Which 38 blanks for M781 40mm chalk rounds?

General Firearms NFA
1

I recently got a 40mm launcher and have been playing with several accessories for it (12gauge adapters, hornet’s nest, etc.) I am loading some M781 chalk rounds and they need .38 blanks. I am finding so many options and have no idea what exactly I need. Does anyone know 100% which I need? Don’t want a kaboom so very hesitant to just buy anything…

2

I believe it’s .38S&W NOT .38 Special.

3

So after some more investigation I have found that its actually a very specific 38 S&W launcher blank and as it happens pretty much no one makes them. current prices are around $2/round on gunbroker. ugh.

4

You can trim 38 spl down to 38 s&w length. Trick will be on how to make a blank out of it. I guess it’s like a shotgun wad and small amount of powder only.