Cycling Issues

[chrisfc923]

Check the gas block and gas port next

how common is it to have a gas port thats not large enough on barrels?

 

[Nectarp]

If its a sig sauer barrel Im sure that it is to spec especially for a carbine length gas system, but you never know things always slip through the cracks at quality control, thats why I would have it checked, I dont think its very common but like I said it can happen did you put the upper together yourself or buy it from someone reputable? Just check it and the gas block, you just have to find the the source of the problem by process of elimination. I just looked at teh Sig sauer website and it seems that all of there sig sauer barrels of 16", so did you chop this barrel down yourself or did it come in that length from Sig Sauer? If it was cut down it is possible that the gas port would have been sized for a 16" barrel (needing a smaller gas port) that for a 14.5 inch barrel, EITHER WAY CHECK IT

 

[chrisfc923]

turns out it was the gas port... compared it to another barrel and was def smaller. gunsmith drilled it open more and all is good!

 

[rojodiablo]

A note to all AR based platform shooters on this:
When you clean your bore, I recommend you DO NOT use bore foam type cleaners in these rifles. It tends to be sticky as heck and WILL clog up gas ports and tubes.
Also, I recommend you use a dedicated upper or a dedicated barrel for the .22LR conversion thing. While it is nice to save on ammo, the 22lr tend to load gas tubes with powder and lead/ copper gilding. I have had to really go thru several guys' rifles to get them to run right after a lot of 22 has gone down the tube on their rifles.

Chrisfc- we have found that after 15,000 rounds or so, the gas tube tends to open itself up a little bit, almost guaranteeing the port size is no longer a problem!!!