Is a partial primer detonation possible?

[7Acres]

Hi folks,
I've proven now that my S&W 640 hammerles j-frame's striker spring needs to be replaced. Light primer strikes fail to set off the primer. Load the same exact round in my levergun and it goes bang just fine. I was having issues when developing a load for this gun several months ago.

I thought I had somehow contaminated my primers. But sometimes the primer would go off but the powder would fail to completely ignite. Either the bullet would get stuck in the barrel or would barely leave the case and get stuck right at the mouth of the barrel. After proving that I'm not getting a strong primer strike I'm wondering if its possible to strike the primer soft enough that only a small fraction of the primer compound goes off failing to ignite most of the gunpowder? Or is it an all or nothing thing with primers?

FYI, Powder was brand new. Primers were too.

[paul h]

I believe it is possible to get partial primer ignition from a light strike. I thought I'd slick up my super redhawk by putting in a spring kit and my previously always went bang gun went to inconsistant ignition when I put in a softer hammer spring, and as I recall I was using CCI 350's to light off H-110. When I went back to the factory spring, no more ignition problems.

[220swiftfn]

Another possibility, some of the j-frames had a short firing pin that would result in light strikes with anything less than a full strength mainspring. Brownells has a longer firing pin listed, I don't remember off the top of my head if it was Apex or Cylinder & Slide that makes it (or possibly both)......


Dan

[Sasquatch-1]

I don't know if this will help, but I have a Mod. 10. I have had problems with primers. The primers in question were CCI 550 SPM. If I am firing single action it seems they all go off. If I am firing double action at least one in every 6 chambered will not fire. A second strike will usually set it off. I have attributed it to seating depth and have since started priming with a Honady hand primer.

What type of primers are you using.

[felix]

Primer action is all or nothing. ... felix

[7Acres]

Primers are Tula Small Pistol Primers. What does the 550 mean? I looked for that on the box and did not see any numbering like that.

[johnson1942]

just for information, a partial ignition on a primer on a battle wagon 16 inch gun back in the 1960/s caused the death of about 18 sailors. it was a slow partial ignition and when the breech was opened to remove it it went off. sad to say no one survived in that gun mount. be careful how you handle those miss fires as they may go off in a delayed moment and you dont want to be holding them.

[felix]

I remember that big time! ... felix

[leftiye]

I don't know if this will help, but I have a Mod. 10. I have had problems with primers. The primers in question were CCI 550 SPM. If I am firing single action it seems they all go off. If I am firing double action at least one in every 6 chambered will not fire. A second strike will usually set it off. I have attributed it to seating depth and have since started priming with a Honady hand primer.

What type of primers are you using.

It could also be a light hit in double action. Cocking single action gives the hammer a little more spring tension and a little farther to travel. Crank up the tension screw a little?

I think the stuff that explodes in primers can't tolerate heat enough to do anything but blow. No sitting around waiting, half of it goes if the other half goes.

[Sasquatch-1]

550 designates the Small Pistol Magnum primer from CCI. I have never used Tula primers but from what I have gathered from members on this site they must be the hardest cup primer on the market. Federal seems to be the softest cup (I may be wrong there). CCI also seems to have a fairly hard cup which means the strike has to be a little harder.


Primers are Tula Small Pistol Primers. What does the 550 mean? I looked for that on the box and did not see any numbering like that.

[BeeMan]

Partial primer ignition would be a very thin edge to find. It may be possible but I would not like to be tasked with reproducing it.

Failure to ignite the powder charge does happen. I've experienced it 3 times in 35 plus years of hand-loading. All were with published loads from manuals; one instance in a rifle and 2 in handguns. I looked at primer contamination or incomplete seating, powder condition, and firearm mechanical function without finding anything. Not saying there was not a cause, just that I could not identify it at the time.

It sounds like there may be a known issue with j-frames.

[Outpost75]

The enclosed hammer S&W J frames have a short hammer throw and lighter hammer which reduce striker energy from the start. My experience with the Russian primers is that they are less sensitive than the Federal 100 or Remington 1-1/2 so you can expect misfires unless driven striker protrusion is at maximum, the gun is clean, and headspace and endshake of the cylinder are at minimum.

Try Remington 1-1/2 or Federal 100 primers. If you still have misfires, try factory ammo of US make. If it misfires more than 1 in 100 rounds the gun is not suitably reliable for defense carry. I would return it to the factory to adjust hammer throw until it produces not less than 0.010" copper indent using the "C" size copper cylinder in the government holder. The coppers are not available to the gunsmith trade, but the factory will have them as this is supposed to be a 100% check on law enforcement orders.

You might ask if they can put in the firing pin, hammer and mainspring from a model 942, as the 9mm revolvers were adjusted fir the maximum attainablehammer throw and 0.011" copper indent. DA trigger pull IS heavier, but the guns go BANG~!

[leftiye]

Or tighten the mainspring tension screw.

[Old Caster]

According to Widners web site, magnum in a Wolf or Tula primer means harder cup and magnum in an American primer means more power.

[John Boy]

For a primer it ignite crushing the anvil against the primer charge - it has to be hit both HARD & FAST. There is no in between. It is a Go or No Go

[M-Tecs]

Back in the 70's I was a member of a small trap club. The members would bulk order components. On one of the primer orders we had a rash of hangfires and misfires. Multiple reloaders using different powders experienced the same thing. The hangfires ranged for barely noticeable to a couple of seconds with one going about 90 seconds. My dad's friend was shooting next to me when he had a hangfire on his over & under. Since hangfires were an issue he placed the butt on his toe with the barrel pointed up and was waiting for a couple of minutes. It fired somewhere between 60 and 90 seconds after her pulled the trigger. It was in a safe directions but it got everyone attention. After that lot of primers was used up no more issues.

During a HighPower match the shooter next to me had two misfires. In both cases you could hear the primer make a hissing noise for a half of second. The shooter on the other side of him loudly asked "Who farted?" That was during standing. I was laughing so hard I believe I shot a 7 on my next shot.

[johnson1942]

this is a good thread as hangfires can kill, im going to have my son read all of these.

[Outpost75]

Or tighten the mainspring tension screw.

J frame iscoil springaction and there isno strain screw. You are SOL.

[7Acres]

I've got a longer firing pin on order. I'll report back if I get deeper firing pin impressions and reliable Tula primer ignition.

Outpost, why do you say I'm SOL? Any more detail you can provide?