I have an American Spirit, 24" SS bull Lothar Walther bbl with a 1:8 twist.  Accuracy is mediocre at best.  3 shoot groups yield 2 shots within  3/4" then a flyer taking the group out to 1 1/2".  I am shooting 75gr, Black Hill Blue Box.  I've tried 75 gr hand reloads, 62 gr 69 gr amd 55 gr.  As expected the 55 and 62 have a wide spread, the 75 and 69 are better.  A gunsmith who does a lot of AR work checked the gun over today and he indicated to me that the gas port measures .101, and it should be no bigger than .089.  He indicated that this can cause accuracy problems.  No matter what I do, or who shoots the rifle, I cannot get a decent 3 shoot group.....and this is what I hoped for (sub MOA at 100 yards), just me competing against myself.  Does the gas port make that much of a difference?  I want to visit ASA tomorrow, but I want to have info in hand from multiple sources.  Please help me.
Thank you.
Gus  

Not IME, one well know maker of ARs, and one that repeatedly touts the accuracy of their products, uses a .104 gas port in their 20" and 24" barrels. In general, larger diameter barrels have larger gas ports but the final size is determined by function.

[s]I don't see Lothar Walther barrels on ASA's page,[/s] seems odd that a bottom feeder company would offer such high end barrels. How is the barrel marked?


[found it in their catalog]

What a way to destroy a Great barrel blank; perform a shitty reaming on the chamber, and throat the chamber way too long.



Hand them the barrel back, and go find another supplier that actual know how to turn and ream a match chamber for a match barrel blank.

P.S. If you don't know, ASA is the one how profiles and reams the barrel blank, Lothar Walther just supplies them a rifled tube that  they transform into the barrel.

Read this:
[url]http://www.compasslake.com/barrels.htm[/url]

Thank you Tweak and Dano.  I'll see in about 1 Hr how they live up to their LIFETIME WARRANTY !!  Thank heavens I live only an hour from their store, I would hate like the dickens to be shipping this boat anchor back and forth across the country.  I'm going to ask for a W-L barrel blank, and see where it goes from there.
Thank you and Merry Christmas.

Well here's to hoping you get to speak to someone else than Bob, the owner.  At best he will probably cuss you out, at worst he will try to hit you with the barrel, keep your distance.

Yeah, you sure are right Jason, I have heard some real horror stories about him.  I met with Michael yesterday.  A nice young man, although he insisted that he keep my upper so he can go test fire sometime after Christmas  [:(].  I took in 15 targets, all with the same issue, using different types and gr of ammo, and 4 different shooters.  I guess he just wants to do his job and see for himself.  I just hate like the dickens to give my gun up until after Christmas.  He indicated that the L-W bbls come precut and ready for installation, but the Wilsons they do on site.  He also said that their gas ports are .098, and that .101 is not that far off and should not be causing any problems.  He may be right, there may be some other issue and I'm focused on the GP when that is not the problem.  AT any rate, I understand that the GP should be about .089.  More to follow.  Thanks for the heads up about the owner, but so far everyone there has been very nice to me.  Merry Christmas, Gus

I bought an asa upper from a guy who had the same problem but was scared to deal with them.

Long story short I got it for a song then put an adjustable gas tube on it and now shoots as stated.

Just a thought if they don't want to help you or start the run-a-round