A-10 shell casing! I work on them (Avionics) and got one from a

Aeroshell Aviation Oil W100 SAE 50

A-10 'Warthog' Thunderbolt II

DCS F-15C Combat guide for beginners by Sryan [very IMG heavy!] - Flight Sims - Mudspike Forums

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Aerospace, Free Full-Text

oc] Balloon : r/comics

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Could they use a 50 cal gun in the A-10 Warthog? The 50 cal bullet might not be as good as the A10's gun, but still. - Quora

The Case For Flight Helmets - AVweb