l recently bought an AA S410 pcp and the kit included a XT-3005 Chronograph unfortunately there appears to be some parts missing as l could not mount it securely to the barrel/moderator so what l did was to hold it in place and visually check the gap around the moderator then cut four pieces of heat shrink tubing to place on the locating studs check the gap again and then place more heat shrink tubing to place on the locating studs l did this until the gap was filled and the unit sat quite snugly on the moderator , not sure if it will stay in place without rubber bands so to be safe l will secure it with a few bands.