Secondary Explosion Effect (SEE)

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Last Post 14 June 2021

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303PV posted this 20 May 2021

A search has shown that this subject has been discussed before, but I would like to get some recent opinions. I have been reloading cast bullets since 1975. I read the first edition of the Lyman Cast bullet handbook and I started from there. I read the original article about Cast bullet loads in military rifles published by C.E Harris that I liked very much because of the systematic approach. Since then I have shot many .. many thousands of cast bullets. Recently I have seen a lot of discussions on German reloader forums that the powder volume should not be lower than 80%. Vihtavuori mentions in their 2021 reloading guide (german version)." Risk of detonation through reduced loads etc" Quick Load also warns for a SEE. Are these warnings, caused by product liability concerns? More discussions on the internet? A mystery factor created by infallible people who won't admit that they could have put a double charge in the case? I have only used fast-burning pistol and shotgun powders or the fast rifle powders like N110.

Please help to put my mind at ease.

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CBA President

John Alexander posted this 14 June 2021

I guess I didn't state my thoughts clearly enough in the last post.

I think this thread has degenerated into bickering and complaining about each other, with occasional car pictures but little or no progress.

All future posts will be deleted.

John

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John Alexander posted this 13 June 2021

I thnk Ric is right. I can't see that we are really getting anywhere with the SEE discussion. We seem to got to the bicckering stage. If some want to have a discussion about hot rods please start one. I don't intend to delete this thread unless the discussion continues. Can we just let it drop.

John

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RicinYakima posted this 13 June 2021

All I'm looking for is a wooden stake and a silver bullet to close this thread out.

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MP1886 posted this 13 June 2021

Squid Boy that is a pretty cool ride for sure. Could we say your cylinders are getting 100% full charge with that super charger on it? My forte was quarter mile drag racing and illegal street racing.

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Squid Boy posted this 13 June 2021

Larry, since you addressed me by name, I shall answer in kind. It isn't a personal attack either and I did not insinuate that you were trying to con me out of a rifle at all. That you had this data POSTED at another site and did not mention it here all the while challenging us to send you a rifle and you will prove what you say. That is where the BS is. You could have just said look over at such and such and I have that posted but you didn’t come forward until it was found out and revealed. I still believe that you are a smart guy but you try to razzle-dazzle everyone with long winded dissertations about how you would do something and then switch the subject or ignore questions as it suits you. People on this forum are smart too. Smart enough to keep asking questions and looking for real answers. If Einstein had not questioned over two hundred years of the supremacy of Newtons Laws, we would never have gotten the general theory of relativity.

Once again it all seems to have changed with the revelation that 100% loads could cause an SEE. This flies in the face of all that was true and figured out long ago. Obviously, something is happening in all of this and your explanation is certainly possible but where is the proof?

Here's my ride, Squid Boy

"Squid Pro Quo"

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shjoe posted this 13 June 2021

i bet those plymouth 440s with appropriate gears would have made a great hi-way pursuit vehicle.

larry, that "click-bang" description seems very accurate and something that many of us have experienced before. i had bought some old wartime turk mauser ammo and had 2-3 out of 5 shots go click-bang. even with good primer contact. i upgraded my firing pin spring to a 25# and ignition was much more reliable. hard primers? old powder? dont know for sure. but, i always looked for a new bullet hole in the target before sending another down range. best regards

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Larry Gibson posted this 13 June 2021

MP1886

What is a good question is denigrated by the personal attacks, can we discuss this without those?

To answer your question; even though at 100% load density the powder is still not a solid mass. The firing of the primer creates pressure throughout the case volume while while the flame is igniting the base of the powder. The bullet is pushed into the leade where it sticks. The pressure drops because of the expanded volume in the case with the bullet moving into the leade which can cause the ignited powder to smolder or even go out (in which case there would be no SEE but only a bullet stuck in the lead and powder spilled in the action. Those have been reported often).

If smoldering the powder begins to burn and the pressure can reach an abnormal level before the bullet moves enough to maintain"normal" pressure levels.. Many times a "click.....bang" is now believed to be the result of this.

The pressure can also reach a catastrophic level before the bullet can begin moving again and move fast enough with sufficient expansion of bore volume to lessen the building pressure, in which we see an SEE.

That knowledge comes not from not from "ignorance of science" nor from "immorality of ignorance" but from observation of the pressure traces and attendant data during scientific testing. Also understanding what is occurring and having an open mind helps.

LMG

Concealment is not cover.........

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RicinYakima posted this 13 June 2021

That vintage Nova was not a slouch either. Our FD investigators inherited two "Police Specials" from the PD detectives about 1980, both low miles with no history of patrol background. The de-tuned 350's were worked over by fire truck mechanic. They were pretty fast and handled better the Plymouth 440's we had before.

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shjoe posted this 13 June 2021

great cars, ken! nice to see that old time hot rodding is still alive. and yes, the open discussion has been informative; thank you to all who have participated. that corvair must be a missle!

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MP1886 posted this 13 June 2021

Larry so how do you explain a 100% loading SEE? You have to admitt that a reduced charge of slow burning powder, bullet getting blow out of the neck into the throat tight, lots of volume created , pressure drops, then pressure catches up and comes back strong and BOOM...bore obstruction because of the bullet. Not much volume created with a 100% charge. Were other 100% loading SEE's done at a lab too?

Everyone makes assumptions, you too. In fact I think you make quite a few of them.

The Immorality of Ignorance

[/I]"In April of this year as part of my contribution to the rites of spring, I delivered the installation address to the Notre Dame chapter of Sigma Xi with the deliberately provocative title above. What I said can be summed up in rather simple terms.

"For anyone who has taught freshman chemistry, the end of the freshman year when some of the youngsters take home their unused chemicals and oddments of apparatus, is a frightening time. The amateur chemist is a dangerous person. An innocent parent might permit him some freedom of action, but only an idiot would take his advice.

"In this technological age, ignorance of science can be dangerous. It is inexcusable in those who have talents of leadership. It is immoral when the ignorant elect to lead and when the informed let them."?

[/I]

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Larry Gibson posted this 13 June 2021

Obviously some choose not to learn nor understand. I'm done with this thread.

Concealment is not cover.........

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Larry Gibson posted this 13 June 2021

It's not the "last word". That was discovered 30+ years ago. A lot has been learned since then. You all are making assumptions attempting to assuage your own disbelief. That not only is dangerous but probably foolish to.

John, I told you that documented She's have occurred with full power 100% load density loads.

MP1886, multiple caliber cartridges have been documented to be susceptible to SEE. I suggested the 6.5x55 simply because it was what was used in the article. I have 3 of my own and told squid boy I'd return it one way or the other. His insinuations I was sim7trying to con him out of a rifle is bs.

LMG

Concealment is not cover.........

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MP1886 posted this 13 June 2021

Oh Gosh No Wheel Weights, darnn I over looked that. I retract that and thanks for pointing that out. I must have hand a bad neuron ignition in my brain!

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Wheel Weights posted this 13 June 2021

Come on MP are you suggesting some expert handloader could have made an error / Or some automatic loading system fouled up ? NAH, why look at the Space Shuttle's perfect safety record ---- ah ----

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MP1886 posted this 12 June 2021

It doesn't matter that a bore obstruction is too easy to comprehend. That's what happened in the article in my opinion and others including the author. There are many kinds of bore obstructions you know, from stuck bullets to stuck wads to dirt plug in the muzzle to putting a 20 gauge shotshell in a 12 gauge shotgun to Kapok filler the list goes on. I think SEE became a mystery because those that had it happen probably felt they did nothing wrong. I think it was something they worked up the loads on a pressure barrel all to specs and all the loads looked just great, then they go to the actual rifle and boom. No mystery to me.

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MP1886 posted this 12 June 2021

Couldn't agree with you more John. It was jacketed high velocity loads they were testing. The question is did Larry blow up any 6.5 Swedes at all with SEE? We know while testing he said he saw the "comings" of SEE and stopped. Not good enough. That's like saying I'm racing a 1/4 mile car and I'm really setting a record 3/4 quarters the way through the run and I shut her down for some reason. Then later on saying I could have set the record. You don't know, you just don't know what would have happened. I'm beginning to wonder if Larry really did blow up a 6.5 trying to show he replicated a SEE and whose rifle was it???

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CBA President

John Alexander posted this 12 June 2021

So if you have an old 6.5x55 Mauser with a really rough throat, avoid shooting it with with reduced loads of slow burning non-cannister powder, long heavy high friction bullets in case necks with low release tension.

I'm glad to know that.

==========

I didn't see anything in the article about reduced loads. The rifle blew oup with loads they were intending to sell - probably not reduced loads and 2.600 fps with a 140 grain bullet is a full charge for a 6.5 x55.. So if this is the complete word on SEEs, staying away from reduced loads wouldn't guard against a SEE.

Yet, many of the SEEs I have read about were when handloaders were fooling around with reduced charges of slow powders.

It would be interesting to duplicate the load used, or a reduced load, with a bullet lodged in the lands before hand and fire the primed and charged case with no bullet and see what the pressure would be. My bet is that no unusual pressures would appear. This is what breech seaters do all the iime without blowing up guns. If I win this bet, then are we sure that a bullet stopping in the same place was the cause of the high pressures? Bad assumptions are the curse of experimenters.

John

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Wheel Weights posted this 12 June 2021

Bore obstruction is too easy to comprehend. SEE is more mysterious.

The other thing that's odd is, I don't see how the pressures listed would take apart a 96 Swede like that. Stretch it yes, grenade it ???

I remember an importer back when, was "sporterizing" 96 and making the into 264 Win Mags. No reports of pieces and parts littering the landscape.

Since the event has not been duplicated and given 96's value will not be -----

Now we could take some el cheapo modern rifle like a Ruger American 6.5 Creedmore, rust up the bore and try the receipe.

The world watches.

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MP1886 posted this 12 June 2021

Wineman that's what I got out of that article. So my bet to Larry is can he blow my 6.5 Swede up if I show up at his place, but after I had a brand new barrel installed on it, brass with very good neck tension, and cleaning after every shot? I bet not. The other thing I got from the article was the author saying that there could be a better name for the event besides SEE. I agree, my pick so far is Bore Obstruction.

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Wheel Weights posted this 12 June 2021

So if you have an old 6.5x55 Mauser with a really rough throat, avoid shooting it with with reduced loads of slow burning non-cannister powder, long heavy high friction bullets in case necks with low release tension.

I'm glad to know that.

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