I have a CDI bottom metal to fit the Howa 1500 Short Action.
I never got round to fitting it as I mostly single loaded at the Range.
It will accept AICS 5 or 10 round magazines.
Far superior to the plasticy ones .
Details along with fitting instructions here,

http://www.cdiprecisiongunworksstore...-vanguard-dbm/

I dont think these are available in the UK now due to ITAR restrictions.

135 posted to your door.