yes and they sell rifled slugs that shoot better
I own a glenfield 778 without the magazine plug it can hold a maximum of 6 rounds on in the chamber and 5 in the magazine
$200
The Glenfield 12 Gauge Model 778 shotgun uses 12-gauge shotgun ammunition. It can fire various types of shells, including birdshot, buckshot, and slugs, depending on the intended use. Standard shell lengths for this shotgun are typically 2¾ inches and 3 inches. Always refer to the manufacturer's specifications for the best performance and safety.
Marlin started producing the 778 in 1979, production ended in 1984
To remove the buttstock from a Glenfield Model 778, first ensure the firearm is unloaded and safe to handle. Locate and unscrew the screws that attach the buttstock to the receiver, typically found at the rear of the receiver and possibly on the underside. Once the screws are removed, gently pull the buttstock away from the receiver, being cautious not to damage any surrounding components. If the stock is stubborn, check for any additional screws or clips that may need to be released.
I am not 100 % sure, but the research I have done indicates that they were produced from 1978-1984, with 1984 being the last year of production. The Marlin Model 120 is the continuation of the Glenfield 778 with some parts being interchangable.
Answer the glenfield by marlin is compatible with marlin 120 12ga barrels are available for the 120 the only difference is the stocks wich are also interchangable the 120 is higher quality I love my glenfieldThat model is obsolete and you are not going to find a slug barrel. If you must use slugs, you can have the existing barrel modified to accept interchangeable choke tubes and use a rifled tube when shooting slugs.
you can find them here... http://www.e-gunparts.com/productschem.asp?chrMasterModel=082Zz778
This is actually a Marlin 120 with a cheaper grade stock. In good condition I would take less than $200.00 for a sturdy and reliable weapon. It has been mechanically compared to the Winchester Model 12.
It has value as a shooter only - not a collector piece. $100-$200.
In good working condition $150 to $200
The Glenfield Model 778 shotgun, produced by Marlin Firearms in the 1960s and 1970s, had a retail price of approximately $100 to $120 when it was new. Prices varied based on the specific model and any additional features. As with many firearms, the cost could also fluctuate due to regional differences and market conditions at the time.