Hi guys!

I mounted an Ultimak on my Arsenal AK. I noticed that after I mounted it, my groups opened up noticeably.

I followed the directions and attempted to center the mount (leaving a tiny space between the rail and the gas block and trunion). I noticed in a video on Youtube (can't find it anymore) where Jim Fuellar stated that he disagreed with those instructions and mounted their Ultimak rails up against the trunion (I think trunion and not the gas block).

My first question is, what are you guy's opinions on this? My second question is, could this mounting method be part of my accuracy issue? How can I resolve this?

Thanks!

after shooting with ultimak and irons the groups opened or with red dot the group opened?  same ammo?? i have had quite a few ultimaks on my arsenals and never had an issue... I usually made sure my ultimak was mated up to where it needed to be on gas ports by gas block and tighten them down. and allwasy mounted red dot as close to receiver as possible..  never had a issue one thing is cheaper reddots and heat.... did this a couple years ago

https://www.akfiles.com/forums/threads/ak-47-ultimak-micro-temp-results.349458/#post-4713329

I believe that the iron sights opened up as well.

I felt like the mounting brackets altered the barrel harmonics. I could be wrong of course.

I plan to move my optic back on the receiver using an M.I. mount. This is to move the center of gravity back.

I have a couple of Arsenals with Ultimaks and Aimpoint Micros, and the groups aren't noticeably different from when I sighted them in with irons prior to mounting the optics. If anything the red dots helped me tighten them up a bit.

Mine aren't snugged up to the barrel or the gas block, per the instructions. I do have the optics mounted towards the rear of the rails which allows me to fit a Surefire M340 to the front end of the rail.

It's been a long time ago, but I think I had to a little hand fitting to get my Ultimak rail to just fit on my WASR.

If it's so tight it binds, or worse it's loose, your are going to introduce harmonics into the system.

I can't see the iron sights, so everything is an improvement for me. I'm using a 2.5X handgun scope with crosshairs on my rail and it shoots great up close and further away.

I haven’t found any detriment to accuracy due to the addition of Ultimaks. I have 6 of them I think.