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View Full Version : Does Upper to Lower fit affect accuracy?


Teletiger7
11-27-2007, 9:42 PM
Just put together another OLL rifle recently and noticed that there is a little bit of play between the upper and lower when they are put together. It's not really that noticeable unless i really wiggle them in different directions, but I'm wondering if this affects the accuracy all that much. A previous build that I did doesn't do this and is snug. I'm sorta new to ARs in general so I'm hoping any of guys might be able to answer this question. Thanks

chuck762
11-28-2007, 3:21 AM
Doesn't make a bit of difference. The bolt, barrel and sights are all on the upper so having a little movement between the upper and lower doesn't affect anything. If the sights were somehow mounted to the lower then it would affect accuracy as the barrel may be pointing in the same direction every shot.
The play might bother some enough to try and tighten it up but it is just a personal thing.

uscbigdawg
11-28-2007, 6:50 AM
FINALLY!!!! Someone understands!!! I could seriously hug you.

Rich

ar15barrels
11-28-2007, 8:06 AM
If it plays with your mind, it can effect the group size.
If you decide that it's not important, you won't notice the difference between a loose gun and a tight gun on the target.

Put another way, if it bothers you, fix it.
Otherwise get on with more important things like sight alignment and trigger squeezing.

Sgt Raven
11-28-2007, 9:31 AM
If you have a sub MOA rifle and you're shooting at 300+ yards you might see a difference. Just like you can change the way a bolt action rifle shoots by changing the tightness of the action screws. ;)

uscbigdawg
11-28-2007, 4:31 PM
SGT Raven,

Have to disagree. My 3-Gun rifle shoots sub-MOA all day. And like Randall mentioned unless it's playing with your head, there is no mechanical reason that it would change. A shooter's psychology is not the fault of the rifle.

Rich

Sgt Raven
11-28-2007, 4:55 PM
SGT Raven,

Have to disagree. My 3-Gun rifle shoots sub-MOA all day. And like Randall mentioned unless it's playing with your head, there is no mechanical reason that it would change. A shooter's psychology is not the fault of the rifle.

Rich

For running and gunning you won't see the difference, but if you sit down at the bench with a real rest and rear bag you could see it. If the rifle doesn't recoil the same every time the group will open up.

5968
11-29-2007, 5:21 PM
If it plays with your mind, it can effect the group size.
If you decide that it's not important, you won't notice the difference between a loose gun and a tight gun on the target.

Put another way, if it bothers you, fix it.
Otherwise get on with more important things like sight alignment and trigger squeezing.

Amen! Take it to the range and out some rounds through it.

uscbigdawg
11-29-2007, 6:17 PM
sarge - shoots .25 MOA all day. I've benched it more than a few times.

Rich

Fjold
11-29-2007, 6:38 PM
The only real way that it would affect you is if the upper is loose enough to move when you squeeze the trigger or when the hammer falls. Because the hammer is mounted to the frame and the upper pivots on the front pin. If the upper moves during the time that the hammer falls the the POI will change.

Ahhnother8
11-29-2007, 8:06 PM
I used to shoot a spacegun out to 1000 yards quite a lot, in competition with iron sights and a sling, prone. The upper and lower were not tight, but not sloppy loose. It didn't seem to make much of a difference. I did put in several Accu-wedge's, but they compressed over time, so got progressively looser. :confused: I only shoot the spacegun out to 600 yards now, and things are MUCH more forgiving shooting this close. So, tighten things up for some peace of mind if you must... :eek:

Lane