Since my squib load in my 44 mag, I have been enlightened greatly by the many comments and experiences of others. I have a question about primers. Is the ignition of a primer an all or nothing event or can primer ignition be reduced by say
a light hammer fall? If one uses a lighter main spring, which continues to cause primer ignition, but because it is a lighter spring can the primer ignition be less and possibly cause a squib round?

Thanks,

JimC

There's quite a bit of evidence that primer strength varies with the strength of the firing pin hit. The was an article in Precision Shooting about how the pressure guns use some sort of a rope-pulled trip and you can change velocity by pulling harder. One of the powder or ammo companies rigged up an electric rope puller so they could get consistent results. I've also read several accounts of how changing the firing pin spring messed up a great shooting load.

Bye
Jack

There's quite a bit of evidence that primer strength varies with the strength of the firing pin hit. The was an article in Precision Shooting about how the pressure guns use some sort of a rope-pulled trip and you can change velocity by pulling harder. One of the powder or ammo companies rigged up an electric rope puller so they could get consistent results. I've also read several accounts of how changing the firing pin spring messed up a great shooting load.

Bye
Jack

Also believe it is NOT an all or nothing event. Think, and some first hand evidence, leads me to belive that at a certain point, the primer will still ignite, but won't ignite as energeticly (OK..make that detonate...it's much closer to a detonation than an ignition).

Havne't noticed any velocity differences, but have noticed the grouping differnece. Can tune a gun to get 100% firing, but get much poorer groups than when the primer is hit more solidly..cvould be a differnce in primer ignition, could be micro-hang fires (too small to notice, but we as people have a hard time moticing things in the 1/300 to 1/500ths of a second range).
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Know its not the same thing, but had a lot of WW .22LR ammo taht gave nearly 20% missfire rtes in some handguns. Pulling the bullets of the duds, found primer compound missing from teh rim, but shattered and mixed in the powder. Pulling unfired rounds showed NO missing/shattered priming mix

Shooting the same ammo in a Rem. rifle, gave NO missfires. Accfuracy was absolutly putrid, but they all went "bang".

While rimfire primer mix isn't the same as centerfire, it does show that it can be struck too softly to ignite consistantly. Temp. modifications to the handgun (revolver) to increase the pin hit reduced the missfire rate to 5%...going back to factory standard spring pressure brought it back to 20%.

In this case, suspect the cases...if there was some oxidation or cantamination, then the primer mix wouldn't "stick" to the rim recess...and it would tend to shatter rathe rthan ignite when hit too softly.

This adds another variable to accurate and safe shooting. To be as safe as possible should one never reduce the spring strength? My SRH 480 has a standard spring strength of 18lbs (I think) and I put a 12lb Wolfe spring in it. It seems to shoot just fine but I'm rethinking my loading and shooting technique in light of my recent squib load.

JimC

This adds another variable to accurate and safe shooting. To be as safe as possible should one never reduce the spring strength? My SRH 480 has a standard spring strength of 18lbs (I think) and I put a 12lb Wolfe spring in it. It seems to shoot just fine but I'm rethinking my loading and shooting technique in light of my recent squib load.

JimC

Will see an accuracy difference first...still getting 100% firing, but the groups are larger than they had been with a stronger spring.

Spring strenght is only part of the system...polish the pivot points and slick up the moving parts to reduce friction and that 12lb. spring may supply MORE force to the firming pin than the 18lb. spring did.

Is group size the gold standard for determining if primer
detonation, i.e. spring strength, is optimal?

JimC

Is group size the gold standard for determining if primer
detonation, i.e. spring strength, is optimal?

JimC

Think change is the standard...either a change in group size or a change in velocity (using the same ammo).

Don't think you original "squib" shot was a result of mainspring strength or primer failure.

What I mean to ask is how do you know if you're striking the primer with the optimum force? What is the end-point?

JimC

Think change is the standard...either a change in group size or a change in velocity (using the same ammo).

Don't think you original "squib" shot was a result of mainspring strength or primer failure.

Good question....not one I have an aswer to. Have to think about it, but there has to be some limit above which nothing advantageous happens.

I mainly shoot revolvers. When I was competing in Bullseye matchs I used Federal primers exclusively, with few, one every couple thousand rounds, misfires. When I would shoot the odd PPC, IPSC or IDPA match I'd have to remember to adjust the hammer spring for shooting Winchester primers. Nothing like cycling the intire cyclinder through twice to get off all six rounds, per stage.
Since I no longer compete I use Winchester primers exclusively, with the hammer spring adjusted to suit.
I quit using Remington primers because I would get one, never in this life time, primer that would not go off, even if I hit it with a sledge hammer, per hundred.
With one revolver I found scratches on the side of the hammer, up near the firing pin, from the hammer hitting the back of the frame. This caused some misfires.
A little stoning on the frame and the problem went away.
Jim

I sent my SRH 480 to the gunsmith this week for a trigger job and to have the innerds polished. In light of this discussion it seems a smooth action with a strong hammer strike, not just proper powder charge, makes for safer shooting.

Clean cases
Clean primers
proper powder and powder charge
tight bullet to case fit
tight crimp
smooth action
strong and solid hammer strike

JimC

I think it would more likely be that the compound in the primer is either contaminated (Oil/Moisture) Maybe deterated by heat exposure-fualty mixture of the compound. Doesn't take much to mess up a primer! To much pressure while seating it can and does dislodge the anvil/ crack the compound. All these thing will lead to misfire-squibs!

How much heat exposure does it take to weaken a primer? Can temperatures, normally encountered on planet earth, degrade a primer or does it take artificial heat?

JimC

How much heat exposure does it take to weaken a primer? Can temperatures, normally encountered on planet earth, degrade a primer or does it take artificial heat?

JimC

Co0nsidering that "earth normal" covers a rather large range of temperatures, have to say "yes" normal temps. can degrade primers. Considering that inside a locked car (or garage) it can reach 130 degrees or better on a summer day, heat seems the main enemy.

HAve some 50+ year old corrosive primers that will still fire...the outer wrapper is lost, but the little primer trays are wood, the primers are convexed shaped (you'll need a concave seating stem), and each peimer is embossed with a "W".

They survived becasue for all this time thwy were stored inside the house where the owner lived...they only experineced the temperature fluxuations that a person can endure.

Have to hunt up some old reports used in military testing just pre-WWII when non-corrosive was still kind of new. They put the various compounds through some sever tests (thought the phosporus based compounds that made the ejected cases glow were a bit odd...so the tests stuck in my mind).

You will not believe this but those Federal Primers came from a gun shop that burned down. The owner had a sale selling "smoke damaged" goods. He had a couple cases of primers that he claimed just shot "just fine" and they were priced right and the rest is history.

Egg on my face,

JimC

My father-in-law owned a Ben Franklin store that burned down.... back when a store could have a gun counter, and no one cared.

Anyway..... they salvaged all sorts of powder, and primers that were literally drenched in water... as they only carried one brand, could sort them back out by color of the foil disk.

Said he shot them all up (once they dried out, of course), no problems... and still has cans of powder that went through the fire and didn't light off.

Now.... a can of hair spray in a fire is a truly dangerous thing!

I went to the range today using some loads I loaded after my squib load but still using the federal primers.
I was using 21 Grs of IMR4227 behind a 265 gr GC. I was very careful with case preparation, powder weight, bullet to case fit, etc. One of my loads acted like it only half ignited, the bullet made it out of the barrel but the gun did not go "bang", it went "puff".
My chrono had been reading at 1100fps read "error" for that round. I said all that to say this, the federal primers are going into the primer grave! I think these have been heat damaged.

JimC

I went to the range today using some loads I loaded after my squib load but still using the federal primers.
I was using 21 Grs of IMR4227 behind a 265 gr GC. I was very careful with case preparation, powder weight, bullet to case fit, etc. One of my loads acted like it only half ignited, the bullet made it out of the barrel but the gun did not go "bang", it went "puff".
My chrono had been reading at 1100fps read "error" for that round. I said all that to say this, the federal primers are going into the primer grave! I think these have been heat damaged.

JimC
Use an aggressive crimp..that might help

Thanks for the input, actually I do use an aggressive crimp and since that squib load it's gotten more aggressive. Not one time have I had a problem with any round I've loaded until I bought those federal primers that went through a fire. I've fired approx. 20 rounds with one squib and one "puff". I think these primers need to be retired!

Regards,

JimC

The question of how much heat is too much is a hard one to figure, I'd guess that the priming mix from each manufacturer is a bit different. Last spring a friend showed up a with a newly-purchased 41 Magnum, to show me. I was going to the range anyway, so he tagged along, and I brought some old 41 reloads that had been sitting in my shed for years, exposed to temps of 130 or more, and 10 or less. They not only fired, he shot some very good groups with them! Most were cast bullet loads with AA9, some 210 grains, others were 295 grains. I don't still have my reloading records that far back, so I don't know what primers I was using, but probably Winchester Large Pistol, which I used almost exclusively back then. Most of the loads fired were from 1991 or '92, and while all the loads fired, some of the brass cases split from the neck down. Apparently the powder and primers weathered the years better than the brass!

Papajohn

There are a lot of speculations on what happens. Here is my story.
I had several misfires with my Ruger Super Red Hawk. Once when I had a nice fat doe in my sights- click nothing happened. She just wiggled her ears so I pulled the hammer back again and bam! I have a freezer full of deer sausage.
I sent the RRH down to Hamilton Bowen for a beauty treatment, new sights, a trigger job and a look at the firing pin which I thought was the culprit . He did the trigger job and replaced the sights ,but replaced the hammer. He said there was a problem with the dog of the hammer and some other problems with the hammer. I haven't had a misfire since.
My guess is the quality control a Rugger will ocassionally let sloppy parts get through.
My guess is that if the hammer doesen't smack the firing pin with enough force on a firing pin that tends to run on the short side of the industry standard ( its a few thousands shorter than the average) you will get a misfire. This could be the problem with the squib load. IMHO 21 grains of W296 is not a light load.