7 mm STW feeding question

[Blacktail]

A buddy of mine is thinking about builiding an STW. He has jsut about all the parts and a facory barrel in 7 dakota he will obviuosly swap out with a maybe a shilen or brux maybe a hart. He wants to build a lighter pack rig without bottom metal and has been told this wont work in the dakota as wont feed well. He was asking me about the stw having a feeding issue with a blind mag. I didt have an answer as mine has a removeable mag. Any thought or suggestions? Thanks guys