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View Full Version : new to forum, slight extraction problem


bennie96
January 12, 2007, 23:30
new to forum and want to say that i've learned a lot from these pages.

just completed test firing my new build, a metric dsa with imbel parts kit.

My first rounds were with 7.62 SA that tended to stick in the chamber. Gas setting was open completely. Adjusted gas setting with factory remington .308 at about 2 ( did seem stange to have the gas setting that high). Continued to fire about 45 rounds SA, remington. Last few rounds seemed to have more recoil than previously.

The problem arised with the last two rounds. A round had its rim partially torn off. Closed bolt and pulled charging handle at which point it ejected. The last round , however, failed to extract and had to be pounded out with a cleaning rod. Rim was also buggered.

Any ideas? I seem to think that it may be that the gas (too much, violent extraction?) with the gun finally breaking in. Also my rifle headspaces fine but may be a little tight with 7.62 as opposed to .308

shootist87122
January 13, 2007, 00:40
How far is it throwing the brass and where is the HS set? The small amount of .308 that I've shot has generally required less gas (higher number) than 7.62. BTW, 7.62 fits just fine in a gun head spaced at .308 minimum (1.630").

Probably just needs a good cleaning from stem to stern including the recoil tube and spring, then set the gas per the manual using the specific ammo you plan to shoot.

Other issues could be a plugged up gas port or a gas piston that is binding. The piston (with spring removed) should drop free into the upper receiver.

bennie96
January 13, 2007, 02:21
thanks for the help. Think tommorrow I will open the gas up and start fron scratch . cleaned the gas system tonight and double checked the headspacing which is fine. Hopefully I can blow out the bullseye!

shootist87122
January 13, 2007, 08:53
bennie,

The rounds that were sticking in the chamber with the gas full open were the result of the rifle re-chambering a fired (expanded) case. Do a search on "pogo" if you don't already know what that is.

Good luck with the build and welcome to the Files.

Joe