The AR-15 design incorporates weights inside the buffer. These weights slow the action and reduce the cyclic rate.

Another function of the weights is to reduce or prevent bolt bounce. The weights are able to slide inside the buffer, which lets the weights slam forward just after the bolt closes.

Do any other rifle designs have problems with bolt bounce?

Do any other rifle designs use this system of sliding mass to prevent bolt bounce?

If they don't use this system, how do they prevent bolt bounce?

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Interesting question.  I wonder which came first, the buffer weight or the deadblow hammer. 

I know of no production weapon that had a bolt bounce problem.

Exactly.

I'm just trying to figure out why the AR is susceptible to bolt bounce and why other designs don't seem to take bolt bounce into account at all.

Almost all HK G3/9x series firearms have a buffer in the stock. There were some other designs that included moving weights inside the bolt carriers. In some designs, there's enough friction/drag to make it a non issue.

Part of the susceptibility of the AR15 type to bolt bounce is the nature of having all the parts arranged in a very linear fashion, and the simplified nature of the parts and receiver. Most any other design has some of that extraneous energy being dissipated in non-linear/yawing motions, with some friction etc. None of that wasted motion in the AR15, so there's a little bit of bounce that is controlled via a buffer.

I will google the G3 buffer system. I had thought there wasn't anything in the stock because so many of that design have a collapsible wire stock.

The non-linear yaw/friction makes sense. It is interesting that one of the ingenious parts of the Stoner design, its straight line action, is a weakness when it comes to bolt bounce.

Lots of mechanisms include buffering. It's just reality. The plumbing in your house likely has buffers.

Sure, I've just been wondering how other designs deal with the weight and reciprocating mass part of buffering, not so much the little rubber piece that keeps metal from hitting metal part of buffering.

Usually, the buffer is a really stiff spring, if the intent is to reutillize the recoil energy:



Or, a hydraulic damper if the intent is to dissipate the energy:



Interesting fact about the MG-42, the mainspring's sole function is to load, chamber and fire the first round, after that, all the energy required to keep the gun firing is from the bolt rebounding off the buffer.

That is interesting, thanks.

From what I remember, the history of the "Carbine" wasn't pretty. The M16 rifle was "perfect" in that they could cycle the M193 ball ammunition perfectly and it could do so in full automatic. When they tried to shorten it by cutting the barrel (what is now known as the dissipator), they found that they had to time the dwell just right so enough gas is coming back to cycle the bolt. In automatic, the gun wasn't very reliable.

The original Vietnam era CAR-15s were made with a specialized muzzle that acts like a suppressor (thus why we can't get true clones without having to go through the NFA). It cycles the bolt by allowing enough gas to go back and cycle. Throughout the years, the carbine version of the M16 went through many iterations and eventually became as reliable as their big brother in full automatic without excessively over heating in normal firing.

Eventually through experimenting, they figured out how to master the carbine length. However, after decades of using it, and because Tungsten steel were somewhat of a pricier item, the military finally figured out using a H buffer is ideal enough to slow down the rate of fire.

This is all military though. On the commercial side, we figured out for years how to get the carbine running. The military is just slow because they don't want to adopt anything easily.

From my own personal experience, and I have no idea about bolt bouncing, I found that using a H buffer and a really strong spring like the red spinco is the best with a carbine gas. The only rifle I use a H2 with is my Bushmaster upper because the gas port is opened a bit more and the H2 helps make it feel like a H buffer is in there. I'd imagine unless there was excessive bolt bounce, for a typical shooter it wouldn't be a problem and you'd never notice unless you were doing constant mag dumps or you got crappy ammo.

I don't plan on using standard buffers any longer and will use extra power springs for any future builds. It just feels better and cycles for 100s of rounds without issue or fail.

I do know with the HK MR556 (or HK416), the piston system is much harsher in a AR15. It's common that the life of the bolt and barrel goes down due to the harsher action system.

The HK brand came to the same conclusion as a lot of other folks did: heavier buffer with a very strong spring. Their MR556A1 rifle has improved buffer/spring combo. The odd part is the system still doesn't last as long as the typical DI AR15 even though there is less fouling.

Thanks for all the replies.