Failure to Feed

[plant_one]

thats where my thoughts were going too Al, but figured getting the data on the port first would be the cautious route to proceed with before suggesting modification.


while it may be a valid route to travel to resolve the issue, its something that personally i feel should be a last choice due to the risks involved with it (chipping the lands, etc) and we should try to help him eliminate all other variables first before he proceeds down that road

[Al in Mi]

agree there Plant.

Last summer I worked with a members 20" rifle gassed upper, it just sorta dumped cases out, no flinging at 4:00 and 4 feet back thing. Did it with everything I ran thru it, factory, reloads, didn't matter. I guessed a small gas port, but seeing it worked, I never tore it down to look.

[m113103]

Didn't Hoot walk this road a while back. Another member had a similar problem that he sent gun back to manufacturer and they had to polish the chamber.

[Blusqualo]

I have a 6-position M-4 stock, my other lower also had a 6-position stock, and the Wyndham lower also did. The stock is a tan/fde UTG and I'm pretty sure the buffer and spring came with it. I also have a Guntec "G2" buffer and spring. Will check on gas port size.

I tried chambering some rounds with the bolt locked back and a round in the the magazine; if I hit the bolt release it chambered the round fully, if I pulled back on the charging handle and released, it also fully chambered a round.

When I fired the last round on an empty mag it locked back, but not all the way; it locked about 3/4" forward of all the way back.

I took pictures, but i can't seem to get them to upload, it says they are too large to attach.

[plant_one]

When I fired the last round on an empty mag it locked back, but not all the way; it locked about 3/4" forward of all the way back.

.

this indicates ones of two likelyhoods - gas port is too small, or gas block alignment blocking the port.

pull the gas block, and look at the carbon ring around the gas port.

if it looks like this - you didnt have an alignment issue


if the carbon ring intersects the gas port - even a little bit, you probably have an alignment issue.

now is also a godo time to verify that the gas tube/block is not blocked, give it a good cleaning just in case and verify you have good airflow

also check for leakage around hte gas block - you'll again have carbon stains around it that will look similar to this

I took pictures, but i can't seem to get them to upload, it says they are too large to attach

its easiest if you upload them to a 3rd party website like photobucket and use the image sharing link with the [ img ] tags on it

[Avenger10]

It sounds like you are under gassed at rifle length but I have also seen this problem fixed by simply changing to another magazine.

Verify your buffer system. A good 450 will run on both standard rifle or standard carbine buffer systems. People think you need a heavy buffer to absorb 450 recoil, that is wrong thinking. A heavy buffer doesn't protect your rifle from a 450 pounding. Recoil is over before anything starts moving on the buffer system. So once you verify you have the correct buffer system the problem is either a gas issue or a mechanical issue.

-Barttman