Lots of good information in this thread. Now that I'm retired, I can offer some comments...

I was a firearms instructor at the time the 1076 rollout in the field offices began in earnest after 1991. New Agents at Quantico began receiving them first. The NYO - largest field office and at the bottom of the list to receive anything new - didn't get 1076s for issue until 1992. The transition school from revolver to 1076 for Agents started at 5 days, and was soon reduced to 4 days. They shot a lot of rounds during that week, well over 1000 rounds per gun. The 1076 was reliable, and with the issue 180/950 load, not difficult to shoot, and grouped well.

Having said that, it wasn't without its detractors. For starters, it was far heavier and bulkier to carry than the issue S&W 10-5 or 13-3. Considering the majority of agents worked in business attire, and investigating white collar crime and counter-intelligence, the added size and weight were not appreciated with that sector.

The POI of the issue guns was lower than what was common with the prior issue revolvers or pistols (S&W 10-5, 13-3, 459, SIG P226). The 1076 was zero @ 25yards using a center hold, with half the rounds above and below the POA. Most Agents could not tell the difference on the Q target, but many instructors - required to shoot the Bullseye Course for qualification - did not like this. They sent their guns back to the Quantico Gun Vault for sight adjustment, to be told that the guns were zero. Personally, I don't like rounds impacting below my line of sight at distance.

The magazines had some issues with the top round sliding out when carried in the issue magazine pouch - you would draw the 9rd magazine for a reload and there would be 8 rounds in the mag, and a single round laying in the bottom of the magazine pouch. There was at least one magazine modification by S&W to try and prevent this.

We still used Hoppes 9 back then, and this caused problems with 1076 due to the inevitable improper cleaning methods. I say "inevitable" because most LEOs - including Agents - are not "gun people", and m any have little or no prior experience or interest in firearms. The weapon is a tool, and there are a lot of other tools, rules and fools to be concerned about. Using copious amounts of solvent is one aspect of that situation. While never a good idea on any handgun, if done to the revolver, it rarely prevented it from firing even if the action got sluggish. In the 1076, Hoppes 9 accumulated in the FP channel, mixed with brass shavings and carbon fouling, and on enough occasions prevented free movement of the FP and caused misfires. I saw one FP that was stuck poking through breech face after firing and could not be moved. Examination of the FP channel indicated a horror show of gunked up fouling and Hoppes 9. This was not a rare occurrence, as there was no relief hole in the slide to blow out such matter.

Finally, there was considerable debate amongst firearms instructors over the selection of both the cartridge and the 1076. And it was not just .45 vs 10mm. The 9mm was favored by many experienced instructors, including my old partner (20 years my senior), who had been an original SWAT operator and later PFI in another field office. He and others favored a high-capacity lightweight pistol in 9mm, with improved ammunition, such as the 147 grain JHP.

The SIG P226 was already issued to some Special Operations Agents, and was authorized as a POW in 1987. In fact, the P226 was just fine by them, as it had a better trigger action than the S&W pistols, was more accurate, and had what was considered the better decocking device. The argument for the 9mm boiled down to the fact that actual hits in gun fights are lower than qualification scores, and having more rounds gives the Agent more chances to make a hit without reloading. The lighter recoiling 9mm also made hitting easier for most Agents. With more effective penetrating ammunition (eg. 147 gr JHP), many instructors thought this was the best solution.

Obviously, the big-bore camp eventually won out. The resulting 1076 was coyly referred to as a "SIG & Wesson" , as it was supposed to be a blend of the characteristics of both guns. When the S&W 645 and SIG P220 were authorized as POWs in 1988, I bought the former and was very pleased with it and carried it for years very successfully. I worked Violent Crimes and Drug Cartels so I didn't mind the weight and size. I had my own POW 1076 in 1989, but saw no advantage to my 645.

I won't rehash the whole 1076 debacle, but will say all the guns had to be returned in 1993. The dilemma of what to arm the Agents with was solved by purchasing thousands of SIG P228 9mm guns off the existing DEA contract. After the 1076 was "re-worked" at the S&W Performance Center. Agents had the option of receiving a 1076 back, with 7 new magazines and a log book, all in a Performance Center blue box. Less than 10% of those who turned in a 1076, asked to have it back.

While I personally was not a fan of the P228, nearly all of the Agents loved it. It was lighter, more compact, had more magazine capacity, fit more hands better, and had better accuracy from the practical standpoint. The difference in "power" was not noticed in the reality of actually shootings. The issue load was the Speer 147 GDHP. More than any other handgun, when down the road all the P228s had to be turned in for a Glock, there were many long faces.

Re "too much recoil" for Agents with the 10mm. The full house 170 grain Norma was never issued. FTU Unit Chief John Hall and crew fired it in his Colt Delta Elite when they were examining the 10mm and decided quickly it was a ridiculous choice for a LE load. The 180/950 was the issue for many moons, until a 190/950 load which performed better in the MP-10 was adopted. I remember the tiniest female Agent I had ever met coming to the range for quarterly qualification in 1991. She had just graduated from the Academy and because her hands were so small, she was issued a 1086 DAO pistol, with the skinny grip option, in order to reach the trigger. The pistol seemed to be about half the size of her. Yet, she was a good shot, the 10mm recoil didn't faze her, and after the guns were recalled wished she could have it back. No luck.

Those that retained the 1076 viewed it as some mystical light saber, slayer of dragons. I think that last one that I pried out of an Agent's hands was in 2007. The entire day at the range he swore at the Bureau and "its cheap plastic Glock". His negative attitude - over a gun he didn't pay for and was issued as a condition of his employment - affected his shooting for years, but of course he blamed the Glock.

I retired my 645 in 1995 when I was issued a Glock 22. As an instructor, you have an obligation to instill confidence in the issue weapon, and carry what the troops do. The two weapons were so dissimilar, that I was also doing myself a disservice trying to maintain top proficiency with both, since at that time I was still working drugs full-time and didn't have the time to be an expert with both. I actually liked the Glock, and went on to win many matches and championships - local, regional and international - with a Glock 35, box stock except for sights.

Still have my 645. Nope, not for sale. :-)