Gas relief ports, how big.

[B.Johnson]

I have finished mounting a Savage bolt head, and baffle on a Rem. bolt. I now intend to fit a full sleeve. The Savage head,and baffle shut the gas relief almost completely off, and the sleeve will shut the relief port drilled on the right of the receiver ring off. My idea is to cut a relief port bigger, and on both side's of the receiver ring. I'm trying to figure out how big I should go. The Savage has a .150 port on each side of the receiver ring. That bolt head, and baffle really shut that Rem. action off. With the bolt disassembled, and closed in the action, looking back through the receiver ring you can just see a thin ridge of light. I know no gas port will protect against total case failure. I thinking more of a pierced primer.

 

[Mike Bryant]

I doubt if the gas port on a Remington does anything in a case head failure. There is a hole in the bolt head that let's gas out of the bolt head. I imagine very little of the gas would direct out of the hole in the side of the receiver when it has four times or more surface area for the gas to direct down the raceway. Most of the gas would take the path of least resistance right down the raceway.

However, that's with a Remington. When you plug up the raceway with the Savage baffle, then the port becomes functional. For a right bolt, right handed shooter, I wouldn't put a gas port on the left hand side of the action as it would direct any escaping gas toward the shooters face. I think the rule of thumb is that when you double the diameter, you increase the surface area four times. So, if you want to double the surface area of the port, the diameter increase in size would be somewhere between the original diameter and twice the diameter. If the original hole was 1/8", I'd probably increase it to 3/16". No need to go to 1/4" as rlthat would be a pretty large hole on the side of the receiver.

 

[B.Johnson]

The Savage baffle closes off both right, and left race ways. A gas port won't mean anything to a case failure. Dennis Sorensen has a photo of a Sako .243 on this forum that totally came apart. The whole top of the receiver ring is gone. What is'nt broken is bent. How do people walk away with all that steel in the air? My concern is a pierced primer, or enlarged primer pocket at most. You try to dam up 60,000 lbs. and pieces are going to fly.