Charcoalburner- Mistwolf what quirks are you referring to in the HK and what clones are u saying to stay away from?
I don't say stay away from clones, although any HK91 or CETME clone built by the Angry Beavers (Century Arms) is suspect until it proves itself. They have far too many QC issues to be trusted- something I can attest to from personal experience.
PTR makes a quality HK clone. Serial # with the "A" prefix means the rifle was made by PTR and are reliable.
"B" prefix means it was sold as a receiver only and built by an outside source. Some are of the very best quality, some you should just run from as quick as possible.
"AW" prefix are rifles of later manufacture by PTR. Chances are they use a barrel made by Thompson. These rifles are reliable only with certain types of ammunition as the chamber flutes are fewer and shallower than mil-spec. PTR will not guarantee the PTR-91 will function with any ammo than what they reccomend.
First of all, you have to realize the HK is very German.
Quirks: If you reload, it's hard on brass. Not just the flute marks left on the outside, but the HK is known to often dent the spent brass on ejection. It's also known for tossing your brass two or three zip codes away.
Ever heard of the "HK Slap"? You pull the charging handle all the way to the rear & lock it to hold the bolt open. Insert a fresh magazine and slap the little cocking handle to release the bolt and chamber the first round. It's really kinda cool. But since the rifle doesn't lock the bolt back with the last round, you have to flip out the charging handle which unlocks the bolt and haul it back yourself. It's awkward to use while the rifle is mounted to your shoulder.
Bolt gap is a critical setting. If the bolt gap is too small, the rifle will kick you harder than Missouri mule. As the rifle wears, the bolt gap shrinks. To reset it, you replace the rollers with oversized rollers. If the barrel is set wrong, you'll have a hard time setting the gap correctly. (Don't remember what the gap is supposed to be. The barrel being set & pinned in the wrong place is something the Angry Beaver clones are known for.)
There is a hump where the buttsock meets the receiver. It's at the perfect place to rest against your cheek as your peering through the sights. It's also at the perfect angle to give you a nice case of cheek slap if you're not careful.
When you remove the bolt group, it's easy for the bolt to retract in the carrier and rollers to pop out into the locked position. If you don't know the Secret Handshake to reset the bolt & rollers, you'll never get them back in the receiver.
It's European. The safety is hard to reach for most Americans because we're taught to carry long arms with the muzzle up. To reach the safety without removing your hand from the pistol grip, you need to tilt the muzzle down. (Same is also true for the Fal.)
It's a delayed blow back system. A straight blowback system has to use a heavy bolt group and strong springs compared to a gas system. A blowback system also does not lock the bolt to the action and begins to open as soon as the recoil overcomes the inertia of the bolt & spring pressure.
The HK system simply delays when the bolt starts opening. The roller locks hold the bolt in place while the recoil impulse shoves the bolt carrier to the rear. As the bolt carrier moves back, it lets the roller retract so the bolt can then begin to open. Very simple in operation, it's different than what most are used to and definitely quirky.
All rifles have their quirks. The HK roller locked rifles have some rather unique ones. I like HK roller locked rifles. They're reliable, accurate, and have a very unique Teutonic personality