.50 beowulf on a budget/enlarging feed ramps

[atilla]

so i got a midway catalog the other day and i noticed they are offering stripped barrels and bolts in some oddball calibers such as .50 beowulf.

http://www.midwayusa.com/viewproduct/?productnumber=694634

http://www.midwayusa.com/viewproduct/?productnumber=911522

i really wanted to do a crazy project for my 2009 NES lower and the more i looked into the .50 beowulf the more fun it looked like. the only thing missing for this build would be the actual upper for the rifle along with a bolt carrier, midway notes that:

enlargment of the feedramps and ejection port to 0.637" will be required for proper function.

this is to accomodate the larger cartridge but what exactly do they mean? will the feed ramps need to be cut to this size? is this a universal measurement that the feed ramps and ejection port will both have to be cut to?

i'd love some input on this as i've been short on cash and it was starting to feel like i'd never be able to do this build. compare building an upper to buying one from AA or another retailer stocking them and there are signficant savings when taking this path.

so what do you guys think? can anyone provide some insight into how feasible modification of a standard 5.56 upper really would be?

 

[vellnueve]

Dremel.