...they were so cheap that it was absolutely worth risking.
Per BSA, the Sweet series is not springer rated. The large spring is to hold the objective in place against the adjusting ring. The internals, erector tube, reticle and adjustment assembly has to be strong enough. That being said, I have had a Bushnell AR223 4-12X44 on my Trail NP2 for about 8500 rounds with no problem.
I have found that a designed scope for the AR automatic worked out good for me. I used the abuse of "full auto" logic, for selection. This scope has held up for over 10 yrs on a 12fpe fixed barrel. The Hammers make was my selection. It's a 3-9 compact.Would this same scope work on a tough shooting 16fpe rifle? Who knows...Balancing your optics is a biggie. Name Brand means nothing. Lotsa Hawke horror stories.Cheaper scopes are Chinese Scopes. But they also make some good and tough scopesA scope that stands up to FfUll AUTO" FIRING,,, is designed for abuse for most.Glass vs. Toughness is your personal choice. Todaay's Glass is actually quite good.