I am putting together a customer gun chambered in 28 Nosler. I have a Manners stock set up for the Remington BDL magazine system. I was told I need to get the Wyatt's Outdoors internal magazine but I am not sure what Remington bottom metal to get. Do I need to be sure to order bottom metal for a Long Action Ultra Magnum?

Please let me the difference between the Remington Long Action Magnum and Long Action Ultra Magnum BDL bottom metal kits.

28 Nosler

3.340 Overall length of cartridge

.534 diameter

.308 is

2.810

.473 diameter

300WM

3.340

.5.32 diameter

What you are looking for is AI mags for 300 Win Mag or the magpul plastic version and the bottom metal to match those.  Note they are single stack mags and the 10 round AI ones are hard to come by and spendy.

Not sure how much those long action mags run but the 308 ai are about $90. Magpuls $33. But, just learned that ruger also makes them for their RPR and they run about $29. Check to see if they make a long action version. And they all can be found on sale.

Just checked. I see the rpr in 300wm but I can't find magazines listed.