Geissele MK8 Question

[Springer]

Just finished assembling my first sbr.

I installed a Geissele MK8 and it sits just a touch higher than the rail on the receiver and the gap where the anti rotation screws are is different on each side.

I removed it and re installed and it looks exactly the same.

Is there anything I can or should do to adjust this?

The gas tube seems good horizontally but it seems to sit a touch low so I'm not sure if the receiver is a bit out of spec or if it's not an issue at all. The bc doesn't bind or have any issues when sliding in however it does make contact with the tube.

Will post some pics up shortly.

[tostado22]

Get some pics of the barrel nut area without the rail. And of course the gaps you mention with the rail installed

What are the specs on the upper?

[Springer]

Here are some pics. I will pull the rail off and take pics of the barrel nut when I get home.

20161009_095908.jpg20161009_095918.jpg20161009_100904.jpg20161009_102240.jpg

[themonk]

Whose upper reciver?

[Springer]

A site favorite...spikes. I have put together a bunch of lowers from them and never had a problem. I found a decent deal on stripped uppers from them last year ish and bought a few.

[themonk]

Is it a blem?

No offence but I trust Bill's QC a lot more than spikes. I dont have a solution for you other than to start troubleshooting at if everything is installed correctly there is either an issue with the upper or the rail. I have dealt with Geissele's CS in the past and it was one of the best I have worked with. If you ping them they will probably tell you to send in the whole upper and will tell you who is out of spec.

[Springer]

I trust geissele much more. My first thought was the receiver was out of spec. The upper was not a blem, or at least wasn't listed as one.

I will break it down tonight and see if I can find anything wrong.

[themonk]

I trust geissele much more. My first thought was the receiver was out of spec. The upper was not a blem, or at least wasn't listed as one.

I will break it down tonight and see if I can find anything wrong.

After you break it down I would install the barrel nut hand tight without the barrel and then install the rail over it and see if there still is an issue (I would assume there will be). I would try to gather as many data points for Geissele's customer service as possible.

[556BlackRifle]

I just checked my MK8 / RA Upper and the gap is nearly the same on both sides. (Just slightly more on one side than the other.) The top rail is perfectly aligned in every respect. No difference in height or width. Probably a problem with Spikes.....

[Jwknutson17]

Looks like you put cerekote work in it and have time and money spent. I would Run it. Adjust your front sight Pin a little if needed.