Bolt action idea that I'm sure someone else came up with long ago

[Jubjub]

Bolt actions are either cock on opening (actually on bolt lift) or cock on closing. Neither one strikes me as ideal.

Cocking on bolt lift takes a lot of force to cam back the firing pin, and it comes at the same time that the bolt is doing the primary extraction of the fired case. It works best in an action with 90 degrees of lift, so that the work is spread out more. One of the comments that my uncle, who is a very experienced shooter, made about the Thompson Center bolt gun that he tried out was that it was nearly impossible to work the bolt with the gun at the shoulder, due to the cocking force being so high in the 60 degree action.

Cock on close is used in many actions, including the SMLE, which is renowned as a rapid fire bolt gun, but when you think about it, what you are doing is pushing the gun away from your shoulder due to the extra resistance during the forward stroke. Again, not the best solution.

What would seem to me to be ideal would be to cock the gun with the motion of the bolt being pulled back. Bolt lift angle would cease to matter, so a 60 degree or even less bolt lift would work smoothly. The resistance of cocking would pull the gun back into your shoulder. The forward stroke would just be feeding the round.

With that as my premise, the mechanical solution seems pretty straightforward: a hammer. There were several early bolt guns that used an external hammer, though for this wild notion it seems that an internal one would work best. Wouldn't it be pretty straightforward to put a fire control group something like what you would find in a semi auto into a bolt gun?

I know, what we have works fine, and not one shooter in a busload actually works a bolt gun with any speed. But still, a fella can dream. And in my dream I have a bolt gun that I can shoot faster than the one that fella designed in 1898.

 

[375shooter]

I like that idea. If a manufacturer came up with a good design, I would definitely have a close look at it.

 

[Bwana John]

Lock time would be more of a problem with a hammer than with a striker.

 

[Ohio Gun Guy]

^ I dont see why.


It wouldnt have to cock from the back of the bolt body, it could cock from a centered bolt carrier / bolt configuration. Think SKS with the gas rod removed. Add locking lugs for accuracy and streingth and a traditional bolt configuration and viola.....

I would like to see someone try this, its interesting.

 

[MetalHead]

Why not use a lever to pull the striker back near the end of the rearward travel? With proper lever ratios the last inch of travel could be used to pull back the striker the short distance needed for a modern light weight fast lock time system. The real engineering would be in having it be simple in function, manufacture and not so odd that market share is hurt.

 

[Top_Gunn]

How do those bolt-action rifles the Olympic biathlon people use do it? There is no lifting of the bolt: they just pull it back with their fingers and then (what it looks like on TV) release it and it goes back. Don't know what part of this cocks it. Whole point of those is to have something that's fast and can easily be worked without taking the rifle off your shoulder.

 

[Claymore1500]

I am trying to picture this idea in my mind, I am seeing this, an FN49, SKS or an M1 carbine type action with the gas system disabled.

You would need a bolt carrier ,as the bolt would have to be shortened enough to allow the hammer to contact the back of the bolt to effectively hit the firing pin, it could be made so the bolt carrier would rotate (unlocking the carrier from the reciever and unlocking the bolt from the carrier) then when you pull the handle back it would cock the hammer, move it forward and lock up the action then fire.

My honest opinion, a lot of unnesessary human interface that is already accomplished in a semi auto that does it all for you, and somewhat faster.

 

[Maverick223]

How do those bolt-action rifles the Olympic biathlon people use do it?

It is a toggle action, but I don't entirely know at what point it is cocked. I am certain that the lock time is very good, but I am pretty sure that they are striker fired. I too believe that lock time would be a problem if using a hammer, it may not be horrible, but markedly worse than a comparable striker fired rifle.

 

[LaserSpot]

I don't understand why straight-pull bolt action rifles never caught on; it sounds like a good idea.

The Ross rifle was a straight-pull bolt-action 0.303 inch calibre rifle produced in Canada from 1903 until the middle of the First World War.

"Although the Ross .303 was a superior marksman's rifle, it had many faults in the adverse environment imposed by trench warfare, and after numerous complaints the replacement of all Ross rifles in the three Canadian Divisions by the Lee-Enfield was ordered.

Snipers, however retained a considerable fondness for the weapon."

"Unlike the more common bolt actions found in the Mauser and Lee Enfield, the Ross action did not need to have the handle rotated a quarter turn before the bolt was pulled back, and this feature theoretically offered a higher rate of fire. In addition to this alleged advantage over the Lee Enfield, the Ross was also a pound lighter and could be disassembled more quickly without special tools"

http://en.wikipedia.org/wiki/Ross_rifle

I agree with Claymore; it's a bit late to reinvent the bolt-action now that the semi-auto has been invented.

 

[MetalHead]

reply to post #8

And that would be enough to make it a market failure, unless all the gun scribes fell in love with it.

 

[Maverick223]

I agree, the market is often driven by gun rags, not innovation. I agree with the straight pull design being superior in just about every way, it just didn't catch on for whatever reason, but fortunately the K31 is still out there and a fine rifle to boot.

 

[KodiakBeer]

The K31 Swiss is such a design and it's been around for 70 (?) years.

The speed of a bolt action is more about maintaining your sight picture than anything to do with working the bolt. The amount of recoil, stock design, and the skill of the shooter count for far more than the action of the bolt.

The cock on opening design like the Mauser 98 (when used properly), is simply slapped upward with the palm while the rifle is still in recoil, and then the back and forward motion effort is nearly effortless since the bolt is literally running on greased rails. By the time rifle is back on target, you're ready to shoot again. A bent bolt improves the speed of the mauser design so that the manipulation is even faster and easier.

With the Enfield, since the closing/cocking action is linear to to the rifles bore, doesn't affect sight picture either - and the cocking force is not enough to "pull it away from your shoulder".

Take a look at a K31 some time. It's a neat design and I wish I owned one, but... I have to wonder if used in a real war, would that toggle mechanism occasionally get gritty and affect reliability?

 

[jon_in_wv]

It sounds like a K31 Swiss to me. There is no reason a similar mechanism couldn't be made where the bolt is turned to lock manually instead of cammed like on the straight pull K31. This would cock the striker and allow a stronger locking and unlocking of the action, probably a stronger action too. The problem, in my opinion, is that better doesn't usually drive the market. The fact is it would have to be better to the effect that it compensates for higher cost of production and the higher sales cost and in the end it probably wouldn't affect the overall accuracy of the weapon so it might not be a huge selling point. The current actions are strong enough, accurate enough, and cheap to manufacture. This is probably the biggest reason something "better" hasn't come along.

The speed of a bolt action is more about maintaining your sight picture than anything to do with working the bolt.

Remember this only works if you fire with your head WAAAAY back from the action. In my normal shooting position, working the bolt on the K31 will produce a nice large raspberry on my cheek bone. (don't ask how I know this). I do have to take my head off the butt and away from the sight picture momentarily to work the bolt. It is still a very fast setup though. If it gets dirty the bolt doesn't have a lot of leverage on the round like a regular bolt action does so dirt and grime can make it a lot harder to manage. On the range it makes no difference though. If you dont' have one. GET ONE.

 

[Maverick223]

Take a look at a K31 some time. It's a neat design and I wish I owned one, but... I have to wonder if used in a real war, would that toggle mechanism occasionally get gritty and affect reliability?

Never fear, the K31 isn't a toggle action, it is a bolt action. The only difference is that the handle slides in a spiral groove in the bolt making it rotate without having to rotate the handle itself (you can see the cam pin on the handle in the groove on the bolt in the photo that you supplied)...clear as mud, right? The only problem with muck in the action of the K31 is the tight machining tolerances providing little room for debris (but also serving to keep most of it outside the action), and the reduced camming force because of the straight pull design. However these small disadvantages help play a big role in the speed and accuracy of the design.

 

[KodiakBeer]

Jon in wv: Remember this only works if you fire with your head WAAAAY back from the action. In my normal shooting position, working the bolt on the K31 will produce a nice large raspberry on my cheek bone.

I've never shot a K31, so I'll take your word on that. Perhaps you're the lanky sort that needs a shoulder pad insert? Bolt actions rifles are designed so that you shouldn't have to break your cheek weld, but shooters come in various non-standard designs...

 

[jon_in_wv]

I'm not an odd size. Look at the picture of the k31 with the bolt back. The ring on the bolt comes back a long ways when the bolt is to the rear.

 

[paducahrider]

Different type of bolt action.

Howdy!
There are many actions that have come and gone over the years which had considerable merit.
We tend to get locked into particular habits that can become hard to break, thus allowing us to overlook good solutions.
One previous design which had the features you desire, was the beautifully made Browning "T-Bolt", 22 caliber rifle, imported into the U.S from the mid 1960s through the mid 1970s.
It had a short throw, straight-pull action that had no real vices, but the price and the fact that it was "different" probably kept it from making a better showing.
Since good designs are occasionally retried in different markets, Browning has beat you to it, as they have re-introduced and expanded the "T-Bolt" line to include .22lr, .22 WMR and .17HMR offerings, in a variety of styles.
The t-bolt straight pull design is truly an example of how to do something with a minimum of motion and fuss.
I'm glad you recognize a good feature.
Thanks for your time.

 

[Hatterasguy]

Sounds like a K31 and K11, the Swiss have perfected the straight pull with the K31 but its been around over 100 years.

The only thing with the K31 is you need to watch that ring when your working the action or it will hit you in the face. The rifle was designed to be operated with gloves so everything is a bit oversized.