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Post by ET on Jul 26, 2014 6:58:36 GMT -5
I still see there are mentions of a sabot providing a safety margin for possible hot loads and this is not true. I’ll admit when I first started SML I also believed this to have some truth but found out it does NOT.
Disruption of a sabot’s performance is a condition resulting from a level, rate of buildup and strength of pressure for the temp conditions that the sabot is being used in. Temp alters the integrity characteristic (property) of the plastic sabot. This is simply seen when you don’t address heat buildup in the bore. Barrels have been blown up and damaged with the use of a sabot so where is there any dependable safety margin?
From my perspective and experience a sabot will not prevent you from experiencing the consequences of a mistake. The better option is being diligent to avoid a mistake knowing a sabot does not provide any protection.
Believe what you will, personal experience has taught me the end result.
Ed
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Post by deadeye on Jul 26, 2014 7:53:52 GMT -5
well put & I agree!
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Post by linebaugh on Jul 26, 2014 8:00:53 GMT -5
Thank you for stating this and I could not agree more.
I still see and hear the same thing all the time and it is unsettling knowing people are so misinformed. No idea where this urban legend started but it is for sure false.
I have never had a gun fail but I can give one personal example that should at least show what a sabot can take. I bought a savage .50 from my father and he was using the same powder vials that I was using with 5744 and ery light bullets. Not paying enough attention I loaded a charge with a 300 gr lead bullet in a mmp sabot and shot a 5/8 mild steel plate at 100 yards.
Gun goes off and sounds like a cannon, sets me back and loosened my fillings a bit. Nearly instantly I realized what happened, dads fast powder load for 200gr bullets,and I promptly quit for the day.
A few days pass and I am again shooting and I walk down to hang a target. I happen to notice a large hole clear through my plate. After pondering a while it occurs to me that I had shot this plate days earlier with that hot loaded muzzleloader.
So how much pressure was I running on that load? 300 grain cast bullet in sabot out of a 18" barrel at 100 yards and a hole through a 5/8 steel plate. I have no idea on the pressure but there was certainly some gun metal tested that day.
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Post by Richard on Jul 26, 2014 9:41:42 GMT -5
I will pretty much agree with ET but................If we look back, most if not all failures or bulges in barrels have occurred due to double loading (read----two bullets). No matter if the sabot fails or does not fail, the cause of the problem is the excessive load trying to be pushed out. When I was playing with shooting extremely high velocities out of my 23" PN I would experience some sabot failures...........which was telling me to back it down. I never destroyed a barrel with a sabot due to a high pressure load (double charge? Yes!) so maybe, just maybe they do act as a pressure valve to some extent? Just not with two bullet in front of it.
Richard
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Post by mike243 on Jul 27, 2014 7:06:52 GMT -5
the plastic will give way before the steel will swell imo. how many folks have ruined a barrel shooting sabots with only 1 bullet in place? . in my optima manual it states no bullet weight over 300g with a 150g charge, this was a first year nickel production gun , I know there are limits to every thing but I read a lot of stuff before I bought my gun and will try to stay with what the maker stated as guide lines. no mention was made for shooting sabotless. that doesn't mean its not possible just that lawyers could make a case if they promoted it. shooting heavy for caliber loads will always push the envelope of all the components of the rifle no matter if its a center fire or muzzleloader. bullet selection also plays a roll,very soft lead will expand & give higher pressures than a harder or copper jacketed will imo. safety is #1 here . mine may end up a 45 at some point but it wont be for the option of sabotless shooting
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Post by bestill on Jul 27, 2014 7:33:08 GMT -5
Mike243,
I appreciate your thoughts on shooting manufacturers loads and not using sabotless loads in a factory built gun.
The difference with board members shooting45 sabotless is these are custom built guns with heavy contour barrels designed for high pressure loads and fast twist to allow for shooting heavy 45 sabotless bullets. Imo if you ever had a chance on range to test a quality built sabotless gun to a sabot gun accuracy and down range performance maybe shocked.
All guns are dangerous when loaded beyond there limitations. Obviously bolt guns with heavy contour barrel is top of the list for high pressure loads. Break action builds should have a lighter loads selection .
But you maybe surprised with pressure trace from a 150 grain load of loose triple seven and a sabot300 grain sst and magnum 209 in a factory muzzleloader.
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Post by Deleted on Jul 27, 2014 7:38:57 GMT -5
IIRC the pioneers here that tried "lil gun" powder out still bulged their barrels even though they were only shooting saboted the pressure still spiked too much for the barrel to handle....Thus no more trying out lil gun,lol....
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Post by bestill on Jul 27, 2014 7:41:47 GMT -5
Comparison FYI
Cva optima 50 barrel wall thickness in chamber .241
Custom rebarreled 45 bolt gun thickness is .371
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Post by ET on Jul 27, 2014 9:46:51 GMT -5
Mike 243
As stated anyone can believe what they want to.
In case you didn’t know all steel barrels expand when pressure is applied. The degree of expansion is dependent on peak pressure applied. As long as the expansion doesn’t exceed yield strength it will return to its original shape. This is why we have specific pressure ratings (yield & tensile strength) for specific manufactured steels and thickness involved.
Then of course we have to factor in the powder burn rate and the acceleration of the burn as pressure builds and the time to complete shot that is in milli-seconds. If you believe enough pressure can be dumped or vented from plastic disruption in this short time frame to significantly alter the resulting peak pressure to me this is a myth from results I’ve experienced.
Again believe what you want and you are entitled to express it as I’m entitled to warn others of what I believe can be dangerous.
Ed
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Post by rambler on Jul 27, 2014 9:59:53 GMT -5
Hello, I've been reading these threads with interest. The powder that is being talked about that may cause a barrel failure is smokeless correct??
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Post by deadeye on Jul 27, 2014 10:23:01 GMT -5
slightly off course but related to sabot/plastic-
if plastic is a true safety valve how in the world could it blow mz muzzlebreaks apart?? just something to chew on
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Post by Deleted on Jul 27, 2014 11:59:04 GMT -5
bottom line
the only safety valve in smokeless rests on your shoulders between your ears
correct powders and procedures are a must with any firearm you push the bullet down the barrel. we are our own safety valve.
that's the reason we preach safety so much. anyone can bulge a barrel including me. I bulged one a few months back and still don't know how I did it but it happened. cost me a fluted Pacnor as a learning tool though, only magnifies the need for safety. get lax in your shooting procedure and sooner or later it will bite you..
fast powders such as little gun can turn a gun into a pipe bomb when you reach a point, sabots or not as members can attest to.
I think the difference in the pressure required to swell a barrel is extreme but the plastic will make little difference..JMO
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Post by TGinPA on Jul 27, 2014 12:05:03 GMT -5
Again apologies for being slightly off course.But,it is related to barrel failure mentioned above.
Re: Barrels returning to their original shape after every shot of normal loads: A factoid I was recently reminded of and of which many may already be aware is worth keeping in mind: From an article recently published, it is my understanding , that in all steel barrels, tiny structural changes do occur after every shot fired through it. The author of the article posited that sooner or later, all barrels subject to pressure-induced stress will fail due to metal fatigue. The number of shots needed for failure to occur is directly related to the number of shots fired and amount of pressure-related stress induced by each shot. He stated that by design, the number of shots needed for barrel failure to occur under use at pressures for which a barrel is engineered greatly exceeds the number likely ever to be fired in that barrel. However, if/when one shoots loads significantly exceeding the maximum safe pressure specified for that barrel, the number of shots needed for barrel failure to occur may be greatly shortened. So...even though an unknown number of shots of excessively high pressure loads may be fired from a given barrel without apparent incident, the effect is cumulative. With further shooting, the chance of catastrophic, sudden surprises is significantly increased. IIRC, some time ago on this board, someone (maybe Rossman will comment) may have raised this subject in regard to routine military replacement of tank barrels after after some specified number of rounds had been fired. And maybe, the fact that cumulative structural changes occur in barrels after every shot is common knowledge. It wasn't for me.
TG
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Post by Dave W on Jul 27, 2014 15:03:41 GMT -5
Again apologies for being slightly off course.But,it is related to barrel failure mentioned above. Re: Barrels returning to their original shape after every shot of normal loads: A factoid I was recently reminded of and of which many may already be aware is worth keeping in mind: From an article recently published, it is my understanding , that in all steel barrels, tiny structural changes do occur after every shot fired through it. The author of the article posited that sooner or later, all barrels subject to pressure-induced stress will fail due to metal fatigue. The number of shots needed for failure to occur is directly related to the number of shots fired and amount of pressure-related stress induced by each shot. He stated that by design, the number of shots needed for barrel failure to occur under use at pressures for which a barrel is engineered greatly exceeds the number likely ever to be fired in that barrel. However, if/when one shoots loads significantly exceeding the maximum safe pressure specified for that barrel, the number of shots needed for barrel failure to occur may be greatly shortened. So...even though an unknown number of shots of excessively high pressure loads may be fired from a given barrel without apparent incident, the effect is cumulative. With further shooting, the chance of catastrophic, sudden surprises is significantly increased. IIRC, some time ago on this board, someone (maybe Rossman will comment) may have raised this subject in regard to routine military replacement of tank barrels after after some specified number of rounds had been fired. And maybe, the fact that cumulative structural changes occur in barrels after every shot is common knowledge. It wasn't for me. TG This is interesting! There was an old thread, maybe a sidetrack of a thread, where this was discussed. If memory serves, I think RB said he put a numerical value of 3000 shots for a barrel. Since we don't have a throat to burn out and discard the barrel like a centerfire when accuracy diminishes, at what point do we put ourselves or others in harms way? Personally I worry less about the barrel since we are using centerfire grade barrels than I do the repeated pounding the plug threads take, especially with no bolt lugs to back up the plug. |
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Post by Alabama on Jul 27, 2014 23:39:27 GMT -5
Has there ever been a case of breech plug failure due to thread weakness?
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Post by cowhunter on Jul 28, 2014 0:08:51 GMT -5
Hillbill is right. If sabots make any difference in safety, it is very little. Pressure blows barrels and it builds suddenly, whether behind a sabot or a bullet. Go watch the CVA video where the CVA guy blows up a Knight, a CVA, and a TC muzzleloader with 120 grains HS6. He uses a sabot in all three. I encourage you to go watch that video for another reason. As the guns are ready to blow apart, imagine that Richard, Fishawk, Myers 129 or any of your favorite Board personalities, are sitting behind the gun as it blows. For some reason you will have quite a laugh -- anyway I did.
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Post by ET on Jul 28, 2014 4:49:56 GMT -5
I personally have never had any concern about the thread capabilities of the Savage BP design. If it can survive this without being dislodged from its original position what more proof will convince you?  Ed |
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Post by mike243 on Jul 28, 2014 5:07:54 GMT -5
no shock here on the accuracy or consistency of the sabotless, there is a limit on any load or gun , I just dont want to find it with mine lol
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Post by Dave W on Jul 28, 2014 6:58:33 GMT -5
I personally have never had any concern about the thread capabilities of the Savage BP design. If it can survive this without being dislodged from its original position what more proof will convince you? Ed Originally I thought so too but after doing some reading on bolt thrust and case head seperation occurences resulting in lugs shearing off the bolt, I began to wonder how much torture the threads can take. A double losd is a one time incident probably since most barrels are toasted after that. Guys are gradually going higher and higher on pressures edging closer to centerfire pressures with no cartridge case to swell and absorb some of the rearward thrust on the bolt/ plug. For the majority that shoots less than 50 shots a year, no big deal, for those of us that have thousands of shots on a barrel maybe a different story. |
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Post by pposey on Jul 28, 2014 7:51:48 GMT -5
IIRC the pioneers here that tried "lil gun" powder out still bulged their barrels even though they were only shooting saboted the pressure still spiked too much for the barrel to handle....Thus no more trying out lil gun,lol.... Back in the little gun days loads were part yard sale though,,, washers, shotgun wad bases, sabot bases. Lotsa stuff was added to allow the pressure to build without blowing a sabot. I think the sabot allows pressure relief at a point, with enough fast powder that point may be to late to do any good. The only damage I ever did to a barrel was with a full double load, there is no way that a sabot could provide any relief with the,, powder, saboted bullet, powder, saboted bullet,,, combo of that mess,,,,and it budged the barrel. |
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Post by jims on Jul 28, 2014 8:03:34 GMT -5
Didn't one of our high volume shooters retire his barrel after several thousand rounds just to be on the safe side or was it the breech plug?
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Post by ET on Jul 28, 2014 16:09:22 GMT -5
DW
If you are more comfortable having locking lugs on the bolt then by all means have that on your next build especially when going to higher end pressure loads. If you have any concerns erring on the side of safety is a good practice regardless.
By going with higher pressure loads you are reducing the safety margin if a loading error is made. Instead of a damaged barrel you are more likely to experience a ruptured barrel with flying debris.
I find it ironic that we support increasing the safety margin in 1-area but elect to reduce it in another area. Such is the nature of the beast behind muzzle-loading. At least the shooter has the choice of amount of safety margin or what level he is willing to risk.
As for a suspect BP one can always replace it at specific intervals or do a dye check using a solvent removable dye to see if any discontinuities such as possible cracks are starting to develop. Of course visually examining the BP should reveal any possible stress points in the thread area from cold working.
To reduce possible cold working I really snug my BP down to reduce any possible movement.
Ed
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Post by Richard on Jul 28, 2014 16:27:37 GMT -5
Here is another thought...................How is it that when a sabot "blows", we have a reduction in velocity? Every time I blew a sabot (you know that twisted up piece of plastic you find somewhere in front of you rifle?) my velocity dropped several hundred feet per second and usually resulted in the bullet either key holing or missing the target? Kind of sounds like a bit of a pressure valve to me? No?
Richard
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Post by ET on Jul 28, 2014 18:11:43 GMT -5
Here is another thought...................How is it that when a sabot "blows", we have a reduction in velocity? Every time I blew a sabot (you know that twisted up piece of plastic you find somewhere in front of you rifle?) my velocity dropped several hundred feet per second and usually resulted in the bullet either key holing or missing the target? Kind of sounds like a bit of a pressure valve to me? No? Richard Richard Does it act as some sort of pressure valve is a good question? Okay let’s look at the chain of events and one possibility. Powder is ignited starting pressure build up that in turn accelerates the burn. Pressure build up is maintained because of the sabots ability to contain pressure as well as assistance from load resistance being maintained. So when does the sabot disruption begin. We know that if we don’t exceed a specific peak pressure there is no sign of sabot disruption. So the disruption would likely start occurring near peak pressure but not completed until after peak pressure. This would explain why sabots can contribute to barrel damage or ruptures with exceeded peak pressure. If sabot integrity is lost even after peak pressure resulting with some by pass while travelling further down the bore then the rate of acceleration is also affected by some reduction in velocity. As far as key-holing or missing the target that can be easily contributed to resulting improper RPM or improper launching from a disrupted sabot and the loss of 200fps. So from one perspective sabot disruption can release some pressure after the fact peak pressure has been reached. Then it’s too late to prevent barrel damage. Ed |
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Post by Richard on Jul 28, 2014 18:47:08 GMT -5
ED So, we are actually just guessing, right? I understand the mechanics about the bullet key holing and not hitting the target. My thought was along the lines of the decrease in velocity which has to mean some sort of reduction in pressure. Just where that occurs is anybody's guess. I guess?
Richard
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Post by ET on Jul 28, 2014 19:37:28 GMT -5
Richard If a hypothesis that is derived from proven facts and resulting observations is called a guess then I guess we do a lot of guessing here.  Ed |
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Post by bigmoose on Aug 3, 2014 6:51:40 GMT -5
I agree with Richard, every time I blow a sabot [due to heat] I ended up with a keyhole or a
miss of the whole target board.
Even at 25 yards.
If Bother Rick recommended retiring a barrel after 3000 shots, he never mentioned to me.
The barrel that Toby Bridges had his problem with had 37000 shot fired thru it.
In my 50 I use Benchmark, no high pressure stuff for me. Ricks recommendation, when I wanted to shot 500gr.Tungstun solid bullets. He said I could get 2100FPS at a very safe pressure. However I was unable to buy any, they were discontinued
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Post by Dave W on Aug 3, 2014 7:56:18 GMT -5
Here is his post Marty. I highlighted the part I was referencing in orange. I was wrong, it was 3500 shots. Here is the link to the thread that he posted this in, on page 2 by the way. dougsmessageboards.proboards.com/thread/2072/powder-factory-plug-tbs-incidentrbinar Mossy Horns ***** rbinar Avatar Posts: 674 Jun 25, 2009 at 12:29am Quote Post Options Post by rbinar on Jun 25, 2009 at 12:29am boarhog Avatar Jun 23, 2009 at 5:30pm boarhog said: Ozark, I anylized my "bulge" three ways from Sunday. I am convinced that none of the usual suspects were at fault. I went over it dozens of times, re-weighing powder, testing to see how much powder I could cram into the powder vials, etc. etc. to infinity and beyond! The only thing I could not conclusivly eliminate to my own satisfaction was a failure to seat the bullet/sabot firmly enough, and I doubt that happened either because I was leaning most of my full weight (260+) on the ramrod to seat the bullet. The only way to prove conclusivly that it is possible to blow up, or bulge, a Savage with normal loads is to do so under controlled laboratory conditions. Anecdotal assurances will never be definitive enough for the minds on this board. The only dog I have in this fight is my own safety, and more than that, the safety of my children and grandchildren that may be shooting my Savage. I don't care who's ego gets bruised, or if anyone has some unknown motive behind fear mongering or mud slinging, I want to KNOW that my Savage is safe to shoot. If that takes Savage hiring HP White, or if some other honest group or individual that is interested in finding the truth, then that is fine by me. None of us may live long enough to see such a test completed. Much like the low load volume blow-ups of slow burning powders, I don't think they were able to re-create that event. But all the loading manuals caution against reducing certain loads, just in case. I know that some of those "Never happen in a million years" events do sometimes happen. I'm not sure what you'd want. It seems like a small contradiction in terms. First you mention a test for safety then you suggest that such a test would take forever. Don't get me wrong, please? I think I get the gist of the thought: you want to know it's safe: period. But how to prove that is not answerable in an absolute manner. However here are some thoughts. I have an original barrel off my 2001 model flat rear 10ML-II. It was one of the first second generation rifles. The barrel has 4171 recorded shots and perhaps 200 fouling and unrecorded shots. The loads shot through it are mostly 42-44 grains of either N110 or Imr-SR4759. Every shot was a sabot of some kind no conical bullets. However some duplex loads, a few Lil Gun loads as well as heavy bullet loads were fired in the working life of the barrel. I'm up to allowing anyone to inspect the barrel for damage. I feel that NO barrel (THAT"S NO AS IN NONE) should be shot past 3500 shots so this barrel is not on a rifle. Even if I violated my own rule in letting it go past the maximum it is un-damaged. Besides this rifle I have an embarrassing number of shots fired by my own as well as a few hundred other shooter's rifles. I can't get one to fail. What does that mean? Maybe nothing if you feel lots of shots are not enough. What I'm saying is you had an incident where a rifle was damaged. I never had such an incident. Can I convince you it's safe? Can you convince me it's not? Here's the thing about those who have called for testing or a test. I've spent nearly $6000 in ammunition and powder alone. I've been given many times more than that. It may sound pathetic but I've avaraged 3 trips a week to the shooting range for the last 9 years to test this rifle. Why can't I get it to have an incident? Now some will note that lately I've been shooting the lessor calibers. That's true but I never completely gave up 50 caliber. I take a brand new production 50 caliber to the range about every other time I go. It has a stock plug, barrel and action. So tell me how to make it unsafe and I will. Of course I have to restrict shooting to what has been mentioned in the past: a known good load with reasonable history behind it. Read more: dougsmessageboards.proboards.com/thread/2072/powder-factory-plug-tbs-incident?page=2#ixzz39KetITr2 |
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Post by Alabama on Aug 3, 2014 9:22:32 GMT -5
Parachutes are completely safe unless there is some human error. I'm not jumping out of a plane unless its crashing. But I can almost guarantee any accident is due to human error or not knowing!
My first Ml I bought I had 0 knowledge. CVA v2. Took it to range. Loaded it with 150 gr T7 pellets and shot. Reloaded with a lot of resistance and shot again and again. I know I was not seating bullet on powder but had no knowledge of the possible consequences. After the 5 th or 6 shot or so I couldn't get a 250 gr Barnes sabot to go down barrel and I went home. I was ignorant and I believe very lucky I didn't blow that bergera barrel to pieces. If I wasn't for a message board, I probably would have.
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Post by bigmoose on Aug 3, 2014 13:16:15 GMT -5
Dave W
Somehow I missed that post, it puzzles me. when Brother Rick made my .45, I started testing loads for him each Thurday I went to the range [Thursday was the only morning day] after completed the test, I'd call Rick and give results, and what combo to test the following Thursday. I can't say how long this went on, but it did till he got sick. Without doubt it was many, many shots, 40 or 50 a week, that add's up.
It maybe he didn't want to recommend a high number, least someone try to sue him
Note, I was using PN barrel on the .45
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