The Accurate Reloading Forums
300 Win Mag to 300 Ultra Mag

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10 September 2005, 07:10
Fish30114
300 Win Mag to 300 Ultra Mag
Will the dimensions of a 300 Win Mag allow it to be rechambered to a 300 Ultra Mag?
10 September 2005, 07:39
Kingfisher
Unless the barrel is real thin up near the action (and it shouldn't be) you should be able to have it reamed out to 300 RUM.

You can expect a bunch of folks to follow this with "Why would you want to bother with having it reamed out to 300 RUM when the 300 Win Mag will still do the job... yadda yadda yadda" Smiler
10 September 2005, 08:38
JustC
even a factory sporter tube should handle a rechamber to RUM as long as it has never been set-back or cut off at the chamber end. You may need a new magazine follower and some work to open the feed rails as well. The magazine box is also different in the rem700's (I think)


Difficulty is inevitable
Misery is optional
10 September 2005, 09:21
stubblejumper
quote:
You may need a new magazine follower and some work to open the feed rails as well. The magazine box is also different in the rem700's (I think)


I have a 300ultramag built on a standard 700 magnum action and you are correct about the feed rails and magazine box.
10 September 2005, 17:26
PC
If you want the rum go for it, as others have said if the barrel profile is not to thin you will be fine, you pick the .300 RUM over the .300 win mag for the same reasons you pick the win mag over the 30/06.
10 September 2005, 19:04
skb2706
I believe the bolt face dimensions are different also. I have at times considered this project for my .300 Win Remington Sendero but I always come back to reality and decide the gains don't outweigh the negatives....for me.
10 September 2005, 19:16
<allen day>
I can't help but think that the easiest, cheapest, and best fix is to trade your 300 Win. Mag. in on a factory rifle in 300 RUM......

AD
10 September 2005, 22:26
Fish30114
AD, you would normally be right, but this rifle is an oddball takedown from Sauer that I wound up with, got several in 300 win, and don't have a rum yet, just wondering......
11 September 2005, 00:19
stubblejumper
quote:
I believe the bolt face dimensions are different also.


Not true.The bolt face dimensions are the same.
11 September 2005, 00:35
Snowwolfe
I always thought the 404 jeffery case that the RUM was designed from required a larger bolt face. Dang, I guess I should of read up on it more. Thanks


My biggest fear is when I die my wife will sell my guns for what I told her they cost.
11 September 2005, 00:42
stubblejumper
The 404 jeffery case does require a larger bolt face due to the larger diameter rim, but remington uses a rebated rim on the ultramag cases in order to keep the bolt face the same as the standard magnums..
11 September 2005, 02:22
JBabcock
"Why would you want to bother with having it reamed out to 300 RUM when the 300 Win Mag will still do the job... yadda yadda yadda"

Cool
11 September 2005, 02:52
PC
quote:
Originally posted by JBabcock:
"Why would you want to bother with having it reamed out to 300 RUM when the 300 Win Mag will still do the job... yadda yadda yadda"

Cool


jump
11 September 2005, 04:01
djpaintles
quote:
Originally posted by Fish30114:
AD, you would normally be right, but this rifle is an oddball takedown from Sauer that I wound up with, got several in 300 win, and don't have a rum yet, just wondering......


On a RemChester the conversion is relatively straight forward and not too awfully expensive, thought AD is probably right about just trading for an already RUM. On a Sauer however I wouldn't want to touch the conversion. Parts are too expensive, the magazine box probably won't fit etc.
IMO a RUM is worth doing, but only in the right platform...................DJ


....Remember that this is all supposed to be for fun!..................
11 September 2005, 07:17
Fish30114
DJ, thanks-- I am only interested if the mag box situation will work ok. The action is the same for both calibers, so I was hoping it would be pretty straightforward.

Just wanted a new caliber, I'm sure 300 win is fine, just scheming.... as one of my partners once said;

'once you've got a shower curtain in your trailer, your past the "need" stage'.
11 September 2005, 08:18
Kingfisher
Oh cut it out you two!!! lol
14 September 2005, 01:04
olcrip
[Fisher30114, shame don't you dare touch the feed rails. shame
I have coverterd several Rem. Mags to RUMs. The only modification you need to make is to open the feed ramp as wide as the front openning of the feed rails...... You will need a RUM mag box. I used the original ADL follwer in the ADL mag box but the window cutouts allow for the 3rd round to fit into the mag box. shameCAUTION; don't change the feed ramp any other way except to widen it so the RUM shoulder will pass without kicking it out. All my RUMs work flawlessly with the simple mods I described. I used take off Rem. Stls. barrels and they all shoot under an inch, perfect for a hunting rig. Good luck, I think you'll love it after you try it. beer


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!
14 September 2005, 07:21
Fish30114
olcrip, thanks for the info. I had checked Sauer website, and the action and everything else except the mag box and barrel were the same as the 300 win mag. I'm hoping this won't be that big a deal, I have left a message with customer service to see what would be entailed if I just ordered a factory RUM barrel, they felt it would be just a new mag box, but the lead time on the barrel is 6 to 10 months! I was hoping I could just get my current barrel rechambered and get a new mag.
15 September 2005, 02:32
olcrip
You can rent a reamer and rechamber your 300 win mag on the cheap. You can also buy a Rem. take off from a new gun in Stainless RUM pretty reasonable. beer


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!