I bought my $499 AES-10B RPKs without bipods from J&G and really love the thing but I always regret that they are not original configuration with bipods. When PSA put out the same AES-10B with bipods, I bought them again. With the bipod, the group seems like opens up significantly and worst if I let the rifle supported by bipod only not holding it down with my hand. At first I thought I got a bad one and then realized maybe is the bipod doing it, holding it down and shrinks the group significantly but still much larger than my AES without bipod! With the bipod, it affects shooting from the rest as well. So, is there a shooting technique that I am missing?

I wish I could tell you,  I took my bipod off, put the original muzzlenut back on and took it to the range to shoot for groups at 100 yards but the scope rail must be off because scope turret wouldn't turn anymore (or I'll try another psop)  ...as usual I always end up hip shooting on a rest with "rattlesnake finger" and trying the walking fire technique.

one day I'll shoot for groups with some m67, GT and WWB

I have a few of the Yugo RPKs. I like the bipod because it's how the weapon originally came. It was a machinegun anyway so I am not really concerned with grouping other than initial zero.

Mine seems to be accurate with the bipod. I have no problem hitting steel plates at 200 yards.

at 50 yards I can shoot the wire stands that hold up political and garage sale signs...
at 100 yards I can hit a gong the size of a head all day long

This is using the shimmed shorter bipod that my AES10b came with.

I was also using a 8x POSP scope :)

I have a Krebs Yugo RPK. I don't particularly "like" the bipod for shooting, as it is too tall for me. I do like the way it looks, however and I'll leave it on.

When I had my 4x PSO dialed in, my AES-10B was a tack driver compared to all other 7.62x39 rifles I own. Bipod deployed, shot about 2-3" group at 100/200yd consistently. Standard length RPK bipod.

POI changes significantly with bipod folded up, like nearly a foot higher. Crazy. It obviously puts a lot of tension on the barrel, but it may also be because of how tight the cleaning rod is, and the bipod clamps down onto it when anchored in place

I have considered removing the bipod and fitting one of my Bulgarian AK-74 buttstocks to it. I figure it would be a very accurate AK in this setup.

I have never done mag dumps with the rifle. Bought it for collector interest, but didn't expect it to be as accurate as it is. Ironically when I shoot the RPK I fire less ammo than I do shooting a standard AK. Only problem is the POI shift of the bipod.

It's a copy of a RPK, they weren't designed to be shot for groups. They were designed to put a bunch of bullets down range as suppressive fire. I have a AES10B and a Valmet M78 and I don't shoot either of them off of benches because these were never meant to be used that way. When lying prone I can easily keep my shots in a torso sized target at 300 meters which is plenty good enough for me. If you think about it, with a bipod mounted at the front of the barrel and attached to it, not only is there upwards pressure on the barrel, but the harmonics are altered also.

The Valmet will easily out shoot the Romanian as would be expected, and now that I have a scope on it, I am going to see what it can really do just for the heck of it.