Which bolt action rifle actions are cock-on-closing vs cock-on-opening?

[ChronoCube]

I haven't seen a comprehensive list yet. Here's what I can think of off the top of my head:

Cock on opening:

• Mauser 98
• Mosin-Nagant
• Schmidt-Rubin / K31
• Springfield
• MAS-36

Cock on closing:

• Pre-98 Mausers (incl. Swedish Mauser and Arisaka)
• Lee-Enfield / Lee-Metford
• Older black powder rifles
• + P13/P14/M1917 Enfield
• + Rimfire T-bolt

There's a lot of other rifle types that I can think of for which I am not sure which category they fall into: Steyr-Mannlicher, Ross, Belthier, Gewehr 88, Carcano, Krag-Jorgensen, etc. Please feel free to continue to fill in the two lists.

 

[Mr_Pale_Horse]

IIRC the British 1914 and the US Model of 1917 were cock on closing.

 

[Vern Humphrey]

Correct. The P13, P14 and M1917 are all cock-on-closing.

Cock on closing is a more natural design -- if you were designing the first bolt action rifle, you'd probably make it cock on closing. Cock on opening, were a cam retracts the firing pin as the bolt is rotated, is a later refinement.

The disadvantage of cock on closing is that it is a rather slam-bang process. The sear catches the bent as the bolt is rammed forward and you need a lot of sear engagement to prevent the gun from firing on closing. That makes it more difficult to design a fine trigger pull.

In cock on opening, the bent is lowered rather gently onto the sear as the bolt is locked, and less sear engagement is needed.

 

[Pigspitter]

I have both a Mosin Nagant and a Lee-Enfield and I have to say that i much prefer the Lee. I find the Mosin's bolt requires way too much effort to cycle from the shoulder while the Lee takes a simple flick of the hand. The triggers on both guns are nothing special, but that's to be expected from old milsurps. I use both of these guns for hog hunting only, but I'd fell much more confident being able to take a second or third shot with the Lee.

 

[ChronoCube]

Ease of operation really depends on the overall action design, not just how it cocks. Mosins may be hard to cycle but a bent-bolt K98 action can be worked really quickly. Enfields are fast partly because the bolt turn is only 60 degrees instead of 90 degrees. You can't attain the same rate of fire with an Arisaka, for example.

 

[Coal Dragger]

Then we have the Blaser R93/R8 which is a strait pull with manual cocking for the first shot. Not sure how it is cocked after that.

 

[Waywatcher]

Thanks to Vern Humphrey, that makes a lot of sense.

Personally I think cock-on-opening bolts are easier to manipulate.

When you're doing a cock-on-closing it feels bouncy and like it is resisting being closed.

 

[Maverick223]

Personally I think cock-on-opening bolts are easier to manipulate.

When you're doing a cock-on-closing it feels bouncy and like it is resisting being closed.

I agree, but that is likely more a factor of what I am used to.

About all I can add to the list is that nearly all "modern" turn-bolts are cock-on-open, but nearly all are loosely (or in some cases closely) based upon the M-98 action.

 

[Float Pilot]

Cock on closing is a more natural design -- if you were designing the first bolt action rifle, you'd probably make it cock on closing.

It feels fine with the older Mauser actions which used weaker firing pin springs. If you replace a model 91-93 spring for a 24 pound m/98 Mauser spring then you are pushing against a lot more tension while ramming the bolt home.

The cock on opening design lets you use camming force to cock a heavier spring.

Plus, if you had a damaged or partially damaged sear the cock on closing model 91s or 93s, it might let the firing pin snap forward and set off the round before you are in battery. The improved m/98s will still let down the firing pin as well, but it will be cammed down slowly. Plus the later improved firing pin design will only go all the way forward when the bolt is fully closed.

 

[Norrick]

Rimfire T-bolt is cock on closing (the Japense made ones, not sure about older Belgian ones)

 

[ChronoCube]

It feels fine with the older Mauser actions which used weaker firing pin springs. If you replace a model 91-93 spring for a 24 pound m/98 Mauser spring then you are pushing against a lot more tension while ramming the bolt home.

I tried cycling an Arisaka Type 99 once and the spring felt very stiff. There was a lot of resistance when pushing the bolt forward. My arms got sore really fast because of the poor ergonomics when exerting this force. Is this normal on an Arisaka? Now that you mention swapping springs, I am wondering if the factory spring was replaced by a heavier spring.

 

[Pigspitter]

A semi related question. Does anybody else think Enfield bolts feel like they're just going to pop open when you fire the gun? it's so easy to flick the bolt arm that I'm always worried it's going to get shaken loose and eject the bolt square into my jaw. Am I being paranoid or could that actually happen?

 

[nathan]

I m more concern on the robustness of the bolt design. The mauser K 98 with its huge extractor claw is the best. The Lee Enfield is the least robust in my opinion. The bolt head is screwed to the bolt body. With constant turning and extracting spent shells and chambering the next round, those threads could get battered pretty bad. In the end you got a loose fitting bolthead and a new bolthead or bolt body is in order.

 

[jpwilly]

K31 cock on closing

 

[ChronoCube]

K31 cock on closing

How do you figure? I had put it (Schmidt Rubin) under cock on opening, because the action is clearly cocked when you pull the bolt back. Just look at the position of the firing pin relative to the bolt. If it is cock on opening, the firing pin will be in the back position without pushing the bolt forward.

Also, it's possible to cock the K31/SR rifle by carefully manipulating the bolt so that it rotates to unlocked position without extraction. Push the handle forward to rotate the bolt closed. At this point the action has been cocked without the back/forward motion.