I have read about, tested and used commercial, well known brands of .22, .38 and .44 shotshells for many years in non-ported, "modern" S&W revolvers. Shotshells have come in very handy for head shots on both wounded turkey and upland birds hiding in bramble, and of course for dangerous snakes and rabid critters. Never had or heard of any substantive problem.
This year I purchased a Pro Series 637 with a PowerPort 2.125" bbl., but soon thereafter a Forum member posted a question merely asking about the advisability of shotshells in a PowerPort bbl. Nobody gave him an authoritative answer.
So, before using my new 637 with shotshells, I e-mailed S&W asking if (1) it would harm the gun or (2) it would be somehow unsafe even though many shotguns are ported.
The e-mailed reply was simply, "No, don't use anything other than the specified ammunition in your handgun."
That did not answer my question about the well-proven safety of ported shotguns, or about any harm to/from a ported revolver; the reply sounded like lawyer speak. I therefore telephoned the S&W employee who had e-mailed me and asked why he had simply said "no".
He replied that S&W revolvers "were not chambered" for shotshells ! "Even non-ported guns?", I asked. "Yes, use only specified ammunition", he replied.
"Why, then, do the well-known shotshell companies and gun writers say shotshells are absolutely OK in good condition revolvers?", I asked. "They will say anything", he replied.
Now, gentlemen, I want to play it safe, so I ask you: Is there any reason you know of why I should not use shotshells in my new Model 637 PowerPort revolver? (Of course I will disregard his advise regarding non-ported revolvers.)

The theory is that the relatively soft and yielding plastic shot capsules will upset and snag on the edge of the muzzle ports, become temporary obstructions, and cause barrel damage. To prove this would require extensive testing and firing of shotshells in ported guns. In the absence of such testing, it is much safer for manufacturers to state to use only approved, "normal" ammo in their products.

Thanks, John.
It has never happened, to my knowledge, in the many millions of shotshells fired through ported shot guns, even with the relatively large holes on shot gun muzzle breaks. So I wonder why it could happen with the very large single port at the end of the barrel on a 637 PowerPort?

Just now found this on a July 09 Ruger Website. The poster writes:
"CCI Web site says you must not use shot-shells in a ported handgun, and email from their staff explained why - their concern is that plastic pieces of the cap and the pellets themselves could/would escape through the ports and cause injury.
"I don't know if it's just a liability concern (i.e., once in a Blue Moon there can be such a small pellet that it escapes) or a real threat (i.e. 1% of all the pellets would likely escape through the ports)."

Looked it up on the CCI site; it says,"WARNING: Do not use these or any other shot cartridge in handguns having ported recoil compensators." So, I guess I probably could safely fire shotshells a thousand or (fill in the number) times through my PowerPorted 637, but on the 1,001 time a pellet or two and/or some of the plastic cap might escape upward through the PowerPort. I wouldn't blame any company for saying don't use shotshells in ported barrels, if they explained why. S&W should address the shotshell question in their owners manuals.

Curious to see if any of the Smiths on this board have seen or heard of actual damage occurring to a ported handgun (or worse, to a person) because of a shotshell.

Well, it appears to be safe to assume that no one here has seen or heard of damage to a PowerPort (large port on top, forward of the front sight) handgun from a shotshell.

One difference I see between shot capsules in ported handguns and plastic wads in ported shotguns is in the type material they are made of. Of necessity, shot capsules have to be made sturdy enough to withstand handling since much of the shot charge is contained outside the case. Plastic shotshell wads are much softer since they don't need to do this; their only purpose is to protect the shot from being deformed by friction with the barrel.

Since the capsule is rotating with the rifling in the handgun barrel (at least up to the point where it is shredded), I guess that could cause plastic fragments to be ejected from the ports....maybe pellets (or bits thereof) as well; I don't know.

Even if this happened, I can't see it causing any damage to the gun. I could see the possibility of the fragments injuring someone, so maybe this is where S&W is coming from on this.

cjw3, I agree with you and John; it appears to be a highly unlikely but theoretically possible injury/liability issue rather than a damage to a PowerPort handgun issue.

Well not a conculsive test, I did fire one box of CCI .45 ACP shotshells through my ported 1911 (barrel, slide and bushing is MagnaPorted). No fragments hit me in the face or my shooting glasses. Gun was extented out in normal firing stance however.

CD

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