Best left to a gunmsith. Actually on the high Standard 22 target pistol
it is very easy to remove the barrel. You don't even need tools. Start
by locking the slide back (small lever on the right side) Then you'll need
to depress the large plunger which protrudes forward under the barrel.
The best way is with a plastic mallet or a piece of wood. The spring is
quite strong so it takes quite a bit of force to depress it all the way in.
While holding the pin fully depressed, the barrel just lifts off. (straight up).
After the barrel is off, the slide can be slid off toward the front.
Contact High Standard with the Serial Number and they will tell you when it was manufactured.
BLue Book of Gun values
I own a .22 High Standard Victor and owned it for over 30 years. I have put over 30,000 rounds through it. I have the 4.5 and 5.5 inch barrels. This is the most accurate pistol I have ever owned. It is easy to clean and shoot. J.C. Beaver, OH
The Supermatic Trophy used the ML prefix from 1951-1953.
The term usually refers to GENTLY changing the curve of the lips of the magazine to improve feeding. Usually by bending.
Who made it?
For the most part, the high standard victor was made from 1971-1981 depending on the features. The 4 1/2 and 5 1/2 in slabbed sided barrel with the vented steel ribs were made from 1971-1973. The 4 1/2 and 5 1/2 in barrel solid aluminum rib were made from 1973-1977 and the 4 1/2 and 5 1/2 in slabbed barrel with the vented aluminum ribs were made from 1973-1981.
No, you need to buy another 12 inch barrel with spyder threads on the back.
25-100 USD or so
High Standard.
Under $100.
The odds are almost nil.