True that!
And as a reliability nuance. Swap out the solid cam for a POF-USA roller cam. As the bolt is being forced to return to battery, the cam is scraping down the side of the upper receiver until it drops into the locked position.
The roller just makes it that much easier by reducing the fiction. On the standard 5.56 it is just a nuance upgrade as the solid one will work very well. On 308’s we found it to be almost a mandatory upgrade. Providing the extra momentum to make a solid lock-up on the next round.
P.S. Our POF-USA, P-416 machine gun ran over 16,000 rounds through it with the roller cam equipped bolt. It looked and functioned like the day we received it.
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“As the bolt is being forced to return to battery, the cam is scraping down the side of the upper receiver until it drops into the locked position.”
There’s a reason for that MTHead.
While roller engagement with the cam cut in the carrier has merit, Stoner designed the enlarged head of the cam pin like that on purpose.
It’s to ensure that while the carrier assembly begins to close i n counter recoil, that the bolt doesn’t begin to rotate, and thus possibly impact the bolt’s lugs with the barrel extension lugs until it has fully entered the extension.
IIRC the term is ‘Anti-Preengagement’.
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Yes! We give all do deference to St. Stoner! Just as we canonize St. Browning!
But these men would be the first to innovate their own inventions if they could. And would not hesitate to upgrade if it improved function and reduced wear.
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Oh man. Brings back memories of IDF basic training.
True that!
And as a reliability nuance. Swap out the solid cam for a POF-USA roller cam. As the bolt is being forced to return to battery, the cam is scraping down the side of the upper receiver until it drops into the locked position.
The roller just makes it that much easier by reducing the fiction. On the standard 5.56 it is just a nuance upgrade as the solid one will work very well. On 308’s we found it to be almost a mandatory upgrade. Providing the extra momentum to make a solid lock-up on the next round.
P.S. Our POF-USA, P-416 machine gun ran over 16,000 rounds through it with the roller cam equipped bolt. It looked and functioned like the day we received it.
“As the bolt is being forced to return to battery, the cam is scraping down the side of the upper receiver until it drops into the locked position.”
There’s a reason for that MTHead.
While roller engagement with the cam cut in the carrier has merit, Stoner designed the enlarged head of the cam pin like that on purpose.
It’s to ensure that while the carrier assembly begins to close i n counter recoil, that the bolt doesn’t begin to rotate, and thus possibly impact the bolt’s lugs with the barrel extension lugs until it has fully entered the extension.
IIRC the term is ‘Anti-Preengagement’.
Yes! We give all do deference to St. Stoner! Just as we canonize St. Browning!
But these men would be the first to innovate their own inventions if they could. And would not hesitate to upgrade if it improved function and reduced wear.
Oh man. Brings back memories of IDF basic training.