Some firearms instructor buddies, tell me that only the Glock 23 and SIG 229 .40 are on the current approved list for new Special Agents, but the SIG must be purchased privately. A few are grandfathered in that may have Smiths still (I haven't seen any), but all new SAs are issued only the Glock 23, and the SIG is being phased out as optional, as well. Until recently, SAs who were with the Bureau prior to 1990 were authorized to carry revolvers as back-ups, but no longer. Most are switching to the sub-compact Glock (27, right?) as a back-up to a Glock 23. The last time I shot the qual. course (Sept.) most of the senior SAs showed up with their SIGs, but had their carry-Glocks in their vehicles...not the best practice. Despite reports otherwise, the 10mm MP5 is still in many armories as the primary longarm. HRT still has their Baer SRPs, but are not real fond of them and use Glock 21s whenever they are called out domestically and Glock 17s overseas. For those Springfield Armory TRP-Pro afficianados (I love my standard TRP, personally), regional SWAT has mostly gone to Glock 21s, as well. The argument being that the TRP-Pro had too much input from competitive shooters in the Bureau and not from the guys who would be carrying them, and consensus is that it is too tight to meet their reliability desires.
-RHM