This is one of the first questions a new Colt “D” frame owner asks. The answer depends on the model and the vintage of the individual gun.
What Colt says
Post-1972 (shrouded ejector rod) models: The owner’s manual says that these guns are rated for +P ammunition. The manual calls for a factory (gunsmith) inspection every 1,000 rounds for the alloy models (Cobra and Agent), and every 3,000 rounds for the steel-framed guns (Detective Special, Police Positive Special, Diamondback.)
Pre-1972 (unshrouded ejector rod) models: None of the Colt guns with unshrouded ejector rods are rated by Colt for +P use. These guns, made prior to 1972, were sold before the advent of +P ammunition.
However, there are some other things to consider before you load your gun with that hot ammo!
+P ammunition is loaded to higher pressures than standard .38 Special ammunition. This results in increased muzzle velocity and recoil.
When this ammunition is fired, it puts increased stress on the chambers and cylinder, and the frame is subjected to more force than normal. Colt “D” frame cylinders are certainly up to the task of containing the pressure, but the frames and action parts really take a beating.
This means that the ratchet (ejector) and hand experience increased wear, shortening their life and requiring more frequent replacement.
For the alloy frames, not only do the action parts wear but the frame itself will stretch slightly. After a number of rounds, the frame may be so deformed as to result in headspacing problems. While the steel frames don’t generally stretch so much, the alloy frames will require replacement after a diet of +P.
This increased wear is the reason for the re-inspection intervals given in the owner’s manual. To put it another way, your gun probably won’t suffer catastrophic failure from the use of +P ammunition (it’s SAFE to use), but wear will be greatly increased (it may not be very SMART to use.)
Should you use it?
First, if you plan to use +P ammunition in any Colt, it is imperative that the gun is within factory specifications in every respect. If there is any deficiency, the increased wear patterns from +P use can render the gun unusable or even unsafe in short order.
Regardless of the model, you will experience increased wear if you use +P ammunition. Colt revolvers are not cheap to work on, and some parts are becoming quite scarce, so use should probably be restricted.
What do I recommend?
(What follows is based on my experience shooting, repairing and customizing Colt revolvers. Nothing written here is intended to be predictive, but is simply a recap of what I’ve observed. Use what follows at your own risk and expense.)
For steel-frame models, I’d limit +P use to a few hundred rounds a year, and observe the 3,000 round inspection interval. I’ve found that, if the maintenance is done properly, this will result in many years of shooting service.
Regarding the alloy models, frame stretch is a major concern. In addition, the alloy frames will suffer more wear in the action than the steel guns because their lessened mass results in a higher recoil pulse.
Since the alloy guns are so scarce, and replacing a stretched frame is essentially impossible these days, I recommend that you shoot very few +P rounds in them. If you plan to carry it, you can certainly shoot two or three cylinders full just to acquaint yourself with the increased recoil – then practice with regular pressure loads. Absolutely observe the 1,000 round inspection schedule, and make certain that the gun is in perfect condition beforehand.
What about the older models?
In general, I wouldn’t. Any of the pre-72 guns are now so collectible that it just doesn’t make sense to subject them to the pounding that +P ammo will give them.
But, should you insist…if the gun is a steel model made in the mid-50’s to late 60’s, it is probably strong enough that it won’t suffer catastrophic failure with +P loads. However, in my experience the pre-72 models have slightly softer metallurgy, which results in increased frame wear. Thus, it’s not a question of “will the gun handle it,” it’s more a question of how much expensive maintenance it will require!
If it’s earlier than that period, or any pre-72 alloy frame model, “just say no.”
The bottom line
You don’t have to be afraid of +P ammunition, just understand that each +P round you put through your Colt will result in more wear than a standard pressure load. It is up to you to maintain the gun appropriately.