Pistol Primers

[Bob Wright]

I learned some tme ago that when a cartridge is fired in a revolver, the primer backs out agains the firing pin bushing. Pressure then backs the case out to re-seat the primer then everything relaxes and the fired case sort of slips back into the chamber.

Curious about this process, I clamped an empty primed .44 Magnum case in a vise with the head exposed. Using a decapping pin from an old Lee Loader set, and a mallet (Wearing leather gloves and safety galsses) I tapped the primer like a firing pin striking the primer. There was the expected loud "pop!" as the prtimer fired. What surprised me was that the primer was blown out of the case and impaled on the pin to its full length!

Bob Wright

 

[Hvymax]

I learned some tme ago that when a cartridge is fired in a revolver, the primer backs out agains the firing pin bushing. Pressure then backs the case out to re-seat the primer then everything relaxes and the fired case sort of slips back into the chamber.

Curious about this process, I clamped an empty primed .44 Magnum case in a vise with the head exposed. Using a decapping pin from an old Lee Loader set, and a mallet (Wearing leather gloves and safety galsses) I tapped the primer like a firing pin striking the primer. There was the expected loud "pop!" as the prtimer fired. What surprised me was that the primer was blown out of the case and impaled on the pin to its full length!

Bob Wright

I wish I would have zoomed the Betamax camera in to capture this back in my Mad Scientist Days. We were focused on the Cylinder Gap and Muzzle to find forcing cone and crown designs to minimize the turbulence at these points.

 

[Bob Wright]

I wish I would have zoomed the Betamax camera in to capture this back in my Mad Scientist Days. We were focused on the Cylinder Gap and Muzzle to find forcing cone and crown designs to minimize the turbulence at these points.

Uh Huh!

Bob Wright

 

[contender]

Many people are very surprised at the amount of pressure or force a primer can have. If I recall correctly,, they used a vise, a tube to encase the head of the case, and a decapping rod. I think their results mirrored what you had happen Bob.

 

[Hvymax]

Uh Huh!

Bob Wright

I was shooting IHMSA back in the 80's. Dan Wesson's were the Mad Scientist platform of the day. When I started pushing 300+gr bullets past 1,200ish fps accuracy began to suffer. I finally had to settle for 330gr cast linotype with a gas check going around 1,400 fps through a Douglas barrel with a rifling cut that kinda looks like Marlins Microgroove. We even milled our own bullet molds. Lesser Competitors were limited to what factory guns were available.
I would spec out 2-3 custom cuts and twist rates, turn and thread the barrel blanks and get to work developing loads.
Using the Betamax I settled on a forcing cone design I called the Spade and ran .002 cylinder gap. The Spade started as .004 larger than the cylinder face bores, opened up before tapering back in to the bore in about the same space as a normal forcing cone. I was doing it by hand on the lathe. I don't remember the exact specs for the muzzle crown after 40 years. I would start with the blanks a few inches long for experimenting for the camera before trimming and recrowning to match the barrel sleeves. Mad Science not limited by what normal people had to settle for. Kinda like having a friend at a machine shop to build your High School Racing Engines. On a whole nother level from the normies.

 

[Bob Wright]

You ought to consider getting into that more seriously!

Bob Wright

 

[sandspider500]

I once loaded some speer .451 round ball in 45 colt cases. The ball was about halfway into the case. I used unique for the powder, I forget the amount, maybe 7gr. I fired one with ear protection on, I couldn't hear it go off. There was a hole in the target 7 yds away. The cylinder was difficult to rotate, so I opened the gate of the Ruger Blackhawk and rotated the stiff cylinder by hand, the primer had backed out and was dragging on the recoil shield. The loads were too light. I seated the ball flush with the case mouth by pressing the loaded rounds against a bench. After that, all was well. All rounds had an audible report and primers didn't back out.

 

[Hvymax]

You ought to consider getting into that more seriously!

Bob Wright

You might not have noticed my latest recommendations for what Ruger should do with the "Super Redhawk"
My last few Science Experiments involved the 350 Legend and 357sig. I have 90gr Lehigh XP's going around 3,100fps with the Legends in the AR and 2,300fps from my Frankenglock 357sig.
I have 350gr subsonics for the legend and 250gr subsonics for the sig I also worked up a few bonded core JHP hunting loads. I even worked up a 357sig load for my Bond Arms that comes out at 2,100 fps just because I was jacking around at the press one day. It helps that I load about 15' from where I shoot so I can throw a few charges and seat a bullet and shoot for group over the Chrono seconds later!!!

 

[Hvymax]

I once loaded some speer .451 round ball in 45 colt cases. The ball was about halfway into the case. I used unique for the powder, I forget the amount, maybe 7gr. I fired one with ear protection on, I couldn't hear it go off. There was a hole in the target 7 yds away. The cylinder was difficult to rotate, so I opened the gate of the Ruger Blackhawk and rotated the stiff cylinder by hand, the primer had backed out and was dragging on the recoil shield. The loads were too light. I seated the ball flush with the case mouth by pressing the loaded rounds against a bench. After that, all was well. All rounds had an audible report and primers didn't back out.

An accuracy trick for 1858 44 Remington's is to bore out the cylinder to 45. The barrels are actually 45 while the cylinder swages the ball down to 44. That's why all the cartridge conversations use 45Colt.

 

[Hvymax]

Sorry if I took your thread off the rails. You seemed sceptical about my ability to capture this phenomenon on film. I think I've established that if I had focused that same camera on the breech face there's a pretty good chance I could have caught it on film. I would be willing to bet that if someone forwarded this to the Ballistic High Speed guys that they could easily document this on film for their YouTube channel. They are always looking for interesting things to capture at the ludicrous speeds their cameras are capable of.