Questions on HK91/CETME design

[ks_shooter]

Does the charging handle on a HK91/CETME rifle only retract the bolt carrier (as on the AR-15) or can it also be used to force the bolt closed? If it only retracts the bolt, is there any provision for allowing the user to positively close the bolt without drawing the bolt all of the way back and letting it fly home (forward assist feature)? Also, since the HK91 uses a delayed blowback style action, what is the tube along the top of the barrel for? It appears from the diagrams that I have seen that the action spring is housed in the receiver. Why didn't they just but the charging handle on the side of the bolt carrier?

 

[Destructo6]

The cocking handle cams the bolt carrier away from the bolt head as it unfolds, then is used to retract the bolt only. The cocking handle does not operate as a forward assist.

You can close the bolt by pushing the bolt carrier forward through the ejection port with your thumb. Sounds kinda cheesy, but the HK33 and Norwegian G3s have serrations on the bolt carrier for this exact purpose.

The PSG-1, MSG-90 and a few others have a real forward assist, which you could add, given the desire and money.

The tube over the barrel is the "Cocking Tube" in which the cocking handle support and the bolt carrier extension ride. The cocking handle support is about 2.5" and the bolt carrier extension is about 6".

The G3/HK-91's recoil spring is attached to the backplate, to which the buttstock is attached. The spring and guide go through the back of the bolt carrier, bottoming out in the bolt carrier extension.

Having a charging handle attached to the bolt carrier that reciprocates with it would require a long slot in the receiver. Removing this metal would probably weaken the receiver significantly, since the G3's receiver is open on the bottom for the fire control parts.

 

[4v50 Gary]

In my best imitation...

Non-reciprocal.

Sam

 

[Marko Kloos]

In the military, we used the buttstock as a forward assist. A good smack with the palm onto the butt, or a brief strike onto a solid surface, will press the bolt home if you were forced to cycle it quietly.