Blow back bolt action?

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Beiruty
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Blow back bolt action?

Post by Beiruty »

My 522 .22 rife is a blow back action. First you will notice it is a very dirty rifle.
The question, how the bolt is delayed from retracting before the bullet leaves the barrel?
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G.A. Heath
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Re: Blow back bolt action?

Post by G.A. Heath »

I assume we are talking about a Sig 522. It works similar to the 552 which means that the bolt does not move until the bullet has passed the gas port in the barrel, at that point nothing will stop that bullet unless its in its way.
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Beiruty
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Re: Blow back bolt action?

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G.A. Heath wrote:I assume we are talking about a Sig 522. It works similar to the 552 which means that the bolt does not move until the bullet has passed the gas port in the barrel, at that point nothing will stop that bullet unless its in its way.
Yep. It is Sig 522, It is a blow-back operated not gas operated like SIG 556. Sig 522 does not have a gas port, this is why I am asking.
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Re: Blow back bolt action?

Post by G.A. Heath »

oops, I'm still half asleep after a long night. Spring tension is what makes it work as with all blowback guns. I really need to hit they before 6:30am.
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WildBill
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Re: Blow back bolt action?

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G.A. Heath wrote:oops, I'm still half asleep after a long night. Spring tension is what makes it work as with all blowback guns. I really need to hit they before 6:30am.
Correct me if I am wrong, but to answer Beiruty's question, there is nothing to delay opening the bolt. It opens when the pressure of the expanding gases exceeds the strength of the spring. By the time bolt opens, the bullet is long gone out of the barrel.
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Beiruty
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Re: Blow back bolt action?

Post by Beiruty »

WildBill wrote:
G.A. Heath wrote:oops, I'm still half asleep after a long night. Spring tension is what makes it work as with all blowback guns. I really need to hit they before 6:30am.
Correct me if I am wrong, but to answer Beiruty's question, there is nothing to delay opening the bolt. It opens when the pressure of the expanding gases exceeds the strength of the spring. By the time bolt opens, the bullet is long gone out of the barrel.

Yep this is what is called a simple blow back with no delay. It seems that .22 cartridge is used to keep the chamber "sealed" while the bullet is travelling forward and exiting. The trick is to time the travel backward of the bolt while the cartridge did not exit the chamber to happen after the bullet exited the barrel.
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Re: Blow back bolt action?

Post by WildBill »

Beiruty wrote:
WildBill wrote:
G.A. Heath wrote:oops, I'm still half asleep after a long night. Spring tension is what makes it work as with all blowback guns. I really need to hit they before 6:30am.
Correct me if I am wrong, but to answer Beiruty's question, there is nothing to delay opening the bolt. It opens when the pressure of the expanding gases exceeds the strength of the spring. By the time bolt opens, the bullet is long gone out of the barrel.
Yep this is what is called a simple blow back with no delay. It seems that .22 cartridge is used to keep the chamber "sealed" while the bullet is travelling forward and exiting. The trick is to time the travel backward of the bolt while the cartridge did not exit the chamber to happen after the bullet exited the barrel.
That is why Sig has gun designers to figure out all of that stuff. ;-)
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