.257 Roberts AI feeding issue

[BUSTINDOGS]

Anyone have trouble getting the .257 Roberts Ackley improved to feed out of a rem 700 long action? I have my rifle that I re barreled to a 6.5-284. that I'm now going to re barrel again to the Roberts. I bent the feed lips of the mag to work for the .284 case and I'm hoping that I can just buy a new standard magazine. As I'm sitting here playing with a dummy round for the Roberts it's not feeding from my modified mag at all.
Thanks

 

[ShtrRdy]

in what ways is it not feeding?

 

[xr650rRider]

I've got a Defiance Classic long action and 257 Roberts AI feeds fine but I'm using a Wyatt's extended box and using hinged floorplate.

 

[Philward]

Bdl, adl, factory dbm? Or some other aftermarket dbm setup?

 

[Crockett12]

The 284 brass is different than .257 Roberts Ackley improved! I'm not surprised it won't feed!

 

[BUSTINDOGS]

The issue is the either the back of the case pops out and gets above the bolt or the front of the shoulder jams up on the back of the barrel. This is factory Remington detachable box mag