snipersustainment

i shot a friends tikka t3 varmint 223 last week. 1 in 8 twist, and mag fed. i think this would be a great rifle for the ai. my question is, has anyone successfully modified that plastic mag to accept a longer oal?

doesn't look like the t3 has much of a following. can anyone recommend a detachable mag system that would feed a long oal 223ai? this project is starting from scratch, so it's a blank canvas.