yes
Have it examined by a good gunsmith. This rifle use a .22 caliber bullet, long rifle.
22 Long Rifle
The marlin model 781 was chambered for the .22 long rifle.
There were .22 'shorts' and .22 LR (long rifle) models made. Read your barrel to determine which you have.
Use a Marlin 57 firing pin. It's the same rifle, just re-branded for Sears.
22 Short, 22 Long, or 22 Long Rifle rimfire interchangeably.
Your rifle is a Marlin Mdl 100, made for Sears under the Sear brand name. It was chambered in 22 LR, (and can also use .22 Longs and .22 Shorts) Caliber is generally marked on the barrel. It is prudent to have our rifle checked by a gunsmith before shooting for safety's sake.
No it does not the shells load from the top
That depends on the exact make, model, and condition of the rifle.
SLLR indicates that the weapon is chambered for Short, Long and Long Rifle rimfire ammunition.
A Marlin Model 60 fires a .22 Long Rifle cartridge. The Marlin Model 60 fires a .22 LR cartridge.
The rifleman as seen on the old TV series used a Winchester model 1892 rifle,or a reproduction of that rifle.