Info sought on cycling of semi-auto actions ...

L

Lefty

New member
In semi-auto acions like the Garand, M1A, FN-FAL, SKS or AK variants (primarily those using 30cal or 30cal-short ammo) what stops the rearward movement of the bolt/bolt carrier??

Is it just the compression of the recoil spring or does a typical action bear up against or "crash" into the rear of the receiver??

If it hits the receiver, does this happen every cycle or is it ammo dependant [meaning it might on heavy rounds]??

In 223-size actions, like the Ruger mini-14, does it tend to be similar?? I understand there are different operating principles, some with op rods around the action [Garand, M1A, etc.], while some are straight in a blow-back-type action [SKS], I'm just curious here. I have seen some METAL to METAL contact in a semi-auto and well ... would like some reassurance.

Any comments would greatly be appreciated!! Tight groups!!
 
Well I know in the AK and the FAL there is metal-to-metal impact. Despite the recoil spring the bolt carriers are stopped by metal at the rear of the recievers, hence the benefit of recoil buffers.
 
That's the reason behind my inquiry. Looking at recoil buffers, some of them sold for the SKS-type 56 rifles, move the impact area to the receiver cover [like the Buffer-Tech model].

If one looks at the design of this rifle, the area of the receiver that is designed to handle any impact [potential or not] is the thick, webbed "H"-shaped block immediately forward of the receiver cover mounting area. The steel here is 1/4" thick.

My fear is that using buffers that move the energy [read: impact] to the receiver cover is a far more potentially dangerous situation, as it is only held by a crossbar pin, which was not designed for this express purpose.
 
Lefty - I've successfully used a Buffer Technologies recoil buffer in my AK for thousands of rounds. It is easily installed in minutes and I now would never shoot the rifle without one installed. It fits solidly at the rear of the receiver block, slipped over the recoil spring guide rod. There is no transfer of energy to any weaker points, at least in the AK series. There is a significant reduced feel in the recoil and the action is quieter, as the metal to metal contact at full open action is eliminated. I have these buffers in my 1911, Glock and M1A as well, with equal results. Go for it.

Noban
 
Some actions depend for correct forward movement on the recoiling part bouncing off the stationary part. For these guns, a buffer can actually cause malfunctions by absorbing impact and thus reducing the forward momentum of the recoiling part (bolt, slide, etc.).

Steel is highly elastic, and the Model 1911, for example, is designed so the frame, through the recoil spring guide, absorbs energy and returns it to the slide. This is why a slide manually released from the rearward position and allowed to run forward under only spring pressure does so more slowly than when it returns to battery after firing.

In general, the benefits or drawbacks of buffer use depend to an extent on the design of the gun. Again, there is no such thing as a free lunch.

Jim
 
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