UPDATE: high pressure handload; damaged M29
I had solicited opinion awhile back in one post re the cause of excessive pressure in a handload, and in another post, the resulting bulged chamber in the cylinder of a S&W 29. As I recall at least one or two men had requested that I let them know how things played out. I've been occupied with tax returns, a job application, and other matters, so I haven't made a lot of progress yet, but I did talk to a very knowledgeable man at Hodgdon Powder Co.today, and thought I would share the content of that conversation with those who are interested. First, a brief review is in order:
THE LOAD(and related info)
Primer: CCI large pistol
Powder: Hodgdon Titegroup(10gr. max.; 9gr. start; I had the measure set to 8.7gr.)
Bullet: Berry's copper plate, 240gr. HP
The powder measure threw inconsistent charges, which I discovered soon after beginning. Apparently static electricity caused the powder to cling to the wall of the drop tube; a rap with the knuckles would drop it. I've since run 50 more charges through it(and dumped them back in the container), trying to duplicate what happened so as to find the source of the problem. Those charges ranged from 8.0gr to 9.25gr.
The third round fired generated enough pressure to bulge the chamber, which I noticed later when it contacted the bottom of the frame while opening and closing the cylinder. Not knowing this until you fellows enlightened me, I fired five additional rounds from the other end of the box(last rounds loaded) with no apparent problem.
TODAY'S DEVELOPMENT(S):
I spoke at length on the phone with a man from Hodgdon who had had a great deal of experience with handloading and evaluating handloading accidents. Prior to joining Hodgdon he had spent 12 years designing bullets for Hornady. He said he had seen dozens of bulged and blown u p guns over the years. Here are his conclusions:
Some of you suggested the problem might be an undercharge, which allowed the powder level to drop beneath the center of the case, creating a 'detonation'. This man categorically ruled this out. He said that Titegroup was designed for small charges which often fill only a small portion of the case. It is typically used for cowboy shooting, in .45 LC and .44-40, and will burn properly regardless of its position in the case.
I wondered if I had the bullets seated too deeply; when given the OAL of my cartridges he ruled this out also, as did several of you.
He said that on occasion he had observed copper-plated bullets lose the plating either in the chamber or forcing cone, leaving an elevated ring of copper which then caused excessive pressure in the next round fired, the second bullet being forced through the smaller diameter opening. He said in those instances the plating was damaged enough by the crimp to allow it to peel during firing. I neglected to mention to him that the high-pressure round was the first to be fired from the chamber it occupied. That would rule out this explanation.
I mentioned to him that I had noticed that each round fired left some copper residue on the left side of the forcing cone, but not the right side. He said to have a gunsmith check the alignment of each chamber with the barrel, and also the barrel/cylinder gap; then send it to S&W to get a new cylinder. I guess the idea of sending it to a gunsmith first was to see if the source of the problem was the gun itself.
My curiosity was aroused after talking with him, and so I got out my feeler guage and checked the barrel/cylinder gap. I discovered that it was around .003 more on the left side than on the right. This was roughly the case with each of the six chambers in the firing position. Was the barrel not cut squarely at the breech? I looked down at the cylinder from above the top strap, and it definitely appears to sit at a slight angle in the frame, accounting for the difference in the gap. I guess I'll bring that to S&W's attention, also.
Sorry about this long-winded post. I'll let you know of further developments as they unfold, and attempt to be more concise next time. Thanks again for your interest, concern, and advice.
THE LOAD(and related info)
Primer: CCI large pistol
Powder: Hodgdon Titegroup(10gr. max.; 9gr. start; I had the measure set to 8.7gr.)
Bullet: Berry's copper plate, 240gr. HP
The powder measure threw inconsistent charges, which I discovered soon after beginning. Apparently static electricity caused the powder to cling to the wall of the drop tube; a rap with the knuckles would drop it. I've since run 50 more charges through it(and dumped them back in the container), trying to duplicate what happened so as to find the source of the problem. Those charges ranged from 8.0gr to 9.25gr.
The third round fired generated enough pressure to bulge the chamber, which I noticed later when it contacted the bottom of the frame while opening and closing the cylinder. Not knowing this until you fellows enlightened me, I fired five additional rounds from the other end of the box(last rounds loaded) with no apparent problem.
TODAY'S DEVELOPMENT(S):
I spoke at length on the phone with a man from Hodgdon who had had a great deal of experience with handloading and evaluating handloading accidents. Prior to joining Hodgdon he had spent 12 years designing bullets for Hornady. He said he had seen dozens of bulged and blown u p guns over the years. Here are his conclusions:
Some of you suggested the problem might be an undercharge, which allowed the powder level to drop beneath the center of the case, creating a 'detonation'. This man categorically ruled this out. He said that Titegroup was designed for small charges which often fill only a small portion of the case. It is typically used for cowboy shooting, in .45 LC and .44-40, and will burn properly regardless of its position in the case.
I wondered if I had the bullets seated too deeply; when given the OAL of my cartridges he ruled this out also, as did several of you.
He said that on occasion he had observed copper-plated bullets lose the plating either in the chamber or forcing cone, leaving an elevated ring of copper which then caused excessive pressure in the next round fired, the second bullet being forced through the smaller diameter opening. He said in those instances the plating was damaged enough by the crimp to allow it to peel during firing. I neglected to mention to him that the high-pressure round was the first to be fired from the chamber it occupied. That would rule out this explanation.
I mentioned to him that I had noticed that each round fired left some copper residue on the left side of the forcing cone, but not the right side. He said to have a gunsmith check the alignment of each chamber with the barrel, and also the barrel/cylinder gap; then send it to S&W to get a new cylinder. I guess the idea of sending it to a gunsmith first was to see if the source of the problem was the gun itself.
My curiosity was aroused after talking with him, and so I got out my feeler guage and checked the barrel/cylinder gap. I discovered that it was around .003 more on the left side than on the right. This was roughly the case with each of the six chambers in the firing position. Was the barrel not cut squarely at the breech? I looked down at the cylinder from above the top strap, and it definitely appears to sit at a slight angle in the frame, accounting for the difference in the gap. I guess I'll bring that to S&W's attention, also.
Sorry about this long-winded post. I'll let you know of further developments as they unfold, and attempt to be more concise next time. Thanks again for your interest, concern, and advice.
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Forgot to mention that the gentleman from Hodgdon offered to examine/test some of my ammo for pressures and so on. Think I'll send it to him -sounds like a wise thing to do. 0 -
A couple of things come to mind (I missed your earlier posting on this subject so if this is a repeat of others, sorry)
First is that the most probable cause was a double charge, very easy to do in a large case with a small (relatively) charge. If you were noticing the static problem or otherwise distracted while reloading, it is an easy thing to do.
Second, the plating on a plated bullet is VERY thin and bonded to the lead core, unlikely that it 'pealed'. I could accept that possibilty with with a jacketed bullet but not a plated one.
Third, is it possible that your alignment problems are a result of the overpressure and not a cause? Just seems more likely to me.
Do keep us posted with any other news, always ready to learn more.
Quod principi placuit legis habet vigorem.Semper Fidelis0 -
That uneven cylinder gap sounds like a slightly stretched frame. I would guess the larger gap would be on the sideplate side which is less supported side. It would be interesting to see if S&W could true up the frame but I suspect you just have a barrel, grips and internal parts, a bummer. 0 -
I love my S&W's but frankly it is not unusual to have a barrel forcing cone that is not perfectly square to the cylinder. I had one where the foreward edge of the cylinder would actually hit the barrel when you closed it. In any event, it is highly unlikely that this condition had anything to do with the cylinder bulge. It really does sound like a classic over charge. 0 -
I use a single stage press. I visually inspect the powder charge in each 50 cases. This way it is easy to spot a squib or kaboom load.
PC=BS0 -
When you look at the front of the frame at the joint where the cylinder crane meets the frame do you see any gap? If there is, all may not be lost.
On rereading your post,it sounds like cylinder misalignment has
resulted in copper in the left side of the barrel throat. A bent crane would result in both leading on one side and a gap where crane meets frame in the front. As you stated, there appears to be a visible cylinder misalignment when viewing the gun from the top. This would be consistant with the larger cylinder-barrel gap being on the left. There may still be some hope for this beastie because cranes can be straightened if that's the only other problem.
In any event it would have to go to S&W for the cylinder at the very least. Don't hope for a favorable outcome and you can only be pleasantly surprised.0 -
Interesting responses; thanks. Please allow me to note an observation or two. For Shootist's benefit, I'll offer a bit more review. In my first post, which dealt only with the loading problem, there were at least two if not three responders(including Saxon) who, upon reading my description of things, guaranteed me that I did not load a double charge. I had said that the only noticeable evidence of excessive pressure was that the case was difficult to extract. The recoil and report were not noticeably greater, and the primer wasn't flattened severely(maybe that doesn't happen in handgun loads anyway). They seemed to imply at least that a double charge would have blown the gun and perhaps me with it.
A second observation re the pressure problem: in my first post I had asked if cartridge length was a factor(as I asked the man from Hodgdon), since I had failed to see the OAL figure in the data and loaded mine anywhere from .020 - .035 UNDER that figure. Everyone who responded to that ruled it out as a factor, as did the man from Hodgdon. However, I just read another topic headed "seating depth" by colt100 which dealt with the same general issue, and those who responded to him unanimously agreed that short cartridge length in a handgun round will increase pressures dangerously. Do you blame me for wondering whom to believe? Or am I missing something here?
I've read and reread your comments re the gun, examined it again with a dial caliper, and I still have questions. I'm not an engineer, but I do have an above average mechanical aptitude, and some of the pieces of the puzzle don't seem to me to fit. Do you think the folks at S & W will be able to settle the issue conclusively? Will they know what to do without my input, or do I need to point out what should be looked at?
Well, I could go on, but it's entirely too late for me to even be up. Thanks again, guys, for putting up with my ignorance. I'll let you know when other news develops.0 -
I replied on the original post, and I still believe an overload caused the damage. Unlike some others, I do not believe all is lost with this revolver.
A Smith M29-2 (am I recalling the model number correctly?) probably would have been made in the lower quality era of Smith. I have a couple of Smiths from that era that have uneven cylinder gaps. On one, the cylinder rubs the barrel hood.
If the frame is sprung, spring it back! The process is not sophisticated. The old method is to hold the gun by the grip and frame and bang the barrel on something solid that will not mar it (pine, etc.) until you bend it back to where it should be. As a Colt representative at bullseye matches in the 1930s, Fitzgerald of Fitz Special fame used to do this with Colt revolvers to change point of impact, etc..
A press would be more easily controlled, and that is what I would use. Block up the revolver with wood at each end and apply pressure at the point of the bend. Go slow and you can probably realign the frame as good as new. In the alternative, leave the frame bent and shoot it anyway. The bend probably is slight enough that it will not bother much. The cylinder will have to be replaced. I do not know if Smith still has recessed cylinders. My guess is not. An aftermarket search might be necessary to find a recessed cylinder. I think they will be hard to find, but not impossible.
Keep us posted.
Edited by - JudgeColt on 04/25/2002 09:59:230
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