Suppressing the M1A... What am I doing wrong?

[JoeSig]

Hello. Posting here because I need some help suppressing an M1A. Yes, I know Springfield's opinion of suppressing these rifles, but there are plenty of solutions out there. I have the rifle built but the suppressor is not centered with the barrel. See below.

WAY off center. Not safe to shoot, at all.

The barrel is the stock 16" SOCOM with an SEI gas lock adapter (wanted the Fulton Armory adapter, but I cannot find one in stock) and CGS Hyperion suppressor. Shortened gas plug from SEI is installed to clear the suppressor.
Things I have gone through troubleshooting:

• Not the suppressor - it fits perfectly centered on my 300blk and another 308. I wouldn't suspect this can either as there aren't many issues reported online.
• Bore alignment rod is perfect. Rolled it on granite to check and flipped it 180 degrees when installed to see if it aligned in the same spot each time, which it did (notice the small white mark on the bottom left of it in the photo)
• Not the SEI adapter threads as the suppressor spins in the exact same orientation as the above picture when loosened, meaning those threads are true.
• Tried shimming the SEI adapter with varying shims with no effect on alignment.

I do not know how to upload the video, but I believe I have figured it out and want opinions on this. With the suppressor tightened against the SEI adapter, I loosened the gas lock adapter so that the suppressor and adapter spin freely on the Springfield barrel. When I spin it, the gap you see between the rod and front cap follow the rotation, which leads me to suspect that it is either the factory barrel threads, or the SEI gas lock assembly itself.

I have not tried a different adapter since the Fulton Armory one is out of stock.

I am thinking of buying the Hughes Precision Adapter but am worried it isn't long enough to clear my gas plug. Also looking at Fulton barrels while I am at it. However before I start throwing parts at this rifle, wanted to see if anyone here has had this issue or can help me troubleshoot further. I believe I narrowed it down to the factory barrel threads or SEI adapter. From what I read, neither Springfield or SEI seem to have stellar feedback in the quality control department.

 

[edwea]

Cut and rethread or get a new barrel.