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Post by Richard on Feb 18, 2009 18:51:49 GMT -5
Again, I thank everyone for their concern. AS you read, you will see why I started a new thread. It was just plain NOT thinking. Of all the duplexes I have put together, I never did what I did. The fact that I had loaded ten vials of 62 gr. 4198 and they were adjacent to the the duplex load.....then having only shot five of them, they were right next to the 10 gr. 5744 vials (which of course nest to the 50 gr. vials of 4198) I have them marked on the front in masking tape. Just a mistake I will not make again. No longer will is mix single powder charges in the same box I load duplex's. As Kerry said, the bore scope will not show anything but a blatant problem. Soooooooooo, here is the story. Today I took the took the breech plug out to do my normal cleaning and to JB the bore. Yes, there is a slight enlargement. After throughly cleaning it out, I ran a saboted bullet down and can feel a very slight enlargement. I am not talking where the bullet falls thru. It still goes down with pressure. The good thing in my mind in this.....It is just slightly forward of a seated bullet. What I did was load 60 gr. of 4198 with a saboted bullet and seat it. I then marked my ram rod. With the rifle in the muzzle down position, I unscrewed the breechplug, stuck a .38 bronze brush into the primer pocket so I could remove the plug, then pushed the powder and bullet out the bore. (save cleaning up the powder form the action). When I run the tight patch in, the enlargement is about 1.5" forward of the bullet.
So what is your thoughts on this..... Here is my thought. As long as the bullet sabot goes in tight all the way to the powder (aside from the slight (and yes, slight) looseness), would not the "neck".....where it get tight again, act like a throat on a center fire? Those following three duplex "super loads" all shot to the same elevation (yes, they strung horizontally) and the two that were chronographed were within ten fps. Don't know exactly what that means but they were close in velocity. One thing came to mind....If I replace my modified BP, it should push the powder column about 1/2" further up the barrel. Using larger amounts of slow powder could push the bullet (70 vs. 60 gr) another 1/2 further. Just some thoughts. Then again, it may just shoot fine? Now sabotless might pose a different story.....Hmmmmmmmm. Richard
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Post by edge on Feb 18, 2009 19:36:48 GMT -5
An enlargement means that you exceed the yield strength of the material. It has permanently changed the grain structure of the metal in that area of the barrel.
The good news, bad news and the risks!
The good news: The barrel, while weaker in that area and assuming that it has not cracked is "probably" safe to shoot;
The Bad news: There will most likely be a permanent loss of pressure and duplex may be needed to ensure consistent ignition;
The Risks: Clearly there is always a chance that there is a fatal defect to the barrel that may show up later. A hidden crack would certainly grow if high pressures are encountered. If you have another incident this would be the logical place for any failure to occur.
Since you continued to shoot the rifle with very high pressure loads you may have answered most of the questions concerning the barrel integrity, but you may never know for sure.
edge.
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Post by Dave W on Feb 18, 2009 19:46:03 GMT -5
Can the barrel be tested for cracks Edge?
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Post by jims on Feb 18, 2009 19:46:32 GMT -5
Richard: My damaged barrel is now 2 inches shorter. You could cut off the bad spot and still have some usable length as long as the taper did not leave under 1.060 inches in diameter as I recall on size needed. You had a longer barrel to start with as I remember. I did magnaflux my barrel and found no cracks as edge mentioned so I felt good to go. I personally would have some reservations about shooting with the bulge that close to my face. I have a friend who shoots a slightly bulged Browning Superposed but that bulge is nearer the muzzle and at shotgun pressures. To each his own but be safe.
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Post by edge on Feb 18, 2009 19:50:00 GMT -5
Can the barrel be tested for cracks Edge? As jims wrote, you could have a magnetic particle inspection, but the ID is pretty small to get a good look at. Another option would be to x ray the barrel. edge.
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Post by Richard on Feb 18, 2009 19:50:42 GMT -5
Edge.........thanks for commenting on this incident. Like I indicated the buldge is "slight"...The bullet/sabot still has pressure when its passing thru this area. Would you feel that since the bullet starting from a "looser" section and transitioning to the normal and final 22", that there should be an accuracy issue? Those last three shots were definitely extremely close in velocity. Thanks Richard
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Post by edge on Feb 18, 2009 19:54:19 GMT -5
Being that the bulge is near the breach I would not expect an accuracy issue except if ignition is affected. Any reduction in pressure at the point of ignition can easily halt the ignition completely.
edge.
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Post by dave d. on Feb 18, 2009 20:14:57 GMT -5
:)richard sorry to hear about the barrel but be safe.a buldge is one thing a burst is another.not trying to be a downer but your safety is more important.
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Post by mike3132 on Feb 18, 2009 20:22:18 GMT -5
Since it has a buldge IMHO I would scrap this barrel and buy another. Life is too short to take a chance it might let go sometime down the road. Mike
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Post by younghunter86 on Feb 18, 2009 20:26:25 GMT -5
Could the barrel be drastically cut down... like taking 5-6 inches off? If that would remove the bulge, could you assume (I know you should never assume anything but can't think of a better word to use) the structural integrity on the rest of the barrel would be ok? Just a thought taken from jims post, but trying to be "extra" safe.
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Post by smokeeter on Feb 18, 2009 20:34:58 GMT -5
Richard I am sorry for your mishap but happy you are alright and commend you on reporting such an occurance. The location of your bulge is classic ( just ahead of the bullet and charge). I'm not sure I would trust the integrity of the barrel after such an experience , you were lucky the first time don't press your luck on using a questionable barrel, that thought of it blowing up will be with you every time you pull the trigger.
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Post by ET on Feb 18, 2009 20:36:18 GMT -5
Richard
Kind of uncomfortable here with my comment because of my end result but will tell it like it was with my double load with the 10ML-II. The lands were peened but no indication of barrel bulging was found on the outside of the barrel. So the actual integrity of the barrel appeared okay and the lands took the brunt of the double load. I did fire some rounds afterwards but the accuracy I had before the incident was lost. Here I felt the peened lands were playing havoc with my sabot. I did replace the barrel and made the previous mods, as before and my previous accuracy returned.
Wish I had a more encouraging comment and hope you fare better with your barrel condition as I did. This is one time I really hope you prove me wrong about an end result of a double load.
Ed
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Post by tcmech on Feb 18, 2009 20:38:58 GMT -5
I don't know that if it was mine I wouldn't keep shooting it. I would replace the barrel before I would cut it though.
There are plenty of used stock barrels that make their way to the trade blanket.
I know a lot of the guys here like the pacnor 40 and 45 caliber barrels, but I think I would stick with the 50.
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Post by Dave W on Feb 18, 2009 20:41:44 GMT -5
Trying to put myself in your shoes and I ask myself-Could I sit behind the stock and pull the trigger with the confidence that nothing bad will happen and the answer is NO I could not. Money is one thing but there is no price on your health and well being.
I would do what Jim has done and have it cut down and re-chambered to a stubby like P Posey's gun. You can get another barrel if that does not work for you and that would give you all kind of experimenting with two different barrel lengths.
One other thing, there is no absolute that the same thing could not possibly happen again but on a already stressed barrel.
Sorry you had this experience.
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Post by ET on Feb 18, 2009 21:03:37 GMT -5
Not trying to be smart here but do hold certifications for NDT in RT, LPI, MPI and UT. My choice for looking for cracks would be LPI (Liquid Penetrant Inspection) Remove barrel from receiver Wipe the suspected area for testing clean with a solvent. Apply solvent removable Penetrant with a loose fitting cloth on a Jag. After about 15-minutes wipe bore with a cloth saturated with solvent a few times. Wipe bore with clean cloth to verify the surface Penetrant has been removed. Carefully spray in a light coating of aerosol developer. Monitor area for any linear/jagged bleed outs for about 30 minutes. Recheck for bleed outs after an hour, as very small cracks sometimes takes longer to appear. If no bleed outs appear then no cracking.
Ed
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Post by KerryB on Feb 18, 2009 21:15:48 GMT -5
I am standing with the guys that suggest replacing the barrel. This bulged barrel shows the signs of the tremendous pressure that it contained in the mishap. There is no guarantee how much more pressure it can withstand without a failure. I sure wouldn't play Russian Roulette for $350-$400. It is a bit of a pricey lesson, but why take a chance on making this incident much more pricey with a possible loss of life or limb? I would replace that puppy and count myself ahead of the game............still alive and with all limbs intact! Good luck, whatever you decide buddy. KerryB
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Post by craigf on Feb 18, 2009 21:47:53 GMT -5
Richard, when this happened to my old 50 barrel, I could never get it to shoot accurately. I would cut it down and rechamber it. If you didn't want it you could resell it as a short hunting barrel. PPosey has proved that a short length can shoot well.
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Post by olegburn on Feb 18, 2009 21:56:54 GMT -5
I'm sorry to hear about problem spot there,Richard. I like the idea of shortening the barrel by few inches and making it a "shortie" or brush gun. Question to the experts would be: How far past that "bulge" is safe cutting it? IIRC,yours is 28" barrel and it might have enough length to make that "tactical" ML with the Aimpoint ACOG.
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Post by Richard on Feb 18, 2009 22:00:32 GMT -5
A lot of good comments and suggestions. As Edge indicated, the fact that I did fire three hot loads right after the mishap and it did not "let go!", it appears to show the barrel cannot be all that hurt? With that said, I just spent a bit of time in the shop with my micrometer taking measurements. It appears that there is enough diameter to cut 3 to 3 1/2" off and still have enough to do the external threading. This would put the "start" of the buldge within the receiver and barrel nut. Most of which would have the BP threads. I'm thinking of calling PacNor and see if they will cut and re-do the breech end. Thanks Richard
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Post by sw on Feb 18, 2009 22:34:52 GMT -5
A lot of good comments and suggestions. As Edge indicated, the fact that I did fire three hot loads right after the mishap and it did not "let go!", it appears to show the barrel cannot be all that hurt? With that said, I just spent a bit of time in the shop with my micrometer taking measurements. It appears that there is enough diameter to cut 3 to 3 1/2" off and still have enough to do the external threading. This would put the "start" of the buldge within the receiver and barrel nut. Most of which would have the BP threads. I'm thinking of calling PacNor and see if they will cut and re-do the breech end. Thanks Richard Richard, I think this is the right thing to do. It is what I still plan to do with my bulged 50 cal SMI. Currently, the barrel's yeild strength is an unknown. However, it is safe to assume that it is less than what it was.
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Post by jims on Feb 18, 2009 22:39:39 GMT -5
Richard: With "liability" concerns today I would be surprised if Pac-Nor would do that but I have been wrong before. The shorter route seems the safer, it will be a better brush gun and aren't some of the most accurate bench guns only around 20 inches in length?
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Post by Harley on Feb 18, 2009 22:55:11 GMT -5
Richard, every bit of advice you are getting has merit. After reading them all I like best your idea of contacting Pac-Nor for a cut and thread. If they say "no", don't think twice, order a new barrel while on the telephone. If they say "yes", balance the amount of money savings over ordering a new barrel against any loss of confidence you have that the re-worked, shorter barrel will satisfy you.
I'm really sorry this happened to you; I'm pretty sure you want it exactly "right" and won't be happy with anything less.
Harley
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Post by sagittarius on Feb 19, 2009 1:43:59 GMT -5
Rich, Do what you think is right for you as far as shooting your barrel. You know much more about their characteristics than I ever will.
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Post by tar12 on Feb 19, 2009 3:35:36 GMT -5
I would not continue shooting it.The integrity of that barrel has been compromised.It would how ever make a excellent donor barrel for some testing.There are a lot of people on here who would like to know if a sabotless gun can withstand a double loading.. I am not trying to be funny.I am sure this thought weighs heavily on the minds of some. I know it does mine. It is the one unknown shooting sabotless.Do as you wish......
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Post by Al on Feb 19, 2009 3:44:11 GMT -5
I'd play safe and replace it.
Is there anyway to caculate what the pressure of that load was?
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Post by wilmsmeyer on Feb 19, 2009 5:30:45 GMT -5
I am always shocked that this happens to folks. Glad you weren't hurt.
There are so many ways to avoid this...the best being the actual use of witness marks. Gotta take every shot, every time with care. Even the best bomb makers blow themselves up.
You couldn't get me to touch that barrel no less pull the trigger on it. It is sullied....or worse.
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Post by bigmoose on Feb 19, 2009 6:53:09 GMT -5
It is cheap insurance.....change it
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Post by screwbolts on Feb 19, 2009 7:23:36 GMT -5
Richard, If you decide to replace this barrel I would gladly except you bulged one. I would cut the chamber off and then recut it for another Breech plug? If you would like the barrel back that I bought from you so you still have a backup for a backup I would gladly sen it back to you, just let me know the check is sent. I did get the broken screw successfully out of the Thimble hole.
A question or 2 for all you experts:
a) Why does Savage use a Breech Plug that is larger than a 5/8x20 threaded Plug?
B) is this simple a carry over from the ML10 breech plug designed for inserts?
If Richard was to cut his barrel down, and then have it fit or do the work himself for a 5/8 x 20 threaded BP this would leave him with more material thickness supporting the BP.
Richard: I know you know that short stubby barrels whip less, and I would gladly ship you your old barrel back. :-)
Ken CNY
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Post by edge on Feb 19, 2009 8:56:19 GMT -5
SNIP Is there anyway to caculate what the pressure of that load was? Not really. You could calculate fairly closely what the pressure would have reached if it had not yielded! Since it did yield, if you knew the heat treatment of this barrel then you could probably come close to saying that it definitely reached "X", but how much past "X" would still not be known. Exceeding the yield is not always bad, the extent that it passed it is what is lacking! edge. FYI every barrel that Pac-nor makes has had the barrel exceed the yield point since the use "button rifling". They start with a round hole and pass a carbide rifling button through the barrel. If that "button" did not exceed the yield point of the steel the hole would simply be rebound to its original shape of being round with no rifling! Of course Pac-Nor has a precise measurement of the pre-rifle bore and they know the the exact size of the "button"
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