I too have an Officer's ACP that does this.
However, you may need to have an experienced smith look it over for a problem with the receiver. Back several years ago, Colt was having labor/QC problems. I don't know if union workers were intentionally damaging guns or if unskilled replacement workers were the problem, but the steel framed Officer's ACPs made during that time had numerous flaws.
On mine, I eventually discovered that the hammer pin hole in the receiver was machined with an oversized and off axis hole. With the gun stripped, inserting the pin from the RIGHT side, you could move the pin side to side by .110".
It was if there were 2 intersecting holes with a common point about half way through the receiver. It wasn't a very visible flaw when you were just looking at the gun. What put me on the trail was watching the pins as I pulled the trigger & lowered the hammer. First with no resistance, then riding it down with my thumb.
While this is aggravating in the extreme, it probably is not unsafe with stock parts at full depth engagement. I wouldn't want to do a trigger job on one for someone else as the tolerance/slop could add up to a problem.
The cure? Send it back to Colt, send to a good smith, have a precision bushing machined & pressed into an oversized reamed hole, or just live with it.
Mine also has a curved frame SIDE under the thumb safety.
I thought it was bent originally, but later determined that it was machined/ground/polished into that condition.
All in all, a dud. By the time I found it, I had already done a bunch of tuning/fitting, so Colt wouldn't touch it. I learned an important lesson from that. Always get out the gauges & check it out FIRST!!!
[This message has been edited by BBBBill (edited September 12, 2000).]