06-25-2023, 05:43 PM
Last I knew Midway AR Stoner is rebranded Bear Creek Arsenal. Im curious if these barrels are stainless steel or Chrome Moly Vanadium steel barrels? The 18 mid length gas port size I have is .078, rifle length is .094 minimum. The 16 carbine length gas port .0625 and 16 mid length gas port .076-.078.
I would remove the bolt carrier from both barrels. Get a fresh factory cartridge and drop the cartridge into the chamber and ensure it is fully seated. Raise the muzzle and see if the cartridge falls out of the chamber under gravity. If the cartridge fails to fall out use a cleaning rod to push out the cartridge. If it takes minimal push to have the cartridge fall out you might clean the chamber. The chamber could be rough and it might help to polish the chamber. I use Flitz polishing compound on a barrel mob attached to a short cleaning rod spun by a hand drill. Re-clean the chamber and barrel and retry putting the cartridge in the chamber to see if the cartridge now falls out under gravity.
If the cartridges still sticks use a black marker to color the bullet and cartridge neck and see if the rubbed off black marker indicates the bullet is jammed into the lands. If the bullet is jammed into the lands the chamber is probably out of spec. If the manufacturer uses the same tool to long the cutting surfaces dont cut deep enough resulting in a short chamber. This is a relative common problem with mass produced barrels where quality control is lacking.
It is possible the bolts/BCG are out of spec if the cartridges fall out of the chamber under gravity. It is also possible the gas block and alignment pin are not square and inline so you have insufficient gas. It is possible the gas block is not centered over the gas port resulting in insufficient gas. Id inspect the carrier key and bolt carrier for carbon from gas seepage caused by the carrier key not being installed properly.
I would remove the bolt carrier from both barrels. Get a fresh factory cartridge and drop the cartridge into the chamber and ensure it is fully seated. Raise the muzzle and see if the cartridge falls out of the chamber under gravity. If the cartridge fails to fall out use a cleaning rod to push out the cartridge. If it takes minimal push to have the cartridge fall out you might clean the chamber. The chamber could be rough and it might help to polish the chamber. I use Flitz polishing compound on a barrel mob attached to a short cleaning rod spun by a hand drill. Re-clean the chamber and barrel and retry putting the cartridge in the chamber to see if the cartridge now falls out under gravity.
If the cartridges still sticks use a black marker to color the bullet and cartridge neck and see if the rubbed off black marker indicates the bullet is jammed into the lands. If the bullet is jammed into the lands the chamber is probably out of spec. If the manufacturer uses the same tool to long the cutting surfaces dont cut deep enough resulting in a short chamber. This is a relative common problem with mass produced barrels where quality control is lacking.
It is possible the bolts/BCG are out of spec if the cartridges fall out of the chamber under gravity. It is also possible the gas block and alignment pin are not square and inline so you have insufficient gas. It is possible the gas block is not centered over the gas port resulting in insufficient gas. Id inspect the carrier key and bolt carrier for carbon from gas seepage caused by the carrier key not being installed properly.