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Forums10
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Apr 29th, 2024
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Joined: Feb 2002
Posts: 14,165 Likes: 208
Sidelock
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Sidelock
Joined: Feb 2002
Posts: 14,165 Likes: 208 |
Keith, I am not familiar with any definitive testing of the results of a primer in the powder charge accellerating the ignition to a dangerous pressure. However, I have read of barrel failures that seemed to have eliminated other obvious causes. Some testing of the effects of a primer added to the powder charge would be interesting. Some loaders (the machine, not the person) effectively eliminate the possibility. Some loaders make it more possible by design. Some loaders (the person, not the machine) leave powder cannisters open, making it possible for a loose primer to drop into the powder cannister. Bad idea. On another aspect of this discussion, I think it is very unlikely that a wad would be left from a previous discharge close enough to the breech to cause the pictured blowup. I also think it is rather ridiculous to be discussing a barrel blowup without first eliminating the possibility of thin walls.
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Joined: Feb 2006
Posts: 3,744 Likes: 57
Sidelock
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Sidelock
Joined: Feb 2006
Posts: 3,744 Likes: 57 |
Since were are all trying to be Sherlock Holmes on this Baker blow-out, it seems that only Randy can answer most of the questions that all are trying to figure out.
Indeed the greatest pressures would be right where it blew, so if Randy would give some information of said barrels wall thickness, I think we are all speculating, and I agreee with Bill's last sentence.
David
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Joined: Feb 2003
Posts: 1,116
Sidelock
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Sidelock
Joined: Feb 2003
Posts: 1,116 |
I have a piece 2" X 1/2" from the blown area. It came from the area adjacent to the straight tear near the breech. Measurement wall thickness is .112" at that point. If anyone would like the series of closeups etc of the Baker and could post them here please send me your email and I'll send the photos. Unless a loose primer was in the 8lb Clays jug, the loose primer seems unlikely. The only unusual thing is the rear of the tear seems to be following a weld line, if that is possible. Other than that, I don't have a clue. The photos give a good view of the evidence. Hope some new light can be placed on this incident. Randy
RMC
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Joined: Feb 2002
Posts: 14,165 Likes: 208
Sidelock
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Sidelock
Joined: Feb 2002
Posts: 14,165 Likes: 208 |
JDW, thanks for the statement agreeing that measurements of wall thickness are normally step one in diagnosing a blowup. Thank you RMC for the attempt to give pertinent measurements. Unfortunately, many more measurements are neccesary to eliminate "thin walls in the area of the blowup" from the possible causes of the blowup. All past suggestions of primer related blowups have been without testing to prove the primer at fault. Is anyone willing to give this a shot? Is anyone willing to donate shotguns, however cheap or worn, to the testing? I will agree to test with one or more primers in the powder charge, with one or more witnesses, and report the results. Give me some time, but it is the dead of winter, so I can do it. I will accept no more than six working shotguns. They don't have to be fluid steel, but Damascus guns should be fairly intact and show evidence of having been fired in the last thirty or forty years. If you want your shotgun back after testing, all you have to do is pay for shipping. Email me if you want to ship me a gun. Pre 1898 guns would simplify the process, but later guns will be accepted. I will reply with my shipping address. wilmrph@verizon.net Bill Murphy
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Joined: Feb 2003
Posts: 1,116
Sidelock
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Sidelock
Joined: Feb 2003
Posts: 1,116 |
Pete has been sent the photo file on the blown Baker. If it doesn't crush his computer, some interesting pics will be up for your review. Thanks Pete. Randy
RMC
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Joined: Nov 2005
Posts: 4,598
Sidelock
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Sidelock
Joined: Nov 2005
Posts: 4,598 |
Randy,
Thank you for sharing. Randy sent 21 photos. I opened a new thread as this one is getting a bit long.
Pete
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Joined: Jan 2006
Posts: 15,456 Likes: 86
Sidelock
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Sidelock
Joined: Jan 2006
Posts: 15,456 Likes: 86 |
 Here's A Nitro load I shoot in my 1881 Scott 10 ga hammer gun...the gun was reproofed at 4 tons with 3 & 1/2" chambers. Federal 10 ga. 3 & 1/2" hull, Win.209 primer BPD wad with 20 ga. Fiber fillers 1 & 5/8 oz of Bismuth 4 shot, 33.6 grains of IMR 7625, 1260 fps. I shot this at a measured 40 yards.
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Joined: Feb 2004
Posts: 13,880 Likes: 16
Sidelock
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Sidelock
Joined: Feb 2004
Posts: 13,880 Likes: 16 |
I don't know if a cocked wad has been discussed yet since I haven't followed this thread completely. But cocked wads are the most common type of problem I've encountered in a PW. Usually stems from a worn/deformed wad guide or shell plate (indexing). The cocked wads I've encountered most often have the lower base area folded up sideways but the shotcup in the normal orientation. The only tattle-tale sign was a bulged side of the shell. The crimps were normal.
I'm wondering if a pressure test of weighed charge shells with the wads straight vs cocked is valuable?
Last edited by Chuck H; 12/11/08 08:33 AM.
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Joined: Feb 2004
Posts: 13,880 Likes: 16
Sidelock
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Sidelock
Joined: Feb 2004
Posts: 13,880 Likes: 16 |
William Greener tested some bars of various damascus metal by pulling them till they broke (Prior to wrapping into a bbl). The better grades showed tensile strengths of 60-76K psi. Some cheap bbls which contained no steel showed only 40K or less. This was 1834, no doubt these cheaper bbls fell by the way side & bbls were likely produced which had even higher strength than the Best of '34. By way of camparsion Wrought Iron has a strength of about 48K, Low Carbon open hearth steel about 56K while a piece of plain carbon 1035 steel will show from 83 to 96k depending upon its temper (1300°F to 800°F). More modern 4140 alloy steel (A common steel for gun bbls) starts at 110K at a temper of 1300°F up to 180K at 800°F. These are the tempertures to which the steel is tempered or drawn after heat treating. There is no question modern alloy steels used in todays guns exceed the strength of the vintage gun bbls whether steel or Damascus. Plain carbon steel having a carbon content greater than about 40-45 points was not really suitable for gun bbls so most early steel bbls are not really stronger than good damascus/twist bbls. By the time the breech loaders became commonplace most of the really poor damascus had been done away with. In speaking of a CA 1900 vintage Parker, Smith, Lefever, ETAL I think it really matters little which type bbl it has. That's why it pays to only shoot Vintage Damacus barreled guns that were originally High Quality...the higher grade guns had higher grade barrels. On the 4140 steel, I believe most barrels will be near the lower end of the numbers quoted. Barrels are typically very soft, even modern barrels. The exception seems to be the hammer forged barrels that are work hardened.
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Joined: Dec 2001
Posts: 12,743
Sidelock
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Sidelock
Joined: Dec 2001
Posts: 12,743 |
Chuck;
According to an older Machinery's Handbook chart 4140 when drawn to 1300°F has a Rockwell hardness of C20 & shows a yield strength of 85K & tensile of 110K. This puts the yield higher than the tensiles Greener tested. Remember though his tests were reported on in 1834. No doubt by 50yrs later these strengths were most likely improved & those really low ones totally weeded out.
Interestingly around 1981 I read an article in a "Machining Trade" magazine where the Ithaca Corp was reporting on their switch to "Roto-Forged" bbls for their shotguns. Sure was not even similar to Ads appearing in the Gun Rags, which stated what an expensive process it was but they adopted it in order to give the "Consumer" the best possible bbl they could make.
In this article one of the cost cutting advantages mentioned was they no longer used 4140, but a lower grade of steel, which due to the process ended up with essentially the same strength. This saved them many $$$ over the course of a year & labor savings of course amounted to much more. As I recall they had totally amoritized the switch in approx 2 yrs. Wish I had managed to save a copy, but was in the Co's magazine & was just showed to me as was well know I was a gun enthusiast.
Miller/TN
I Didn't Say Everything I Said, Yogi Berra
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