Upper \ Lower Play

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Originally Posted by spleify

Upper and lower play is somewhat common and does have the potential to mess with accuracy but not likely.

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How can {normal and reasonable} upper/lower play mess with accuracy?

I've done a little informal testing on a combat-oriented carbine and I did not find any degradation of accuracy.

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Originally Posted by TheBelly

I've done a little informal testing on a combat-oriented carbine and I did not find any degradation of accuracy.

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Yep. A "combat-oriented carbine" probably won't notice any difference either way. But, if you were putting together a "precision" type rifle you might see 1 MOA groups instead of 1/2 MOA. Unless the thing just rattles around to the point where it bothers you I wouldn't worry about it too much.

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Originally Posted by TheBelly

How can {normal and reasonable} upper/lower play mess with accuracy?

I've done a little informal testing on a combat-oriented carbine and I did not find any degradation of accuracy.

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Well, first off you even quoted where I said its possible but not likely but you can read and twist it however you want, but if you want to get picky about it, its simply physics, if the upper and lower move it WILL effect accuracy, and like Ray stated it will not be noticeable on a "combat carbine" but for precision rifles you will see it.

And while we are at it, who is to say what is "normal and reasonable" play....is it just "normal" because its what we've come to be used to?? Just because we have tolerated sloppy upper/lower play its now suddenly become "normal"??.......

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Originally Posted by SouthPaw

I bought a seekins billet lower and it has an adjustment screw for lower to upper retention.

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Easy drill and tap operation.

I dont mind a little wiggle. Too tight and it can make taking the upper off or breaking it down a pain.

If you want to try and make a benchrest gun out of your AR then yes it is a good idea.

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Originally Posted by spleify

Well, first off you even quoted where I said its possible but not likely but you can read and twist it however you want, but if you want to get picky about it, its simply physics, if the upper and lower move it WILL effect accuracy, and like Ray stated it will not be noticeable on a "combat carbine" but for precision rifles you will see it.

And while we are at it, who is to say what is "normal and reasonable" play....is it just "normal" because its what we've come to be used to?? Just because we have tolerated sloppy upper/lower play its now suddenly become "normal"??.......

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OK, if you took my post as an attack, that was not my intent.

I don't think upper to lower slop can affect accuracy. If the upper is locked up when the gun fires, then the lower can't really affect the accuracy. All the magic is happening strictly within the upper, which, again, should not have any play in the barrel-to-upper, bolt-to-receiver extension, etc. This is dealing strictly with the mechanical accuracy of the gun, and not including user inputs, such as poor fundamentals, uneven pressures on the gun, etc.

there is an acceptable amount of play, and it has been codified in the Technical Data Package for the military M4. I can't remember it off the top of my head, but Astandard exists.... whether or not that standard translates into platforms made by other manufacturers is up to them.

The combat-oriented carbine I used was my stanard issue M4. I used same lot of ammo, same range, same day (atmospherics), etc. The only thing that I changed was that for one testing group I put the accu-wedge in, and for another group of testing I took it out. I saw no difference.

I've taken to using o-rings to tighten up the fit too......but i hate rattles, wobbles, wiggles, etc. (I'd have gotten rid of the buffer spring if there was a cheap non-noisy alternative). I put one on the front lug though.