SigLeader

So the issue ended up just being a dirty chamber. We thoroughly clean the chamber of all of the preservative they put on when it leaves the factory. I actually wasn't aware that that was there until I talked to my gunsmith. once we cleaned it out that problem I was having where the brass would stick after I put a fired brass back in completely went away the chamber was nice and shiny and everything worked well. Cycles perfectly will all the rounds I put through it. To help with recoil and to help extend the life of the weapon I will also change out the buffer spring and buffer when I get a chance.

Sorry, rough day yesterday. I will have to order some parts and do some testing. I want to try a lower from a friend too as his works. However, he won't be back in town for another week. I will post my findings as I get more information. Thanks again for the help.

Actually the same type of factory ammo was shot in both guns. I barrowed some rounds from him to test with. To be clear the brass was tested in the rifle it was fired from in both cases. I normally reload and wanted to try a couple different rounds. Before picking up this rifle I did a lot of bolt action stuff. The only time I had an issue with brass sticking was when it was a super hot load or a problem with the chamber. While I do understand they are different worlds, Is it possible that there is an issue in the chamber that is causing it to stick and then that little loss in power causes a short stroke?

Thank you! For your time and help! I think I found another problem. The spent casings stuck in the chamber. I put an unfired round in the chamber and it come out easily. So head space is good. Then I put a fired brass in and it stuck. Not just a little. I had to get a hammer to get it to budge. My buddy tried one of his spent brass in his chamber and it came out by hand. Mine had to be hammered out.

Ya that is a picture before trying it lubed up. I put oil that was dripping off and then it still did it. I am new to all of this, so excuse my ignorance. I thought that the larger weight and stiffer spring is for a over gassed set up, but you mention that the gas port is borderline small? Can you please explain the mechanism for what you think might be happening. So I can better understand. Aero precision today said that it might be under gassed for the spring since it is a rifle length gas tube with a carbine buffer tube. However, every thing I find says that should not be the problem. It seems like everyone (online) says that it will be an over gassed problem like what you are saying. I called springco and he wanted me to check the casing trajectory before he would recommend a spring. He didn't really think I had looked everything over in the gun. And was not convinced that the spring was the issue So I stripped it again. Looking for gas leaks. There was a little leaking around the gas tube in the gas block, but the hole is lined up perfectly. The gas port is lined up perfectly. There is no leak around the gas key where it meets the bolt carrier, the BCG without bolt closes at less than 45 deg and the bolt will not go in the the BC with gravity. Without the spring the BCG sits clear of the bolt catch. Sorry for the long post, but I hope this helps explain where I am. (Lost)

Internal depth of the buffer tube is 7", Spring is 12" with 25 coils, buffer is 2.5"

Hi, new here. I read other posts here, and white they were useful didn't fit my setup exactly. I am having an issue with short stroking. The bolt will not lock back after firing the last round, and will not consistently pick up a round. Picture of what happens (added more oil than is seen here later). Rounds do eject consistently. I purchased a complete M5 upper and complete lower from aero precision. It is an 18" barrel with rifle length gas block. The gas port is on speck with the 0.089" size they say it should be. The gas block is lined up with the gas port. The BCG/bolt were well lubed before going to shoot. The bolt rings were set so they are not all in alignment. It is a rifle length gas tube with a carbine lower. 3.8oz buffer with aero precision 308 buffer spring. Any help would be greatly appreciated