Ported Gas Plug Brass Ejection Pattern

[dross]

I haven't shot my full-size Garand in a while, but I took it out today. I installed a ported gas plug in it, and I can't remember for certain whether I've shot it since I did that, but I think I did.

I was shooting 150 grain Remington Core Lockt ammo and it was throwing brass from 2 o'clock to 11 o'clock. Some seemed to go straight up and landed on the shooting table. Thoughts?

[Punch The Clown]

The more I slow down my BM59, the further back it throws the empties. Bleeding off no gas the brass would go straight down range. I adjusted until the brass was ejecting at around 5 o'clock. It also lessened the recoil.

[dross]

The more I slow down my BM59, the further back it throws the empties. Bleeding off no gas the brass would go straight down range. I adjusted until the brass was ejecting at around 5 o'clock. It also lessened the recoil.

This is the ported plug, not the adjustable plug. But that's what I figured, it's acting as if it's overgassed.

[timshufflin]

May not be over gassed, just a longer gas curve being maintained. Don't know for sure but you might ask the inventor to see what he says?

[dross]

May not be over gassed, just a longer gas curve being maintained. Don't know for sure but you might ask the inventor to see what he says?

I did just that. Here's what he said:


Hello Dan,

The bolt speed when using the ported gas plug is lower then with the USGI gas plug due to the lower pressures in the gas cylinder. Ejection patterns should be about the same round to round with the last shot always ejecting more to your right when the bolt locks back.

If you're seeing round to round changes then you might want to inspect the operating rod spring for wear or breakage. If you see any flat spots on the coils or breaks then the spring should be replaced with a USGI spec spring.

Second, make sure all the grease points are greased on the rifle. Finally check to make sure the operating rod isn't binding on the stock. This is very common with the new CMP rifles that use the Boyd stocks. Look for shiny spots on the wood where the operating rod may be rubbing.

Here is a good video showing the tilt test. http://www.youtube.com/watch?v=tlIoxbtdPXY (Preview)

With the ported gas plug installed peak pressures will be much lower then with M2 Ball. So the problem isn't a high pressure one or a overgassing one.

You might also want to take the bolt apart and inspect the two springs in the bolt. If the extractor spring or ejector spring are binding or stuck then you can get erratic ejection patterns.

Eric

[timshufflin]

I could see a new oprod spring having an impact. I took for granted the other items would have already been checked by you.

[dross]

I could see a new oprod spring having an impact. I took for granted the other items would have already been checked by you.

I'm pretty new to the M1. I know the rifle is lubed because I lubed it, but it wouldn't occur to me to check the oprod rubbing for this particular problem. I'll check it, but even now it doesn't make intuitive sense to me in my ignorance as to why that would make it throw the brass to 11 o'clock.