Sorry to resurrect such an old thread, but this comes up in my Google searches and seems like an appropriate place to ask...
I have a Super X2 3" Magnum that I bought with a rifled barrel. I don't have much use for a rifled barrel so I sold it and bought a 28" FN SLP barrel that fits just fine, as I expected. I also bought a 24" SX2 barrel with a 3.5" chamber. Based on some research on some other websites, I expected the 3.5" barrel to fit on my 3" receiver just fine.
I partially based that on sprayandpray's comment:
Problem is, it doesn't go in all the way and I can only just barely get the barrel nut on. Here is the 3.5" chamber barrel in as far as it will go. The vent rib is what is stopping it from being inserted any further. Here is the barrel "extension" (I'm not sure of the proper term) that is not seated completely inside the receiver. The 3" barrel seats completely without the gap shown here. Here are the two barrels 3.5" chamber on top, 3" chamber on the bottom. I have measured and compared every conceivable dimension between the two barrels and the only difference, aside from the chamber, that I can find is where the vent rib starts. So, now the question.... can I just cut off 1/4" or so of the vent rib so the barrel seats all the way? Anyone think this is an exceedingly bad idea? Of course, I would only be shooting 3" or shorter shells from this combination. Also any ideas on how to move the ejector pin to the forward 3" position or just leave it where it is?
sprayandpray - do you have any input on what I'm seeing based on your experience? Does your 3.5" barrel seat fully in your 3" receiver?