I know the M40 is not the M24 - I know this... Just wanted to chime in with something here.
Remington is doing a sale program right now where they have 'bought back' the Army's M24 SWS and everything they could get their hands on related-wise. They are offering them up for sale in like a 6 tiered program, starting with like active duty Army snipers, then retired snipers, then active duty army, then retired army, then active LEO, etc. and eventually if there is any left over after they hold their chinzy-aces out for long enough, they will be lottery'saled to the general public.
I know I IMMEDIATELY tried to get in on it with my Dad's retired cop-boss creds and he could not get them to even take his name down, they were like, there is basically not a point because we are not going to get to the point where we have them for you to buy, but IF AND WHEN it actually gets to that point , call us back.,
BUT IF you actually are a retired Marine Sniper who carried an M40 back in the day, you might be able to get in on it and get yourself a "COMPARABLE" (although not the exact same thing) M24 SWS from Remington... Check www.remingtonle.com
for the Remington Law Enforcement (and military) site. for the real deal info.
Or could do just like me, and build yourself a M80 SWS (M for Me, 80 for my favorite number, Scrappy Weapon System for my own damned takticool SWS), get a Remington 700 AAC-SD Tactical, Harris bipod, a cool VTAC Sling, eventually maybe the McMillan General Purpose Hunting stock the M40A1 was built on, and build your own little copy