New member here, first post ever-  not sure exactly where this sort of topic should be posted so please move or advise as needed.....  On an AR15 with adjustable gas block, it seems that as the gas is closed off, the BCG's rearward force into/against buffer and buffer spring is reduced, and the shooter feels less recoil.  As far as my understanding goes- to get the softest shooting rifle with least possible muzzle movement and/or recoil, this limiting of gas being sent to the action is one of the main ways to accomplish this.

So as we dial down the gas to the bare minimum needed to just cycle the action fully... we achieve the optimal setup in terms of felt recoil.... is this correct?  And if the gas is completely shut off to the point of not even cycling the action at all, we have basically now got a bolt action rifle, correct?

It also seems to be the general consensus that for the same caliber and ammo, a bolt action rifle will have more recoil than a gas operated rifle.... yea or nay?  What gives?

Still got a lot to learn. Most everything I have learned began from my searches here, and then my practicing in the field and at the workbench.  Thanks for all the advice y'all have put up for all these years, and for any of ya that want to respond here.

There is recoil and then there is felt recoil.

Two guns weighing the same launching the same bullet at the same speed will have the same recoil . as you mess about with a gas gun and its action the felt recoil can change for various reasons , partly due to the time recoil is felt

just get a big muzzle brake and call it a day.

I've never really understood the concern of recoil with an AR.

This question was posted - not to solve a problem of 'too much recoil' of my AR - but to help further my understanding of the mechanics at work in different rifle systems and how they contribute to felt recoil.

I still have a lot to learn, and I thoroughly enjoy building, tweaking, and shooting rifles.  

Thanks for the responses.  

Yep, I have a muzzle brake intalled also to help me tame this heavy recoiling beast of a 5.56

As stated, there is felt recoil and recoil.

With a bolt gun the felt recoil is the same as the bullet induced recoil.

In a automatic, or semi-automatic, you have to several things influencing the felt recoil.  The total felt recoil is the sum of the recoil due the the bullet and propellant gases moving forward (positive value), the recoil of the bolt mass moving backward (negative value), the impact force of the bolt mass when (or if) it bottoms out (positive value), and the recoil of the bolt mass moving forward on the counter-recoil stroke (positive value).  How this is perceived by the shooter depend on how fast the impulse is delivered, when the impulses are delivered,as well as the actual magnitudes involved.

Generally, by reducing the amount of gas introduced to the system, you are reducing the felt impact force of the bolt mass when it bottoms out in the receiver extension and slowing down the the speed in which the impulses are delivered, a long slow push, as opposed to a hammer-blow.

I was a bolt rifle guy first, like many shooters.  My biggest surprise with my .308 AR10's was how soft they "felt" compared to my Savage .308 bolt rifle in terms of recoil.  I think some have already pretty well explained how the gas control and energy absorption of a BCG, buffer, and spring all contribute to how the recoil impulse is dampened in an AR design.  The other issue is weight of many of the bolt platforms vs. the AR.  My Savage bolt rifle was just under 7 pounds without a scope.  My AR10 is about 9 pounds without glass.  That alone aids in felt recoil.

On the gas control in an AR10, the length of the gas system also contributes to the ability to optimally tune the amount of gas which aids reduced recoil.  My 20" AR10 has a rifle gas length and doesn't need an adjustable gas system.  My 16" AR10 has a mid-length gas design, and it benefited slightly from an adjustable gas block.  It wasn't absolutely necessary, but it did allow the recoil to be softened a bit...which was also easier on brass for reloading.

Great info. Thanks for the reply.

Yes because the recoil is gradualized

(in addition to a very slight forward push in the gas port, but that's very slight)

Think of the gas as pushing the rifle forward away from you against the bolt (which moves twords you)

And since the bolt is traveling on a big-ol spring it makes a very gradual push rather than a snap

....

Lastly, most bolt actions have the barrel line just over the shoulder stock top, this causes a slight rotation and concentrates the recoil on the top of your shoulder

.... While the AR has a barrel well below that line, which makes a more strait-back kind of recoil (using your whole shoulder)

Very good illustration of how each rifle is set up.  Thanks.

 

I'm really hoping your being sarcastic.....

Don't be silly, the 5.56 has the sheer-power to drop a rabbit in as little as 2 hits

Um, yeah, you can rest easy now. It indeed was a bit of sarcasm.

For my application,  the 5.56 is the all around perfect caliber.  My targets are small to medium (2-40lbs) varmints/rodents. Crows, groundhogs, coyotes.... mostly 100ish yard shots, occasionally out to 3 or 400 but not near as often.

Readily available ammo and lots of bullet choices at fair price appeal to me. Also, this whole talk of recoil, is to me about watching bullet impact thru scope and faster easier follow up shots