AR15 upper assembly question

[Koda]

Another inquiry.

Snap a picture of your iron sights on the rifle you were able to group well with. If they are heavily adjusted as well, you should be able to determine if it is the scope or upper/rail. Most irons don't require a ton of adjustment if mounted to a properly made rifle with decent components.

Good suggestions. Both uppers irons dont seem to be over adjusted. But this made me think that maybe the scope was maybe close to maxxed out on the old upper.... I should do a bore sight to see if I can check how much travel was used, if a lot or near the maxx... Its the scope.

(Pic of old upper sight... Hard to tell...)

 

[308]

Maybe try to cowitness the dot with the zeroed irons...the issue should become apparent then.

 

[Member 34319]

Good suggestions. Both uppers irons dont seem to be over adjusted. But this made me think that maybe the scope was maybe close to maxxed out on the old upper.... I should do a bore sight to see if I can check how much travel was used, if a lot or near the maxx... Its the scope.

(Pic of old upper sight... Hard to tell...)View attachment 1009441

If the sights are not overly adjusted, I'd come to the conclusion the upper/barrel are within reasonable spec and not horribly off. If you started with the optic on the last uppers zero, and had to further adjust and ran out of adjustment, which is kind of questionable especially if both of the two uppers have the same barrel lengths, than I'd say the optic is at fault or the mount is at fault. A decent scope should not need 10-20 moa of adjustment in any direction to zero an AR15 in 223 at 100 yards. Only exception being if the mount has built in moa, which is done to allow further adjustment for long distance shooting, but if that's the case, you could literally start from centered and just adjust the amount of pre moa in the mount and be close to that 2.9" low again.

 

[Koda]

If the sights are not overly adjusted, I'd come to the conclusion the upper/barrel are within reasonable spec and not horribly off. If you started with the optic on the last uppers zero, and had to further adjust and ran out of adjustment, which is kind of questionable especially if both of the two uppers have the same barrel lengths, than I'd say the optic is at fault or the mount is at fault. A decent scope should not need 10-20 moa of adjustment in any direction to zero an AR15 in 223 at 100 yards. Only exception being if the mount has built in moa, which is done to allow further adjustment for long distance shooting, but if that's the case, you could literally start from centered and just adjust the amount of pre moa in the mount and be close to that 2.9" low again.

Agree.
The old upper is 16", the new is 18". I always zero open sights first then zero scopes. Had no problems zeroing both on the old upper. Had no problems zeroing the open sights on the new upper.... Swapped over the optic and it wont zero. The scope base is 0moa.

Youve given me some good ideas to test when I get home (traveling). I want to put the optic on the old upper and bore sight it to see if it used almost all its elevation... That would tell me its the optic.

 

[Kruel J]

UTG "optics" are cheap junk. That's a known fact. If anything, this gives you a reason to ditch that paintball-grade gear and upgrade to something that will last. Even a cheap Bushnell is better than UTG.

 

[Koda]

I know i know...
I just wanted something to get by and experiment with since I dont shoot this rifle a lot.

 

[Kruel J]

I know i know...
I just wanted something to get by and experiment with since I dont shoot this rifle a lot.

Oh I can absolutely appreciate that for sure. But.......and I kinda mentioned this before.....you're looking for a problem with your rifle that is POSSIBLE but incredibly RARE instead of starting with the obvious. It's not so much that I'm trying to "force" you to ditch that UTG but I know you are a shooter and honestly that scope you have should be on a paintball or airsoft toy, not your firearm.


You're better than UTG crap my friend.

 

[Koda]

Ok, Ok, ....ill get a nice... A real optic for this.
Good to have friends looking out for us...

 

[Kruel J]

Ok, Ok, ....ill get a nice... A real optic for this.
Good to have friends looking out for us...

I've seen you shoot, and I KNOW that you will put a quality optic to good use.



All that said, if the receiver is indeed out of spec that much it will be the first time I've ever seen that.

 

[edzz]

A few thoughts.

The scopes age has nothing to do with when / if it may fail.

Can you mechanically zero the scopes windage / elevation settings using the mirror method? If not it's the scope.
Not the greatest video but it gets the idea across. https://www.youtube.com/watch?v=GZ-pF52t4TQ

Also you can try turning the scope 90 degrees in the rings so the windage is now your elevation adjustment as a test to see if the scopes elevation adjuster is wonkey. This combined with bore sighting may indicate what's going on.

My vote is the scope has failed.

 

[HB of CJ]

Yes. Several possibilities. First, (but not most likely) is the upper receiver front face is not square. They now make a nifty truing shaver to check and correct this. Quite cool. You just want to square the face.

I do not think proper barrel torquing techniques would enter that much into it. Various ways to put on a barrel. I was taught that the upper floats and the barrel is locked down. This may have changed today.

The top receiver rail may not be square. The scope mount rail may not be square. The rings may not be square. A .22 laser tool is a good way check parallel with the bore and scope. Center the adjustment.

Unlikely the barrel is bent. Have somebody run a series of .223 bore straightness gauges down the bore. It does not take much to throw off impacts. Also make sure the scope adjustments are centered.

Or ... like already said, try another scope. Usually one gets what one pays for. Just saying.

hundreds of builds but years ago and far away. How times flies.

 

[rob1516]

UTG

 

[308]

Ok, Ok, ....ill get a nice... A real optic for this.
Good to have friends looking out for us...

Just bend over and get an Eotech or MRO

 

[Idaho44]

BORE sight the upper without the BCG in place and then check the mounted scope to see if it matches the bore sight picture. Only need a "sighting object" 25 to 50 yards away. 100 would be ideal but sometimes it's better to start closer.

 

[CV-66]

do you have the scope base(s) clamped half onto the receiver and half clamped onto the handguard rail? would help to see a photo or two of your setup

 

[titsonritz]

Just bend over and get an Eotech or MRO

https://www.northwestfirearms.com/threads/trijicon-mro-at-midway-350-low-mount.383144/#post-3026721

 

[Jonnyuma]

I was having some issues getting a similar "budget friendly" build on track earlier this year. The culprit turned out to be me, but there might be something in this thread that can help you out...

AR Accuracy Question.

This involves an 18" JSE upper mated to a PSA lower. A couple of typical extras (B.A.D. lever, BCM charging handle, stuff like that), nothing to effect accuracy. Two new variables; 1) R&R barrel to replace drop-in handguard with a FF tube (ALG Defense). 2) Added a Vortex Spitfire 3x red/green...

www.northwestfirearms.com

 

[Koda]

Home from travels for a few days, did some tests suggested in this thread.... long story short its the UTG scope.

No promises I will buy anything soon but need something to home in on. Help me decide on a new scope for this rifle... Im not a tactical operator and more of a practical hunter. This is my "freedom rifle" though so Im wide open but I see myself more using this as a backup hunting rifle than anything. I have a 30mm cantilever mount with thumscrews since I also enjoy using the open sights. I lean to simple hunting style reticles and want a variable starting in the 1x low end. Bonus points for an illuminated reticle...
At the top of my list in the "buy once cry once" category is the Leupold VX®-3HD CDS 1.5-5x20mm firedot. Im a huge Leupold fan but this is a bit over my budget.... Next is the Vortex Strike Eagle 1-8x24 ...if I could be convinced to spend the coin it would be between these two.
At the very bottom of the list is a budget friendly Primary Arms 1-4x24 SPF illuminated... simple, cheap but I could work it. No idea if its another lemon so be brutally honest...
Help me pick a scope for this rifle... convince me to "buy once cry once" or show me a good but budget scope in between.

 

[American123]

I can't believe that a UTG scope warranted 3 pages of back and forth to figure out if the scope had an issue. PSA can have some quality control issues at times but they aren't THAT bad.

I'd bore sight the upper at a shorter distance and see if I could get the UTG scope to match. Personally, if the upper receiver was physically out of spec that you run out of adjustment on the scope I would presume you could visually see the out of spec it issue on the upper.

If the MBUS zero was fine and they don't look crazily over adjusted to compensate, it's rather obvious the scope at that point.

 

[titsonritz]

Home from travels for a few days, did some tests suggested in this thread.... long story short its the UTG scope.

No promises I will buy anything soon but need something to home in on. Help me decide on a new scope for this rifle... Im not a tactical operator and more of a practical hunter. This is my "freedom rifle" though so Im wide open but I see myself more using this as a backup hunting rifle than anything. I have a 30mm cantilever mount with thumscrews since I also enjoy using the open sights. I lean to simple hunting style reticles and want a variable starting in the 1x low end. Bonus points for an illuminated reticle...
At the top of my list in the "buy once cry once" category is the Leupold VX®-3HD CDS 1.5-5x20mm firedot. Im a huge Leupold fan but this is a bit over my budget.... Next is the Vortex Strike Eagle 1-8x24 ...if I could be convinced to spend the coin it would be between these two.
At the very bottom of the list is a budget friendly Primary Arms 1-4x24 SPF illuminated... simple, cheap but I could work it. No idea if its another lemon so be brutally honest...
Help me pick a scope for this rifle... convince me to "buy once cry once" or show me a good but budget scope in between.

Color me shocked. My advice is don't get another cheap LPVO instead get a solid red dot, see post 56.