Originally Posted by Grand
Originally Posted by TWR
You can observe wear marks but mostly it's something I look at after all else is done.

I have tightened groups by simply swapping bolts, I figure it's a tolerance stacking issue. I do run a field gauge before shooting.


Headspace is often overlooked. MSTN, know for producing some top quality AR's, matches the bolt to the extension, to achieve proper headspace.
Originally Posted by hanco
Buy a good one to start with, got two Rock Rivers that will do 1/2” groups with 62 grain Barnes

Good advice there. I also like buying good barrels that come with matching bolts. Always check headspace. If I have a good shooting AR with matched bolt and I upgrade the BCG, I'll usually keep the bolt and put that in the new carrier.

Good advice about buying from well known sources with a good reputation for accuracy. I'm not suggesting RRA, as I have sone buddies that have them and none of them shoot as well as I think they should. Keeping in mind, this is 10 shot groups, not 3 shot groups. Funny things happen when you have a rifle that is out of tolerance by just a little bit. Like TWR mentioned: stacking tolerances can lead to problems, especially when firing more shots per group downrange.

A funny story I need to bring up: I bought a good upper from a buddy last year and it was shooting great. I believe I started a thread on it because I was so impressed with the accuracy I was getting out of it:
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]

That sob was shooting lights out when I got it, but I didn't want the A2 front sight on it and wanted to just have that barrel on one of my rifles. I stripped everything, and when I pulled the bird cage off, I noticed about 1/8" of carbon build up on the muzzle. Well, my OCD would not allow that!!! I removed the carbon and after that, it has not shot the same since!!!

I should have left that damn thing alone because it was a tack driving sob. My friend puts together great AR's. He's a retired Airborne Ranger, so he has all the time in the world to work on guns. Anyway, after putting the barrel on one of my ar's, this is how it looked:
[Linked Image from i.imgur.com]
Now it has a freefloated handguard and nice clean crown and it does not shoot as well as it did in the non freefloated magpul handguard and the A2 front sight out front. It still shoots well, but not sub 1" at 400 yards:
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]
[Linked Image from i.imgur.com]
Just sharing an experience of how I somehow went backwards, and I'm thinking it's my knucklehead move removing the 30 years worth of carbon buildup on the crown and how accuracy degraded. I may be wrong?

Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.
Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.

BSA MAGA