Blind mag question

[ofdscooby]

I asked this in the past but for the life of me I did a search and could not find it. I have a 116 action with a 7mm rem mag barrel on it I need to be able to load a berger load into the mag that exceeds the mag but not the action opening. How would I go about this? Thanks for any input.

I think u would Newark open it up to ultramag specs but how do I find a mag and the specs to do this