Purpose of lines on Finnish bullet?


#1


#2

This type of crimping is usually done to help keep the jacket for separating from the core in firing. Of course if it is at the mouth it is to grasp the case mouth to keep the bullet from slipping and can also be used to do double duty with above as well. Sometimes such cannelures are used for identification but not as a standard practice. These Finnish 7.62s had core separation problems in temperature extremes as I understand it. ON CASES ; these rings were often used to indicate a dummy round but the Germans used them on blanks as well.


#3

Thank you!
Too much Finland cartridges here could be ectracted from the ground. :)


#4

I doubt if that is the purpose of the cannelure on a FMJ military bullet since there is little or no danger of the jacket seperating. But CSAEOD would know more about these things than I would so I bow to his expertise.

It is ironic that some bullets with a cannelure like the one pictured, such as the old Western O.P.E. (Open Point Expanding), were cannelured to ASSIST in bullet mushrooming by actually weakening the jacket at that point. Most cannelures are for crimping however.

Ray


#5

I beleive in this case the annelure on the bullet identifies the type of bullet. I have only seen this cannelure on Finnish bullets called Ball, Special “FAT” bullet, 167 gr… The standard ball bullet for Finland is Ball, Type D 166, 200 gr… The “FAT” bullet has a different profile.


#6

In this case, I beleive that the lines are not deep enough to be considered a cannelure for the purpose of securing the core. I beleive this is simply a way of identifying a different (heavy in this case) projectile type. I sectioned one of these cartridges a few years ago and do not recall the “cannelure” being visible inside the jacket. I’m not sure if I took a pic of this round or not. I’ll have to look.


#7

Add FINLAND to your post title and see what they have to say. Military Jacket bullets are the type which have the most problem with jacket separation. If you look at the base of most you find that they are well rolled over to avoid just that. Hot machinegun barrels and rifle barrels(not so much) cause the metal of the projectile to expand and the lead core to soften. This allows gases to get between the jacket and core and leads to striping of the jacket. Being differant metals they expand at differant rates as well. Barrel failures can also occur when these expanded bullets start to foul up and sometimes stick in the barrel. The Germans made an experimental bullet which expanded just this way in an effort to save on lead. No lead-just an iron core and steel jkt. The gases pushed the jacket into the grooves of the rifle. It didn’t work due to striping and erratic flight as the barrels heated up. Interesting that the Russian sniper bullet has an open base. They,of course, won’t be shooting enough to over heat the barrel. I would like to see a couple of hundred of these go through a machinegun.


#8

I gotta say, I’ve never heard that before now. You would think that with the Gazillions of FMJ bullets fired in the last century that reports of that would have leaked out and the military would have taken steps to address it.

There are instances where guys have “hollow pointed” FMJ to make them into hunting bullets and the cores have shot thru the jackets with bad results, but it’s hard for my military mind to picture a jacket stripping and leaving the core in the barrel. JMHO

Ray


#9

[quote=“CSAEOD”]Add FINLAND to your post title and see what they have to say. Military Jacket bullets are the type which have the most problem with jacket separation. If you look at the base of most you find that they are well rolled over to avoid just that. Hot machinegun barrels and rifle barrels(not so much) cause the metal of the projectile to expand and the lead core to soften. This allows gases to get between the jacket and core and leads to striping of the jacket. Being differant metals they expand at differant rates as well. Barrel failures can also occur when these expanded bullets start to foul up and sometimes stick in the barrel. The Germans made an experimental bullet which expanded just this way in an effort to save on lead. No lead-just an iron core and steel jkt. The gases pushed the jacket into the grooves of the rifle. It didn’t work due to striping and erratic flight as the barrels heated up. Interesting that the Russian sniper bullet has an open base. They,of course, won’t be shooting enough to over heat the barrel. I would like to see a couple of hundred of these go through a machinegun.

[/quote]

For some reason the Russians are doing the same with 5.45x39 and 9x39.


#10

You are right.


#11

[quote=“Ray Meketa”]I gotta say, I’ve never heard that before now. You would think that with the Gazillions of FMJ bullets fired in the last century that reports of that would have leaked out and the military would have taken steps to address it.

There are instances where guys have “hollow pointed” FMJ to make them into hunting bullets and the cores have shot thru the jackets with bad results, but it’s hard for my military mind to picture a jacket stripping and leaving the core in the barrel. JMHO

Ray[/quote]

These are the kinds of things which ammo designers deal with in advance of sending the shells out for combat use. Notice all of the EXPERIMENTAL ammunition refered to in these pages. These issues are addressed before troops are supplied as best can be in given circumstances.

What is your theory on why manufacturers spend MONEY to make special machinery to roll crimp the jacket on a jacketed bullet OVER the base of the bullet? Since you have heard about improvised hollow points shooting the core out why are you surprised that there is such an effect on the core? It has been heard about and addressed. Swaging and crimping the bullet jacket in any number of ways is a typical way in which it was addressed. If you have a real rather than a rhetorical interest in such science I suggest that you get a machinegun and a supply of WW2 era ammo, since that is what we are talking about, pull the bullets, file off the roll crimp which is over the BASE of the bullet, reseat and crimp the bullets and fire several hundred. Report back. The bullet design in the newer Russian bullets and others include new technologies of pressing, glueing, special compounding any number of aproaches to keeping the core and the jacket together. Some of the new 6.8mm have the core loaded from the front of the jacket so that there is no open base at all. The nose is then swaged shut to avoid being considered a hollow point.


#12

CSAOED

I’ve always thought that the jacket was rolled over at the base of the bullet to finish the base with a smooth profile to aid in bullet seating and to help secure the core. Additionally, an unfinished or sharp edged base tends to form “fins” from metal displaced by the rifling, which in turn degrades accuray. As far as I know they were made that way since the beginning of small caliber high velocity military cartridges.

What I question is your statement that the seperation of core and jacket was, is, or has been a problem. I have never seen any references that would indicate such. I would rather see actual documentation than your suggestion that I get a machine gun, a supply of altered bullets, and shoot them to see for myself.

Some bullets like tracers and incendiaries do not have the rolled over jacket. Are they subject to jacket/core seperation? Could the 6.8mm solid base bullets be constructed that way for greater accuracy?

Ray


#13

Here is a scan of the information that the lines on the Finnish 7.62x54R are an identifying marking for the lighter weight 10.8 gm ball bullet called the FAT profile bullet. These pages are from the book “Munitions Sovietiques et des Pays de L’est” by Phiillippe Regenstreif. The 3rd cartridge from the left and the text about midway down the page shows and discusses the cannelure as an ID. Click on the image to enlarge it.


#14

[quote=“Ron Merchant”]Here is a scan of the information that the lines on the Finnish 7.62x54R are an identifying marking for the lighter weight 10.8 gm ball bullet called the FAT profile bullet. These pages are from the book “Munitions Sovietiques et des Pays de L’est” by Phiillippe Regenstreif. The 3rd cartridge from the left and the text about midway down the page shows and discusses the cannelure as an ID. Click on the image to enlarge it.
[/quote]

Thank you Ron! Here in St. Petersburg FATs are common buy near Moscow (for example) they are pretty rare.


#15

CSAEOD,

If you look at any Soviet made 7.62x54r type “D” ball projectile, you will see that the base of the jacket is not turned over, exactly like the sniper ball you pictured. Since this “heavy” ball projectile was intended primarily for machinegun use, your assertation that this feature is needed is not exactly correct in every case. “most” modern FMJ projectiles have turned over bases, but this is likely for a variety of reasons. Holding the core and jacket together is just one reason I’m sure . My examination of this Finnish round shows that the “Identification” cannelure is not deep enough to contact the core at all. If you go to the Mosin-Nagant.net website and look at the ammunition section under Finnland, you will see the two Finn 7.62x54r ball rounds I sectioned for Gene Whitehead. The one on the right is this type with the cannelure ID mark and as you can see in the pic, the cannelure does not extend into the core and the base is turned over.

AKMS


#16

[quote=“Ray Meketa”]CSAOED

I’ve always thought that the jacket was rolled over at the base of the bullet to finish the base with a smooth profile to aid in bullet seating and to help secure the core. Additionally, an unfinished or sharp edged base tends to form “fins” from metal displaced by the rifling, which in turn degrades accuray. As far as I know they were made that way since the beginning of small caliber high velocity military cartridges.

What I question is your statement that the seperation of core and jacket was, is, or has been a problem. I have never seen any references that would indicate such. I would rather see actual documentation than your suggestion that I get a machine gun, a supply of altered bullets, and shoot them to see for myself.

Some bullets like tracers and incendiaries do not have the rolled over jacket. Are they subject to jacket/core seperation? Could the 6.8mm solid base bullets be constructed that way for greater accuracy?

Ray[/quote]

Ray,

Some early .303"s did have a problem with blow-through of the core, however these were mainly the hollow-point types. They tried increasing the amount of turnover at the base but this didn’t cure it. What happened was the lead alloy core extruded through leaving the tubular jacket in the bore, where the following bullet hit it. Most adapted (mutilated) military ball rounds which have the tip of the jacket cut off are at risk of the same failure. Generally, cannelures are insufficient in themselves to hold a bullet together. When the .303" hollowpoint (Mark III, IV and V) were phased out the replacement RN bullet had a thickened nose jacket to prevent splitting. The bullet cannelures generally weaken the bullet to the point where breakage occurs at the cannelure on impact.

gravelbelly


#17

[quote=“Ray Meketa”]CSAOED

I’ve always thought that the jacket was rolled over at the base of the bullet to finish the base with a smooth profile to aid in bullet seating and to help secure the core. Additionally, an unfinished or sharp edged base tends to form “fins” from metal displaced by the rifling, which in turn degrades accuray. As far as I know they were made that way since the beginning of small caliber high velocity military cartridges.

What I question is your statement that the seperation of core and jacket was, is, or has been a problem. I have never seen any references that would indicate such. I would rather see actual documentation than your suggestion that I get a machine gun, a supply of altered bullets, and shoot them to see for myself.

Some bullets like tracers and incendiaries do not have the rolled over jacket. Are they subject to jacket/core seperation? Could the 6.8mm solid base bullets be constructed that way for greater accuracy?

Ray[/quote]I suggest that you go back and examine the invention of the jacketed bullet and find what the problems were. The Europeans do not all agree on the inventor but last I heard Rubin was credited with the invention. You might ask yourself why the French continued to use SOLID bullets when the jacketed were available. The conjunction of high pressure physics , manufacturing necessity , 100 years of production and development and anecdotal experience don’t always smoothly mesh with logic or facts. You might want to reread my answer in TOTAL to the question of the first order.


#18

[quote=“CSAEOD”][quote=“Ray Meketa”]CSAOED

I’ve always thought that the jacket was rolled over at the base of the bullet to finish the base with a smooth profile to aid in bullet seating and to help secure the core. Additionally, an unfinished or sharp edged base tends to form “fins” from metal displaced by the rifling, which in turn degrades accuray. As far as I know they were made that way since the beginning of small caliber high velocity military cartridges.

What I question is your statement that the seperation of core and jacket was, is, or has been a problem. I have never seen any references that would indicate such. I would rather see actual documentation than your suggestion that I get a machine gun, a supply of altered bullets, and shoot them to see for myself.

Some bullets like tracers and incendiaries do not have the rolled over jacket. Are they subject to jacket/core seperation? Could the 6.8mm solid base bullets be constructed that way for greater accuracy?

Ray[/quote]I suggest that you go back and examine the invention of the jacketed bullet and find what the problems were. The Europeans do not all agree on the inventor but last I heard Rubin was credited with the invention. You might ask yourself why the French continued to use SOLID bullets when the jacketed were available. The conjunction of high pressure physics , manufacturing necessity , 100 years of production and development and anecdotal experience don’t always smoothly mesh with logic or facts. You might want to reread my answer in TOTAL to the question of the first order.[/quote]

There are many types of tracers and incendiaries including those with solid bases and side weep holes.


#19

Hi!

It is funny to see here an excerpt from my old(1981) book (almost entirely obsolete to-day) .Anyway (this is for Yuri and others), I confirm that the cannelure on this bullet jacket was made only for ID. I got the information years ago when I obtained this round from a very serious source and had it confirmed later by VPT people.

All the best to everybody on this extremely interesting forum!

Phil.


#20

Good to hear from Dr. Regenstreif. His book is long out of print and very much in demand, I would like to buy a few cases of them. To recap this point from my initial answer to this question quoted here “Sometimes such cannelures are used for identification but not as a standard practice”. The use of a cannelure for identification of a load is an uncommon practice. It is impractical in tactical applications and the COLOR TIP is the far more usefull and common standard to identify various loads. Many countries adopted color tip and color primer rings to identify loads on the same cartridge. I have additional documentation about this particular type of cartridge which I will post when I find it. In the mean time the facts remain. Projectile cannelures serve three major purposes; 1) to stabilize the structure of a jacketed bullet , 2) identification (rare) and 3) to act as a seat for crimping.