09-28-2019, 04:45 PM
From a machining perspective, especially in this day and age where everything is done on CNC, you get true receiver face surfaces......before the anodizing is done.
This is where the problem comes into play. During the anodizing process, it is pretty common for build up of material to occur unevenly.
This is why we lap the upper face, and why we don't need to mess with quality barrel extensions normally.
Barrel extensions aren't anodized since they are steel alloy. Not all barrel extensions are created equally, and most on the market do not know about or adhere to the TDP in materials, processes, and dimensions.
I really like BAT Machine extensions, which are held to very tight tolerances in concentricity, uniformity, and dimensional call-outs.
I do know a gunsmith who trued and squared his barrel extensions though before attaching them to the barrels.
His 6.5 Grendels shot .5 MOA out of the gate.
We've seen most samples of the cheaper barrel options out there fail to meet basic dimensional call-outs from the TDP regarding OD, chamfer for the lugs inside the lock-up area, threads undersized, feed ramps way off of the land marks, and basically every dimension very loose from where they are supposed to be.
Just because something looks like a barrel extension doesn't mean it even halfway meets the criteria that has been developed over many decades of hard lessons learned.
This is where the problem comes into play. During the anodizing process, it is pretty common for build up of material to occur unevenly.
This is why we lap the upper face, and why we don't need to mess with quality barrel extensions normally.
Barrel extensions aren't anodized since they are steel alloy. Not all barrel extensions are created equally, and most on the market do not know about or adhere to the TDP in materials, processes, and dimensions.
I really like BAT Machine extensions, which are held to very tight tolerances in concentricity, uniformity, and dimensional call-outs.
I do know a gunsmith who trued and squared his barrel extensions though before attaching them to the barrels.
His 6.5 Grendels shot .5 MOA out of the gate.
We've seen most samples of the cheaper barrel options out there fail to meet basic dimensional call-outs from the TDP regarding OD, chamfer for the lugs inside the lock-up area, threads undersized, feed ramps way off of the land marks, and basically every dimension very loose from where they are supposed to be.
Just because something looks like a barrel extension doesn't mean it even halfway meets the criteria that has been developed over many decades of hard lessons learned.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com