Crosman 459MTC 4-Piece 3/8-Inch Airgun Scope Dovetail Mount Rings

Everything That Was Needed To Repair Was Included In Kit.

These mounts are specifically manufactured, and advertized to fit the Crosman 13XX series variable power pellet pistols (1300, 1322 & 1377) AND some other specific Crosman pistols and rifles (2240, 2260...). If you don't have one of these, then don't buy them and give them a bad review (or do your THOROUGH research first- but don't complain if they don't work for YOUR application).These are of good design to fit the aforementioned guns and are manufactured with close tolerances making a secure attachment 100% possible. There is no way these will "normally" become loose, or not fit on the barrel- even without shims or tape- unless you bang your attached sight (red-dot, scope, etc.) around or have stripped the screws. What some of you might experience is the slight movement of the barrel in the receiver which imitates a loose mount. And in RARE conditions you did find the need to shim in order to tighten the mount's grip, I'd place some plastic or metal at the TOP of the 3/8 (dovetail) "rail" in order to keep that area of the Intermount 459MT from closing in while you tighten the screws. This may, however, widen the "rail" some making your attachment of the sight a little more difficult. Make sure the barrel and mounts are oil and grease free before attaching! Also, if you over-tighten your scope, red-dot, etc. on the mount, you will, of course, loosen the grip of the mount on the barrel (DUH). If this occurs, remove the sight, carefully re-tighten the mount then re-attach your sight firmly but not too tightly.Although I don't have all the pistols this mount will fit, I do have both the Crosman 1300 Medalist II and the 1377 which the mounts fit perfectly and have a set each on both guns. Could they be designed better... possibly. Are they Mil-Spec... no. Could they be made of higher grade metal... of course... but then they would probably cost more than the gun they were designed for.So... I hope this clears it up for both those who claim they won't fit and those of you whom are indecisive on whether to purchase or not. Amazon has a good return policy and will provide a return shipping label if you do have (legitimate) issues... provided you aren't yelling at them when you contact customer support!Food for thought about any complicated process (like this): If you're an adult having a problem attaching these mounts, give it to a kid to handle... If you're a kid- give it to an adult to fix.

As several other reviewers have mentioned, the mounts and the added weight of the scope cause the barrel to move. This is not a great design. It is easily fixable, but I'm a firm believer that you shouldn't have to "fix" something that was specifically designed for this purpose. That's called bad design. It is probably because they designed these to work on multiple pellet guns, so they had to loosen tolerances. I understand that, but it seems like they should have built in "adjustments" to make the design work as intended.I installed these on a 1322 and mounted a rather heavy scope with integrated laser and LED reticle. Everything worked well, but there was clearly "slop" between the barrel and the rest of the pistol caused by the scope/mounts. I read several reviews somewhere, as well as here on Amazon, about putting tape or other "spacers" under the mounts to "stop the slop". This works. Again, bad design/implementation by Crosman, but at least there is an easy solution.For my particular situation, I first used small pieces of rubber eraser. That didn't work. They rubber flexed to much and slid out of place. Then, when I made the rubber shims thicker, the mounts chopped them in half. Rubber eraser was a fail.I then cut off small slices (3/16"x1/2") of a point-and-shoot camera strap. It was the typical nylon webbing strap most old 35 mm camera's had to dangle the camera around your neck. There were several other webbing straps on all kinds of devices that I thought about using, but since I never use my old camera (Canon 35mm waterproof) any more, it's strap got cannibalized.That said, after I cut off 4 shims from each side of the strap, I just melted off the end of the strap with a lighter and can't really notice that it was shortened. There was plenty of extra, unused strap length. Cutting off less than an inch of it didn't really make a different.I took the "shims", but places them under the feet of each mount. Tightened them down (carefully, since other users have made me paranoid about the screw threads stripping). The webbing shims worked perfectly. Closed the space under the mount. No more wobbly scope.It's been rock solid for months now. Stays zeroed on the scope and laser.

Fits my 1377 & 1322 perfectly, it also fits my crosman drifter pistol as well. I've always wanted to mount an optic on these pistols but never could until now.

It would be better if they were steel but they are hard plastic. I just don't know how long the scope will keep it's accuracy.