Are the DA Grizzly forend nuts the same thread as factory 870 nuts?

[Mr. Spectacular]

I bought a Magpul forend for a Dominion Arms Grizzly, but couldn't fit it over the DA forend tube, so I sourced a new Remington 870 forend tube from Brownells as I was unable to locate one in Canada. Today I attempted to switch the forend over permanently, and it slid over the new Remington tube just fine, but I feel as if the thread on the DA forend nut is different than than the thread pitch on the Remington forend tube.

Does anyone know if they're the same, or if they should be the same?

I can get the nut on the tube, but it only goes on about 1.5 threads and than stops, but not because it's tight, but because it feels like the threads are binding.

 

[Grove]

Mine is, but it is from the first batch of guns that came into the country in 2008.

I've got a Magpul MOE fore end on my shotgun and the factory end cap I had to replace as the sling swivel would not allow the action to close fully.

I'm using a DS Tactical smiley face end cap but I've also used the end cap off of an 870 Express as well.

Not sure if anything has changed since then.

 

[EL34/6L6]

Thread is the same, and yes the Magpul forend sometimes needs some shaving. The DA tube is just barely milimeters bigger in diameter than the 870.

 

[Mr. Spectacular]

I can confirm that the thread on mine were indeed different, and I have now stripped the threads on the forend tube and now get to pay a $75 stupidity tax to Brownells. :/