Tikka T3 Long Action DBM. Replace your plastic and expensive factory DBM setup with CNC Machined DBM and Steel mags. uses AI 300 Win mag magazines, A great system for a fine rifle, it is a must do upgrade. There is a Maximum Overall length limitation on the rounds you can use with the T3 Long Action. Factory Length 300 WM mag length is 3.400" Approx, and you can't go longer. The 300 Win Mag is the only round that this is an issue with, 7MM RM or 30-06..etc are no trouble, just same Max OAL of 3.400". Install is required, and we can provide inletting and install services as well. Installs are free at CDiPrecision, so click Install option and send your rifle in for install. Easy and fast. 3 week turnaround or faster. US Addresses only. Mags Must be purchased Separately.