Yesterday in the concealed class one of the participants was trying to decide what to purchase for home protection and concealed carry. My response was to think about the abundance and cost of the ammo. While a well placed .22 shot would certainly be effective, and economical, it may not be the best round for home protection and concealed carry. .22 caliber can be purchased in bulk for an extremely low-cost and can provide hours of fun at the range.
Typically 9 mm is the least expensive round you can purchase. WalMart has 100 round packs of Federal for $20 and at times you can find ammo for even less. Now for carry I would suggest hollow point defensive ammo, but for the range, as long as the gun will function properly use what is affordable. Next comes .40S&W comes in second as an economical round and the 100 round pack is $27 at Wallyworld. On occasion .380 Auto can be found for a reasonable amount, I just found a rogue box hanging out at a Dick’s for $10.97. Generally .380 Auto and .45 ACP are about the same cost. Wally has the 100 round Federal in .45 ACP for $30.
In the case of this student I would suggest a 9 mm would be a good economical cartridge to select for concealed and home protection. If a revolver is more your style opt for a .357 magnum and you can shoot mostly .38 special at the range and carry .357 magnum cartridges and practice with .357 on occasion.