opening the feed rails on a 700

[340wby]

Has anyone out there ever opened the feed rails on a Remington 700? I was going to make a 300 ultra mag on a standard Remington 700 Magnum action,(which was a 7mm mag), but I see in order to do this i need to open the feed rails.

[quack1]

I have never owned a 700, but if I remember correctly from when I worked in a bluing shop 35 years ago and litterally took hundreds of 700's apart, the feed rails are part of the sheet metal magazine box. The actions were all the same (long or short) and the magazine boxes had different bends at the top for different calibers. Maybe someone else with a better memory could chime in.

[fourarmed]

I would suggest taking a good 6" steel scale or caliper and finding a gunshop with a RUM rifle in stock. Measure the gap between rails, and compare to your rifle. Or ask somebody on this board to do it. Surely somebody on here is shooting cast boolits at 3700 fps.

[Nobade]

I've done quite a few of those, and it's not really a big deal. I do the feed rails on a milling machine to get them straight and use a die grinder on the feed ramp to open up the sides. I do recommend that if you have an ultramag action available you put the two side by side and look at the differences. They are minor but important. You'll also need an ultramag magazine box. That all said, I don't recommend you convert one to ultramag. Even the factory guns don't feed very well, and sometimes it's very challenging to get them to work right when you convert one. If it were mine and I had to get more speed, I'd just rechamber it to 7mm STW and have basically the same thing but it will feed properly.