Due to demands of the war, very few civilian firearms were made in England in 1944. Makers were producing the .303 caliber #4 Mk1 rifle, and the #5 Carbine. A small number of the SMLE rifles were converted to .22 rimfire weapons (military trainers). Search Wikipedia for the term SMLE for some good information.
Impossible to answer without knowing who made it and what type of action it is.
Chinese-made Type 56 and Type 100 rifles.
the firs=t one that performed was the ones that made the nutcracker Ballet it make sure its a type that could made all this in 1944
Many makers made bicentennial rifles with coins.
RPA rifles are made in a number of different calibers. There is not one single caliber- sorry.
Assuming you have a Golden State Arms Santa Fe Model 1944 rifle here. Golden State Arms didn't manufacture rifles - they bought surplus military rifles, and sporterised them. What you have is PROBABLY a surplus Short Magazine Lee Enfield rifle, and would be chambered for the 7.7x56R cartridge, also known as the .303 British. However, if you're not certain about the calibre, then you need to take it to a gunsmith to have them measure out the chamber - not all of the Santa Fe rifles retained their original .303 cartridge, and, although less common, rifles converted to .308 Winchester and .45-70 are not unheard of.
The two types of cartridges used in rifles and pistols are rimfire and centerfire
Rifles, shotguns and handguns differ mostly on the type of cartridge used.
Standard
FMJ
The Browning BAR model and the bolt action lineup that included the Safari and the Medalion.
This would be a Browning BAR semi-auto rifle