- Thread starter Raptor77
- Start date
That sounds right, but in my experience, you'll commonly get things that look like pressure signs, (mainly ejector swipes) but actually aren't with an ar10. What you are describing may be a good method for load development that I've never thought of. Keep us posted
The high pressure event is when the bullet is still very near to the chamber, so what you will be getting in terms of high pressure will have something to do with the peak pressure and more with how your gas action treats the case upon extraction.
To a degree, higher pressure will also cause higher extraction forces if the pressure is high at the port, but those are secondary effects compared to the pressure at the chamber end when the bullet is seeing factors more pressure.
That said, it is worth a look but don't spend too much time with the port closed if you intend to run the gun normally later on.
To a degree, higher pressure will also cause higher extraction forces if the pressure is high at the port, but those are secondary effects compared to the pressure at the chamber end when the bullet is seeing factors more pressure.
That said, it is worth a look but don't spend too much time with the port closed if you intend to run the gun normally later on.
As stated above. The high pressure event that leaves “signs” and causes case expansion happens long before your gun reaches its dwell time (between gasport and muzzle).
So while turning off your gas and manually cycling your BCG you would save yourself going to pickup brass and or any external damage..i.e. shell deflector or other marks made during cycle of function.
But the pressure signs would be there regardless of gas.
Measuring above the extractor groove with a ball micrometer is the only true way to see pressure.
Some of the “signs” people use are more profound with gas guns. And don’t always means what they do with a bolt gun.
You can get ejector swipe from low power loads. And primer markings can be very different depending on gas gun build quality and firing pin hole to pin fitment.
In answer to your specific question I do believe that would be a YES. If you shut the gas completely off on your AR, it SHOULD function as a straight-pull bolt action and eliminate the effects of over/under gassing, reciprocating mass, timing, etc etc.
However, I would only use this tactic to possibly assist in troubleshooting. I would NOT use it for load development and trying to push the upper limits of pressure. If nothing else when you return your AR to normal operation, all your load data is out the window.
