Gunsmith or maker.
H&R Handi-Rifle
50-165
1/10
50-200 USD or so
$200-$250, depending on condition.
The year is determined by the first letters not the numbers.
About $225, depending on condition, caliber, scope, etc.
No published sn data. You will have to call the factory.
To determine the year of manufacture for a Handi Rifle with the serial number 219827, you would typically need to refer to the manufacturer's records or a reliable database, as they often use specific serial number ranges to indicate production years. Generally, the Handi Rifle is produced by H&R 1871, and their serial number system can vary. It's recommended to check with H&R customer service or a firearms expert for precise information regarding that specific serial number.
The one issue with 5.56 in a handi rifle is the harder primers. You will almost absolutely have to install a heavier hammer spring. I have some Malaysian 5.56 and it often won't fire in the handi. I have heard the same about the Rossi single shots. As far as your concerns about pressures, the Handi handles all sorts of calibers on the same frame and barrel blank. Many of those push 65k or so. I don't worry about any difference in 223/556.
Handi means activities done with the hand
Gun is dirty- needs cleaning and lube. Parts worn, parts broken. Start with a proper cleaning and lube. If that does not fix the issue, have a gunsmith inspect parts. And it is a Handi-Rifle, not handy.