Cocks on Opening/Closing

Uncle Fester

While reading a story about a new hunting rifle, I noticed that the author advised readers that it cocks on opening.

For the life of me, I can’t understand why I would care if my bolt action rifle cocked on open or on close.  Thoughts?

earlyagain

To the best of my memory. I've never shot a rifle that cocked on close. Other than reading the thoughts of others, I'm without experience from which to form opinion.

Justsomedude

I prefer cock on opening so that the brunt of the force to do so is pulling the gun into my shoulder and not away from me.

Bigslug

If I have an option, I VASTLY prefer cock on close, as seen in the Lee Enfields, P14 and 1917 Enfields, and early Mausers.

Several reasons for this:

1.  When breaking a fired case loose from the chamber, you are not adding the force of cocking the striker spring to the effort of primary extraction.

2.  With cock on close, you have a running start going forward before the cocking tab on the striker hits the sear to start compressing the spring.  With cock on open, you have to start squeezing the spring from a dead stop.

3.  The extra force needed to cycle SOME cock on open systems causes a lot of folks to slap the bolt handle upwards with their palms.  Ideally, you should be operating the bolt with the thumb and first knuckle of your trigger finger - a lot less motion required to do this, and no challenge at all on the cock on close system.

In a nutshell, there's less effort involved in running a COC rifle, making them faster to cycle.

To get a little extra nerdy, the COC systems are not FULLY COC:  as a safety measure, they retract the firing pin slightly on bolt lift so that the tip is not protruding through the breech face, elliminating the chance of an out-of-battery slam fire.  The bulk of the cocking effort is done on the way forward.

While not a function of the cocking system, the Lees are extra speedy because they have a less-than-90-degrees bolt lift and rear locking lugs that reduce the amount of necessary front/rear travel.

The 1914/1917 action's bolt lugs are basically an interrupted screw thread, making for A LOT of leverage to break a case loose from the chamber.

It all combines for a couple of GREAT systems.  I wish we'd see more of them in modern guns.

Varmintmist

I run both on vintage rifles in matches.

I HATE cock on close. I can run a 03A3 a heck of a lot faster than the m1917. To get 10 off in 80 seconds from standing to prone and a reload with any kind of accuracy I need ALL of the time. Might be faster if you are not trying to aim with any significance, but in a hurry with accuracy, COC with a M1917 action is slower.

COC pushes the butt out of position when in prone. You WILL NOT run that bolt with a finger and thumb. It goes fwd and then you push through the wall.

Gene L

Big Slug is right...on military rifles.  Although the British had a choice,  they went to CoC.  Faster and the other traits as listed above.  However, CoO replaced the system in everywhere but Great Britain. 

For hunting, speed isn't generally a factor.  I wouldn't let either method keep me from a good deal.  I have both types and they both work fine.

Big Al1

CoO and a controlled feed, also provides a camming action that helps extract the fired case, helpful in a combat situation, (or hunting dangerous game) where a case may stick due to dirt, etc!! 

Pegasus

Varmintmist said:

I run both on vintage rifles in matches.

I HATE cock on close. I can run a 03A3 a heck of a lot faster than the m1917. To get 10 off in 80 seconds from standing to prone and a reload with any kind of accuracy I need ALL of the time. Might be faster if you are not trying to aim with any significance, but in a hurry with accuracy, COC with a M1917 action is slower.

COC pushes the butt out of position when in prone. You WILL NOT run that bolt with a finger and thumb. It goes fwd and then you push through the wall.

Hey VM, I thought I would bring up the term "Mad Minute".

Mad minute - Wikipedia

Varmintmist

Pegasus said:

Varmintmist said:

I run both on vintage rifles in matches.

I HATE cock on close. I can run a 03A3 a heck of a lot faster than the m1917. To get 10 off in 80 seconds from standing to prone and a reload with any kind of accuracy I need ALL of the time. Might be faster if you are not trying to aim with any significance, but in a hurry with accuracy, COC with a M1917 action is slower.

COC pushes the butt out of position when in prone. You WILL NOT run that bolt with a finger and thumb. It goes fwd and then you push through the wall.

Hey VM, I thought I would bring up the term "Mad Minute".

Mad minute - Wikipedia

""Lying. Rifle to be loaded and 4 rounds in the magazine before the target appears. Loading to be from the pouch or bandolier by 5 rounds afterwards. One minute allowed".

"The "Second Class Figure Target" was 48 inches square (approximately 1.2 x 1.2 meters), with 24 in (61 cm) inner and 36 in (91 cm) magpie circles. The aiming mark was a 12 in × 12 in (30 cm × 30 cm) silhouette figure that represented the outline of the head of a man aiming a rifle from a trench. Points were scored by a hit anywhere on the target."

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Again, I said with accuracy. The second time I have shot the rifle in comp I kept all under 13" and a lot under 7" at 200 yds. Not 48". Its still a pretty interesting feat, starting from prone with the rifle rested even, but missing fast is still missing.

mitdr774

I prefer COO.  I have never had an issue making a quick follow up chambering for a potential follow up shot.  I have used both for hunting.  Neither really bothers me but I prefer a COO.

joeg52

Again, I said with accuracy. The second time I have shot the rifle in comp I kept all under 13" and a lot under 7" at 200 yds. Not 48". Its still a pretty interesting feat, starting from prone with the rifle rested even, but missing fast is still missing.

To quote someone who is sometimes revered and sometimes hated "you can't miss fast enough to catch up".

Bigslug

Varmintmist said:

Pegasus said:

Varmintmist said:

I run both on vintage rifles in matches.

I HATE cock on close. I can run a 03A3 a heck of a lot faster than the m1917. To get 10 off in 80 seconds from standing to prone and a reload with any kind of accuracy I need ALL of the time. Might be faster if you are not trying to aim with any significance, but in a hurry with accuracy, COC with a M1917 action is slower.

COC pushes the butt out of position when in prone. You WILL NOT run that bolt with a finger and thumb. It goes fwd and then you push through the wall.

Hey VM, I thought I would bring up the term "Mad Minute".

Mad minute - Wikipedia

""Lying. Rifle to be loaded and 4 rounds in the magazine before the target appears. Loading to be from the pouch or bandolier by 5 rounds afterwards. One minute allowed".

"The "Second Class Figure Target" was 48 inches square (approximately 1.2 x 1.2 meters), with 24 in (61 cm) inner and 36 in (91 cm) magpie circles. The aiming mark was a 12 in × 12 in (30 cm × 30 cm) silhouette figure that represented the outline of the head of a man aiming a rifle from a trench. Points were scored by a hit anywhere on the target."

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Again, I said with accuracy. The second time I have shot the rifle in comp I kept all under 13" and a lot under 7" at 200 yds. Not 48". Its still a pretty interesting feat, starting from prone with the rifle rested even, but missing fast is still missing.

The Mad Minute needs to be understood in context.  It was one drill among a whole bunch that made up the pre-WWI British qualification, and it you had a bunch of guys performing competently on all of that, you were fielding a formidable body of troops.

Doctrinally, the Mad Minute came about from a severe lack of Vickers machine guns.  The idea was that an officer could quickly deploy five or ten guys, tell them to run their sights to a desired distance and each fire five rounds to beat the living hell out of a designated target.  Functionally equivalent to the water-cooled belt-fed you unfortunately do not have, and easier to lug and faster to set up as well.

The target used was fairly forward-thinking too.  Yes, you got max poins for hitting the prone man silhouette, but you also got points for hitting the simulated ground in front of the silhouette, the idea being that a solider killed by a bounce or blinded by gravel or jacket fragments is no longer a problem - just as good, practically.  Much like the Highpower Rapids, it's a pretty good game for teaching you to balance your speed with a little bit of control.  Unlike Highpower Rapids, "accuracy" was directly about incapacitating a human-sized target, and less about grouping on an arbitrary one.  The precision was there when they wanted it, but the Mad Minute was about suppression.  The thing here is that the mechanism was really good for both.

I've not experienced this "pushing forward out of the shoulder when cycling" you speak of.  The left hand is what keeps the rifle mounted, so a bit of rearward pressure there does the trick.  What I HAVE experienced with Lee Enfields is that their smooth buttplates and low-comb stocks tend to slide downward out of your shoulder pocket under recoil.  Haven't quite got that sorted out yet.

Varmintmist

One black spot is no less arbitrary than another black spot. A hole in the black circle is no different than a hole on a black silhouette. Both are about putting holes in the target, IE the bad guy as quickly as possible. One is to actually make hits and it aint the mad min. To call one arbitrary makes as much sense as saying you cant practice for deer hunting unless the target looks like Bambi.

With the mad min you also get points for hits high, left, and right which would snap over or around the head of a person in a trench by a pretty wide margin. Very similar to the 5V which we used and the US was known for its accuracy and ability to make hits. Any hit scores a 2 even though there is no way it would have been effective.

The mad min is impressive for tossing rounds down range, but that is about it. Its suppression. You MAY be able to do that faster with COC but if you hit the target with COO, you dont have to.

Maybe my 1917 has a different spring, but you WILL NOT run it with your thumb and finger. You need to force the bolt the last bit and that takes the butt out of position because you need to move your right arm to much and takes your bolt elbow away from a solid rest. COO I roll out to the right, run the bolt, and roll back in. Butt, right and left elbows stay in place. I have never had a problem losing position under recoil with any steel butt plate. Pressure from the off hand and good position controls that.

None of which has any bearing on a COC on a hunting rifle BTW.