M16 Charging Handle

[gute]

Read Dr. Fackler's findings on the 5.56 - quite interesting. He is a fan of the 6.8 SPC.

[jtan163]

]
As for Stoners later designs, he had already given up any rights to his direct impingement design and so had to pioneer other ideas. I don't think the AR 18 is much better than an AR 15.

I'm not sure that Stoner had any rights to give up re the direct impingment design.
I believe direct impingment had been used designs prior to Stoner's the AR series, e.g. Ljungman AG42, so I am not sure that Colt could really have precluded him using it again if he so desired.

[SethB]

The Ljungman was nowhere near as refined as the Stoner system. In Stoner's system, the bolt is pushed forward by gas, unloading the bolt and rotating it at the same time. This is what makes such small lugs successful. Piston guns require a lot of work to keep the load even on the lugs.

[GI Zhou]

Read Dr. Fackler's findings on the 5.56 - quite interesting. He is a fan of the 6.8 SPC.

The 5.56 findings showed how 'explosive' the wounds were caused under 25 metres to soft tissue, not covered by body armour or other material. All dual core ammunition at velocities over 2,700 ft/sec will separate into two or more wound channels. Soft tissue walls are stretched to their maximum limit at approx 3,000 ft/sec. This is where the 'temporary cavity comes into play, where soft tissue is like a balloon at maximum stretch, even a small piece of fragment causes a large tear producing an 'explosive' type wound.

I'm a premanent cavity type afficianado myself. Larger calibre with deeper penetration. Do you have a reference to his being a fan of the 6.8 SPC ,as I have not spoken to the good doctor for many years.

[jtan163]

The Ljungman was nowhere near as refined as the Stoner system. In Stoner's system, the bolt is pushed forward by gas, unloading the bolt and rotating it at the same time. This is what makes such small lugs successful. Piston guns require a lot of work to keep the load even on the lugs.

I don't follow what you are saying - I thought that with most Stoner weapons - as with most, if not all, auto/semi auto small arms the bolt is pushed FORWARD (assuming the front is the muzzle, which I do) by a spring and backward via gas.

[SethB]

The weapon unlocks by pushing the bolt forward. This unloads the lugs. And it is why piston operated weapons have had issues with lug breakage in the past.

[Ken White]

Bolt CARRIER backwards -- but before the carrier moves, the gas flows in to the rear cavity and expands, pushing the bolt forward very slightly for a fraction of a second to unload the jugs and ease unlocking and rotation (caused by the beginning rearward movement of the bolt carrier camming the bolt counterclockwise). LINK.

The three little rings on the bolt (inside the red goose egg on the picture below...) are effectively piston rings to enable that.