$300+ is too steep for a used Henry .22 IMHO. Even their most expensive .22, the Golden Boy, can be had for $375 new around here. The cheapest I've seen the basic model for is $239 new. The Frontier (octagonal barrel) model is $315 new. I'm ignoring the custom hand inscribed models which obviously can run hundreds and hundreds more.

Bass Pro Shops had a Remington 597 .22 with 30 round magazine and 3-9x32 scope for $150 on Black Friday. I don't think those sell for significantly more than that normally. I've never shot or held one, but I have a friend who says he really likes his.

I have an old, no longer made, Winchester 190 .22 (semi-auto tubular magazine). They are decent guns, so if you find one used it might be a nice purchase. I think they vary from $100-$200 used these days. Mine was bought for $39 about 40 (or more) years ago.