The .25-06 is a fine round but in my opinion it is on the bottom side for elk cartridges.  If it was me I would load it with the 115 gr TSX just for the added weight over the 100 gr bullet.  Also don't kid yourself a cow elk is just as hardy as a bull when it comes time to drop them so don't underestimate them.  The bullet will still have to crush heavy bone to get to the vitals if a shoulder shot is taken and even a Barnes bullet will be doing all it can to get the job done with that shot.

Now don't get me wrong, there are elk taken every year with the .25-06 and even the .243 but there are better rounds out there where the margin isn't as great.  But if that is all you have then like I said load the 115 gr TSX to around 2900 fps. and practice with that load it will get the job done.   

I would have to argue with the previous post, guide or not, stating that the 25-06 is a fine round for elk.  It is fine for deer, but it's considered a marginal caliber for an animal the size of even a cow elk.  With that in mind, I have a Ruger M77 that shoots the 117 grain Hornady BTSPs with fantastic accuracy and efficiency on antelope and the occasional mulie in Wyoming.  I move up to my 30-06 with the Interbonds when talking about elk and would suggest if you have to use the 25-06 that you get a box of 110 grain Hornady Interbonds and work up some handloads with that heavier grain bullet.  I'm sure you can find a load that will do the job and that bullet will penetrate well if you only take broadside or slightly quartering away shots into the ribs and keep your distance to no more than about 250 yards on a cow.  As stated in another post, they might be smaller than a bull, but they are still a big critter and will need a well placed shot into the lungs with that smaller caliber to get the job done.  Stay away from the shoulder, as mentioned, or you are just asking for trouble.  I'm using 50 grains of IMR 4350 for that 117 grain BTSP load I use and its a couple grains below what my buddie's computer program shows is max and it's moving at about 3000 fps at the muzzle.  Good luck on whatever you decide and have a great hunt out there!

I've killed a number of cows and spike elk with a 25-06 shooting the 120g Nosler Partitions.  It did the job for me.  I fell on some ice and broke the stock of that rifle and when I replaced the rifle I upsized to a 270WSM because so many folks had told me the 25-06 was too light for elk. 

I shoot the 140g TSX in the 270WSM and it has also preformed well on elk.

I've also hit some big bulls with 180g bullets from 30 cal rifles and needed multiple hits to put them down.  So is there a right or wrong here.  No!.  If you are going to use a 25-06, keep it to 300 yards or less. Broadside boiler room shots. And I personally keep it to cow and spikes. No mature bulls. I also stick with shooting calm animals that have not gotten excited and gotten their adrenaline pumping.

We have killed 4-5 elk with our 25-06. 2- bulls and 2-3 cows. The last one was a mature 5 pointer. My wife put 3 or 4 shots into the broiler room and he kept staggering along, thankfully I had the same tag and was able to back her up with 2-3 shots from my .300 Win Mag. He was dead but didn't know it. When we skinned him out, he had 4-5 different hits in his rib cage. We usually load with nosler partitions or Hornady IBs. If I remember right both rifles had Nosler Partitions in them. 25-06 had 115 gr. and .300 had 180 gr. That bull was one tough critter. The cows we have killed dropped after one or two shots into the lungs. I doubt if we will use our 25-06 for bulls again.

i think the 25 caliber is probably ideal for elk. it's a good shooting rilfe. you have to remember that kinetic enerygy= (1/2)( Mass)*(Velocity^2)

forget the 1/2... it's just a constant applied to the equation. pay carefull attention to the V^2. velocity is where most of your energy comes from.

shooting a 100 grain bullet may be light, can you find 130's? my concern with a 100grain tripple shock is that it will expand TOO RAPIDLY and come apart and fragment inside of the elk. i would use the hollowpoint version of the tripple shock not the polymer tipped version

lots of poeple kill elk reliably with this every year. just practice, practice, practice. if you hit your mark every time, you could use a .223 and kill them.

barnes makes some great bullets, and their lead-free  alloy is a bit harder than lead with a copper jacket, so it expands somewhat less rapidly.

i am a HUGE fan of the way hornady interlok perform. they are inexpensive and plain, but they do an acceptional job on game. the weight retention and mushrooming is incredible. it makes me feel wierd when i load them though, because they're so cheap, like i could get something "cooler" to shoot. but they do just as good of a job at half the price.

that being said, i use barnes tripple shock and hornady g-max bullets mostly. i don't know why. because i have money to burn i guess.

I use the same rifle and bullet for Elk.  I have a Ruger 77 and reload 115 TSX.  I do believe you'd want to shoot the heavier bullet - I haven't taken an Elk with the 25-06 but have shot them with .270, 30-06, and .300's.  The 115 TSX will give better penetration and deliver more ft/lbs to drop the Elk.  On the side, I've loaded these with both IMR 4831 and Re-19.  Re-19 has proven very accurate.  I get 2" groups at 200 yds. and velocity is near 3000 f.p.s.  I use CCI lg. rifle primer.  4831 gave me good accuracy also, but preasure's increased quickly and I didn't feel comftorable with it.  Good luck, hope this helped.