870 barrel not locking up with receiver. +3mag extension

[BCshooterFMJ]

After making the needed alterations I installed an ATI mag extension on a newer rifle sighted 20 inch 870 barrel/express receiver. After switching up my 870s and putting the Remington made extension onto it, it will not screw down all the way to give the barrel that snug fit, i can wiggle it with my hand. When I use the mag cap or ATI extension it locks up snug.

Any ideas?

Edit: alterations were drilling out the dimples. Doesn't really apply to this problem.

 

[Tactical Ordnance]

When installing a factory Remington 2 piece extension ALWAYS install the coupling nut first and then screw the extension tube into it. What is happening is that the two tubes are butting up against each other and the coupling nut is not tightening against the barrel ring.

 

[BCshooterFMJ]

Well she was pretty tight on there I must say. The factory should dial that back about 20 to 30 %

But honestly thanks a lot. Had no idea it was two pieces. I think I just got an old one. Just had that moment where I'm like "oh sh!t. I asked a dumb question in front of everyone again"

 

[Tactical Ordnance]

Well she was pretty tight on there I must say. The factory should dial that back about 20 to 30 %

But honestly thanks a lot. Had no idea it was two pieces. I think I just got an old one. Just had that moment where I'm like "oh sh!t. I asked a dumb question in front of everyone again"

Remington factory mag extensions still are made from two pieces, a coupling nut and the tube assembly.
]
he biggest issue with not having the barrel tight is that over time the inside of the receiver gets peened over from the barrel moving back and forth when firing. Also, the ejector tip that locates the rotational position of the barrel gets bent and then breaks off. Barrels need to be tight.

Casey

 

[BCshooterFMJ]

Remington factory mag extensions still are made from two pieces, a coupling nut and the tube assembly.
]
he biggest issue with not having the barrel tight is that over time the inside of the receiver gets peened over from the barrel moving back and forth when firing. Also, the ejector tip that locates the rotational position of the barrel gets bent and then breaks off. Barrels need to be tight.

Casey

Yeah I got that. Was just saying it was CRANKED on there. So maybe it had been sitting a while.