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Carmoney

Cylinder Stop Problem On My 625

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Sam and I shot a USPSA match today with all the great guys at the Black Hawk Pistol Club, plus a couple friends from down this way, and you'll never guess who happened to show up.....

Skip Chambers.

(I hadn't seen Skip in a long, long, while.....although I heard through the grapevine last year he had been spending quite a bit of time in Ohio hanging around with Lefty45....)

Second stage, pulled my 625, BANG BANG BANG CLICK CLICK CLICK. Looked at the moonclip and no primer dents on three of them. Thought at first I had broken a hand or firing pin or something, then I saw little telltale firing pin marks at various places on the cartridge rims (not the primers, obviously). What the @*&^$?? Unloaded and went to the safe area, lo and behold the dang cylinder would sail right on past the stop if I cranked it at all fast.

Got home and looked things over, the cylinder definitely has some peening but nothing really dramatic. But man oh man, you shoulda seen the cylinder stop. The working edge was really worn, very peened, literally pushed down and bent over. And I'm pretty gentle with my revos. This gun was almost new when I bought it almost exactly a year ago. I've shot it in quite a few matches since then, but I don't practice very much and almost never dryfire. And I never do the spin-and-kathunk ritual at LAMR 'cause my hammer spur is all over my basement floor in the form of very fine steel dremel dust. This should not be happening.

Replaced the cylinder stop, gun went right back to 100% with no free-wheeling of any sort. Shot 150+ rounds out back just to make sure it's working OK.

So I'm starting to think in order to maintain reliability, I need to (1) locate some old-style non-MIM cylinder stops, like the ones that have always worked so well in my old high-round-count blue guns, or (2) start treating the cylinder stop like a consumable part that needs to be replaced every 1000 rounds or whatever. Anybody have any thoughts on this?

Now, if this is not just a fluke deal, it seems like these soft cylinder stops could potentially become a problem even quicker for those running Titanium cylinders......am I right?

Mike

Edited by Carmoney

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Conincidence... I broke my cylinder stop a couple of weeks ago. First one I ever broke and it was one of the non-MIM parts.

You could probably have an old case hardened one TiN-ed and never look back.

Weird problem though. I would have expected the light cylinder to give less problems in this area than a big heavy Stainless Steel cylinder.

BTW, Do the cylinder stops require fitting, or can you just drop them in?

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Weird problem though. I would have expected the light cylinder to give less problems in this area than a big heavy Stainless Steel cylinder.

Just to clarify my post above, Spook, I do not have a Ti cylinder in my 625, mine is the standard stainless stock part. You make a good point though, maybe this issue wouldn't be as likely with a Ti cylinder because the stop wouldn't get slammed so hard when the wheel comes around. I guess my initial thought was that the stop might wear faster with a Ti cylinder because the cylinder was quite a bit harder.

Hmmmmm......wonder if both could be true......making it a wash? Randy? Waltermitty?

BTW, Do the cylinder stops require fitting, or can you just drop them in?

The newer MIM cylinder stops are pretty much drop-in, from what I've seen. The older ones usually can stand a little fitting work to make them function properly and smoothly.

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Same happened to me, 4" 625 Jerry M PC gun. The situation was the same as Carmoney. Bang Bang Bang Click click click. Thought the same as Carmoney, Broken hand.

Well the match I was shooting was a winter match at The Smith&Wesson Acadomy in Spingfield, Ma.

Well, I hunted down the armeror and he gave me a new 625 to finish the match with. He Said

I will have a look, come see me at the end of the match. No more than 45 minutes later, he finds me and gives me my 625 back and says all set. He fixed my gun which was a worn cylinder stop. How much do I owe, He says have a nice day and enjoy the match.

Talk about being in the right place at the right time.

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Mike,

I think the MIM cylinder stops definitely wear faster than the forged versions. Both can fail, but the wear on the MIM parts seems more accelerated for an equivalent number of rounds fired.

On the original 6.5" 625 thread, there was some discussion on the cylinder stop slots and edge rollover as the cylinder is opened. Slight peening on the entry side of the slot will also exacerbate skipping. I deepened the entry slot by about .002" on the proto gun. So far my 627 has about 8000 rounds thru the Ti cylinder without evidence of peening, or even wear for that matter. The 625 proto has only about 800 rounds thru the cylinder from match and practice, but again no peening is evident. The 625 has the MIM cylinder stop, but there does not appear to be any accelerated wear on the dome. My 627 has a forged version which also shows normal (less than the MIM part) wear. With the 627, I can get pretty spastic on the trigger pull- 12 lbs of finger force on a sub 4lb trigger pull(I can see Jerry M. shaking head sadly). I believe there is far less inertia related wear and damage imparted to all parts involved with the Ti cylinder.

The 20 stock 625's in the shop ALL show mild to extreme peening. The more used ones obviously show metal deformation on both the stop ledge as well as the entry side of the slots.

For us competition revo shooters(125 pf or .45acp 165 pf), it would be nice if Smith went back to locating the entry notch in the center of the slot. We aren't shooting .44 mag snubbies where the cylinder stop was being pushed out of the slot by rearward recoil impulse. This would also help reduce the liklihood of skipping.

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OK, then setting aside the torque issue for a moment, would the best answer be to replace the cylinder stop with an older forged part, and hard-chrome both the cylinder stop and cylinder (or for that matter, the whole gun)?

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Yes- it would improve the wear characteristics as well as reduce (or at least slow down )the peening process. Hard chroming the entire gun will also slick up the action once all the chrome "feathers" burnish in.

The forged cylinder stop definitely wears more slowly. But as Spook mentioned, they can break too.

If you decide to go the HC route, make sure the plater does a post bake. The plating process can embrittle parts which need some temper.

Edited by Randy Lee

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Weird problem though. I would have expected the light cylinder to give less problems in this area than a big heavy Stainless Steel cylinder.

Just to clarify my post above, Spook, I do not have a Ti cylinder in my 625, mine is the standard stainless stock part. You make a good point though, maybe this issue wouldn't be as likely with a Ti cylinder because the stop wouldn't get slammed so hard when the wheel comes around. I guess my initial thought was that the stop might wear faster with a Ti cylinder because the cylinder was quite a bit harder.

Hmmmmm......wonder if both could be true......making it a wash? Randy? Waltermitty?

BTW, Do the cylinder stops require fitting, or can you just drop them in?

The newer MIM cylinder stops are pretty much drop-in, from what I've seen. The older ones usually can stand a little fitting work to make them function properly and smoothly.

I told you guys you needed to give me a couple of seasons to completely test out the Ti cylinder concept; at least until after Nationals anyway. :rolleyes:

Yeah, I went through MIM stops a little slower than I went through primers, but I definately learned to carry an extra right away.

The first stop went 1.5 years, the next one went 6 months, the third went about three months and the 4th went in between stages at a match in OKC. At that point I decided to replace the cylinder.

I don't have nearly the miles on the Ti(s) that Randy has. So I just don't know what the limits will be. So today I'm carrying two guns in my bag and an extra cylinder stop just in case.

I'll let you take a look at them next time I see you. Are you coming to the ICORE Regional in Arkansas?

B)

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I would think the Ti cylinders would wear the stop down slower, for the same reasons Randy mentioned (less inertial mass impacting the stop). I wore the MIM stop out on my 625 and had Randy replace it with a forged stop for durability.

I would tend to look at them as expendable. As long as it's a fairly drop-in replacement it's not a big deal to just carry a spare for when the problem arises, and now we all know it WILL happen, especially with a MIM gun. Just pray it doesn't happen on a long stage...

Bjorn and Mike, do you think hardening the stop would be worth the effort? It's just going to make replacement more expensive (although the change interval would be longer). This can be a real problem if the stop is made harder than the cylinder and wears the cylinder stop notch.

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I'll let you take a look at them next time I see you. Are you coming to the ICORE Regional in Arkansas?

I'm afraid I'm probably not going to make it down. My work schedule this year is going to be crazy this year, particularly in the first half of '06, so I won't be able to travel as widely to shoot. I'm fortunate to have a number of big matches close to home this year.

I would think the Ti cylinders would wear the stop down slower, for the same reasons Randy mentioned (less inertial mass impacting the stop).

Just for kicks I pulled my 646 (the only revo I own with a Ti cylinder) out of the safe last night and checked out the MIM cylinder stop. The shape of the stop seemed OK, but there was a very definite shiny flat spot on the face of the stop where it was obviously being worn by the harder (and not terribly smooth) Ti cylinder as it rotates around. Not enough to be a problem yet, but something to keep an eye on if I ever put that gun back into regular service. The cylinder itself showed very minimal peening.

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The MIM cylinder stop will definitely wear faster than the forged part. The advantage is that it can be made much cheaper and closer to drop in. The grain structure is not as fine as a forged component(sorta "less dense") so the dome will wear to a flat under extended use.

Take a look at the track marks on a recent model cylinder- they are typically chattered rather than smooth. These chatter marks are in part responsible for speeding up the wear on the c-stops. The wearing down of the cylinder stop as the cylinder slides across it's surface is where most of the dimensional change occurs. Andy Cannon used to mirror polish the back end of the cylinder before hard chroming. Cosmetically cool, but a side benefit was reducing wear.

As Waltermitty noted, replacing the stop without addressing the stop slots on the cylinder, the skipping can and usually will reappear.

I will be talking to Ron Power at the SHOT Show, but last year he mentioned that he was making an oversized cylinder stop. I haven't seen it on his website, so it may be a limited quantity.

It should be pointed out that regardless of whether the c-stop is MIM, forged or barstock, the deformation of the cylinder stop slots are of primary concern to me.

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It should be pointed out that regardless of whether the c-stop is MIM, forged or barstock, the deformation of the cylinder stop slots are of primary concern to me.

This statement by Randy is the money quote.

I would buy a plastic cylinder stop and replace it every 500 rounds (like a shock buffer) if it would stop the notch peening.

I was also considering a suggestion from Bubber that I buy a blue cylinder. I think it is a valid hypothesis that the steel could be tougher, get it set up then have it hard chromed for wear.

Then I became infatuated with the notion of the Ti experiment.... :wub:

I'll try to get some super closeups of my Ti cylinder with ~2500 miles of abuse...er...um...use.

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I'm thinking about hard-chroming my gun now while the cylinder is still probably OK, to see if that slows down the peening problem. I'm not completely sold yet on the Ti cylinder concept although I am very interested to see how things work out with your gun long-term.

It also makes me think maybe the question "625 or 25-2?" has a more specific and definite answer than I had previously thought.....

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Now you guys are freaking me out.I have been shooting my PC-625 almost exclusively for the past 4 years and have never had a problem yet with the CS. I am guessing probably 10,000 rounds. Cylinder has started to peen over a little in the slots. The stop itself does have a pretty good flat spot on it already. My IDPA gun is PC 625v-comp. Probably only 1500 rounds through it and it looks worse than my IPSC gun.

Mike, How many rounds through the gun before this happened?

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I have heard of someone that files a "flat" on one side of the mim cylinder stop to help prevent peening. Anybody know anything about that?

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Mike, How many rounds through the gun before this happened?

Crap, Tom, I wish I knew. I don't really keep track. I'd guess 4 or 5 thousand, with very little dry-firing.

As everybody here knows, I sorta sneered at the whole "peening" thing, but I have to admit I think it's happening to my gun. Looking back I think I had one isolated incident of cylinder "roll-past" at Area 5. At the time, I thought I must've short-stroked it. But there was no primer indent even though I thought it went click (heat of battle, not really sure).

Right now it's just a cylinder stop issue on my gun--but I'm becoming increasingly concerned the cylinder might be gradually getting worse, the same way it happened to Walt and Lefty.

I hate gun problems. That's half the reason I shoot revo.

I have two high-mileage, heavy-use S&W older blue N-frames (the 27 I bought from BE and my 25-2 that Sam currently shoots) that NEVER exhibited this sort of problem. Inexcusable for the factory to have their metallugy so piss-poor, if in fact that is what's going on here.

I'm thinking chrome. And buying another nice 25-2 next time I see one.

What's Jerry say about this, anyway? He shoots 'em harder than anyone.

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Mike,

Put a new CS and run it for a while. I dont think its that big'a deal.

I have they cyl off my old gun installed on my new because the chambers are looser.

The peening is very noticeable but has never skipped a rnd. That cyl has 3 "hard" years of live fire and 100's thousands of dry fire cycles and is still going strong.

Gun parts are going to wear as does the parts on a car. You just got to keep up on the little maintance issues.

FWIW, i've replace the CS at leased 3 times so far at equal intervals.

Also ran a heaver CS spring but didn't really care for that ( to noticeable on the trigger pull).

Dan.....

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I don't think I can help anyone here,(as usuall) but here is a small tidbit of info....take it for what it is worth.

I personally don't like dry fire, not enough feedback so I send bunches of rounds down range......40,000+ last year alone on the 625 and 30,000 the year before.

My 625 that I have shot all these rounds through shows some small amounts of peening on the back side of the cylinder where the CS hits it....about what should be expected.

The CS is starting to show a good amount of wear on it and I expect to have to replace it when and if I get back to shooting a wheelgun.

This is the same 625-3 I blew up the first month I owned it and am still running the same replacement cylinder.

Now, when my 625 was at the doctor getting emegency surgery I borrowed a friends 625-5 and used it. for the first month it ran flawlessly.

At Area-4 in the middle of the 3rd stage of a 10 stage match it started skipping on 1 cylinder( the CS would not lock it up). The next week we promptly sent it back to S&W who installed a new CS and CS spring.

A week later it started again, on the very same cylinder......We again sent it back and they replaced the CS and CS spring, and recut the lead in grooves on the cylinder. It has worked perfectly since.....for him and only in 3 ICORE postal matches.

I purchased a new to me 25-2 and it missed locking up randomly, after I looked at it real close it looked like the lead in cuts were too shallow and the CS was just not having enough time to fall in the groove to lock it up.(The CS spring was pretty soft too)

Sent it back to S&W, they installed a new CS and Spring and it seems OK, but I have not had time to play with it and now my hand won't let me shoot it so time will tell.

But the lead in cuts seemed to be some of the problem, I....Like Randy think that if they would move the CS up just a little and let it fall center of the lead in cuts think this problem will go away. (FWIW)

Carmoney, I hope you get the gremlins out and then get her hard chromed, should look really cool!!!!!!

Later.

HOP

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I'm thinking about hard-chroming my gun now while the cylinder is still probably OK, to see if that slows down the peening problem. I'm not completely sold yet on the Ti cylinder concept although I am very interested to see how things work out with your gun long-term.

It also makes me think maybe the question "625 or 25-2?" has a more specific and definite answer than I had previously thought.....

Mike,

You’re definitely thinking logically, but based on my trials and tribulations going through my first SS cylinder you are way more than half gone with your current cylinder, and spending money to hard-chrome it will be throwing good money at an unsalvageable part.

There are two reasons I wouldn’t plate the SS piece. First, the main problem is the underlying strength of the SS substrate. Stainless steel (which by some definitions isn’t actually “Steel”) is a compromise. Market forces pushed the manufacturers to produce SS guns because the vast majority of us can’t (or don’t want to) properly care for steel guns. The first choice for high stress gun parts is a good carbon steel primarily due to its fundamental strength. So any rational chrome plating thickness (.0003” to .0005”) on your SS cylinder would not impart the functional toughness you desire.

The only way to alter the underlying strength of the part with chrome would be to re-machine your cylinder for oversized dimensions, plate up to about .010” thickness, then re-machine again to spec so it would work. This of course would be prohibitively expensive with debatable outcomes.

Secondly, the area where you want the chrome metal to go is problematic. Plating is one of the electro-deposition technologies where the substrate (your cylinder) is grounded (electrically) and the chrome (in a positively charged solution) is deposited on the part. Large flat areas are perfect for this (think large steel bumper face) however, recesses and notches are horrible (think of the back of the bumper and assorted nooks and crannies) due to the Faraday Cage Effect. The Tennessee elevation and Kentucky windage needed to get the part to come out properly would be huge.

My motivation to consider the Chrome on carbon steel route was to get the strength of carbon steel with the rust and abrasion resistance imparted by a thin, although variable, layer of chrome. This is how I did my Limited guns in the past. I would buy a blue steel gun, get it tweaked and broken in good, and then send it off for hard chrome. The areas that were “thick” needed the protection and the “thin” areas were generally protected, lubed, and/or out of sight.

The end product would have been a pretty attractive piece that should have a dramatically longer service life. Even in the very thin recess areas the rust and abrasion resistance would enhance the tough substrate. I would stick with the MIM cylinder stop to be the sacrificial component in the system and flog it like a rented mule.

IMHO you’re living on borrowed time with your current cylinder. That was my experience anyway, and I found myself having to beg S&W to do a rush job on a cylinder replacement (which they f’ed up anyway) so I could make a Section Championship because I reached a point where a new cylinder stop wouldn’t make it through one long match. So, if it was me, I would go ahead and order my next cylinder and cylinder stop and replace them the next time it throws by (or sooner). Then the old parts can go in your spare parts bin for an emergency.

Which gets you back to the question........

Here's a picture of the boys "A" & "B". (A is Above) About 2500 hard rounds through "A" probably 500 rounds through "B". "B" is also dirty from this weekends matches.

post-5714-1136859696_thumb.jpg

more close ups, dirt probably is clearest marker

post-5714-1136860124_thumb.jpg

I couldn't get the "B: picture to add to the post above.... :angry:

post-5714-1136860664_thumb.jpg

Edited by Waltermitty

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Ken,

I can see that the CS on the TI cyl is not centered to the notch like the SS cyl's either.

What's S&W thinking

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Mike, I hate to hear that Skip has come to visit you but, I'm glad to see he is far from Ohio!

My problem seemed to be more cylinder related than CS related. One thing I noticied was a ridge had developed on the lead in edge of the notch. This seemed not the allow the stop to drop into the notch as quickly as required. I lightly hone that edge when needed. I also had peening of the notch as we all seem to have.

I agree with Sam, the lead in groove could/should be cut deeper to allow the CS to impact the notch as deep as possible

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Ken,

I can see that the CS on the TI cyl is not centered to the notch like the SS cyl's either.

What's S&W thinking

Yep, it looks like a direct clone of the SS system.

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One thing I noticied was a ridge had developed on the lead in edge of the notch. This seemed not the allow the stop to drop into the notch as quickly as required. I lightly hone that edge when needed.

Phil, I noticed the exact same thing on my cylinder, although it was minor. I used a round ceramic stone and knocked off the edge before I put the gun back together. I guess I don't mind if the notch widens (as long as it's only slightly), as long as it engages properly every time. Anyway, with the edges gone and the new (MIM) CS in place, I cannot get it to skip now. Normally I wouldn't mind being the experiment boy on how long you can keep a stock cylinder working with a little "maintenance," but most of my shooting is at matches, and I don't want the damn thing screwing up during a match.

Obviously, I should have at least heeded the warning blip the gun sent me at Area 5. Hopalong will remember how confused I was when the gun clicked with no noticeable primer indent.

Ken, I appreciate your thoughts on the chrome issues. I'm still hopeful that my cylinder isn't too far gone.

God, now I feel like one of those fussy little worried old hens on the S&W Forum! ;)

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