CIP length AICS will .300 Win Mag work?

Wow I do not cease to be amazed with the expediency of the answers I receive on here. Okay so next question would be; will .300 Win Mag feed from a .338 magazine?
 
Yes 300 WM will fit and feed from 300 WM CIP mag. 300 Ultra and 338 Ultra also feed from CIP mag. I use 300 WM CIP mag for my 300 and 338 Ultras in a McRees stock. You have to cut the shoulder stop in the mag away for the ultras. Hope this helps and post if you need more info.
 
Yes, they make both a 300 WM and a 338 LM mags in the CIP, you can get them from McRees. I found the LM was to wide for the Ultra but the WM was better cuz the belt on a WM is the same Dia. as the body of the Ultra. If i'm not clear just keep asking.
 
For 300PRC, you have a couple choices:
  1. Use the 338 Lapua CIP length AICS mag and plan on bending the feed lips so it works properly
  2. Use a 3.850in 300wm AICS mag
MDT’s magazine for option 2 seems like a great choice.