Update:
Storm Lake used to make .45 M&P threaded barrels, but they were part of the whole Remington/Freedom group bankruptcy and sell off, and no longer exist. Most of the barrels that were in stock at dealers are now showing as out of stock, discontinued.
Bar-Sto does not make M&P threaded barrels for .45 ACP
KKM does not make M&P threaded barrels
EFK Firedragon does not make M&P threaded barrels
SilencerCo offers a threaded barrel for the M&P 45, but it is for the full size, not the 4" gun, and appears to be out of stock
Lone Wolf makes threaded barrels for the M&P Shield, but not the M&P, and not in .45
Apex Tactical makes a threaded barrel for the M&P, but only in 9mm
There is a lot of confusion and misinformation floating around about the differences between the 2.0 and 1.0 barrels for the 45 ACP M&P. I have both a 1.0 and 2.0 and can attest that the barrels are virtually identical and are swappable between slides. The loaded chamber witness hole is slightly larger on the 1.0 than the 2.0, but that's the only difference I see between the two barrels.
I guess at this point I need to either look for a different host or perhaps buy a factory 4.5" (1.0 full size) or 4.6" (2.0 full size) non-threaded barrel and see if I can get it threaded.
