I think the other guy got lost, so I'll start it. Going to do some pics of rare/neat ammo types and some useful diagrams to start.
Weapon Art thread
Ian Sullivan
Brayden Allen
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Christian Jackson
Telescoping plastic cased ammunition is showing a lot of promise in testing at this time.
Samuel Martin
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Zachary Roberts
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Christopher Fisher
In case you ever wondered how your average 40mm round works...
Jaxson Brooks
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Ayden Sanders
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Luis Brown
I need to dig around and find out if this thing ever made it to marker. The only comparable thing out there is that odd stacked optic by Leupold.
Ryan Nelson
The very rare 10mm MP-5
Rumor has it a couple of these got converted over to that experimental .224 Boz round that never saw the light of day. It used a 10mm casing necked down to fire a .223 (5.56) projectile at insane velocities. It was supposedly able to defeat some hard vehicle armor when using steel core ammo.