Not trying to bring this thread back to life just for Halloween,but wanted to chime in and pick yalls brain. I put together a 10-1/2" AR pistol recently and have been having some short cycling issues with it. The assembled upper is from palmetto state (carbine length gas system).I built the Anderson lower from a Toms Tactical parts kit and added a PHASE 5 TACTICAL bolt catch.Also added an adjustable gas block. I ran a mag of PMC bronse223 at first and after about 20 rounds it started short stroking(started not feeding the next round). I looked in the action &barrel and there was lots of unburnt powder residue. Cleaned and lubed the heck out of the gun and tried American Eagle 223,It ran great other than the bolt some times not locking back on the last round.Next tried some Federal 556 62g greentip ammo and ,it never missed a lick functioning .Lastly my brother tried some Wolf steel case and it will not cycle that stuff at all. So the gas port dia is .075", What do you all think of the idea of drilling the port open to .077" or .08"? Good idea/ bad idea? -Haven't been here before. Thank you.
Is the gas blocked opened up all the way? Might look at adding a flash can as it can add back pressure.
How have you adjusted your gas block? I'm not totally familiar with short barrel stuff, but I'd suggest running it wide open to assure reliability on ammo, which you had with the premium ammo. If it locks back on premium ammo, tighten it down until it short cycles in 1/4 turns. When you open it back up to hit the sweep spot where it locks back every time, open it another half round to get reliability in low power cheap ammo. Don't try to make a precision adjustment.
If it's still ammo related, you can lighten your buffer to see if that helps. There are different buffer springs out there that may help as well.
The last thing I'd do as a last resort is to drill the gas port. I can't imagine it would be undersize although some may have examples of that.
If it's still ammo related, you can lighten your buffer to see if that helps. There are different buffer springs out there that may help as well.
The last thing I'd do as a last resort is to drill the gas port. I can't imagine it would be undersize although some may have examples of that.
As soon as it started short stroking I began tweeking the gas block closed a few clicks at a time, and it just made the problem worse.The gas block has been wide open sense then with all brands of ammo tested. Have tried a H2 buffer and carbine buffer ,no differance. A friend suggested trying a lightened bolt carrier mayby? Had'nt thought of a flash can tho....come to think of it PSA also listes the 10.5 barrel uppers with a flash can.....always thought it was for looks. Didnt know it could effect function. Might try that . Thanks
No problem. I like trying to work out issues. Gives me personal knowledge.
A lighter buffer will be the same as a lighter BCG and a whole lot cheaper. A lighter BCG won't accomplish anything more than a lighter buffer, but then again, I'm not familiar with pistol length issues.
It is a gas operated gun, so go through the basics of troubleshooting a gas gun.
On your BCG have you checked the bolts holding the gas key and are they staked?
When shooting, where does the brass end up in relationship to the gun? One O' clock, two, three four?
Have you tried different magazines?
You said premium ammo ran great. Cheap ammo ran like crap.
Keep running premium ammo or reloads that have consistent pressures.
Since Pressure seems to be the issue, anything that will increase the back pressure like a can or something might help, but the issue seems to be the cheap ammo.
https://sapoutfitters.com/product/kak-industry-micro-12-28-slimline-flash-can/
I ordered from this place and the KAK cans are on sale.
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