Barrel Accuracy

[Press Check]

What makes one modern barrel more accurate than another? Put a good shooter behind two barrels, why does one shoot a minute, and the other shoots 3 minutes.

Case in point, I have a Colt SOCOM upper that easily shoots a minute, and a BCM SOCOM upper than shoots 3-4 minutes at the same distance, with the same ammunition, under the same conditions.

In the case of both of those barrels in particular, I assume we're talking about the same materials used, the same manufacturing process, etc., so where's the difference?

[markm]

Is the BCM button rifled or hammer forged? Buttons wear out. And steel can have flaws that create uneven bore diameter down the pipe.

Pin gauging is a good way to tell if a barrel is problematic. That and/or bore scoping.

[sig1473]

Is the BCM button rifled or hammer forged? Buttons wear out. And steel can have flaws that create uneven bore diameter down the pipe.

Pin gauging is a good way to tell if a barrel is problematic. That and/or bore scoping.

BCM only makes the SOCOM profile in 14.5" and 16" standard rifled.

[markm]

So the normal button rifle gamble applies. Plus the chrome lining process... If a barrel won't shoot 77gr OTMs well at some point after a break in, I'd see about bore scoping or pin gauging.

[Stickman]

What makes one modern barrel more accurate than another? Put a good shooter behind two barrels, why does one shoot a minute, and the other shoots 3 minutes.

Case in point, I have a Colt SOCOM upper that easily shoots a minute, and a BCM SOCOM upper than shoots 3-4 minutes at the same distance, with the same ammunition, under the same conditions.

In the case of both of those barrels in particular, I assume we're talking about the same materials used, the same manufacturing process, etc., so where's the difference?

It isn't the same unless it is coming off the same machines with the same wear and tear on equipment. There are plenty of barrels that are 1-7 twist which love one bullet and hate another. Switch to a different barrel in the same twist and that special bullet and load just might not be so special anymore.

[elephantrider]

I'll echo what Stickman posted. There are so many manufacturing variables to barrels, let alone chrome lined barrels, that there is no 'same.' If you want to evaluate each barrel, try the same optics on each barrel/upper, with a variety of ammunition, a la Molon. The difference in accuracy you are seeing, may just be a difference in throating. If you are seeing worse accuracy across the board then the BCM may indeed be a 'lesser' barrel, or have defects, or just less tolerant of a variety of ammunition/loads.

[Clint]

There are many many variables involved and each one has a potential effect on accuracy.

[Rascally]

So basically, each barrel is unique and a law unto itself..?

[Pappabear]

So basically, each barrel is unique and a law unto itself..?

Pretty much. Unless your buying high end precision barrels, it's always a gamble. Your BCM might like 55grain bullets or might not. Still 3 or 4 moa with high quality match ammo is not ideal.

What ammo are you shooting in both guns ?
PB

[17K]

Generally, those Colt SOCOM barrels are very accurate! I shot one for awhile in 2016 and shot one very extensively in 2010-2012.

Both were about .75moa shooters, the last group I shot with the first one was 1.2MOA with a NSN ACOG with MK262, prone on the mag. That barrel had over 15K rounds through it and had been cleaned once!