View Full Version : 12.5 changes, progress, and pics

28 March 2018, 16:50
My other post has gotten a little bit derailed with other off topic things (though they were helpful). If the mods want to combine this, feel free, but I have a few new ideas in this thread.

I have made some changes to my original plan for this build and wanted to document them here. I am still using a Lanco Tactical receiver set (my LGS) for the pistol build and still plan on doing a form 1 in the future but am not in a hurry since I have another SBR lower registered. So for now this lower sits as a pistol.

I was originally planning on just using a KAK 12.5" barrel but once I got the barrel it is not dimpled and getting the gas block pinned was going to be more trouble than it was worth. So, I did what any other person on here would do and find a barrel with a gas block already pinned. I just kind of got lucky by finding a lightly used (<300 rounds down the pipe) Noveske crusader barrel with a pinned gas block. I was a bit disappointed to find that the previous owner tried to "polish" the gas block, but it works, so whatever. In any case, I got a higher quality barrel than what I had.

My other question in the last thread was rail length. I looked everywhere for a proper length rail to use without blowing my budget. I ended up going with a Kinetic MREX 11.5" rail which actually measures at 11.65". Perfect length for the barrel (see pic). I have to say, however, that while I really do like the profile of the rail system and the overall look and feel, I would not purchase another one of these in the future because of the DAMN STUPID BARREL NUT (I will expand on that at the end of the post after pics if you care to read on).

Overall, I am liking the progress of the build and only need a few more things to get this gun finished up. Saker mount is on the way. Planning on doing a toolcraft BCG and a Fortis Hammer CH and will have all the parts needed for a functioning rifle.


So...my love/hate with the Kinetic MREX rail. As I said before, it is the perfect length. It is lightweight. It is solid. The profile is actually pretty functional as it actually does promote a comfortable C grip as explained by the company's propoganda. The problem is the barrel nut. The barrel nut design requires the use of shims, which I don't like or dislike per se. The issue is that a large amount of shims may need to be used since the barrel nut is not symmetrical. The top of the barrel nut needs to be timed to the gas tube hole in the upper. There are opposite threads on each end of the barrel nut which can be installed in either direction. This creates up to a half turn of shimming that may be needed. As my luck would have it, the threads on my upper had the barrel nut at 11 o'clock or 5 o'clock when hand tight (depending on which way the nut was installed). When at 11 it required to much torque to time top dead center and at 5 oclock was requiring more shims than what was provided with the kit (not good). I had some other shims on hand, but the shear thickness of the shims was ridiculous and caused a wide gap between the upper and the rail and it just felt and looked shoddy (I had 12 shims of different thicknesses on there!!!).

So, I headed down to Lanco tactical with my upper, barrel, and barrel nut. I explained my problem and they brought out 5 different uppers for me to try with my barrel and nut. I found one that worked the best with my parts and they exchanged my old upper for a new one...because Lanco Tactical is like that. They actually help you solve problems and will exchange parts for you to make you build work. A lot of places won't do that.

I finally got back home and now instead of using 12 shims I was able to get it timed with only 3 shims. Much less gap, and an acceptable amount of shims now.

28 March 2018, 19:37
Can't wait to see pics of the finished product.