Can ejection pattern change affect accuracy?

[rabiddawg]

I was watching my daughter shoot this weekend and noticed that our 16" Alexander Arms was throwing casings in different patterns. It threw two at 1 oclock three feet away, it left two on the shooting bench at 3 oclock and two at 3 oclock 5 feet away. These were factory 123 sst's point of aim was the same for each shot.

After seeing this, I started to wonder if this could be related to the problem that started late last deer season. I blamed the accuracy problem on the scope and sent it in to Zeiss for service. Recently, I installed the scope they sent me (not mine) but wasn't satisfied with the way it was shooting so I installed a new Nikon. In my mind it shot better so I left it at that and shot it again the next day. It shot very well that morning so I thought problem solved. This whole time I am not paying attention to where casings are landing.

This is a factory gun I bought used; round count appeared very low to perhaps never fired. For two plus years I killed everything I shot at. I was supremely confident in this gun until I missed the last three deer I shot at last season. After the third one, I set up the bench and a target at 200. It put the first two bullets 1 inch apart but six inches left of point of aim; the next two were 1 inch apart but six inches right of point of aim.

I blamed the scope but was I wrong?

If so what should I do (if anything) to correct the ejection inconsistencies?

[Drifter]

The inconsistent ejection pattern is likely not causing an accuracy issue, but perhaps it's another clue that something isn't right. 6-moa groups at 200 yards is cause for investigation.

In addition to checking scope and mounts, check for other things like a loose gas block or barrel nut. Something seems amiss.

[rabiddawg]

Thanks Drifter, that's where I will start.

[Double Naught Spy]

Sounds like a lot of confusion. Ejection patterns do not cause anything, but as noted, maybe symptomatic ... and may not.

Since you have blamed scopes apparently incorrectly, I would suggest getting another shooter, a good shooter, to work with the rifle.

What ammo are you using?

[LRRPF52]

Need more info about the gun:

* Upper receiver, to include any markings on the side in white lettering

* Type of handguard, barrel nut

* Was this a complete upper, or assembled from parts

Pictures would help.

[lamrith]

Along with what Double and LRRPF52 said I would even recommend you put the good/other shooter on a sled or real good bag set-up to further isolate the gun from shooter input and narrow down the issue.

[rabiddawg]

Sounds like a lot of confusion. Ejection patterns do not cause anything, but as noted, maybe symptomatic ... and may not.

Since you have blamed scopes apparently incorrectly, I would suggest getting another shooter, a good shooter, to work with the rifle.

What ammo are you using?

Really not much confusion.

Bottom line is my systems accuracy went away for some reason.

The shooter is not the problem. The issue started lasit season with me behind the gun

The ammo is factory Hornady 123 sst as stated in the original post.

[rabiddawg]

Need more info about the gun:

* Upper receiver, to include any markings on the side in white lettering

* Type of handguard, barrel nut

* Was this a complete upper, or assembled from parts

Pictures would help.

The upper is marked ALEX-A. 6.5 GREN in white
The lower has a shield logo with A A and Alexander Arms LLC etc. it is also stamped as Gren

I bought the gun from an individual and assume it is a AA built gun.

The handguard has no markings at all. It is a two piece, plastic with aluminum heat shield inside. It tucks under a lip behind the gas block and is held on the other end by a spring loaded round bitch of a ring.

The gas block appears to be pinned and has what looks to be a bayonet lug on the bottom.

The barrel nut is round and has 20 teeth around the outter edge. I have no idea of what to call it.

[rabiddawg]

Along with what Double and LRRPF52 said I would even recommend you put the good/other shooter on a sled or real good bag set-up to further isolate the gun from shooter input and narrow down the issue.

Have had it in a lead sled and on bags. Thanks

[rabiddawg]

Fwiw, i also invested in a torque screw driver and torqued the rings to 25 inch pounds and torqued the base nuts to 80 in pounds.

[rabiddawg]

As for pics, i would be glad to email them to anyone interested. Or can pics be posted from an iphone?

[rabiddawg]

I also need to add, the day i was shooting with the ziess mounted i had been shooting several different guns, 223, 243, 300 wsm. I changed the scope on the grendel and tried to set it 1" high at 100. It didnt shhot bad just not what i was accustomed to it doing. Thinking i may have been pounded enough for the day i packed it in til the next morning.

The next morning i set up my bags and put two bullets 1" high at 100 about an inch apart. So i left it at that until i noticed the ejection issue. Then i got to thinkin and that aint always a good thing.

[NugginFutz]

rd - a few thoughts, not necessarily related.

Just off-hand, those torque #'s seem high, to me. Unless those are the manufacturer's recommended values, I'd suggest going to 18-20 in/lb for the rings, and 30 for the base. The 80 on the base nuts probably won't hurt the accuracy, but that puts the nuts at near shear levels.

I also wonder if you've ever tried a different mount. If nothing else has changed, including your abilities due to injury or the like, then it seems to me that the only thing that may have occurred is the interface between the rifle and the optics. Since you've tried with various scopes, that would seem to leave the mount (a not unheard of source of inaccuracy). What mount is it? Is it a single piece mount or are you using separate rings?

Lastly, as far as the ejection pattern is concerned, you could consider checking the over all health of the bolt assembly - this would include checking for worn/damaged extractor and weak/damaged spring, as well as an inspection of the lugs. Depending on the round count, it may be time for a "spring" tune-up. Further, any debris in the ejector pin hole (brass shavings, etc.) or weak ejector spring can also cause improper ejection. Consider disassembling the bolt completely and blasting the thing with brake cleaner.

That's my 0.02.

[rabiddawg]

Its a burris pepr mount.

I have never disassembled a bolt before but will google some instructions and see what happens.

Duly noted the torque advise. I will back off a bit in the future. Thanks.

[NugginFutz]

Yeah - that PEPR has 6 screws per ring, and only requires 18 in/lb. of torque. You don't want to squeeze that scope tube too much. On my PEPR, I torque the base nuts to 30-35 in/lb. More than adequate. For bolt disassembly, a really good tool to have is the Brownell's AR15 tool -keeps the little ejector from going AWOL when you drive the retention pin out. Also makes re-assembly much easier. Periodic bolt disassembly and cleaning is recommended on a regular basis, especially if you're seeing any brass/debris on the bolt face. Mine gets scrubbed and soaked about twice a year, depending on use.