I had a DSA SA58 that regardless of what I did, I could not get it to shoot very well with a scope, DSA mount or whatever. Best was about 4 MOA, and that was on a good day. The rifle was capable of better than that with open sights. I sold it after about a year.
On the other hand, my HK91 (true H&K) with an
ARMS claw mount repeatedly shoots 2-MOA and below, 10-shot groups, with Portuguese or Aussie surplus, from its bipod. Not much better with reloads or more expensive ammo, though.
Another thing I really like about the HK is that even though I install and remove the scope & mount each time I take it to the range*, it has NEVER changed zero. I changed scopes once, and that was only the second time I had to zero it. (*takes too much room in the gun safe with the scope on.)
I have other, more accurate .308 rifles (DPMS Panther .308, Rem-PSS .308) but the HK91 is superb for being a battle-rifle.