I'm sorry about the confusion, but I've never once heard of a .300 WSM with a 26 inch barrel in a sporter configuration. I'd also be willing to bet you that it specifically says on Remington's website that the WSMs (yes they're magnums, but the "other" magnums are the ones with 26 inchers, you likely didn't ask if the WSMs had 26 inchers). By better performing, longer barrels will give better velocity, but a shorter barrel is a stiffer barrel and potentially more accurate if given the same contours. However, there could be enough variation between your guns that with a tighter chamber, smoother bore, shorter throat, etc, that your gun could be within 40 fps of your friends. Also, due to those differences, you dang well better not be going with the exact same handloads without first working them up, which you should be doing whether or not you also had a 26 inch barrel. Lastly, what difference does 40 fps make in bullet drop? About an inch and a half at 500 yards.
So, assuming your loads are safe in each others rifles, you can still use the same load data. I don't really see the problem, sorry.

Thanks exbiologist. I think in the end it will be Ok, but it is really frustrating getting to that point. The Remington Boone & Crocett is in fact a 26 inch barrel. I am aware of a couple other brands that also have the longer barrel for the 300 WSM. A large regional sporting goods outfit advised me to get the 26 inch barrel if going to the 300 WSM or any other mag. gun. The Remington rep. told me today that their information is not exactly correct because in certain places it says all magnum guns in the CDL 700 series are 26 inch barrels, when in fact only the long action mags are. He said the short action mags are all 24 inch. The problem is he is not correct. What he says is true of the standard 700 CDL line, but is not true for the Boone & Crocett 700 CDL line. No wonder there are so many arguments and disagreements on these forums. The manufacturers can't even get a person the right info. Why Remington would put out a limited edition gun (in this case the 300 WSM) with a 26 inch barrel, and then not follow through with the logic of needing the same barrel on the same gun with a different name is beyond me.

Oh well, dead issue.

In the end you will be looking at a minimal difference in performance(if any) but the quicker handling 24" barrel will be the envy of your buddy with the 26" barrel.

I would not worry about it too much. Consider the 300 RCM which is basically identical to a 300WSM. Hornady achieves (using powder they won't divulge) the same velocities out of a 20" barrel with a 300 RCM factory load that usually requires a 24" for the 300WSM in factory loads.

The 26" and 24" rule really goes back to a time when there was not nearly as wide of component selection that there is today.

You don't need the 26 inch barrel for the short magnums. One of the advantages of the short magnums is that you can to get rid of the longer barrel and still achieve the same velocities. The difference between the 24 and 26 in a WSM is not even worth thinking about.

I have a Ruger Frontier in .300 W.S.M. with a 16.5" barrel, do you think It would be possible to take game consistently at 300 yards with a barrel this short? I know you said a shorter Barrel is stiffer and usually more accurate but is this too short?

                                                Frontier

300 yds will be no problem with that rifle.  You will lose a little velocity but you will still have way more than you need to do the job.