Forgot to mention blow-back in my original post. In my Mustang with 209s, although you never felt any blow backitwould scorch the underside of the scope. If I put a strip of paper towel across the top of the barrel/breech area, one shot would put a black stripe on the towel 1/8" wide and 2" long and carbonize the paper a little. With the ACP, you have to look close to see a mark on the paper towel.

If you're inclined to give it a try, it's cheap and easy to do yourself.

I bought an extra breech plug for $12.50, and a "I" and "J" drill bit from a local tool supply company for $9.86. The I size bit is a little smaller than 25 ACP diameter and a little larger than the 209 hole in the breech plug. The J size is the perfect diameter for the ACP cartridge.

Found a buddy with a lathe. We drilled out the plug with the I bit to just short of the depth wanted, then ran the J bit in to finish up the final diameter and depth. Easy and cheap if you have access toa lathe. Even if you don't, you could probably locate someone on a local forum (Louisiana Sportsman Hunting Forum in my area) who would do the job for you. I have no idea what a machinist would charge to do a job like this, but it shouldn't be much.