Confused with 1903 ria

G'Day everyone,

A good while back I purchased a Rock Island Arsenal 1903.
I will first declare that am no expert on the 1903 and variants, the sole reason for buying this rifle was that I wanted another cast bullet rifle.
I am unsure of the history of this rifle and several things about it are of confusion to me.
The rifle has a RIA receiver, the barrel is marked RA 5-44[are only 1903a3 barrels marked RA?], the bolt marked R under the handle and the 3rd lug is square not scalloped[I could not find this bolt on any chart], most of the rear sight parts are also marked R, the stock has no stamps or evidence of refinish.
I am not expecting this rifle to be the ants pants, I simply brought it to shoot cast bullets however if anybody has any insight to this rifle I would greatly appreciate it.

PS hope the pictures worked as its a first time, thanks for the easy to understand instructions Harlan and Badger.

Thanks Rusty.303

It is a RIA reciever that someone has rebuilt with mostly remington parts ( bbl , bolt , other "R" or "RP" marked parts ) and placed into what appears to be a new production "C" stock. If the work was done well , it should fill the needs you bought it for well.
Chris

PS , Remington produced the '03 before the 'A3 , but a 5-44 bbl would be an A3 bbl IIRC. Examine the rear sight mounting under the wood for shananagins.