I posted this on mcb but I got no response. I have had this marker for several months now, but I am not 100% sure what barrel threads it is using. I have compared the threads to the pictures on Doc's barrel guide and to me it looks like the prerelease impulse threads, but I couldnt find anything about a carter marker using these threads so I am not positive. Since I dont have a shocker barrel to cut down I wanted to get a second opinion before I picked one up for it.

Here is the barrel:

Here is the pre impulse barrel picture on Docs website:

And here is a picture of the complete marker:

Thanks for any help/confirmation anyone can provide