<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body">Shouldn't have any issues with the rifle fit. I'm not sure if you'll want to use the 300 win mag or the 338 Lapua magazines for feeding the ultra mag.</div></div>
That is something I hadn't thought about, good point...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body">Shouldn't have any issues with the rifle fit. I'm not sure if you'll want to use the 300 win mag or the 338 Lapua magazines for feeding the ultra mag. </div></div>
IIRC the boltface for the 300RUM and 300WM are both .540 and the Lapua is .585
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Training Wheels</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body">Shouldn't have any issues with the rifle fit. I'm not sure if you'll want to use the 300 win mag or the 338 Lapua magazines for feeding the ultra mag. </div></div>
IIRC the boltface for the 300RUM and 300WM are both .540 and the Lapua is .585</div></div>
So its safe to say the .300WM mag is the way to go?
Order an AICS 300WM magazine and see if the RUM will fit, I don't know the ID of the magazine but the RUM is approx .2 or .3 longer than the WinMag. If the RUM OAL is too long for the WinMag magazine then exchange it for a LapMag magazine and order the appropriate chassis. Post your findings, I'm not but I'm sure others have a RUM and may consider the AX chassis.
I'm doing a 338 RUM Sendero in a AICS. I have to mill out the front reinforcing rib in the 338LM magazine to clear the shoulder of the case. The 300 RUM is the same case as the 338 RUM, except of course the case mouth dimensions. So, I would say 338LM mag. Call Mile High. They would know for sure.