metal tube. SAAMI specs, ballistic data, historical context — backed by a personal collection of 600+ cartridges and the kind of people who can date a headstamp from across the room.
From .22 Short to .500 S&W Magnum. Every SAAMI-standardized handgun cartridge with pressure specs, dimensional data, and community discussion.
9×19mm Parabellum · 9mm NATO · 9mm Para
Georg Luger removed the bottleneck from his 7.65mm Parabellum in 1901 and accidentally created the most manufactured cartridge in human history. Every major military on earth has issued this round. Every. Single. One.
In 1986, the FBI Miami shootout killed two agents and wounded five. The Bureau panicked, adopted the 10mm, realized their agents couldn't handle it, and asked Smith & Wesson to shorten it. That neutered cartridge is the .40 S&W. It dominated law enforcement for 25 years. Then the same FBI that invented it switched back to 9mm in 2015 because modern bullet technology made the whole journey pointless. I have 23 .40 S&W headstamp variants in my collection. Every single one is a monument to institutional overcorrection.
Precision, hunting, military service, and everything between. The rifle collection spans 140+ years of cartridge engineering.
6.5 CM · 6.5×48mm
Dave Emary and Dennis DeMille designed this at a Hornady test range in 2007. By 2017 it had dethroned the .308 Winchester in competitive circles. The people arguing about it the loudest are almost never the ones winning matches with it.
The 6.5x55 Swedish Mauser did the exact same job in 1894. The .260 Remington did it in 1997. The 6.5-284 Norma did it better. What Hornady actually accomplished wasn't ballistic — it was logistical. They convinced every major rifle manufacturer to chamber it simultaneously, ensured shelf availability, and marketed it to hunters who'd never heard of sectional density. Brilliant business. Decent cartridge. Not the Second Coming.
Note: 9mm and .45 ACP produce nearly identical muzzle energy (~365 ft·lbs). The 9mm does it with velocity; the .45 does it with mass. The physics don't care about your feelings.
Calculated for typical platform weight. Rifle recoil from 7-8 lb rifles; handgun from ~2 lb frames. An AR-15 in .223 kicks less than a 9mm handgun. Think about that.
I'm not saying Advanced Armament didn't improve the concept — the subsonic performance with 220gr Sierra MatchKings through a suppressor is genuinely excellent. I'm saying the wildcat community had this figured out a decade earlier. The .300 Blackout's genius isn't ballistic engineering. It's that Kevin Brittingham convinced SAAMI to standardize it and convinced the AR-15 market it was new. You can literally make brass from .223 cases with a chop saw. I have both .300 Whisper and .300 BLK headstamps in my collection. Same cartridge. Different price tag.
Named after case diameter, not bullet. The .357 Magnum uses the same bullet. The names are both wrong.
Close enough? Sure. Safe to shoot 5.56 NATO in a .223 chamber? Absolutely not. Same bullet, different pressure.
The "06" is the year: 1906. Same .308" bullet as .308 Winchester, .30-30, .300 Win Mag.
Also called 9×19, Parabellum, Para, NATO. Five names, one cartridge. Thanks Georg.
ACP = "Automatic Colt Pistol." John Browning rounded down. The man was too busy designing genius.
Not even close. Named from .44 Russian → .44 Special lineage. Dirty Harry's gun shoots .429.
The takeaway: Every cartridge name is a historical accident, a marketing decision, or a rounding error. Never assume the number on the box is the actual measurement.
215 SAAMI cartridges today. 600+ from the personal collection coming. Eventually, literally everything that shoots out of a metal tube.