detonation in handguns with fast powders

[olafhardt]

The past week I have been trying to calculate the maximum pressure possible if a 38 was fired with the chamber plugged up tight. The answer I came up with is 67,000psi per grain of cellulose nitrate using the following assumptions:

1.) The powder is pure cellulose nitrate C6H7(NO3)O5.
2)The reaction is 100% complete.
3) Reaction products are, H20, CO, CO2 and N2.
4) Reaction temperature is 2000°F.
Applying the Ideal Gas law (which is a real stretch), I get that the pressure is 70,000 psi. Now if we unplug the chamber, allow the bullet to move one inch, reduce our reaction efficiency to 70%, reduce the efficiency to 70% for departure from ideal gas behavior we have a pressure of 50,000 psi. I did these calculations because I wanted to see if it is feasible that small charges of fast powder usually detonate. I think they might.
At the moment of firing I picture the small charge being fluidized into hot primer gasses. The whole charge lights simultaneously and the boolit takes off. The pressure doesn't rise high enough to rupture the gun. This would explain the lack of position sensitivity that many fast powders display. This theory may not have much application to larger bottle necked cartridges but I am working on it.

[Artful]

Winchester/OLIN told me its impossible for detonation to occur in a straight walled pistol cartridge such as the 357 Magnum or 44 magnum with normal pistol powders even with light loads.
I have never seen a Bullseye Surprise that wasn't proven to be a double or triple charge of fast burning powder.

I do know if you use a fast powder in a large enough case and then point the muzzle down before firing you will have different pressure profile
then if you point it muzzle up before firing. What's thought to happen in that case is something along these lines.

1.The reduced load of slow burning powder is laying on the bottom of the case or at the front.
2.The primer flashes over it and doesn't get a complete high-pressure burn going and if laying on the bottom can move the powder forward.
3.The bullet moves from the case (this can be from just the action of the primer alone), and sticks in the first inch or so of rifling.
4.Then the remaining charge lights off and pressure rises so fast the stuck bullet can't get out of the way fast enough.

Don't confuse Deflagration with Detonation.

In larger cases you can find many quirky happenings.
http://africanxmag.com/secondary_explosion_effect.htm
http://reloadammo.com/liteload.htm

[DrCaveman]

It might also explain the huge pressure spikes when fast powders are loaded too hot

Full detonation prior to boolit exit from case, with a case full, seems like quite a bit of pressure. Of course, we are probably comparing 0.1 millisecond to 0.6 millisecond for a slow powder, or something like that. It is always relative and never instantaneous

[Harry O]

I have been keeping track of reported "detonations" since the mid-1980's. I have never heard of one that was well documented that was caused by small amounts of fast powder (such as Bullseye, Red Dot, 231, etc). The few that have been reported leave considerable reason to suggest a double charge. I have heard of well documented detonations from small amounts of relatively slow powder in large cases (usually slower than 2400). I have personally fired many thousands (probably over 10,000 or two) .38 Specials with 2.8gr of Bullseye without any hint of a problem and so have many others.

The reason I started paying attention to detonations is because I developed a theory about them after seeing an explosives test. I was in the Aberdeen Proving Ground back in the mid-1980's and witnessed some explosives tests with shaped charges (I was there for something else, but had some extra time). An amount of explosives that was laid on top of armor plate would just remove the paint. The same amount of explosives in a shaped charge would blow a hole through it.

My theory was (and still is), that a very small amount of powder lays in the bottom of a large case below the primer (less than 50% fill). The primer happens to throw sparks to the front and the rear of the powder charge at the same time. The powder burns from each end equally and meets in the middle. The shockwave from the two burns meeting in the middle acts just like a shaped charge. The shaped charge blows up the gun. That would also explain why it is so infrequent. If the powder burns in more than one place or the burn on one side is much more energetic than the other side, it won't act like a shaped charge.

[161]

I'm going to sit here and be quiet while the smart people talk. Interesting stuff even if I don't understand most of it.

[AbitNutz]

I have first hand experience with the "Bullseye Surprise". The good news is that all I came away with physically was a well stung, very red, right hand. The bad news is that it destroyed one of the finest guns I have ever owned. It was a S&W Model 52 38 spl with a Bar-Sto barrel. The explosion was so stout that it blew the hood of the barrel 90 degrees through the ejection port and swelled the slide outside the frame. The custom 6 shot magazine was fired down with enough force that it was rippled.

That was about 3 years ago and I almost weep every time I think of it. The load was the classic 2.7 grains of Bullseye with 148 grain wadcutter that I had shot thousands of times. The only difference was that I used a hollow base bullet for the first time. Previous to this I had always used a double bevel base bullet that I cast myself. This time I ran across a deal at a gunshow for 500 Berry's plated hollow base bullets.

The rounds were loaded on the same dedicated Dillon 550B that I had loaded all the rest on. The only difference was the bullet. Could I have double charged it? Sure, it's possible. Given all I have read about this I've started to doubt everything I do when reloading. It took away any notion of confidence for a long time. I'm still not back to normal regarding faith in my reloading.

I'll always wonder if the added space from the hollow base is what caused it all or if it was my own ineptitude. Either way, I only use loads that when double charged will pretty much overflow the case.

I have developed a deep and abiding love for Trailboss when loading big 45 Colt cases.

[Dave C.]

If seated to the same OAL and not backward in the case, then the space used is the same as a double ended wad cutter.
However if the bullet is seated backward it will lessen the powder space in the round and raise the pressure. Is it possible
that after years of loading double ended bullets you seated a HBWC backwards?

Dave C.

[geargnasher]

I have first hand experience with the "Bullseye Surprise". The good news is that all I came away with physically was a well stung, very red, right hand. The bad news is that it destroyed one of the finest guns I have ever owned. It was a S&W Model 52 38 spl with a Bar-Sto barrel. The explosion was so stout that it blew the hood of the barrel 90 degrees through the ejection port and swelled the slide outside the frame. The custom 6 shot magazine was fired down with enough force that it was rippled.

That was about 3 years ago and I almost weep every time I think of it. The load was the classic 2.7 grains of Bullseye with 148 grain wadcutter that I had shot thousands of times. The only difference was that I used a hollow base bullet for the first time. Previous to this I had always used a double bevel base bullet that I cast myself. This time I ran across a deal at a gunshow for 500 Berry's plated hollow base bullets.

The rounds were loaded on the same dedicated Dillon 550B that I had loaded all the rest on. The only difference was the bullet. Could I have double charged it? Sure, it's possible. Given all I have read about this I've started to doubt everything I do when reloading. It took away any notion of confidence for a long time. I'm still not back to normal regarding faith in my reloading.

I'll always wonder if the added space from the hollow base is what caused it all or if it was my own ineptitude. Either way, I only use loads that when double charged will pretty much overflow the case.

I have developed a deep and abiding love for Trailboss when loading big 45 Colt cases.

If you hear hoofbeats, think "horses" instead of "zebras".

Gear

[243winxb]

The Manufacture of Smokeless Powders and their
Forensic Analysis: A Brief Review-
In addition, certain smokeless powders with a high-nitroglycerine concentration can be induced to detonate. http://firearmsid.com/Feature%20Articles/McCord_gunpowder/index.htm To much powder or a defect make these photos http://www.photobucket.com/kabooom

[AbitNutz]

I've doubted myself on every step. So yes, it is possible. Is that enough to cause an over pressure? I don't know. At this point I'm sure I'll never be sure of what happened. All I can do is assume that all of it is true. I did something that caused it, that small loads of fast burning powder can blow up without obvious reason.

So my solution is to make sure that any load I use can overflow the case on double charges and that I never use fast burning powders...ever. So no matter if it's my fault or not I'm hoping I can avoid the situation by changing to a procedure that will not allow it to occur.

[fecmech]

HP White Labs did a test for the American Rifleman back in the 70's and could not duplicate a detonation using Bullseye.
Blowing up handguns with target loads is pretty much operator error in the loading process not detonation.

[Shiloh]

That was about 3 years ago and I almost weep every time I think of it. The load was the classic 2.7 grains of Bullseye with 148 grain wadcutter that I had shot thousands of times. The only difference was that I used a hollow base bullet for the first time. Previous to this I had always used a double bevel base bullet that I cast myself. This time I ran across a deal at a gunshow for 500 Berry's plated hollow base bullets.


I would think that HBWC would be more forgiving as there wi a lot more area for the pressure to fill. Unlike a BBWC.

Shiloh

[BeeMan]

Assuming a similar nose shape and loaded cartridge length, two projectiles of the same weight will occupy the same internal volume in the loaded cartridge.

[AbitNutz]

I would think that HBWC would be more forgiving as there wi a lot more area for the pressure to fill. Unlike a BBWC.

Shiloh

I think the point was is that a HBWC is longer than a BBWC. If it was loaded backwards then there is less space in the case. Is that mistake enough to cause an over pressure? I'm not sure. As I said, I'm never going to know what really happened, my fault, weird load explosion or just bad ju ju. All I can do is to change EVERYTHING so that there is no possibility of having a repeat event.

[bangerjim]

Winchester/OLIN told me its impossible for detonation to occur in a straight walled pistol cartridge such as the 357 Magnum or 44 magnum with normal pistol powders even with light loads.
I have never seen a Bullseye Surprise that wasn't proven to be a double or triple charge of fast burning powder.

I do know if you use a fast powder in a large enough case and then point the muzzle down before firing you will have different pressure profile
then if you point it muzzle up before firing. What's thought to happen in that case is something along these lines.

1.The reduced load of slow burning powder is laying on the bottom of the case or at the front.
2.The primer flashes over it and doesn't get a complete high-pressure burn going and if laying on the bottom can move the powder forward.
3.The bullet moves from the case (this can be from just the action of the primer alone), and sticks in the first inch or so of rifling.
4.Then the remaining charge lights off and pressure rises so fast the stuck bullet can't get out of the way fast enough.

Don't confuse Deflagration with Detonation.

In larger cases you can find many quirky happenings.
http://africanxmag.com/secondary_explosion_effect.htm
http://reloadammo.com/liteload.htm

Which brings up a point I mentioned months back................Dacron fluff in 38SPL's and 45LC's. Just a pinch...not a whole solid wad. With fast powders there is a bunch of room in there and the powder lays on the side of the case as Artful sez. Dacron will hold it upright and back against the primer where it belongs, giving even burning and should be even propulsion of the slug. I'm talking 5-7gn of a powder like TightGroup or ones in that fast burn range. TrailBoss fills the case up, alright , but you cannot find it and it seems to be very pricey when you do. Most load data show TG and TB loads almost the same weight, but a whole world of difference in volume fill in the case!

I am sold on Dacron in rifle carts..................now how about big pistols?

Thoughts?

banger

[rsrocket1]

I am sold on Dacron in rifle carts..................now how about big pistols?
Thoughts?
banger

Read #1 of your quoted scenario. "1.The reduced load of slow burning powder..."

Titegroup and Trail Boss are very fast burning powders. They will ignite just fine in your rifle or pistol cartridge without the Dacron. Will the Dacron cause more problems? No. So if you feel more "secure" using it, go ahead, but you won't actually be any more safe than you already are.

[olafhardt]

I just applied this theory to a 30-06 loaded with 30 grains of powder and a bullet travel of 3 inches. The results were 290,000 psi. If I interpret this correctly it means that:


1) The charge has to at least somewhat detonate for whatever reasons.
2) It's harder to blow up a gun with a bore that is closer to cartridge size.
3) Enough powder must be available to do the job.
Now this is only a theory. I derived this using nitrocellulose. I could apply it to double base powders but the results would be about the same. The fudge factors for efficiency, departure from ideal behavior, breakdown products etc came straight from where the sun don't shine. Nitrates are especially notorious for unpredictable behavior. Lots of true experts have died fooling with them. Often in chemical history we found that out the product was explosive when experimenters blew them selves up.

[a.squibload]

...They will ignite just fine in your rifle or pistol cartridge without the Dacron.

I think the point of filler in pistol cartridges is consistency of burn, not whether the powder will ignite.
With dacron filler the powder is held in a normal relationship with the primer
so the primer won't ignite all the powder at once (safety?), or different amounts of powder
for different shots. Different pressures making different velocities making different points of aim?
Tests have been made on loads that don't fill the case, it does make a difference.

[PAT303]

I shoot Trail Boss in all my light loads,pistol and rifle,no double charges,no detonations. Pat

[rsrocket1]

Squib, you are absolutely right about consistency when it comes to position sensitive powder. Thanks for the clarification.

[rhead]

Do not rule out the possibility of a skirt failure on the previous round leaving a partial obstruction in the barrel.

[olafhardt]

I have often thought that detonations occur all the time with small loads of fast powder. They just are too small to blow up the guns. These calculations support that idea. I am contemplating their possible contribution to pressure spikes

[scattershot]

I used to be skeptical of the detonation theory, believing instead that a double charge of powder was the culprit. If a 2.7 grain of Bullseye was doubled, it would only amount to 5.4 grains, hardly enough to blow up a pistol. I don't pretend to know what's going on, but it's just one more thing to think about.

[Whitespider]

If a 2.7 grain of Bullseye was doubled, it would only amount to 5.4 grains, hardly enough to blow up a pistol.

I'm not so sure about that...
Although 5.4 grains don't seem like a lot, it ain't about the quantity (grains), it's about the relative percentage... and strange things happen to burning rate when pressures increase much beyond the design limits of the propellant.
If you figure that 3.5 grains is the safe maximum, 5.4 grains is a 40% increase over that‼
Think about a 40% increase in other cartridges. For example, that would be like loading your .44 Magnum with 30 grains of 2400 or H110‼ Or 80 grains of 4350 in your .30-06‼

[AbitNutz]

Many times a handgun Chernobyl has more than one cause. Perhaps I did double charge it but also what if I seated the longer HBWC backwards by accident, as well as one astute member pointed out. Or the skirt separated on the first bullet leaving some chunks in the bore, as another member mentioned. Then the second round fired was an over charge?

I guess what I'm going back to is that I'm never going to find out for sure. All I can do is make sure I put in to place a protocol that makes it almost impossible to happen again.

[35remington]

Supposing that powder just "lays there" in the case and allows primer flash to "ignite it at both ends" is an extremely weak understanding of how primers work to ignite pistol powders.

This is not how events happen, nor does this contribute to blown up guns

[35remington]

Ask yourself why "detonations" of fast powder happen supposedly only in pistols.....when it is extremely common to shoot very light charges of Bullseye in rifle cases and you never hear of problems.

It ain't the powder. It's the goof running the powder measure and loading the ammo.

[WallyM3]

"I'm not so sure about that...
Although 5.4 grains don't seem like a lot, it ain't about the quantity (grains), it's about the relative percentage... and strange things happen to burning rate when pressures increase much beyond the design limits of the propellant.
If you figure that 3.5 grains is the safe maximum, 5.4 grains is a 40% increase over that‼
Think about a 40% increase in other cartridges. For example, that would be like loading your .44 Magnum with 30 grains of 2400 or H110‼ Or 80 grains of 4350 in your .30-06‼"

Richard Lee lists 5.7gr B'eye as max for .357 Magnum, more than twice the 2.7gr. load the WC 38 Special. Not too much difference between a Model 10 and a Model 13 S&W.

[Elkins45]

Ask yourself why "detonations" of fast powder happen supposedly only in pistols.....when it is extremely common to shoot very light charges of Bullseye in rifle cases and you never hear of problems.

It ain't the powder. It's the goof running the powder measure and loading the ammo.

What about rifle shooters who blame Secondary Explosion Effect (SEE) for blown up guns? A Google search for the term finds a whole bunch of instances where small charges of fast pistol powders are blamed for blowing up rifles.

I dont know if the phenomenon is limited to pistols, but the blame isn't.

[olafhardt]

Note: in the 30 06 I used a powder charge of 30 grains.reducing this reduces pressure. Increasing it could change detonation conditions. Powder characteristics were not considered because I have no idea how to. I picture the powder being caught up in a cloud of very turbulent, very hot cloud of primer gas and debris. The reason I went threw this was I think they various detonation theories I have read don't make a lot of sense. This theory shows that the powder only has to burn. What makes it burn so much faster, I have no idea, maybe it does "detonate". I have no conception of what the difference between "burn real fast" and" detonate"is. I also don't trust organic nitrates to be thoroughly predictable especially in high temperatures and pressures.

[35remington]

Wrong effect, Elk. SEE is. specifically, reduced loads of SLOW rifle powder blowing up guns. Does not happen with very small charges of pistol powders in rifles.

Ever. You have to wonder why.

[MtGun44]

IMO high pressure events are double charges. I am extremely skeptical of
the claims for unusual burning of normal pistol powders the "somehow" magically
create double pressure.

Occam's Razor - simplest solution which requires no magic and relies on one of the
most reliable forces in nature - human error.

Many folks would much rather believe in magic than believe that they made an error
when they were trying their best not to.

Bill

[Bullwolf]

I used to be skeptical of the detonation theory, believing instead that a double charge of powder was the culprit. If a 2.7 grain of Bullseye was doubled, it would only amount to 5.4 grains, hardly enough to blow up a pistol. I don't pretend to know what's going on, but it's just one more thing to think about.


I'm not so sure about that...
Although 5.4 grains don't seem like a lot, it ain't about the quantity (grains), it's about the relative percentage... and strange things happen to burning rate when pressures increase much beyond the design limits of the propellant.
If you figure that 3.5 grains is the safe maximum, 5.4 grains is a 40% increase over that‼
Think about a 40% increase in other cartridges. For example, that would be like loading your .44 Magnum with 30 grains of 2400 or H110‼ Or 80 grains of 4350 in your .30-06‼

Not trying to single you out here Whitespider, Just replying to your post as my reply seems to fit here the best.

The Hercules Powder company did some testing regarding this very subject regarding the use and potential of overcharging Bullseye with 38 wad cutters some years back.

Here's a reprint of the original article from American Handgunner magazine.

This subject has become a something of a re-occurring theme on the board every few months. Typically when it rears it's head again, this article gets re-pasted. Since no one else has added it yet, I am doing so here.

[click on the thumbnail images to make them larger]

105592

105593

105594

Others reading this thread for the first time may find this information on the subject to be extremely educational.




- Bullwolf

[WallyM3]

It's telling me an otherwise properly loaded double-charge (5.4gr. B'eye) will not destroy a modern Model 10 or 14 type, since a nearly identical Model 13 is rated for 357 Magnum (35,000psi). Not wholesome, but probably not catastrophic.

Cram the bullet down into the case...then you could get hurt.

[Old Caster]

If light loads of fast powder could detonate in pistols, virtually every bullseye shooter that has been around shooting for 50 + years like me and all my friends would have had it happen. We are always trying to see how light a load we can shoot in timed and rapid fire to stay away from recoil and the only thing that keeps us from going even lighter is lack of accuracy at too slow of a speed. In some guns, this is around a bit over 500 fps, specifically 32 long with a 100 grain HBWC.

[wmitty]

Doesn't the detonation of a high nitroglycerin content smokeless powder require a high brisance initiator, such as a blasting cap or detonating cord?

[mpbarry1]

very intesting thread. thanks for the discussion. I just had a friend warn me about this, but I am a skeptic. I appreciate the info.

[Larry Gibson]

Bullwolf's excellent post, #33, is the answer.

A small amount of Bullseye such as 2.7 gr just does not have the potential energy to cause the destruction shown. Ask any chemist familiar with such. This has been discussed numerous times including SEE with all the usual myths brought up regarding "detonation". Detonation of smokeless powders is not a proven theory but double and triple charging of cases or using the wrong powder is proven.

Many years ago I investigated several "blowups of PPC revolvers using the 2.7 gr load with WCs of both Bullseye and 700X. After bulling several hundred bullets with kinetic bullet pullers myself and 2 others found 3 additions cartridges with overloads (2 - 2.5 times as much) from 2 different batches. The loads had all been loaded on the same type of inline progressive press that is addressed in the Handloader article. That press was very popular at the time but was discontinued because of the overload problems. With any progressive press, even the new ones of today, of any make it is easy to get a double or even a triple charge of powder if you aren't paying attention (most often getting interrupted) or when clearing a jam or have miss a step like not putting a bullet in a case.

It is human nature to want to blame something else when most often the fault lays with ourselves. The OP may have "thought" he didn't double charge a case with his progressive press but he most likely did. I have the same press and have done it myself when distracted, not paying attention of miss putting a bullet on a case for seating. When restarting from an interruption or when clearing a jam or a case w/o a bullet or powder in it is all to easy to double charge a case. I have seen others do it too many times to believe otherwise. I also have double charged cases when clearing a jam on my auto advancing progressive press. When I get interrupted or am clearing a jam I now remove and clear all unloaded cases from all the stations and simply start over. I have kept myself out of trouble more than once by following that simple caution.

Larry Gibson

[243winxb]

Don't do this. Fill a 357 mag case with Bullseye powder. Put a card wad over top, light crimp. Drip candle wax to seal. On firing, you may blow your revolver up or think you did. :dung_hits_fan: