I just installed a TACMOD stock on my AR with the intention of using my JP SPS. The TACMOD includes the tube that the stock is attached to, and it says it uses a carbine buffer and spring. When I put the JP Spring in it doesn't come flush with the reciever extension, it's about a half inch or so inside. This makes it so when I send the bolt forward it doesn't seat all the way.

Has anyone had this issue before? I can take a picture when I get home if what I'm trying to describe is confusing.

I'm assuming their tubes are slightly longer than normal carbine tubes, but short enough that they still work with a normal spring and buffer.

I'm thinking I can cut  the size needed off of the included delrin spacer that JP includes for an A2 rifle tube of no one had any other suggestions.

That's what I did with my Silent Capture and Vltor A5 tube.

You modified the spacer and it worked fine?

Cut about a 1/4" piece and put it in the buffer tube and it works perfect now, thanks for the tip!

Yea I just cut downt the plastic spacer. How I did it was insert the Silent capture buffer in to the tube. Put the plastic spacer on top. Then slighly pre load the spacer and mark it acording to the lip on the buffer tube.  Then simply cut it on the mark with a hack saw.