Mossberg .22s are an addition. You start with one then you end up scouring the shows for them. They are gaining alot of popularity the last couple years too. I have a few myself. They were well made and many had some very nice wood on them. I would have jumped on a complete 152 for anything under $225 in very good condition.
Here's my small herd, front to back: 146B T-bolt, 144LSB, 25A, 44US
And here's a weirdo, PMA-1P. Yup, it came from the factory like that:
I have others, but they're camera shy.
Good Mossberg info sites:
http://www.rimfirecentral.com/forums...splay.php?f=51
http://home.epix.net/~damguy/index.html