Woodleigh bullets produce correct .287 bullets for the .280 Ross. I have owned several .280 Ross' over the years. Formed brass from .300h&h through FL die and trimmed, belt left on. Worked with mixed results. Finally sold rifle with the dies, bullets, brass etc.
My advice, enjoy it 'as it is'.
I bought the rifle that Longbranch* mentions. Beauty. I have since acquired 2 more in 280 Ross.
My handloading experience with these rifles is quite the journey. One of them shoots 175 gr Hornady .284 bullets and 160 gr .287 Woodleigh bullets just fine.
The rifle I got from Longbranch* only shoots the .287 Woodleighs with any degree of accuracy.
The last M10 I got keyholes targets at 25 yards regardless of bullet diameter and I am considering having it re-barreled in 7mm Rem Mag.
Just note that if you choose to do this, you will need to have a larger diameter shank on the barrel where it mates to the receiver. I measured mine at 1.3 inches. by comparison, my FN Mauser is 1.1 inches. You will need to find a barrel maker who can make such an item in the correct dimensions.
Note that there is a member on here , Eagleye, who had a MKIII re-barreled. He needed a custom barrel for the job. The MKIII action and the M10 action have the same barrel shank dimension.
With regard to reloading for the 280 Ross
I have used 300 H+H brass to form 280 Ross cases and I find that they split just above the belt after only 2 or 3 firings. I like some aspects of the 300H+H case. Body taper in particular is well suited to forming the 280 Ross but the case has to be shortened to 2.6 inches.
Lately I have used 375 Ruger as a parent case and although it takes a few more intermediate steps to get the case down to 280 Ross dimensions, it does work and the case head diameter is slightly larger than the 300H+H. The 375 Ruger cases do not need to be shortened.
The latest parent case that shows great promise to be formed into 280 Ross is the 28 Nosler. It is the right length, the right case head diameter and it should be a one and done process through a 280 Ross sizing die. I haven't tried this one yet.