Hello Patrick,
According to Jim Mock-
" the bayonet lug provides a far more secure method of holding the barrel band to the barrel, stock and handguard without shifting and therefore provides far more reliable and better accuracy than the narrower barrel bands."
Found at the bottom of this link:
The U.S. Caliber .30 Carbines - Barrel Manufacturers
I have a IBM I shoot a lot that began to wander off center. I assumed the bore was getting worn as I had made no changes in ammo or the recoil plate set.
I found that the barrel band when tight had some side to side and teeter totter movement.
While tearing down to clean the Bayonet band slid very easily off the wood work and up the barrel. Normally I oil or lightly grease ahead of it on the barrel to limit scratches... but didn't need to this time. Later I took it off along with the front sight and compared it to a NOS Bayonet band. The 3 inner pads on the front end of my old Bayonet band showed a lot of wear, they looked like worn out brake pads. They stood proud on the NOS one. When I put the new one on I had to oil/grease the barrel again to limit scratches to the barrel.
After getting things back together it was accurate again. So just note those 3 inner pads that put finish wear on 3 spots on your barrel do in time wear down and don't get the bite on the barrel, stock and hand guard.
Maybe yours is doing the same thing?
On another I was getting a little forward and rearward movement of the barrel band (as much as the barrel band spring would allow).
The Band being as tight as I could get it also allowed movement between the stock and hand guard.
I used a thin strip of leather over the top lip of the hand guard (cut boot lace) as a shim.
The strip of leather snugged it up and has worked well. I've read about guys using that 2 sided tape the same way.
Guess we have to expect some wood crush after all these years... So we intervene as lightly as we can.
Good Luck, Keep in touch how things go for you.