The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Gunsmithing Converting Rem. 700 to 300 Ultra from belted Mag.Go | New | Find | Notify | Tools | Reply | |
| Converting Rem. 700 to 300 Ultra from belted Mag. | Login/Join |
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Do you have to change the magazine box and follower? Can you use Rem. factory parts? | ||
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I don't think it will work! The Ultra Mag's are a lot longer than the belted mag cases. EXAMPLE: There is barely enough room on an RCBS Rockchucker press to load 300 RUM. Sorry guys, but I didn't think it would work! I've loaded both and just didn' think they were close enough for the conversion! I know some of you guys are gunsmith's and know that you are more knowledgable than I! Chuck - Retired USAF- Life Member, NRA & NAHC | |||
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The U'mag box has holes in the sidewall to allow 3 ctgs. to be in the box, available from Brownells. Slight work needed on the feed rails, also. Compare factory rifles in both calibers and you will see what is required. | |||
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I have done it. Order a ultramag box from Remington and reuse the "regular" magnum (300Win, 7mmRem, etc.) follower and spring. The feed rails need to be opened up a bit. You can do it carefully with a file. Remington uses just one length long action for everything from 270 Win to 416 Rem Mag with different bolt faces. The Ultramag and "regular" magnums use the same boltface. Good luck. "There always seems to be a big market for making the clear, complex." | |||
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To convert my 4 ultra mags all I had to do was open the feed ramp to full width and replace the mag box. It holds 3 in the box and feeds flawlessly. Not a really bad conversion. Not hard to do. Careful about opening the feed ramp. Did nothing to the feed rails. Olcrip, Nuclear Grade UBC Ret. NRA Life Member, December 2009 Politicians should wear Nascar Driver's jump suites so we can tell who their corporate sponsers are! | |||
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Olcrip, Do you have any photos of the before and after for the feed ramp mods? RELOAD - ITS FUN! | |||
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Elk Hunter, I don't have any pictures. The mods I made were really quite simple. The feed ramp is narrower than the front portion of the feed rails. I opened the feed ramp up so that it was as wide as the front part of the feed rails. That allowed the shoulder of the case to feed up the ramp without flipping the case out of the restraints of the feed rail too soon. It feeds just fine now. The shoulder was the culprit that wouldn't allow it to feed without jumping out of the mag too soon. The only change to the feed ramp is to make it wider and not change the angle or any other aspect of it. Olcrip, Nuclear Grade UBC Ret. NRA Life Member, December 2009 Politicians should wear Nascar Driver's jump suites so we can tell who their corporate sponsers are! | |||
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so i have a rem model 700 in 7mm mag i could change this to a 300 ultra with a new barrel? | |||
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Well, there are probably more than one way to skin a cat or get an Ultramag to feed. I didn't touch the feed ramp, but did open the rear part of the rails from about .555" to more like .565" wide. I would be a little goosey about removing much metal from the ramp just because it is in fact the rear of the lower lug recess. That said, I have a stainless 338 RUM factory action that does look like the ramp was widened and maybe laid down a bit from the factory. As far as why do it, I suspect the most common reason is to get a better than factory barrel chambered to a RUM. I did it because I wanted a blued Ultramag, while at that time Remington was inflicting some hideous scaring to their receivers and selling it as "enhanced engraving" and I objected. An unused 300 Win mag action, a new takeoff barrel from ebay and I was happy. Since I have a lathe and do my own work, it was affordable also. Good luck! "There always seems to be a big market for making the clear, complex." | |||
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I have a 300ultramag that was originally a standard belted magnum.The feed rails were opened up slightly and the magazine box changed and the rifle feeds fine. | |||
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Interestingly enough, I have yet to hear of an ultra mag which doesn't feed great and have yet to see one which does! By opening up the feed rails to Remington's dimensions and replacing the mag box with the factory offering, you should end up with an ultra mag which feeds no worse than the factory offering. This means, if you operate the bolt quickly, you should be able to get the second round into the chamber before it stovepipes or jumps out onto the ground. Another trick employed by satisfied ultra mag owners is to hold your fingers over the loading port to help guide that cartridge home. A better system is to widen the mag box and mill the receiver to accept the wider box. This is probably what Remington should have done in the first place rather than to simply cut windows in the box. Regards, Bill. | |||
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I have two 300ultramags built on 700actions and both feed well even when cycled slowly. | |||
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Stubblejumper, That's good to hear. Like I said, I never hear of any which don't work well but every one which comes into the shop does not. In every case, the rifle is brought in for bedding or some other work. At some point the customer will say. "Oh, by the way, sometimes there is a bit of a problem with the second round. Could you have a look at it?" It seems to me the Ultra mags are a lot like the WSM's and SAUM's and WSSM's. They all work perfectly in all respects. They shoot faster, farther and more accurately than anything previously seen and represent the zenith of American cartridge developement knowhow. The rifles are perfectly engineered and the companies involved are to be admired for their innovative research and development. It says so in the brochure. Regards, Bill. | |||
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McRay,  I didn't change anything about the feed ramp except widen it. The angle or pitch remained the same as well as location. The alteration is exactly as the factory change for the ultra mag. The shoulder is wider on the ultra mag and pops the case out before the bullet can enter the chamber area. Widening it allowes the case to enter the chamber area without problems.  Olcrip, Nuclear Grade UBC Ret. NRA Life Member, December 2009 Politicians should wear Nascar Driver's jump suites so we can tell who their corporate sponsers are! | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Gunsmithing Converting Rem. 700 to 300 Ultra from belted Mag.
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