I am planning on having a custom remington 700 built in .338 Ultramag. My friend has already started the same project and was told by a gunsmith that he needed a .338 Ultramag action on which to build a heavy barreled target rifle. The reason being that there is a cartridge specific difference ("the feed ramp is different") in the receivers for .338Ultra rifles compared to the receivers of rifles in different LA calibers. The impression that I get is that all Ultramag receivers should be the same, including the feed ramp. Is there a difference in the recievers for .338 Ultra rifles and those of other calibers, including the other Ultramags? The reason that I ask is that I am trying to obtain a suitable receiver and it seems that .338Ultra rifles are the most scarce. It seems more likely that I will be able to get a good deal on a rifle of a different caliber, possibly a 7mmUltra or .300Ultra. Also I will be using an Accuracy International stock which uses a center feed magazine. Using this magazine the bullet nose uses only the uppermost part of the feed ramp. Does this change the story on the whole feed ramp issue?

any advice or imput would be greatly appreciated. Any Remington experts out there?

Elephantrider--
Not to disrespect your 'smith, but BULLSHIT... I have a .338 RUM built on a regular M700 magnum action and with the addition of the RUM mag box, it works fine. There is no difference in the geometry of Remington magnum actions(especially the feed ramp), regardless of caliber. The rails may be able to use a little tweaking, but that is true of all factory actions, especially when you rebarrel to a different caliber. You also will need the RUM magbox and follower, if you want to get two in the mag using factory equipment. Using the center feed AI stock/magazine should fix any feeding concerns you would have with the factory stuff. Good luck, CJ

[ 02-21-2003, 02:01: Message edited by: Chris Jamison ]

I have built several Ultra Mags on regular M700 Long actions with the magnum bolt face. Ultra mag actions from Remington are the same as the other magnum actions. Difference is the windowed magazine box, a short cut to give a wider stack in the box for feeding.

BUT!!!! for reliable feeding one needs a wider magazine box, rail tweeking, and some ramp work (this is bullet nose shape dependent) to widen out the ramp to a broad U shape. AND!!!!! to use the potential of the Ultra Mag case one also needs a longer magazine box for about a 3.750" or longer cartridge overall length. (Allows getting the base of the bullet out of the powder space, standard M700 magazine length of about 3.650" is too short for the Ultra Mags)

A center feed box, with a vertical stack, would certainly remedy some of the feeding issues.

Feeding can be tricky with the Ultra Mags. I have had new, fresh out of the box, 300 Ultra Mags that were on the ragged edge for reliable feeding. Depending on how I worked the bolt and how fast, I could cause a stove pipe or have a round jump out of the magazine and miss the chamber.

To sum up, take the rifle to someone that has experience with making the Ultra Mags feed.