300 weatherby vs 300 remington ultra mag


Mar 21, 2004
Any thoughts on comparing a 300 weatherby accumark vs a 300 remington ultra mag sendero. Will the weatherby be less accurate than the RUM because of the freebore?
I have always believe that. A good friend of mine has worked at Douglas Barrels here in WV for 25 years and he told me that yes the freebore Weatherby's have less accuracy.

My practical experiences with the Weatherby rifles lead me to believe that also. I've never been satisfied with the accuracy of any I've had a chance to fire or see someone else fire!

But does the Accumark have the free bore? I was also under the impression that not all Weatherby's have freebore. But that might only be non (Weatherby) magnum.

Between the two I'd go for the Remington for sure! I like the 300rum better also!

"The Chuckster"

[ 04-12-2004: Message edited by: Huntinfool ]
My Weatherby Accumark in 300 Win Mag has quite a bit of freebore compared to other 300 Win Mags that I've owned but after removing the spacer in the mag box I was able to seat the bullets out farther thus increasing powder capacity. I've shot 180 Nosler BallisticTips at 3100fps with MOA accuracy to 400yds. I believe all Weatherby chamberings have the long freebore unless reamed with a custom reamer. After saying all of this I would pick the Sendero 300 RUM over the 300 Weatherby Accumark because in the end I think you can end up with a more consistantly accurate rifle with the Remington over the Weatherby. Plus as the previous poster replied "I like the 300 RUM better also"
I would seriously concider the Sendero and use the money you saved for a great scope. I just swapped my .300 Weatherby for a Bushmaster, my .300 ultra is more accurate than the Weatherby was. Weatherby didn't like boattails. It's my understanding that all Weatherby cartridges have the freebore, standard calibers don't.
I've heard that Remington is now "incorporating" the use of "factory throat erosion" in their rifles too. It allows the lawyers to be happier, and a cartrige to use hotter loadings safer. Although detrimental to accuracy. Although if I had to do it over again, I would go for the Remington also. NO belt, thats a big one, and Remington parts are extremely easy to find. OH yes, and the money you save you can invest in a scope! Think somebody already said that, smart!
Personally, I don't like Weatherby rifles much, never will own one. I don't mind a belted case if pressures are kept down, but always prefer a nonbelted, the Ultra for example would get my vote.

I talked to John Hoover today, he said he was getting 3500 fps out of his 32" barreled 300 Ultra with a 210 JLK with brass lasting 3-4 firings. He said it does a number on the deer meat though.

Freebore might be a source of inaccuracy but, I think it may have more to do with people bumping the shoulder back too far on the belted cases that leads to problems with alignment to the bore.

I think you're better off with a Winchester or Remington in the long run, Armalite make a **** nice rifle too. Aftermarket goodies for a Ruger are still better than a Weatherby and they make a good rifle, just not as much out there for them like there is for the remchesters...
Well, I like my 300WBY, but it is a custom job so I was able to control for alot. It shoots .35 groups at 100yds consistantly. I don't like the Remington - because then you are stuck with remington brass, which I have not found to be good. I do like the 300UM, but I just would like to have better componants available - I know you can get federal ammo - but I reload. Weatherby/Norma brass is way better. The headspace issue with the belted mags is not an issue anymore if you reload - so don't be food by that old mantra.
I have had several problems with remington ammunition and componants, so I am not very objective on this one. Remington has also been less than helpful when I have went to them with concerns about their products. I also love the 300WBY. You can get a little more speed out of the 300UM, but in reality not that much. But you can go either way - you wont be disapointed.
I like my 416WBY, but I converted my Ruger Magnum bolt gun in 416 Rigby.

My Grandfather's fav is the 300WBY, he's had it forever and pounded tons of Moose with it many a year.

Problem is, guys adjust the die down on the shellholder and get to loading, paying no attention to how far they're pushing the shoulder back, which is TOO FAR to keep the shoulder snug against the chamber and the case well aligned with the bore... improper die adjustment IMO.

Black Hills and Midsouth Shooters Supply has Federal brass for the Ultra, I'm told, which shouldn't be a soft as Remington stuff.

Federal case weights are all over the place, remington's a bit better. I did measure the Remington stuff I had from three seperate lots of factory ammo. A 4 grain spread in case weight proved to only be less than two tenths of a grain spread in actual case capacity when weighed with water though, and that was checking all 60 cases. It don't get better than that.

Once you overload a belted case and it gets sticky over the belt, which they will, you can't size it down with a FL die like you can this same pressure expansion ring area on a non-belted case, simply an inferior design from a reloaders standpoint.

I'm not ready to get rid of my WBY chamber but, I do keep the pressure down below what expands the belt after the initial fire forming. If I could, I'd but Lapua brass for any belted case I could.
I wonder.........?

Brent, you mention the brass being of the same approximate internal capacity even though the weight is off by as much as 4 grains. This means the brass is inconsistent in its thickness. Now, when that brass expands to fit the chamber walls snugly and consistently...isn't the internal capacity inconsistent? In other words...the eventual external capacity is always the same at the time of pressure peak...namely that of the chamber dimensions. But the internal capacity at this same moment is equal to the (consistent) external capacity minus the (inconsistent) case wall thickness.

Not sure my mind is saying that clearly...leaving for prairie chicken photography in a few minutes...4 am!!! Gotta get some caffiene in me.

[ 04-13-2004: Message edited by: Len Backus ]
Littletoes, some of the early ultra's had excessive freebore. With the pair I bought, I could kiss the lands with most hunting bullets and still fit in the magazine. I've also picked up a .223 and a .270WSM in a rem, and they both have "normal" throat lengths.

The .300 Weatherby can be made to shoot accurately, look at some of the 1000 yard benchrest match results. For an over the counter rifle, I'd take the ultra.
AJ300MAG-Yea, it was the early ones that I knew about. Didn't know Remington decided to do something right! My Weatherby shoots well, although just a deer/elk rifle. But it does like flat based bullets better. It was the premier 1000 yard caliber at the Pennsylvania club for years. I love mine, and would not trade it for a Remington, but COST, when we are talking over the counter rifles. I think the Weatherby action is quite a bit stronger too. Talk about over-kill!

I think the 4 grain spread in this case was not inconsistant case wall thickness but, rather inconsistant extractor groove cuts and primer pockets... that's my guess anyway. These factory loads were all fired, so the cases were formed to the chamber in my rifle pretty well.

Sounds like BS, but I assure you I was just as surprised myself. Anyone that weighs and segragates their cases may want to look a little further and weigh them with water too. The easy way is to tare the scale with each case and record the weight of water. I weighed the case, then both, then subtracted the case weight to learn what I did.

Weatherby, stronger. Boy that sounds like a good debate.
Thanks for all the feedback. Boy, tough call. Sounds like the 300 RUM is getting the nod. Here's some more food for thought. I am currently not set up for reloading and will be buying factory ammo. Now how would the accuracy compare? I suspect with the riduculous price of weatherby factory ammo it should be of high quality and comparible to handloading in the accuracy department. One would at least hope so.
If you arn't into handloading, and buy the Weatherby, you soon will be. Or you just won't be able to shoot very much. The price IS high, and the availability isn't there. Of cource the same may be true of the Ultra Mag too. I have never purchased them, so don't know.
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