lazi, I have a remington speedmaster model 552. It's got a mini shroud over the ejection port. I used one like it that belonged to a friends older brother back in the 60's. I'm not sure when mine was made thought. Nice rifle. 22 short, long or long rifle! Not many of those around today!
Talk about coincidences! I have one of those too. It's actually my dad's, but I approprated it years ago. Love to shoot it. I killed my first squirrel with it, and my first deer as well. Lots of memories with that gun....
