Ammo-related issue?

Windini

Windini

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I'd like a revolver Guru's opinion(s) on something. The rest of you can chime in, too! :)

Is there an ammuntion-related event that would cause an otherwise reliable revolver to hang up on hammer cock & cylinder rotation?

I ruled out recoil bounce - cases sliding out & hanging up on the hand/star, etc. Further, I saw no evidence of loosened projectiles protruding from the front of the cylinder.

The problem felt like it was somewhere in the cylinder advance or hammer travel (backward) department, always in double-action mode and the majority of times in single action. The cylinder stop appeared to want to drop at the appropriate time. Lockup and timing were fine when the gun operated normaly.

The problem occurred on each cylinder-full of live rounds, and persisted when completely unloaded. Yet the following day, the revolver operated perfectly. (EDIT: when dry fired) I marked the offending chamber (Sharpie) and it was consistent to that chamber for the duration of the session (24 rds total, plus a lot of dry fire cycling).

Factory ammo, well within the capacity of the revolver (assuming it was loaded properly). Fired rounds felt consistent and recoil was unremarkable. No sign of overpressure on spent cases.

I am deliberately omitting the brand, model & caliber; I'm looking for a known- or theoretical situation. But lemme know if there is a documented issue for Revolver X in serial # range umptyseven through gigumptythirty.

Physical damage from one overpressure round should not have disappeared the following day... right? Temperature related?

I R baffled. Hep.
 
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Only happened with one chamber of the cylinder? Same one every time?
 
Any burrs on the ratchet for that chamber? Any debris, even minute, under the ejector or in the recess for the ejector?
 
Dale Gribble said:
Any burrs on the ratchet for that chamber? Any debris, even minute, under the ejector or in the recess for the ejector?
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There did not appear to be... they all looked uniform.

And again, the problem persisted when the gun was "hot" but empty, then went away some hours later.
 
If possible I would have a look at the internals , on smith pop the side plate off , others watch a YouTube video on the how to take apart the action.
 
keepcalmandcarryon said:
heats up under firing
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Something like that was what I was wondering.

BrettB said:
If possible I would have a look at the internals , on smith pop the side plate off , others watch a YouTube video on the how to take apart the action.
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I was (am) kind of hoping to avoid that at this stage. I don't really need another project! Theorizing for now...
 
I had a revolver lock up tight once. After I got the cylinder out, I determined that the cause was a single round of factory ammo had a rim thickness that exceeded SAAMI specs. I'm pretty sure it was WWB (.44 Mag). One round out of many hundreds, but it only takes that one.
 
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New info: same revolver, different shooter with several other brands of ammo.

Functioned fine.

Issue seems to be related to that particular (batch of) ammo. Help me understand how that might work.
 
Windini said:
New info: same revolver, different shooter with several other brands of ammo.

Functioned fine.

Issue seems to be related to that particular (batch of) ammo. Help me understand how that might work.
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interesting…was the new ammunition loaded hotter or about the same?
 
keepcalmandcarryon said:
interesting…was the new ammunition loaded hotter or about the same?
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Unknown; all ammunition tested so far has been factory loads. As mentioned, there wer no visible signs of overly high pressure in the spent casings I examined.
 
May be helpful to measure the cylinder gap on each chamber along w how much end shake is there. I had binding issues between the cylinder and forcing cone on a 686 that had very tight cylinder gap. IIRC fouling on the cylinder + certain ammo types with thicker case rims would result in the cylinder binding. May not be same issue for you but cylinder gap measurements may be useful in terms of determining source of binding.
 
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Windini said:
Issue seems to be related to that particular (batch of) ammo. Help me understand how that might work.
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Case rim thicker than spec or case length keeping the round(s) from fully seating in the chambers.

I ran into that once with a batch of Federal .357 Magnum ammunition. They were headspacing on the chamber shoulders at the throats. I caught it before I fired because the cylinder would barely close. Good thing. It would have caused a serious pressure spike.
 
John Travis said:
Case rim thicker than spec or case length keeping the round(s) from fully seating in the chambers.

I ran into that once with a batch of Federal .357 Magnum ammunition. They were headspacing on the chamber shoulders at the throats. I caught it before I fired because the cylinder would barely close. Good thing. It would have caused a serious pressure spike.
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Thank you! Very helpful, & something I'll look into.
 
So... I conducted an informal ammo test yesterday.

The ammunition in question is 158g FMJ from American Reloading.

I assembled a small herd of 5 revolvers:

S&W mdl 627 .357mag
S&W mdl 15 .38 spec
S&W mdl 36 .38 spec
Colt Official Police .38 spec
Taurus 651 .357 mag

I fired Fiocchi 148gr LWC first, then fired the suspect American Reloading 158gr FMJs in each. I followed up with some handloaded .357 I had, but obviously did not put them in the 38 spec. guns! Handloads were 125gr JHP over 8.5g BE-86.

In respect of @John Travis 's comment about out-of-spec brass, I visually inspected the cases of the Fiocchi & American to see if the case rims thickness was different. I could not see that it was, but did not have a micrometer to make that official.

Fiocchi vs AmRe Cases.jpg

Fiocchi & AmRe in 627.jpg

I did not chronograph the loads, so don't have any velocity, ES or consistency data to give. Nor did I note POA/POI. Given different makes, models, & bbl lengths plus the limited quantity of rounds fired, such info (IMO) would not be very relevant. This test was for function/reliability in a variety of firearms for which this ammunition was designed.

Both the Fiocchi and AR worked in all the guns, but the previously ultra reliable Taurus exhibited a "stiff" trigger pull & reluctant cocking several times (mostly on 2 chambers out of 5 total) as well as several light primer strikes that failed to set off the round on the first try. (It exhibited the hang up trigger/hammer cycling briefly the last time I shot it, but I attributed that to a temporary interference by shooting debris - crud - at the time. I don't remember what ammo I was shooting then.) It's worth noting that this was the issue in the revolver that started this whole exploration. That one isn't mine, so I'm not identifying it here; however, it is a well-known and highly respected revolver. The owner of that one has fired several different varieties of ammo since I had issues with it and reports it performed flawlessly.

The AR 158g definitely felt hotter than the Fiocchi 148g, but not as hot as the hand loaded .357. Each revolver handled the ammo I fed it according to its size/mass, with the S&W 627 (💕) performing to its usual superior standard.

Earlier, I emailed AR and asked if there had been any reported issues or recalls of this lot. I haven't heard back from them yet, but will add their comments when I do.

The results were inconclusive at best. I could not isolate any consistent performance issues with the ammunition in question. All I discovered for real was that the Taurus needs some attention.* Are you supposed to clean revolvers?

Insights and commentary (please read the footnote) appreciated.





___________________________________
* "Taurus blah blah Sux blah blah Bad blah blah Shoulda Had A blah blah Waste of $$ blah blah!!!" Heard it. I've had two of this design, one sucked, this one has been ultra-reliable until now, hundreds of rounds downrange, carried regularly in years past. Please move on if that's all you have to offer.
 
I have a Taurus mod 94 that had similar binding issues. The problem was a worn out bushing on the crane that allowed the front of the cylinder to intermittently contact the rear of the barrel ( forcing cone). I made a new , longer bushing . Problem solved.
 
John Travis said:
Did you clean out from under the ejector star with a toothbrush?
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On the Taurus? Did not have toothbrush (there's usually one in my range bag, but... derp), but I checked and blew and wiped like, with a cloth and did not see any gunk. The plan now is to clean it very well & try again. A toothbrush will be involved.

I no longer had the first one to clean, but the owner says it's been fine since.
 
Bahamadon said:
I have a Taurus mod 94 that had similar binding issues. The problem was a worn out bushing on the crane that allowed the front of the cylinder to intermittently contact the rear of the barrel ( forcing cone). I made a new , longer bushing . Problem solved.
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Any idea of how many rounds fired, or was there another factor that led to bushing wear? (In other words, was it unusual for the gun's age and use?)
 
Is that a fixed firing pin or floating firing pin? Look for burrs around the firing pin hole.
Also check for high primers. Primer drag or setback can lock up a revolver.
 
georgel said:
Is that a fixed firing pin or floating firing pin? Look for burrs around the firing pin hole.
Also check for high primers. Primer drag or setback can lock up a revolver.
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Both that had "issues" are floating firing pins. The S&W 36 is Olde Skool toothy; it functioned fine.

Primers all seemed flush, both before and after firing (though I admit I didn't check every one before firing). If anything, a few primers in spent cases of the subject ammunition appeared slightly dished from the surface of the case head.

None were pierced, bulged, cratered, and there was no discernable case swelling or splitting to indicate overly-hot loading.
 
Windini said:
Any idea of how many rounds fired, or was there another factor that led to bushing wear? (In other words, was it unusual for the gun's age and use?)
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I purchased it used and it was in really good condition cosmetically. Had it a year or two before problem arose. Unknown round count. Judging by appearance of rest of gun I want to think the bushing was short or out of spec when I got it. I sent it back to Taurus and they replaced the hand which did absolutely nothing. Don't remember exactly but want to say the bushing I made was .008-.012 longer than original.
Here's the bushing , the front is beveled to avoid hitting the bottom edge of the barrel as the cylinder rotates. It's kind of thin at this area.20230929_145610.jpg Which I think is a poor design. IMHO.
 
Windini said:
I visually inspected the cases of the Fiocchi & American to see if the case rims thickness was different. I could not see that it was
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You probably wouldn't be able to. Revolver headspace is typically .005-.007 inch, with .006 being the target dimension. A difference of just .004 inch...the thickness of the average human hair... could create a problem.
 
Windini said:
And again, the problem persisted when the gun was "hot" but empty, then went away some hours later.
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I am no pro as are some here, but it seems to me that it is not the ammo if it does the same thing when it has no ammo in it.


I must say that I have learned a great deal from reading the posts of the very knowledgeable and experienced people who post here. Many thanks to them for their time and efforts to help others with less experience.
 
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