A few of questions...
First, what is the brand of the rifle/carbine? Second, did the carry handle rear sight which you have attached to it come with the rifle/carbine or did you purchase it separately? Third, what type of groups (in size/inches) do you usually shoot with a weapon with which you are completely familiar and comfortable, at 25 meters?
All of these questions are valid... I have seen some very expensive, well known brand carbines leave the factory within the past 6 months that suffered problems with the rear sight assembly regarding maintaining zero. On one particular rifle, after 50 rounds, the group was still wandering around in a 6 inch circle at 25 meters with iron sights... We put the EOTech on the weapon and had it zeroed in 9 shots, with it shooting 1 hole groups at 25 meters for the following 9 shots. We contacted the factory and found out that they had a batch of bad carry handle sights that had gotten out of the factory.
If the carry handle was an aftermarket $25 special, you have to remember that you often get just what you pay for... I have seen carry handles that, side by side, look just as good as anything coming out of Rock River, Bushmaster (or at least when they don't have a batch get out that shouldn't, such as referenced above), or Sabre. They will appear to be locked down well and have no play in them at all - but under recoil, they will move and thus change the zero.
The third question is not one for you to answer here on the forum, but just for you to ask yourself... I don't know you at all (as far as I am aware), and I wouldn't even pretend to suggest anything about your shooting ability, positive or negative.
You could be Alvin York reincarnated for all I know! It is just important that we all understand that we shouldn't expect a rifle to make a difference in our marksmanship ability. The bullets go where we point them.
At 25 meters, in a 1:7 barrel, either of the 55 grain or 62 grain bullets should be printing 1 hole groups for you (barring weather, eyesight, or other outside factors) if you sandbag the weapon and take your time. The old 1:12 twist will not always stabilize the 62 grain bullet, even at that distance. (I've seen them keyhole many times.)
If the barrel is not new, it could be warped from someone using the old NRA "braced with sling" position such as what is seen in the CMP matches. It wasn't uncommon for barrels to warp to the left (for right-handed shooters) because guys used to heat up the barrels on full auto while using the sling position.
Another possibility even with a new barrel (we've also seen this many times) is when someone
just has to take off the flash hider to see what is underneath. They take it off, and then over-torque the barrel when they put it back on. This will warp a barrel just like the previous scenario. It was worse in the old days with the flash hiders using the split washers or peel washers. Folks just kept cranking on that flash hider in order to get the solid portion of it down at the bottom (called timing the flash hider, so that no dust would be kicked up when firing from prone and thus give away your position.) Now the factories use a crush washer that eliminates the need for all of that over-torquing of the flash hider.
About that Wolf ammo... Please, please, please (and this is meant for everyone reading this) do not shoot any brand of steel cased, lacquer coated ammunition through any AR-15/M-16 weapons system. That lacquer coating melts and flakes under the intense pressures generated inside the chamber of the weapon. It starts to build up, decreasing the actual chamber size of the weapon. This, in turn, increases the pressures contained within the chamber, and at the same time makes extraction harder. Sooner or later, one of several things will happen: a) the case head rips off (leaving the rest of the case in the chamber) causing either a catastrophic malfunction in which the next round will not chamber or (even worse) the round chambers enough so that the weapon fires and suffers an explosion when the hammer drops on the round; b) the complete fired case sticks in the chamber and the extractor is broken, in which case you have to replace the extractor and use an assembled cleaning rod to get the fired cartridge out of the chamber; c) the round only partially chambers, leaving the bolt carrier still partially in the buffer tube (you can't disassemble the weapon that way, it won't open no matter what position the take-down pin is in). In this case, you are stuck trying to drive a live round back out of the chamber with the cleaning rod down the muzzle, while the base of the round is firmly seated in the front of the bolt - the problem is that the AR-15/M-16 weapons system has no firing pin return spring (it just floats) and every blow to the front of the live cartridge causes and inertial blow of the firing pin to the primer of the live cartridge. (How is that for a "hairy situation"?) So, it is just better all the way around to use brassed cased ammunition in these rifles/carbines. The old AK's, SKS's, and RPD's were designed to take the steel cased stuff - but not the AR's. BTW - Not all lacquer cased ammo comes out of Russia or China... I saw some on the range this past Friday that was by HORNADY! HORNADY headstamp and everything... One police department had bought it for their officers to use in our AR-15/M-16 Operator's course. If you get a rifle though which someone had been running the lacquer coated ammo, get several chamber cleaning brushes (phos-bronze) and some lacquer thinner. With the rifle/carbine completely disassembled (and no ammo anywhere in the room) clean the chamber thoroughly with the chamber brushes and thinner until you can see a bare metal/chrome surface in the chamber using a good bore-scope. It makes a mess, so don't do it on the kitchen table or anywhere that will put you in the dog house.
Please let us know what you find out or discover regarding your situation. We all learn that way.
Regards,
Mike