I've acquired a nice Stevens Walnut Hill target rifle in .22 Hornet that belonged to my wife's grandfather. He was a chemical engineer at Dow Chemical Co and was experimenting with manganese alloys, so he added a manganese butt plate, fore end, and pistol-grip end. I can't find a serial no. or model no. on this rifle, so if anyone can help me identify it, I'd appreciate it. 

This is a beautiful firearm, though I haven't fired it yet because the old Weaver scope is cloudy so you can't get a good sight picture. And there are some odd features about this rifle. One, there is no safety, or even half cock. And when you work the lever to chamber a round, the hammer doesn't cock, meaning that you have to thumb cock it. But the small hammer spur makes that difficult and uncomfortable. Is this normal for a Walnut Hill? 

I hope the photo I've tried to attach will give someone enough info to help me identify this rifle. 

Thanks guys.

Should be speed lock as previously stated. If the barrel is marked Walnut Hill it should be one. Stock is not factory. The loop lever was an option as I recall. Think I have one on a .22. The .22 Hornet is extremely hard to find in these. Too bad the stock has been changed. I recomend light loads and .223 bullets if you can find them. Early .22 Hornets had .223 barrels instead of .224. The 44 action proved to be not strong enough to handle the Hornet and tended to loosen up the action quickly. Thats why they droped it after a year or so. They are accurate like most Stevens but I recomend light loads and shooting it sparingly with .223 bullets. Seria should still have them. More photos especially of the barrel markings would be helpful.