I think what he is talking about is the MT2 taper on the elk guts I sell. He is trying to use the Latta method to turn them down to 1/2" straight bore.
The big call companies have their own cast in china or some other place. They normally do not sell them to the public. Be careful with casting Primos stuff. They seem to patent a lot of their call parts and they like to intimidate small call makers.
The easiest way around this is to simply buy a MT2 tapered reamer.
Enco has them
www.useenco.com search for reamers and choose Morse Taper
McMasterCarr also has them
www.mcmaster.com again, search for reamers and look for MT2.
They can be pricey, but they last a long time.
These guts are tapered for a reason. The taper keeps the end of the guts closed and tight. If they open up, the reed could be blown out or fall out, worse case scenario, or, they could separate enough to lock up the call when blowing or at the very least, really effect the sound. So a reamer is needed for the best results if using them right out of the box. The down side is that sooner or later, someone is going to try to seat the guts in the barrel and the barrel is going to break. That is one of the advantages to the Latta method. The guts end up with a lip on them like the ones you pictured, so they cannot be forced into the barrel. The O rings keep the guts sealed closed.
Now, Bob, please let me know how many sets of guts you ruined by trying the Latta Method and I will send you replacements at no cost. I might even have an old reamer laying around that you could use till you get a new one. Shoot me an e mail or PM and I will get you taken care of! Honestly - I want you to be happy with the guts and not get stuck with something that didn't work for you, so please contact me and I will get it taken care of.
AL @ THO Game Calls