They look nice and all, but some of them really have too many details. The handguards of the M4 & magazine, M16 & magazine and SR25 are the worst. Some weapons are way too thin (L96 and AK47) and octagons should do it for barrels/scopes/etc. You could give it a try making some bevels bigger or removing them.
One last thing: The suppressor on the SR25 could be thicker.