AR Sponsor
Posted: 1/1/2014 1:22:15 PM EDT
| have a RRA ar-15 and i have put 2 different scope rings with and without risers with 3 different scopes and on every occasion i run out of elevation adjustment...e.g. with elevation turned all the way up i still have to shoot 8 to 10" low to hit target @100yds. its like the upper reciever is pointed skyward...what are my options besides turning it into a boat anchor?????/ |
|
Pull the upper off. Pull the BCG out. Set the upper on a set of rests. Stand back about two feet and look through the bore at a target 50 yards away. Center the target in the bore. Get close to the scope without touching the upper. Check the reticle alignment. Adjust the reticle. Repeat until the target in the bore and the reticle are roughly aligned. Now shoot and fine tune the reticle. |
|
Anytime I hear "rings" or "risers" I immediately think "junk".
AR15 scopes should generally be mounted using quality scope "mounts". They start at around $50 and go up from there. This is not a common issue, I'd bet your problem is in the rings/risers you are using, or trying to bridge the connection by attaching one to the receiver and one to a railed handguard? Can you post pics of your setup? |
|
Quoted:
Pull the upper off. Pull the BCG out. Set the upper on a set of rests. Stand back about two feet and look through the bore at a target 50 yards away. Center the target in the bore. Get close to the scope without touching the upper. Check the reticle alignment. Adjust the reticle. Repeat until the target in the bore and the reticle are roughly aligned. Now shoot and fine tune the reticle. This works very well for me. Sighted in a red dot today doing this and was within 3 inches at 100yds. |
|
I guess I'll ask another question. Too late to go to garage for levels.
Does the barrel run parallel to the upper rail? If so check to see if upper is out of spec. If so RRA should provide new upper. Replace upper yourself. Use Burris Signature Rings with Offset Ring Inserts. |
|
i dont have machinist tools but free hand measuring the flat top to the bottom of the scope is equal if not very close... the only conclusion i can come to in my pea brain is this barrel is pointing upwards.. i gave up trying to hit a 200 yard 1 foot round target it seemed the round was still shooting skyward.. so really this all above my wit being so new to this, unfortunately i live in a small valley, so it appears perhaps i will have to send the gun off to someone that knows wtf is going on... so bummed.. just wanted to kill a few song dogs, now here i sit with all the gear and NO rifle.. pissed
|
|
I think I would be checking the allignment of the barrel to the top of the upper. If the opening in the front of the upper was not cut or threaded square to the axis of the upper then the barrel and the upper are not in allignment. Sounds like there is a slight upward cant to the barrel in reference to the upper. Assuming your barrel has an area that is of even diameter (not tapered) mount the upper in a vice and set it so that you fine level left to right on the upper, and level front to back on the barrel. The top of the rail should be level with the barrel level, if it's not then there is a production problem with the upper as the axis of the upper and the mounted barrel do not match. Now this can be a "lesser" issue if it's simply the face of the upper is uneven. A solution to this can be to lap the face the front of the upper as the front edge of the upper where the barrel extension meets the front face of the upper. Lapping the upper receiver with a lapping tool and compound can correct minor faux pas with the manufacturing, but minor machining may be necessary with something drastically misformed (which this is sounding like it might be). I personally lap all of my uppers before I build them and this has never been an issue with me, and i do believe it makes sighting my rifles easier as the lapping tool will tell you very quickly how well your upper was made.
Here's the one I use, and I use the 600 grit compound. Most use the 300 grit but I like to have a bit more control and take my time to get it right. After just 15 or 20 seconds of use you should be able to see what is being contacted and what is not, indicating the imperfections to the face of the upper. If it hones evenly then the barrel opening in the upper is not alligned with the axis of the upper and that cannot be fixed. http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/receiver-tools/ar-15-m16-upper-receiver-lapping-tool-prod20220.aspx Here's a decent article about it in, of all places, Shotgun News: http://www.shotgunnews.com/2013/03/22/squaring-the-ar-receiver-face/ Like I said I do this to all of mine before they are ever built and it seems that all of them need it to some extent. I'm not sure how big of a difference it makes but I only use quality barrels and they all shoot very well. It would seem to me though that if the face isn't true the barrel isn't evenly torqued around its circumference and can therefore cause accuracy issues, so to me this makes for one less thing to worry about. If it's under warranty because it's new though I think I'd be sending it back to the manufacturer. Whatever you choose good luck with getting it corrected. |
|
Just as a thought, have you tried contacting RRA for technical/customer service? We can even bring it at no cost to you (assuming it's a complete RRA upper half) in to have a look at it if necessary. Factory assembled upper halves have a limited lifetime warranty...
Steve/RRA |
AR Sponsor