The case against the dimpled case head...

[Bill Calfee]

The case against the dimpled case head...


CYA friends:


There's a wonderful discussing going on, on another forum here at CYA, between Timo, Bob Finger, PedroS, 404tbang, Deveng and Tony K Harper, about what's the ultimate rimfire ammo....


Timo brought up the Russian ammo with the dimpled case head.


CYA friends, I do not want to step on that wonderful thread......


So I've sneaked off here on this forum to post something:


"The case against the dimpled case head..."

______________________________



CYA friends, I ran a spearment today, while I'm waiting for the MD-PAS triple pistol to become available to the masses.


I took a bunch of pictures....


I'm going to show why no one uses the dimpled case head today........because of one major fault.


Your friend, Bill Calfee....


_______________________



PS:


I'm headed to the range............to shoot my new MD-PAS pistol.....


It's September, and deliciously hot...........I love it.....makes my old bones feel good.

 

[404tbang]

The case against the dimpled case head...


CYA friends:


There's a wonderful discussing going on, on another forum here at CYA, between Timo, Bob Finger, PedroS, 404tbang, Deveng and Tony K Harper, about what's the ultimate rimfire ammo....


Timo brought up the Russian ammo with the dimpled case head.


CYA friends, I do not want to step on that wonderful thread......


So I've sneaked off here on this forum to post something:


"The case against the dimpled case head..."

______________________________



CYA friends, I ran a spearment today, while I'm waiting for the MD-PAS triple pistol to become available to the masses.


I took a bunch of pictures....


I'm going to show why no one uses the dimpled case head today........because of one major fault.


Your friend, Bill Calfee....


_______________________



PS:


I'm headed to the range............to shoot my new MD-PAS pistol.....


It's September, and deliciously hot...........I love it.....makes my old bones feel good.

Howdy Bill,
I read this shortly after you posted it. Something sorta rattled around in my brain about not using dimpled cases, but I could not quite pin it down. So, I went down to the family room to a book cabinet, pulled out a copy of a book that a kindly Kentucky hillbilly gave me awhile back, sat down in my Papaw's old rocking chair, and went looking for something. I looked for awhile, saw alllllll kinds of good info I had not read in awhile, but could not figure out where it was that I saw what I was looking for.

By the way...........the author of that book made a pretty bold prediction in February 2007. He said in the middle of a sentence "(this is why one day, all, rimfire, accuracy type actions, will use firing pins located at 6:00, but that's another story)". Yep, pretty bold thing to say.............

Then I finally pinned down that thought rattling around in my brain. It wasn't the info, specifically, that I was looking for, but I think it directly ties in with your experiment. Sorta. At least I think the light bulb came on for me............dimly.

Some time back, on this site, you talked about case heads and factory stamps. That should be obscure enough to not clue anyone in. Shucks, might be so obscure I lost you, too. But I think I know a bit about what you're going to be talking about. I am looking forward to what you have to say. I might re-ask a couple of questions that I had asked on the other thread.

Take care,

Greg

 

[Bill Calfee]

Friend 404tbang

Howdy Bill,
I read this shortly after you posted it. Something sorta rattled around in my brain about not using dimpled cases, but I could not quite pin it down. So, I went down to the family room to a book cabinet, pulled out a copy of a book that a kindly Kentucky hillbilly gave me awhile back, sat down in my Papaw's old rocking chair, and went looking for something. I looked for awhile, saw alllllll kinds of good info I had not read in awhile, but could not figure out where it was that I saw what I was looking for.

By the way...........the author of that book made a pretty bold prediction in February 2007. He said in the middle of a sentence "(this is why one day, all, rimfire, accuracy type actions, will use firing pins located at 6:00, but that's another story)". Yep, pretty bold thing to say.............

Then I finally pinned down that thought rattling around in my brain. It wasn't the info, specifically, that I was looking for, but I think it directly ties in with your experiment. Sorta. At least I think the light bulb came on for me............dimly.

Some time back, on this site, you talked about case heads and factory stamps. That should be obscure enough to not clue anyone in. Shucks, might be so obscure I lost you, too. But I think I know a bit about what you're going to be talking about. I am looking forward to what you have to say. I might re-ask a couple of questions that I had asked on the other thread.

Take care,

Greg

_______________________________


Friend 404tbang:


Greg, there was a bunch of moaning and groaning about that 6:00 firing pin prediction back in 2007........now 6 ignition is taken for granted, even by the moaning and groaning folks.

_______________________________


You're in the automobile manufacturing business.


Finders and hoods and side panels of automobiles are designed with creases and corners in them, because the creases and square corners give stiffness to the body panels....


Now I bet you know where I'm going with this spearment.


Here's a picture.


I took a new, unopened box of Federal and I found a box of Eley from 2011.


The 2011 is not near as old as the Federal, but at least the brass of the Eley has aged somewhat.

_________________________________



I used my new MD-PAS pistol to run this spearment..



In this first picture below I've de-cocked the breech bolt, so the firing pin is resting on its mechanical stop...


Chamber empty, of course, and the spring tension of the extractors are holding the locking lugs against the lug seats in the action.


I zeroed the dial indicator in this position.

I then fired a round and took a second reading.....


As you can see the firing pin is now off its mechanical stop .010"............which is what it's always been, even with late Eley...


So the 8 year old Eley brass hasn't hardened up much, from age.



By the way, .010" is the minimum I now use off the mechanical stop......


I used to use .005" as my minimum, but, I got burned a couple times so I went to the .010" minimum.

____________________________



Tomorrow I'll show the test results of the Federal, with the dimpled case head...


Greg, I already knew, roughly, what the results would be.........but I was even shocked at how they turned out.....



Your friend, BC

 

[Bill Calfee]

I've always known, but even I got a surprise.

_______________________________


Friend 404tbang:


Greg, there was a bunch of moaning and groaning about that 6:00 firing pin prediction back in 2007........now 6 ignition is taken for granted, even by the moaning and groaning folks.

_______________________________


You're in the automobile manufacturing business.


Finders and hoods and side panels of automobiles are designed with creases and corners in them, because the creases and square corners give stiffness to the body panels....


Now I bet you know where I'm going with this spearment.


Here's a picture.


I took a new, unopened box of Federal and I found a box of Eley from 2011.


The 2011 is not near as old as the Federal, but at least the brass of the Eley has aged somewhat.

_________________________________



I used my new MD-PAS pistol to run this spearment..



In this first picture below I've de-cocked the breech bolt, so the firing pin is resting on its mechanical stop...


Chamber empty, of course, and the spring tension of the extractors are holding the locking lugs against the lug seats in the action.


I zeroed the dial indicator in this position.

I then fired a round and took a second reading.....


As you can see the firing pin is now off its mechanical stop .010"............which is what it's always been, even with late Eley...


So the 8 year old Eley brass hasn't hardened up much, from age.



By the way, .010" is the minimum I now use off the mechanical stop......


I used to use .005" as my minimum, but, I got burned a couple times so I went to the .010" minimum.

____________________________



Tomorrow I'll show the test results of the Federal, with the dimpled case head...


Greg, I already knew, roughly, what the results would be.........but I was even shocked at how they turned out.....



Your friend, BC

______________________________________________________________________



I've always known, but even I got a surprise.



CYA friends:



Putting a dimple in the head of the 22 RF cartridge makes the brass extremely stiff......


Which makes it much harder to drive the firing pin footprint to the proper depth.


I've known this ever since the first days that folks started using the Federal, with the dimple.......same with the Russian ammo.


Even though I've always known about the difficulty of driving a footprint in these dimpled cases, I was even shocked by the results of my test yesterday.


I'll post the pictures later, after I add some graphics to the pictures.


Your friend, BC

______________________



By the way, there were some folks who had some pretty good success with this Federal......back in the day.


This Federal had one other flaw.......that the Russian stuff didn't.


The wax, or whatever it was called.......it was a dry lube, I heard rosin based?........and it was terrible on barrels.



The Russian stuff used wax, and a lot of it.......which I loved.


But it was not a hard was.........it was very pliable........


I've seen boxes of it where the bottom of the box was covered with the soft wax, and the bullets simply smeared with it all over...


But man that stuff shot, just like Timo said.


After the 1984 Olympics in California, I believe that's the correct date and place, the Russians left a bunch of it here in the US....


Selby Wright and I obtained a bunch......


And it was excellent stuff.....

 

[404tbang]

Howdy Bill,

You said in your earlier post "now I bet you know where I'm going with this spearment". Yep. That is what I meant by referring to a discussion we had on here a few years ago. Took me awhile to get it recalled right, but that is why I posted something about you talking about case heads and factory stamps. I wanted to leave it obscure so as not to interfere with what you were going to say. A few years ago you made a comment about loading your ammo in the chamber so that the firing pin didn't hit near the area of the case head that was stamped, because that part of the brass would essentially be work hardened from the stamp and you didn't want anything to negatively affect ignition. At least that's what I understood from it at the time.

Looking forward to seeing the rest of what you have to say.

Oh.........man I hate to even ask this. As much good as I have heard about Olimp-R and UM1, and I have heard a LOT over the years.............is it possible that today's ammo is better? What do you think contributed to the reputation of Olimp-R (beyond the wax) and UM1 in light of what you are showing regarding the dimple making the brass harder? Were there other things being done in making that ammo that might be good to bring back today?

Take care,

Greg

 

[Timo]

As Bill tells about dimpled case, many times when we make something we get something and also same time lost something.Dimple case helps when using old priming system,but it is not the thing what makes Olimp-R shoot so good and constantly.Lot by lot.

But mostly those ammo what we got to west comes from best SU:s prone shooters and they got from factory best ammo available.

Was all production as good? We cant never know this.

What there came after year 1998 are not so good as before this year.

Everybody knows that if we find good lot, it can work excellent many other RF.s but not all.There is also difference between bränds.

I told before was Olimp-R so good as stories or has time golden memories? Greg! I can tell you that it was/is.

Wax is also amazing.It dont dry or oxidize. Those 40 years old ammos wax is like bought yesterday on my table.
(I am pretty sure I now know what it is).

Olimp R was/is whole package.Many details combination.But NOT mass produced thisway what we understand today.

We must continue hunting the Ultimate 22 LR ammo!

BR, Timo

 

[Bill Calfee]

Friends Bang and Timo

Friends Bang and Timo


(The ole Hawk calls you Bang, Greg, so that's why I do sometimes)


_______________________________



Yes, what Timo said is correct.......the wax on that Russian ammo never hardened or oxidized.......


I've still got a little of it, and the viscosity of the wax is like it was when I first obtained it.


_________________________



Before I proceed, I need to say something:


The dimple may have aided in the even distribution of the priming compound....


But....................................................


The greatest benefit to accuracy it gave, was to direct the fire forward, toward the front of the case......helping light the powder more to the front.


The longer the combustion process can be contained inside the case, the more uniform is the combustion process, which results in better accuracy.


Now that we have universal 6 ignition, that function of the dimple is no longer needed.


_______________________________________



I got a surprise.


I've always known the dimpled cases took more firing pin spring force to drive the footprint to the same depth as flat head cases.


But until I ran this test, I didn't realize exactly how much more spring pressure would be required.


Here's the picture of the Federal test.

CYA friends, I've just lost .011" of case head penetration.........


I was amazed by this finding.


And I checked it several times.....


There could be a thousandth, or so, either way, because of the rim thickness difference between the Eley and Federal.....which I didn't check.



But to lose .011" of case head penetration, or very close to it, kinda blew my mind.



This has been a most revealing test.........


Your friend, BC