It seems that you want an absolute, in a question that has several variables.
So an unknown barrel(hog hunter/ sporter) adds to the unknown in accuracy dept.

As long as you don't use a 1/2" wide chop-saw and heat the crap out of it, while cutting it; it isn't going to affect accuracy in the sense that you mean.
Harmonics will be different of course, so don't expect that the same load that USED to work will be amazing after cutting. When things change, they change. A shorter barrel will have more rigidity, so the loads will need to be worked again for accuracy.