Problem with detonation

[Big T]

I been loading 45 lc for 5 or 6 years now ,i have a friend who's been loading since 1969 told me he had a detonation occur once loading light loads in 45 lc , I have always used the low side of the spectrum on the website of the powder I currently use , I have loaded with trailboss,unique, bullseye , powerpistol an never had a problem yet but apperently he had one detonate an blow up his blackhawk in 1978 an showed me the case in the cyl next to the one that blew an it was mangled badly , blew the topstrap off a flatop ruger ,anyone had any experience out there with this ?t

[Shotgun Franklin]

There's been a lot of research on detonation. It's a big problem in the oil industry and in grain storage. Many claim that it can not be replicated in the Lab using a cartridge. I've seen the results in the field several times. I won't use light loads of fast burning powder. I know of several times guns have been destroyed by what was claimed to be a double charge of powder but this couldn't be replicated.

[Pettifogger]

No factory has ever been able to duplicate a "detonation".  In all cases these are reloads and the problem, where the event has been analyzed, is a double/triple charge or two bullets in the case.

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[Red Cent]

Ahhh, the old and infamous 148 HBWC with 3.2 gr of Bullseye. As stated, this combination /concoction has been tried and tested in labs and they ain't never had it to go KABOOM.

Over the years, new cowboys have went to the ridiculous trying to develop that no recoil load that will knock over  a tank. All they did was stick bullets in barrels. They eventually give up or they are ran off.

Anything is possible but I think (short of using nitro glycerin) you will either stick the bullet in the barrel or it dribbles out of the barrel. A lot of cowboy shooters use 3.2 gr of Red dot with a 165  ::)gr cast lead bullet. Runs about 500fps. Whoa I can hear the rumbling from here !!

[Shotgun Franklin]

In all cases these are reloads and the problem, where the event has been analyzed, is a double/triple charge or two bullets in the case.

Not in all cases. I've seen a couple of guns that were blow out but the powder used wouldn't have caused that damage even with a double charge of powder. It is possible to duplicate a detonation with a lot of products it just hasn't been done with a loaded round. I think it takes a load of powder where the powder itself has broken down into finer size than intended by the maker. Researchers haven't given up on studying this as far as I know.

[rickk]

Is there a chance that what he "thinks" happened, and what really happened, are not the same?

A light charge of the wrong powder, a double charge of the right powder, a bullet lodged in the barrel from a previous light or squib load - all could have done what you described and it is fairly hard to prove or disprove any of them other that possibly trying to repeat what happened.

[cpt dan blodgett]

The never ending quest for the non-recoiling CAS load.  If 45 cal 250 or so grainers are too stout at minimum published data go to a lighter bullet or maybe drop caliber to 44.  Repeat process drop to .38 if still to stout drop to .32 repeat process if still to stout forge birth certificate and shoot at a 10 yo with 22 pistols, rifles and a .410 shot gun

[Big T]

i was just curious because i always follow the lowest chg in recipes for the cowboy thing dont care about the recoil as i am 6-1 300+ lbs an shoot hot 44 mag alot but I was concerned about my guns an my eyeballs , I shoot a 200 gr rnfp in pistol an 250 gr in the rifle lazer cast hornady only because i got a deal on them an about 5.7 of trailboss  according to their website its a low end load ,t

[pistol1911]

The infamous load was 2.7 grains of Bullseye in 38 special with a148 grain HBWC .Loaded thousands of these for NRA competition.I never had a blowup.

[Red Cent]

There are many theories. One is the "excessive volune/bad powder? one. Lots of space, the powder ignites in a slow burn to a deflagration (primers detonate, powder deflagrates) and creats excessive pressure. Never been proven.

The one I like. Loose crimped bullet. Primer detonates. Powder begins to deflagrate and the bullet pops loose way too soon. Plugs the bore but still in the cylinder. Pressure builds with excessive resistnce caused by the forcing cone.and cylinder blows part.

Any other theories?

BTW, somebody mentioned the powder crumbling. This reminds me of the true story when Elmer Keith blew up a Single Action Army in 45 Colt. He didn't over load it in a true ense. He "ground up" black powder so the case would hold more. The handgun let go real good.

[Dynamite Bill]

so thats why they say only use 4FFG  for priming flintlock pans! LOL!

[Trailrider]

     There are many theories. One is the "excessive volune/bad powder? one. Lots of space, the powder ignites in a slow burn to a deflagration (primers detonate, powder deflagrates) and creats excessive pressure. Never been proven.
     The one I like. Loose crimped bullet. Primer detonates. Powder begins to deflagrate and the bullet pops loose way too soon. Plugs the bore but still in the cylinder. Pressure builds with excessive resistnce caused by the forcing cone.and cylinder blows part.
     Any other theories?
     BTW, somebody mentioned the powder crumbling. This reminds me of the true story when Elmer Keith blew up a Single Action Army in 45 Colt. He didn't over load it in a true ense. He "ground up" black powder so the case would hold more. The handgun let go real good.

First of all, in ballistic terminology, you CANNOT have a "detonation" with small arms smokeless powder! The definition of a detonation is where a pressure front of 25,0k0 ft/sec is created. There is NOT enough chemical energy in smokeless powder in a metallic cartridge to cause a true detonation.

Now, having said that, DETRUCTIVE OVERPRESSURES CAN be created under the proper loading conditions. Depending on the burning rate of the smokeless powder, it takes 5,000 - 7,000 psi of pressure before smokeless powders will reach stable, prgoressive burning. Below that pressure, the powder can deflagrate (ignite and begin to burn), but if not obtained quickly enough, the powder can go out or almost go out. If "shot start" (the bullet begins to move) before the pressure comes up high enough, the resulting increased combustion volume can drop the pressure  below the point where enough force is created to engrave the bullet into the rifling, and the bullet stops. If this happens where the bullet stops in the forcing cone of a revolver, you now have a "closed bomb" condition, and the pressure quickly goes up to where the powder starts to burn progessively. That means the higher the pressure, the faster the burning rate, whcih raises the pressure even more. When the pressure exceeds the ultimate tensile strength of the cartridge case, it will probably rupture where it has been stretched the thinnest, releasing not only a lot of energy, but also producing jets of flame that act like a cutting torch on the thin steel walls of the cylinder. Generally, the top of the cylinder then separates taking the topstrap of the gun with it to parts unkown! 

Because it takes about 7,000 psi to expand a brass cartridge case (especially .45 LC, where most of the chambers are quite a bit oversized), it is difficult, if not impossible to see premature shot start using an Oehler M43 pressure measuring system, but not impossible. It can usually be seen as a pressure spike, followed by a drop in pressure and a subsequent increase to maximum pressure. A marked spike was observed by an ammo maker using an M43 with a .40 S&W pistol. No, no overpressure, but that load was never brought to market!  A South African ballistician also detected premature shot start using equipment not used in the U.S.  While the oft-quoted double-charge in the .38 Special 148 gr 2.8 gr Bullsye loading as blowing up guns, such a charge could produce pressure that would blow the old M10 S&W's, that may have occurred/ But experiments run in presure guns showed that such a double charge would produce less pressure than a .357 Magnum, yet I have seen at least one Colt Python with a blown cylinder and .38 Spl. brass stuch in the cylinder. It is also true that the target shooters who used the 148 grain full wadcutters tended to use no crimp, believing it was detrimental to accuracy. We have also seen light loads using the mid-burning powders in .45 LC especially, where low bullet pull (light/n crimp plus too little neck tension) were associated wtih overpressures that blew Colt-type replicas.

Bottom line: stay above the minimum, and CRIMP, CRIMP, CRIMP!

[pistol1911]

The pistol I used in centerfire NRA bullseye competition was not a revolver.Mine was a Colt 1911 built by Jim Clark to shoot 38 wadcutters.S&W 52's and Colt Gold Cups were also chambered for the cartridge.I don't remember anyone  having a blowup with a correct powder charge.One club member blew up a 1911 in a Ransom rest with a double charge of HP38.

[Red Cent]

Trailrider, did we say the same thing?

Have you seen the described "fast start" blowup documented?

[Trailrider]

Trailrider, did we say the same thing?

Have you seen the described "fast start" blowup documented?

Basically, Pard, especially in your second paragraph. I just wanted to expand on it. I've posted this before, elsewhere, and it is in a chapter in my book, "Trailrider's Guide to Cowboy Action Shooting[TM]", which also shows a photo of a Uberti "Colt's SAA", that blew at a shoot I was at, and asked to investigate. I sent some of the remaining loaded rounds to Hodgdons for evaluation, and they ran some pull tests on the bullets versus some of my heavily crimped rounds I loaded. IIRC (don't have it right at hand), the pull on the rounds loaded by the "victim" (he was NOT hurt or anything, just a blown gun), ran about 85 lbs, about half mine. He swore that he had not double-charged, as he and his teenage son were loading on a single-stage press and visually checking each round as the powder charge was thrown.  He was using a manufacturer's listed loading of Universal (which is what I use in .44-40 and .45LC).  As I mentioned, a ballistician working in South Africa, who later went to work at then Accurate Arms, documented similar pressure spikes in rifles, and there has been research done by the U.S. Navy back in the 70's. NOTE: This "premature shot start is NOT exactly the same as the rifle blowups that were documented in the 1950's-'60's in overbore capacity BOTTLENECKED cartridges with sharp shoulders that were underloaded with slow-burning rifle powders. Those were caused by overignition of the powder charge and shockwaves reflecting off the front of the shoulder, which reinforced and sent the powder burning rates exponential along with the pressure, until the cases ruptured and destroyed the gun!

But the caution still applies: If you are going to reduce your charges below the recommended MINIMUMS, in order to get lighter loads, then go to a faster-burning powder...or switch to a smaller caliber! Of course, the faster powders also have their minimums, and increase the possibility of double-charging, especially with progressive presses. Trail Boss was intended to prevent double-charging, but even down still above the minimum recommended loads of Trail Boss, you can get erratic burning. Firm crimping and tight bullet pull (as in NOT over expanding the case mouth) will certainly go a long way toward preventing premature shot start and related problems.  Interestingly, we have not heard as much about such blowups in the past few years. I don't know if this is because they are just not being reported on the forums, or we are seeing folks heeding the warnings and what to do to help prevent them.

[Grapeshot]

Some years ago I read an article in "SHOOT!" magazine that indicated that the cause of the mysterious blow ups of revolvers were the double loading of bullets in the case.  As the article was centered on the .45 Colt cartridge and PROGRESSIVE presses the author postulated that the seating die was capturing a bullet because of lube build up and pulling it out of the case as the ram was retracted and seating two bullets in one case when the operator put a new case and bullet under the seating die.  This would assume that the operator did not notice the bulletless case as it came out of the die. 

I agree with the postulation that two 250 grain bullets in one .45 Colt case would cause pressures to go through the roof and potentially cause a catostophic explosion blowing the cylinder up and sending the top strap into orbit, with a normal charge of fast burning pistol powder.

[Cliff Fendley]

How can you not notice the bulletless case coming out of the press?

[Grapeshot]

How can you not notice the bulletless case coming out of the press?

By concerning oneself with puting new case in shell plate and not watching for the end product.

[Cliff Fendley]

By concerning oneself with puting new case in shell plate and not watching for the end product.

When you go to box up the end product there is going to be one missing a bullet and loose powder in with the whole mess. That should alarm someone that something went afoul along the way.

[Delmonico]

When you go to box up the end product there is going to be one missing a bullet and loose powder in with the whole mess. That should alarm someone that something went afoul along the way.

Should never prevented anything that I've ever heard of.