in ref: to the R51

[johnnysR51]

if you look at the pics on the R51 that posted the barrel with a case still in the chamber ,,, Did anybody take notice to the machining of the lower part were the slide pin release goes in the machining is different then mine , what about any body eles is it different I can post a pic if needed,,,, let me know

                                                                          JohnnsR51

[R51Fan2017]

Johnny,

I think that is the difference between a Gen1 and Gen2 barrel. I believe that Gen2 barrels have that "shelf" or "ramp" or what ever you want to call it on the part where the slide release lever goes. Also, if memory serves, the Gen1 did not have that. It was just machined flat. Hope that helps.