I don't know the maker or caliber, but this clip is in excellent condition. It looks like it would hold a small or medium caliber bullet. It's 4-5/8" long, vented, and the tension works well. The blueing is good. The bottom reads: "19200- ASSY 5508694 MFR. 1M201". Please study the images and ask q's before buying. S/h is $7.00. Please, only money orders