Check your owner's manual or call Glock.
Caliber is .45 GAP (Glock auto pistol)
What does your owner's manual say? Don't have one? Call Glock and they will send you one.
.45 ACP
No
Federal premium ammo
.40 S&W with JACKETED bullets. The polygonal rifling in a Glock does not mix well with lead bullets.
No - they are very different cartridges.
9x19mm, also known as 9mm Parabellum or 9mm Luger.
The Glock 21 was introduced in 1990. It is a .45 ACP caliber pistol developed by the Austrian company Glock, designed for law enforcement and military use as well as civilian markets. The Glock 21 features a polymer frame and a reputation for reliability and ease of use.
yes
Yes