a .45 caliber.
Yes. and just a correction the Thompson is not a machine gun its a sub machine gun because it shoots pistol caliber rounds get your facts straight
.45 caliber Thompson Sub Machine Guns = Tommy Gun
45 caliber Machine Gun and 50 caliber machine gun
You can buy Thompson machine guns on Guns America. They have the Thompson 1927A1 .45ACP for around $1,100.
50. caliber machine gun....period
Depends on the Thompson. If you mean the Thompson submachine gun, yes, they were made in caliber .45 ACP (and other calibers as well). However, there are other Thompsons. I have a Thompson Center muzzleloading rifle that is .50 caliber.
Phosphating
9x19mm
The highest caliber machine gun in standard use is the .50 Cal. Gatling guns are used in 20mm caliber. XXXXXXXXX Russia and China use a heavy machine gun larger than the .50 cal BMG- it is the Vladmirov KDV (for the Russians), in caliber 14.5mm x 115.
An SMG is a Sub Machine Gun that's close to a machine gun but is only...well...a smaller version.
See link below to the US Army Field Manual on the Caliber .50 M2 Machine Gun.