Bolt actions - Why did cock-on-opening become the standard?

[HowieG]

Most modern bolt guns cock the firing pin spring when lifting the bolt handle.



Dosent cover the mechanical difference, but does a decent job of covering the operational difference.

I personally dont care for cock on close actions. Ive almost exclusively used cock on open, and the few cock on close, or partial cock on close, Ive used have felt wierd to me.
I could love everything about a gun, but if it were cock on close I don't think id buy it.

I once felt the same as you. What will change you is if you experience a mad minute with a SMLE. The SMLE is ugly as hell, but yeah buddy, that gun can put some downrange. It has almost autoloader like extraction. So, now I have an open mind. I have some cock on open rifles that are just attrocious. Here is how I think now. If I want to maintain fire superiority in the trenches, then cock on close. If raw speed doesn't matter, then the rifles with cock on open ALL look better than the usual cock on close jobs (SMLE, 1917 Enfield, etc.

My favorite cock on open actions are the Cooper M54 and the Tikka T3. Very slick. The speed point is moot now with all of the AR15 and AK47 rifles.

 

[Archie]

Two questions raise their head in this thread.
At least one person said

I never paid attention to when my bolts cock. I always thought they cocked when you close the bolt.

In reality, this is correct. (If all goes properly) the firing pin is always 'cocked' when the bolt is closed and rotated (or however else it may be locked), Here's the difference: "Cock on opening" rifles use the operation of opening the bolt to compress the striker spring. There's an angle in the rear of the bolt that forces the spring to be compressed when the bolt is rotated to the 'unlocked' position. "Cock on closing" compresses the striker spring in the last bit of bolt travel forward, then the bolt is turned and locked.
Without going into detail, there is and has been a constant 'discussion' (maybe argument with fists and stuff) about which is better since about 1908 - when the Mauser model '98 was announced. That's a whole thread - or series of books - in itself.

Why did cock on opening become the standard? I cannot prove it, but that's never stopped me before...
When the '98 Mauser come on line, the bolt had a third - safety - lug added to the bottom of the bolt to further protect the shooter from locking lug failure and the bolt being wedged into the shooter's face and head. With that safety lug, the '98 Mauser (and the myriad of actions based thereon) have been recognized as 'stronger'. This seems to have put the idea of 'cock on opening' and 'stronger' having the same meaning. Between the Mauser 'small ring' and 'large ring' this may or may not be valid. I don't think the actual locking lugs were changed. They are both equally (with the meaning of the act) strong.
With current metallurgy and manufacturing practice, I suspect one is as strong as the other.
And, the 'cock on opening' was a later development, so it appeals to the 'newer' school of thought. Go figure. It also - for manufacturers - seems to be 'more finished' and 'classier'.

 

[Picher]

I like cock-on-opening rifles, which is used on about all commercial rifle actions. I wouldn't buy a rifle that cocked-on-closing because I don't like that kind of action. They all seem to have a jam, because I'm not used to them. I like "cock-on-opening" because I feel that, when closing on loading from the magazine, I can feel misfeeds better and don't have to use as much force...that can make misfeeds worse.

"You make your choice and pay your dough!"

 

[LoonWulf]

I once felt the same as you. What will change you is if you experience a mad minute with a SMLE. The SMLE is ugly as hell, but yeah buddy, that gun can put some downrange. It has almost autoloader like extraction. So, now I have an open mind. I have some cock on open rifles that are just attrocious. Here is how I think now. If I want to maintain fire superiority in the trenches, then cock on close. If raw speed doesn't matter, then the rifles with cock on open ALL look better than the usual cock on close jobs (SMLE, 1917 Enfield, etc.

My favorite cock on open actions are the Cooper M54 and the Tikka T3. Very slick. The speed point is moot now with all of the AR15 and AK47 rifles.

Ive shot one a few times, but im not familiar enough with them to be significantly faster than I am with a relatively smooth cock on open turn bolt.....at least for aimed fire. Just dumping rounds in the general area it felt alot easier with the LE.

 

[Varminterror]

the '98 Mauser (and the myriad of actions based thereon) have been recognized as 'stronger'. This seems to have put the idea of 'cock on opening' and 'stronger' having the same meaning.

I’ve had the cock-on-close vs. open debate many times over the last ~25yrs, and this is the first I have ever heard this hypothesis presented. It certainly hasn’t been listed as the major driver for subjective preference among those on the pro COO side, and not even mentioned as an aside during the discussion.

 

[westernrover]

The recognition of "stronger" has been a result of locking lugs on the front of the bolt rather than the rear. This perception may have been inherited from lever action rifles where some front lug designs are stronger than other rear lugged designs. It is not related to where in cycling the action the mainspring is compressed or the rifle cocked. However, because the Lee Enfield has the locking lug on the rear of the bolt and it is a popular cock-on-close action, maybe the two things were conflated and the conclusion was drawn that cock-on-close results in a weaker action. There is no truth to it.

 

[HowieG]

Ive shot one a few times, but im not familiar enough with them to be significantly faster than I am with a relatively smooth cock on open turn bolt.....at least for aimed fire. Just dumping rounds in the general area it felt alot easier with the LE.

That technique in the video earlier in this thread is the way to do it. The exercise was actually a formal training evolution according to the British Army's Practice number 22, Rapid Fire, The Musketry Regulations, Part I, 1909. It was a scored exercise. The range was 300 yards.

 

[Archie]

I’ve had the cock-on-close vs. open debate many times over the last ~25yrs, and this is the first I have ever heard this hypothesis presented. It certainly hasn’t been listed as the major driver for subjective preference among those on the pro COO side, and not even mentioned as an aside during the discussion.

You are quite likely correct - in the past ~25 years, at least in the main. But it remains true the appearance of the '98 Mauser did affect some in that manner.
I will even agree there is no theoretical difference between the strength of the two designs. Not in reality, either. The real effect is perception and that also sets the stage for long term production by manufacturers.
I submit your or my opinion does not materially change the corporate decision of the "Really Big Time [anything] Manufacturer".

 

[Archie]

The recognition of "stronger" has been a result of locking lugs on the front of the bolt rather than the rear. This perception may have been inherited from lever action rifles where some front lug designs are stronger than other rear lugged designs. It is not related to where in cycling the action the mainspring is compressed or the rifle cocked. However, because the Lee Enfield has the locking lug on the rear of the bolt and it is a popular cock-on-close action, maybe the two things were conflated and the conclusion was drawn that cock-on-close results in a weaker action. There is no truth to it.

Quite so. The SMLE and all the Lee-Enfield rifles were tarred with this brush for years. The same manufacturing tolerances that allowed ammunition fired in those rifles to deform and abuse brass assisted in the reliability in the field. As one who has done that sort of thing, I prefer having an arm that will fire every time to one from which I can collect brass for reloading. And on that subject, the lever guns that were relatively weaker than others and the SMLE and kin were stout enough to do as they were designed.

 

[Mosin77]

I like the feel of cock-on-opening actions better myself. I suspect many others are the same, and I suspect this is all it takes to explain their dominance in the market today. Witness the many shooters who spent time and money converting their perfectly useable model 1917s from cock on close to cock on opening. There are also the theoretical reasons of safety described already in this thread, and the fact that when you close the bolt on a cock-on-opening design it’s far less disruptive to your sight picture, which really lends the cock-on-opening a lot of useability in a civilian context.

Theoretically, if you have a sticky case, a cock-on-opening action might make it harder to open the bolt, because you have to apply enough force to cock the striker as well as to initiate primary extraction. Equally theoretically, a cock-on-closing action is supposed to be a little faster to operate, when the number of rounds fired in a minute might matter greatly. The argument goes that you need to push the bolt closed anyhow, so you may as well make that movement do double duty by pushing a bit harder to cock the gun. So, in a military context, when things like action speed and out-of-spec cases are big considerations, cock-on-closing appears to bring something to the table, which is why it was favored by some countries.

The Brits liked it for its speed advantage. The Japanese adopted it for the same reasons. Paul Mauser used it for his earlier designs, then decided that cock-on-opening was better for his magnum opus, the 1898 action. The US took great pains to make our clone of the ‘93 Mauser, a cock-on-opening.

In practice the Lee-Enfield is it’s own animal, and is the only gun that really has a decisive speed advantage with a cock-on-closing design, in my opinion. All the rest (like the Mauser designs that form the basis for most of our modern designs) require more deliberate operating motions which really negate most of the advantages that a cock on closing action might provide.

In other words, handle an SMLE and you’ll too be singing the praises of the cock on closing design. Then handle a 93 Mauser or Arisaka, and you’ll feel like the action moves at its own pace and you aren’t gaining as much. The Arisaka particularly is a bear to close which makes it feel like your muzzle is sweeping all over creation as you muscle that bolt home.

 

[Thomasss]

My dad (2nd Marine division) brought home an Arisaka from WW II. Us kids played cowboys and Indians with it when growing up( Never had any ammo for it). The only tension felt was just before the bolt closed. I also target shot a Pattern 17 for a year and found a heavy tension an inch before the bold closed. I shoot a Rem. 700 in 30.06, & Win Mod.70 in .270 Win. for most of my life and prefer them. Recently a gunsmith told me the Enfield is a great gun to upgrade because of their strong actions. And a relative has used one for deer hunting, 50 plus years. He did say ya give them a little extra umph to close the bolt.
The bottom line is you shoot what you are use to shooting...period!

 

[tark]

First, in response to "Of course I have never heard an account of such a thing. I have seen auto loaders slam fire though, and if a bolt rifle slam fires its much more catastrophic." All the bolt action centerfires that I know of have the rear of the bolt where it cams the cocking piece (or doesn't with cock-on-closing) shaped such that the firing pin cannot reach the bolt face unless the bolt is closed. I made my scratch-built with that feature too.View attachment 1093946 View attachment 1093947

That is a fine looking piece of work jdsingleshot !! And in 25-20, one of my favorite calibers. I have three, A Savage 23C, a Remington model 25 pump and a home made pistol.

 

[HowieG]

I like the feel of cock-on-opening actions better myself. I suspect many others are the same, and I suspect this is all it takes to explain their dominance in the market today. Witness the many shooters who spent time and money converting their perfectly useable model 1917s from cock on close to cock on opening. There are also the theoretical reasons of safety described already in this thread, and the fact that when you close the bolt on a cock-on-opening design it’s far less disruptive to your sight picture, which really lends the cock-on-opening a lot of useability in a civilian context.

Theoretically, if you have a sticky case, a cock-on-opening action might make it harder to open the bolt, because you have to apply enough force to cock the striker as well as to initiate primary extraction. Equally theoretically, a cock-on-closing action is supposed to be a little faster to operate, when the number of rounds fired in a minute might matter greatly. The argument goes that you need to push the bolt closed anyhow, so you may as well make that movement do double duty by pushing a bit harder to cock the gun. So, in a military context, when things like action speed and out-of-spec cases are big considerations, cock-on-closing appears to bring something to the table, which is why it was favored by some countries.

The Brits liked it for its speed advantage. The Japanese adopted it for the same reasons. Paul Mauser used it for his earlier designs, then decided that cock-on-opening was better for his magnum opus, the 1898 action. The US took great pains to make our clone of the ‘93 Mauser, a cock-on-opening.

In practice the Lee-Enfield is it’s own animal, and is the only gun that really has a decisive speed advantage with a cock-on-closing design, in my opinion. All the rest (like the Mauser designs that form the basis for most of our modern designs) require more deliberate operating motions which really negate most of the advantages that a cock on closing action might provide.

In other words, handle an SMLE and you’ll too be singing the praises of the cock on closing design. Then handle a 93 Mauser or Arisaka, and you’ll feel like the action moves at its own pace and you aren’t gaining as much. The Arisaka particularly is a bear to close which makes it feel like your muzzle is sweeping all over creation as you muscle that bolt home.

In reality, my experience has shown that it doesn't matter if you have cock on open if an over pressured case gets stuck. What that happened to me, I couldn't begin to even life the handle. It never ever got to the cock point. Had to wrap on the handle smartly with a soft mallet to break the case loose from the chamber walls.

 

[Mosin77]

In reality, my experience has shown that it doesn't matter if you have cock on open if an over pressured case gets stuck. What that happened to me, I couldn't begin to even life the handle. It never ever got to the cock point. Had to wrap on the handle smartly with a soft mallet to break the case loose from the chamber walls.

I agree -a stuck case is a stuck case, and the marginal effort required to cock the striker isn’t something to even worry about. You have to muscle the bolt open (to a small extent) anyhow, so a bit of cocking at the same time is no big deal, and gives the bolt a great feel.

 

[Hikingman]

When one of my straight pull bolts (Swiss K31) reaches the forward position, it cocks. There is also economy of motion, tendency to stay on target, and faster shooting compared to other bolt actions.

 

[Slamfire]

When the '98 Mauser come on line, the bolt had a third - safety - lug added to the bottom of the bolt to further protect the shooter from locking lug failure and the bolt being wedged into the shooter's face and head. With that safety lug, the '98 Mauser (and the myriad of actions based thereon) have been recognized as 'stronger'. This seems to have put the idea of 'cock on opening' and 'stronger' having the same meaning. Between the Mauser 'small ring' and 'large ring' this may or may not be valid. I don't think the actual locking lugs were changed. They are both equally (with the meaning of the act) strong.
With current metallurgy and manufacturing practice, I suspect one is as strong as the other.

While I have not measured them, I am sure the lugs and receiver seats are the same thickness and the same steels in small ring Mausers and large rings. From that aspect they should take the same amount of shear, therefore: same strength.

If you read Stuart Otteson's book The Bolt Action: A Design Analysis, his section on the M98 is particularly long, as Mr Otteson used the M98 as a baseline for good design features. The M98 is superior in safety with its gas handling and third lug. The receiver collar is thought to improve strength and gas venting, but no one has run a CAD/CAM showing it does. I talked to a gentleman who was involved in the lawsuit investigation of a M1888 GEW import, and it was one of the rare ones that was left in .318 caliber. The owner put in 8mm Mauser ammunition, because the rifle had been sold as 8mm Mauser, chambered the .323 round, and the bolt sheared its lugs. As the GEW 1888 did not have a safety lug, the bolt went through the shooters jaw and shoulder. Much pain and agony. I have found on the web, a claim that bolt blowing leading to the deaths of Swedish soldiers was the reason Sweden flushed its Arsenals of all those Swedish bolt actions. The same poster showed a Swedish bolt, minus the lugs, that killed an Australian civilian. .

My Mauser M1871 is buried in the safe, but I think it was a cock on opening. Someone know better?

 

[Archie]

No, I confess I haven't read Otteson's book. I do have an m1888 rifle, converted to the "S" configuration, modified to be more or less a stripper clip fed magazine and surplussed to Turkey (Ottoman, I believe. I have shot it a bit and it seems to handle 8x57mm Mauser without a hitch.
Strikes me as odd that the 'wrong' round would break both lugs on the bolt in such a manner. I can understand cracking one or both lugs, bulging the chamber and damaging the rifle, but to have both bolt lugs shear makes me suspect a problem with manufacturing or metallurgy in addition to the somewhat over sized bullet.
At the same time, my sympathy is with the gentleman injured. That sounds painful way over here.
Swedish Mausers? I have five Swedes currently. Two 1894s (one modified, one stock) two 1896s (one modified, one stock) and a stock 'updated' M1938 (I think) rifle. I've never heard of this sort of breakage being a problem. But I'm young yet.

I used to have a M1871/84 (with Kropatschek magazine) I regret selling. I really cannot swear if it was an 'opener' or a 'closer'. My mind seems to suspect it was an 'opener' but I wouldn't swear to it.

All this considered, reality does not mean much to 'perception'. The reason the '98 Mauser action is stronger than predecessors is the addition of the third lug. Cock on opening or closing does not make the action stronger.

 

[lysanderxiii]

My Mauser M1871 is buried in the safe, but I think it was a cock on opening. Someone know better?

Yes, it is a cock on open system.

 

[Slamfire]

Strikes me as odd that the 'wrong' round would break both lugs on the bolt in such a manner. I can understand cracking one or both lugs, bulging the chamber and damaging the rifle, but to have both bolt lugs shear makes me suspect a problem with manufacturing or metallurgy in addition to the somewhat over sized bullet..

There were plenty of problems with manufacturing and metallurgy in the 1890s and through WW1. I don't know when process technology because mature, but the process controls back in Paul Mausers day were primitive, mostly based on human perceptions, such as smell, touch, and eyeballs. Springfield Armory had one pyrometer, used for sight base leaf springs. It is probably that they did not even use pyrometric cones to set up the forge ovens. So billet temperatures were judged by eye. And, Springfield Armory paid forge shop workers piece rate, so the stampers had a perverse incentive to crank the heat up, to stamp out parts faster. Which lead to a lot of burnt forgings. This was all whitewashed by the Army, but we know from Hatcher's Notebook that production basically stopped in 1918 as the production lines were revamped. And reports of blown up low number 03's continue to surface.

Look at the book "German Military Rifles , 88 and 91 firearms" by Dieter Storz. Mr Storz has a significant section on the "Judenflinten" (Jewish Gun) scandal and metallurgical failures of the 1888 Commission rifles. The 1888 was an early smokeless rifle, the metals of the era, plain carbon steels with a lot of slag and impurities, and the occasional Ludwig and Loewe made 1888 blew up. So did the occasional 1888's made by other manufacturers. But the fact that Ludwig and Loewe were Jewish owned, allowed German Anti Semitics to claim:

The next scandal was caused by a pamphlet of (Hermann) Ahlwardt, “ Judenflinten,” (jewish guns) in which he accused the armament firm of Ludwig Lowe of being bribed by the Alliance Israelite of Paris to deliver inferior guns to the Prussian Army , so that the latter might be defeated in the next war of revenge. The falsity of the charge was proved by a Government official, but it was not until after thousands of copies of the pamphlet had been sold in the streets that it was confiscated, and Ahlwardt, after prosecution, was sentenced to five months imprisonment

Anti-Semitism in Germany. Israel Cohen, 1918
https://archive.org/stream/antisemitisminge00cohe/antisemitisminge00cohe_djvu.txt

 

[Archie]

In Hatcher's Notebook Major General Julian Hatcher reports on the heat treating problem of M1903 receivers during manufacture. Metallurgical (including final processes) are well documented. To my suspicious mind, that implies other nations had the same sort of difficulties.

 

[Bcwitt]

A COC can skip the sear if rammed home hard enough. I have never hear of that happening w a COO.

 

[Bcwitt]

About the time COOs were developed, steel quality improved greatly. They tend to have much stronger springs & shorter striker strokes. They really smack hard.

 

[Bcwitt]

The Germans pretty much perfected ordnance steel by the early 1890s.