i dont want to sound like i am being rude to you but... is that your opinion or is that a profenional opinion? What is your back ground againg please don't take this the wrong way i am just trying to learn like most of us here, I am a metal fabricator, welder.
No offense taken, BTW my current profession is a turret press operator.
Professional opinion, well since I'm not a paid gunsmith no, but I have a fair bit of hunting and target shooting experience under my belt, and read, and seen quite abit...Not to forget the countless hours I have spent talking to those that are professional gunsmiths on this very issue.
For a better description then what I have offered open any Lymans reloading book, and you will see a whole page devoted to barrel harmonics, it is most excellent.
Of note... I have this sweet Swedish Mauser sporter that someone put in a Ramline stock. And in spite of ammo type used I could get no better then 3" groups at 100 meters, mean while my full wood version gets 1" groups at 100 meters.
So I slid some paper down between the barrel and the stock, and sure enough there was contact on the left side. Out came the dremel and I honed down the high spot defect in the plastic stock, and like magic my barrel shot the same groups as my full wood version.
So take a close look at the rivet holding the bayonet in the lug, and even how tight the cleaning rod is.
It is reasonable that extending the bayonet or adding a bipod or hanging a roll of toilet paper from the end of the barrel may affect the point at which the bullet leaves the gun and thereby affecting its point of impact.
Bingo!