My friend bought his sons matching 257 WSSM rifles several years back. Now the ammo is almost impossible to find. He is looking to find a custom reloader that could supply them with loaded ammo. they have about a hundred once fired brass.
The other option would be to rebore and re-chamber to a more popular WSSM caliber if there is such a beast, Did any of the WSSM cartridges achieve enough popularity to remain available into the near future? Maybe a 270 WSSM or a 7mm WSSM?
Suggestions please.

I wouldn't suggest that anyone reload ammo for someone else (liability issues). Back in the early eighties I had what ATF called a manufactures license(I was reloading sometimes a two hundred rounds a week for others) I don't think you can trust other people's safe handling of firearms and ammo(factory or reloaded). We all know how much the courts have sided with the anti-shooting fraternity. I would caution everyone to be careful in going down this path. No offense on my part but be careful just as I always told my two children "It's easier to stay out of trouble than it is to get out of trouble after you act" Hope this helps, Mack

Sounds like they need to start reloading themselves.

The only way I reload for some one else is if they buy the items needed and help out in the process

WINCHESTER SHORT MAGNUMS (WSM)
300
270
7mm
325

WINCHESTER SUPER SHORT MAGNUMS (WSSM)
223
243
25

There was no 257 WSSM. Assume you mean the 25WSSM. There were only 3 WSSM cartridges and none of them are very popular. The 300WSM and 270 WSM cartridges are fairly popular, but a WSSM cartridge could not be rechambered or rebored to these because the action would be too short.

http://www.dallasreloads.com/

This guy posts on the Texas Hunting forum a lot. You might check to see if he could help. I am a reloader so I have not used him personally.

Good luck on finding ammo for your 25WSSMs. I have one It's a great little cartridge but if you don't reload, it would be problematic, as you already know.

Well I don't personally own one. I fill that niche with a 243. I'm trying to explore options for a friend.

Factory ammo is still available at times, as recently as a couple months ago I alerted a friend to some for sale.
I just looked for the email but may have deleted it so not sure which outlet had it for sale.
My thoughts are:
A. watch for factory ammo and load up on it when available and
B. this cartridge would be a great way to introduce the 2 boys to reloading.
C. find a friend to load for them every other couple years.

I wouldn't try to rebore or rebarrel, options are slim and more expensive than A B or C above.

I just checked Gunbroker and there are a dozen listings for ammo in 25 WSSM, 85 and 120 grain.

Also found this place that seems to have it available
http://shop.reedsammo.com/25-WSSM_c165.htm

Winchester made a batch of it last Spring. It disappeared quickly. You can sometimes find some on Gunbroker.com, but it's usually at ridiculous scalper prices

olarmy, thank you. this is exactly what he needs. This should take care of him.

Snellstrom, He does need to start reloading but unfortunately they live 1400 miles from me. I live on the Mexican border and they live near Chicago.

As much as I like the 25 WSSM, I have 15 of them, I think that they are a poor choice within their market niche in 2017 because of the lack of both factory loaded ammo and component brass.

Your friend would be ahead of the game if he sold the 25 WSSMs and bought his kids a pair of 243s or 6.5 Creedmoors. Tell him that CDNN is closing out Marlin XS7s in 243 for around $280.

+ 1 on Dallas Reloads. He does good work.