Speaking of bolts

[Pete Wass]

I am wondering why manufacturers put so much dwell at the top of the cocking cam on bolts? I have noticed that most of them have quite a long ( relitavely speaking) flat from the top of the cam to the notch used to keep the cocking piece centered. Me being a layman and not understanding the engineering of these bolts, if I were making the bolt I would reduce the length of that flat to nearly zero or very short. I think that would help make blots cycle easier. Am I all wet here?

 

[John Kielly]

Peter,

I suspect that it is to ensure a positive, safe notch that is unlikely to permit the cocking piece to be accidentally displaced.

Here in Australia, where RPA 4 lug & Barnard three lug actions are commonly used for belly shooting, instances have been recorded with each where the cocking piece was either jarred off the notch or failed to locate due to insufficient depth of notch. Both have extractors that hold the case close to the bolt face & this condition can & has lead to rounds being discharged from an open bolt, fortunately without significant injury. Appropriate steps have been taken to avoid further instances of this occurrence.

I don't know whether your Remmy derived actions have equally positive extractors, but it would be comforting to know that the possibility of misoperation was remote. There's every chance that the design has persisted from the military-derived Remington 30 actions.

John

 

[Woody]

bolt timing

I believe the "flat" is needed to allow the lugs to rotate and clear the abutments up front. Once the bolt hits the angled part of the receiver, it's going to start pulling the bolt lugs backwards and they obviously must have a clear path. At first glance, these bolts seem rather simple but there really is a lot of mechanical activities going on that require rather intricate timing.

-- Scott

 

[alinwa]

AND, f'rinstance my Borden TPE's have a very small flat, the slightest bump will decock a removed bolt. The handoff is very short. Max cam, min wasted effort. Hence I can cock the TPE with one hand, not disturbing the bags.

al

 

[Pete Wass]

This is what I think

AND, f'rinstance my Borden TPE's have a very small flat, the slightest bump will decock a removed bolt. The handoff is very short. Max cam, min wasted effort. Hence I can cock the TPE with one hand, not disturbing the bags.

al

I would like to see with bolts. I don't think there is a need to have the big flat before the cocking piece begins to fall.

 

[crb]

Before and after.