I recently purchased a PTR 91KF from PTR Inc.
Brother Kyle owns the 18″ barrel version and we were so impressed with it I decided that I would pick one up as well.
This is a clone of the HK 91, which is the semi auto version of the HK G3. They are built from HK blue prints and on machines licensed by HK to the Portuguese when that army was using the G3.
The only issue we have had is that both new rifles ding the brass on ejection, likely due to the extractor gripping the brass too tightly. There have been no resulting failures to operate but the brass needs to be reformed in order to reload it. A proper break in will likely resolve this issue, but if not a bit of adjustment to the extractor will.
If you have an interest in a rifle of this type, you will not be disappointed with a PTR.