I would rethink the 25 because 25-06 is an overbored cartrige with limited application and small bullet selection.
IMO, the 280 is an amazingly efficient cartrige just like the 7mm-08 and 284, all of them often misunderstood in the US market due to bad marketing and limited rifle and application offerings.
Even the reload information is all over the place depending on what manual or source but if you look closely or buy some high performance ammo then you will see what this round can really do.
with a 26" barrel the 280 can propel a 175gr-180gr bullet to 2750fps that is just 100-120 slower than a remmag and 100fps faster than the 30-06 with a 210-220g bullet 30 bullet that will not be as
efficient in the air. Unlike the 270 the advantage is having the option of heavier bullets that provide more momentum on the target w/o the need to get into heavier calibers and thefore more recoil
and potential impact in accuracy with comparable rifle weights. Hornady just released a light 150gr that is supposed to be very good although I have not tried this bullet yet. When compared with the 270
147gr from hornady the 280 comes ahead as expected but not by that much. The big difference is with bullets with 160-180gr to hunt with authority where the 270 and 6.5 fall on the light side.
Even if long range is not the primary focus there is a real advantage shooting flatter and further than the 270, 308 and 30-06 among others by a noticeable margin so make sure about the rate
of twist on the barrel to make sure it can stabilize the longest bullets you want to shoot. The real advantage of the 30-06 is with the heaviest premium bullets for the heaviest game and moderate
ranges where the extra grain and frontal section makes a difference. But in many common uses and specially extended ranges the 7mm is a top performer.
With all that said if you want this in a short barrel, then better stick to the 308 winchester or 7mm-08 or classic 30-06. So unless flatter shooting and long range is important there is more consideration
to the 30 caliber or even the 7mm/08.
I think the 280 is a nice stepping stone in the long range to hunt with certain authority but w/o the need to get into the magnums.
As for the rifle the model 77 is a robust rifle and in a 7mm... seems like the perfect triple 7!
good luck.
........................
Edit:
I forgot, Similar discussion came up the other day with teh 270 and remmag and this is what I posted to look at some loads adn help with caliber decissions...
All the calibers discussed here are good calibers.
But comparisons like this can become arbitrary and meaningless and might drive new shooters crazy.
I would start asking the question about the bullets wanted and speed on the target. Would the shooter like to have the option of a 160-180gr bullets and why?
The type of target or game when hunting, the weight of the game, the possibility of longer distances, all this is something only the new shooter can tell us and
this way decide what bullets are best for that job and what kind of margin for error one would feel confortable with.
The rest is a simple task of deciding what kind of casing I need to deliver the type of bullets I want where they are needed at the desired striking speeds.
Lets say we discarded the 30 caliber so let me give you a few examples with average type of loads to see how this could be relevant to the shooter.
Of course there are better bullets and more powerful rounds in any of those calibers.
http://www.hornady.com/store/270-Win-145-gr-ELD-X-Precision-Hunter/
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2970/2840 2796/2516 2627/2222 2465/1955
2306/1714 2157/1497
Trajectory (inches)
MUZZLE 100 200 300 400 500
-1.50 1.50 0.00 -6.50 -18.80 -37.60
Nosler...
http://load-data.nosler.com/load-data/270-winchester/
http://www.hornady.com/store/280-Remington-150-gr-ELD-X-Precision-Hunter/
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2925/2849 2763/2543 2607/2263 2455/2007
2309/1775 2167/1564
Trajectory (inches)
MUZZLE 100 200 300 400 500
-1.50 1.50 0.00 -6.70 -19.10 -38.00
Nosler...
http://load-data.nosler.com/load-data/280-remington/
The 7mm-08 comes less than 100 yards shorter than the 270 in terms of effectivness withing the critical 2200, 2100fps threshold.
http://www.hornady.com/store/7mm-08-Rem-150-gr-ELD-X-Precision-Hunter/
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2770/2555 2613/2274 2461/2018 2315/1784
2173/1573 2037/1381
Trajectory (inches)
MUZZLE 100 200 300 400 500
-1.50 1.80 0.00 -7.50 -21.60 -43.00
Nosler...
http://load-data.nosler.com/load-data/7mm-08-remington/
This is a rather mild load for the RemMag...
http://www.hornady.com/store/7mm-Rem-Mag-154-GR-InterBond-Superformance/
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
3100/3286 2914/2904 2736/2560 2565/2250
2401/1970 2242/1718
Trajectory (inches)
MUZZLE 100 200 300 400 500
-1.50 1.30 0.00 -5.90 -17.20 -34.50
Nosler...
http://load-data.nosler.com/load-data/7mm-remington-magnum/
In 7mm you have the choice of 160-180grs with superior ballistics launched at very good speeds. You don't have that choice in 6.5 and limited in the 270.
In the 7mm you have the 7mm-08 small volume case choice combined with amazing 160gr-175gr bullets. You don't have that choice in the 6.5 or 270 bore.
You have the 284 variants and wildcats but then you also have the 284 straight that will produce better ballistics.
Of course we could add the WSM line but lets do this based on 30-06 and 308 siblings plus the popular remmag.
I included the 7mm-08 to show one could start with less powder and end with pretty decent effective range in case more is not needed.
Is there ammo that would outperform the above w/o getting into WSM, supermagnums or any other more exotic choices?
The most important question is, can I do more with less?
And when I say "do more" I don't mean just momentum and speed on the target but considering everything is important to the shooter including size, weight, recoil, expense, etc..