Lately I have been firing a LARGE quantity of subsonic 223 ammunition from my AR partially because it is extremely cheap to load but also because it is fun and very addictive as I try to improve the accuracy of my loads without increasing the velocity. The one thing I have observed though and this is not any new development to anyone, is that the subsonic rounds will not cycle the action on my AR. This is due to the use of pistol powders and the fact that they completely burn in about the first 10 inches of the barrel when the round is fired. Now it  makes for a very QUIET round of ammunition many are barely louder than a 22 lr but it also makes my AR a bolt action and this is less than ideal considering that I am shooting for accuracy.  My thought are this. If I had a custom barrel made with the gas port set back appx 7 inches from the chamber would the gas pressure be adequeate enough to cycle the action? or will the pistol powders not generate enough volume of gas to cycle the action regardless of where I position the gas port? Just curious to see if it is worth while to mess with or not.  Before someone says get a bolt action, I have one already.

Quoted: Lately I have been firing a LARGE quantity of subsonic 223 ammunition from my AR partially because it is extremely cheap to load but also because it is fun and very addictive as I try to improve the accuracy of my loads without increasing the velocity. The one thing I have observed though and this is not any new development to anyone, is that the subsonic rounds will not cycle the action on my AR. This is due to the use of pistol powders and the fact that they completely burn in about the first 10 inches of the barrel when the round is fired. Now it  makes for a very QUIET round of ammunition many are barely louder than a 22 lr but it also makes my AR a bolt action and this is less than ideal considering that I am shooting for accuracy.  My thought are this. If I had a custom barrel made with the gas port set back appx 7 inches from the chamber would the gas pressure be adequeate enough to cycle the action? or will the pistol powders not generate enough volume of gas to cycle the action regardless of where I position the gas port? Just curious to see if it is worth while to mess with or not.  Before someone says get a bolt action, I have one already.

I saw something around here about gas operated pistol caliber uppers.   Check the pistol forum.  May be some informationt there.

thw 300/.221 is primarly used to fire subsonic loads. and they get the actions to cycle on them.  i wonder if you could remove the front site base/gas block, and enlargen the hole, and then use an adjustable gas block to dial in between sonic and subsonic ammo.
***************i DO NOT know if thsi would work or not.*********************

so please dont do this until you get some more input on if this would work or not.  i think it would, but not 100%sure.


buy the way....

what are some of your recipies for subsonic loads for the .223, i have been interested in loading some, but i cant find any reliable info.  thanks you, brian.

I think this was brought up a few years back. running a stubby pistol gas tube and such. Talk to Marty on the rimfire and pistol caliber forum.

I shoot quite a few Blue Dot loads in 221FB and 223 bolt rifles. Very accurate and quiet.