That appears to be a Savage build, close to their model 34 or 56/65. You can find mags for the 34 easier than the other 2. At about $15 each, it's a small investment buying one of each for each model and see which one fits best.
You will have to state whether it is a rifle or handgun to get an answer.
10-125 usd
5.56 or 223 cal.............................
No such caliber.
The momenta of the rifle and the bullet are equal and opposite. The bullet has greater kinetic energy than the rifle.
Rifle and bullet (The bullet is dependent on the rifle to accomplish its purpose)
The barrel guides and accelerates the bullet out of the rifle, and imparts spin to the bullet to stabilize the bullet in flight.
d) they have the same momentum,but the bullet has greater kinetic energy the the rifle
Yes.A fine made rifle in a great caliber.I had one in .308Win and loved it.That rifle took many deer.
.45 calliber
There is no one answer- it depends on the rifle. They are generally less powerful than a full size battle rifle cartridge. The M16 rifle uses a 5.56mm bullet, the AK47 a 7.62mm bullet, etc.
The JC Higgins Model 31 rifle was manufactured for Sears and Roebuck by Hi Standard.