doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Reloading hazard

I don't think it's as simple and straightforward as a "hot" primer versus a "cool" primer. I don't believe you can isolate the primer variable from the powder variable. There are interactions between the two that are not intuitive. Such as substituting a R209 for a W209 in one recipe and seeing a major decrease in pressure...make that same substitution with a different powder and see a comparable increase in pressure.

Tough for me to understand how a primer which, unlike smokeless powder, is an explosive, would not contribute to chamber pressure.

Lacking data, I don't doubt anything.

I believer the main charge in a primer is a propellant, not a true explosive.

I believe the stray primer contributes to chamber pressure, but not the difference between normal pressure and a barrel bursting pressure.

There are a couple of "I believes" up there, so I'd really like to see some data. And, I'll have a look at load data to see if there are reversals with "hot" and "cool" primers as to chamber pressure.

As I offered in another thread, send me five guns to blow up, fluid steel, 12 gauge, and I'll do the test. I will load shells with a primer in the powder charge, and shoot them until one shows signs of damage. What could be easier? I will send the guns back to the donors when I'm through and publish the results here. The test will be done scientifically and we'll put this question to bed. Email me at wilmrph@verizon.net and I'll send you my shipping address.

Or, we could put some loads with a primer in the powder charge in a pressure gun and see what the readings are for chamber pressure. Off hand, I'd say that would be easier.

Don, I actually had my post written that way but reconsidered because if I am able to blow up or damage a barrel in some phase of the test, the pressure sensor may be damaged. Another reason we (or I) won't do it that way is that it is too hard to coordinate the loading of the shells and the conduct of the test together with the location of the pressure testing aparatus. If you know of a way to simplify the whole process and also get an unpaid volunteer to do the work, you be sure to let us know.

Well, let's just say "don't do that,it's bad" and leave it at that. Exact pressures arn't really necessary.

Well..... I think I actually did it once upon a time. I was reloading 20 gauge target loads (STS hulls, W-209, AA wad, 15.6gr. Universal Clays, 7/8oz.#8's) for use in an L.C.Smith Field Grade. Loading was done in a Mec 600, no auto primer feed. Several times I caught myself reaching for a primer instead of a wad. It was a marathon loading session, late at night, and I was tired. Not thinking that I had actually gone so far as to drop a primer in the wad guide, I continued on. The next day on the trap line one of the shells produced a report much, much louder than normal. Looking at the gun I noticed a chunk of wood missing from the upper RH stock cheek. I opened the gun (with much difficulty) and found the primer to have been blown- the gas from which no doubt blew out the wood. Everything else seemed normal. Even found the missing chunk of wood in the grass. Upon further investigation I noticed a fresh shell would fall into the the chamber further than it would in the other chamber. That's when I noticed a slight but definite bulge on the RH side of the barrel, right over the end of the chamber.

The previous shot had smashed the clay bird, so I'm reasonably sure there was no wad stuck in the forcing cone. Examination of the previously fired hulls turned up no missing pieces that could have lodged there also. Shaken (but not stirred), I went home. It was later that I remembered the incident of almost dropping a primer into the wad guide and have since come to the belief that I must have done so. Needless to say I dissected the remaining shells from that session- about 600 -only to find nothing but powder, wads and shot. My one brush with disaster gun-wise, and it was enough.

http://www.speer-bullets.com/education/primers.aspx

There are three primary chemical components that create a modern primer. The initiator is a percussion-sensitive primary explosive that will detonate when struck sharply. The fuel provides gas pressure and sustained heat, and the oxidizer provides extra oxygen to support burning in the closed case.

The explosive mix in the earliest primers was mercury fulminate.

The mercury residue in these primers attacked cartridge brass and made it brittle, resulting in case failures.

This situation was remedied in the late 1920's when lead styphnate priming was developed. This primary explosive left no corrosive residue, and meant that shooters no longer had to wash their guns. Today, styphnate priming is nearly universal.

Which primer is "hotter"....R209 or CCI209?

The CCI209 is hotter...

Hull: STS
Wad: Rem Fig8
Powder: 21.0 gr Green Dot
Primer: R209....8,800 psi
Primer: C209....9,700 psi

No, the R209 is hotter...

Hull: STS
Wad: Rem Fig8
Powder: 17.5 gr Clay Dot
Primer: R209....10,270 psi
primer: C209....9,020 psi

No, really, the CCI209 is hotter...

Hull: STS
Wad: Rem Fig8
Powder: 19.3 gr Clays
Primer: R209....9,000 psi
Primer: C209....11,400 psi

Good post, Mike. For sure the styphnate initiator is an explosive. However, there is very little of it and it doesn't contribute enough gas to have a big impact on pressure. The propellant main charge is also small relative to the powder charge, so it is not a big contributor to chamber pressure. Thinking about this, I can imagine that location of the stray primer within the powder might also be an issue. Say we have the stray sitting directly over, or very near, the intended primer, then it might ignite from the first primer firing instead of cooking-off. This would, in effect, give the powder a double dose of ignition and might account for a higher chamber pressure.

Mike, the load data is interesting. "Hotter" probably doesn't exactly describe the way the primer ignites differing powders. Have you looked for a pattern between primers and powder burn rate?

8-b, I'd use a strain gauge glued to a stout test barrel. No big loss if you bulged the chamber.

I load with a P&W 800B. The primer feed tray is directly above the incoming hulls. I have, on occasion, had primers misfeed into the guide rail and drop into hulls. Far as I know, I've always caught this event, but now think I'll rearrange some things.

Another good discussion - thanks all.

Don, in threads where this situations has been discussed, several posters have claimed that the primer in the powder is an impossible situation in several brands and models of loader. The loader with which I have the most experience is the 800B in all four gauges. I have always explained to these people how it could happen with this loader. Thanks for the support. I have also explained how it can happen when using other models of loader. It can happen with any brand or model of loader if a live primer drops off the loading table into a box of empty shells. End of story, except the pressure testing. Sorry, I don't want to request to borrow anyone's test gun to bulge the chamber, which I expect to do before I am through testing. I would rather use the method of shooting defective shells in cheap guns until damage is observed. Send me the guns and I will do the testing and return the guns. wilmrph@verizon.net