Suggested value is from $50 to $150.
Impossible to answer without knowing if it is a rifle, handgun, shotgun and the caliber/gauge.
No such thing as a 20 caliber shotgun. 20 gauge is the correct term. Blue Book of Gun Values will help. Actually, it can be called both. Especially, if the barrel has 20 Cal. etched on it.
Shotguns are normally referred to by gauge, not calbier. 28 gauge is .55 inches.
I saw one in 90 % condition with pitted barrel sell for $150.00
value of any firearms depends on overall condition and collectibility. the h&r is not a great collector piece. Also, there is no 22 cal 'shotgun' ??? check the gun barrel to see caliber listed.
Who made it, what caliber is it, is it a rifle, shotgun or hadgun, how long is the barrel, is the barrel round or octagon, what is the stock made out of, what is the serial number(if any)? Who made it, what caliber is it, is it a rifle, shotgun or hadgun, how long is the barrel, is the barrel round or octagon, what is the stock made out of, what is the serial number(if any)?
Depending on overall condition,the price will range from 200-320 dollars.
what is the value of a Ithaca 12 ga shotgun
Those later Model 24's are bringing around $250 in excellent condition.
You do not mention if it is a shotgun or rifle nor the gauge/caliber. Without a description of all features, markings, etc. there is no way to reliably value it. You could be in the 50 - 500 USD range give or take.
== == What is the value of 30 caliber Winchester 1894 ?