Advantages of different auto rifle actions...Diagrams would be helpful...

[itgoesboom]

I have some understanding of different types of rifle actions (although any diagrams showing them would always be appreciated to help me understand better), I know the difference between the direct gas system of an AR, and the gas system of a M-14, and the difference of those to the CETME/HK roller delayed blowback design. (There is a little confusion to me between the short and long actions (AK vs FAL), and what advantage each presents).

So what are the advantages (and disadvantages) of the different actions. For exaple, is the AK more reliable because of its action, or its loose tolerances?

Kalashnikov
SKS
M-14/M1 Garand
FAL
HK/CETME roller delayed blowback
AR direct gas impingment

Thanks.

I.G.B.

 

[AZ Jeff]

Most variations on operating mechanisms for self-loading rifles have focused on trying to achieve the following objectives:

1. reduced weigh
2. reduced parts count and parts mfr. cost
3. increased tolerance to ammunition variation

Reliability, per se, has not been an issue, because, for practical military purposes, most modern (post WW2) self-loading rifles are generally "reliable enough".

What makes it tough is ammunition variables. When only one maker supplies all the ammo, "tuning" the rifle to run reliably on that ammo is relatively easy.

Now let's add in fouling of the mechanism, ammo degradation due to poor storage (or substandard supply sources). Is the rifle still as reliable? That's what designers generally are seeking to improve.

The M1, while a highly reliable rifle, was finicky about it's ammo, mostly due to the direct gas system employed. Thus, when the M14 was designed, the White cut-off and expansion system was employed to theoretically lessen the ammo sensitivity.

When the M16 was created, the use of the impingement system was thought to lessen parts count and weight, without lessening reliability.

It's all a series of trade-offs.