I recently decided to do a review of the accuracy of two of my barrels in my collection. The first is a BCM lightweight (non-CHF) 14.5" Midlength with a pinned BCM comp, the second is a Daniel Defense lightweight (CHF) 16" midlength with a Ranier Arms XTC comp.
The BCM upper I purchased direct from BCM a couple years ago. It came with a Centurion rail and a BCM BCG.
The DD barrel I purchased from Rainier Arms as a complete upper, from their "combat series" line. It came with a Samson/Rainier Evolution Rail and a Rainier Arms BCG.
Both uppers have their barrels free floated, both using a rail system that uses a stock barrel nut, and both barrels are of the Lightweight variety. Both the DD and BCM have a .625" gas block journal.
The Ammo:
image by Photographer Pilot, on Flickr
For the test I selected three different types of ammo. Federal American Eagle 55gr M-193 clone, Federal American Eagle 50gr Varmint and some handloads consisting over 77gr Nosler CC over H322. These handloads are typically just under sub-MOA with my Larue Stealth. It's the ammo I used for my entry in the sub-MOA thread.
I chose these loads as I figure that M-193 is one of the most common rounds for people to use, the 50gr Varmint is a consistent performer for many people. And I used my 77gr handloads because otherwise someone would complain about using 50-55gr in 1:7 twist barrels.
The Setup:
I shot 3 10-shot groups of each of the above ammo, through each rifle at 100 yards. To keep things consistent, I mounted each upper on the same lower, which has a SSA-E trigger. I mounted my Leupold VX-R Patrol 3-9X scope, which is mounted in a Larue mount. I used an Atlas Bipod for the test, and a rear bag as well. After shooting all of the groups, I measured the extreme spread (outside of the grease ring), then subtracted .224 to get the center to center number. I then averaged the 3 groups. No shots were thrown out. What I shot, is what you see.
The M-193 test I shot from a bench, the others were shot from prone off the bipod.
Prior to starting the M-193 test, I used some PMC X-Tac 55gr to get a rough zero for the test. Each upper got it's own zero. The Daniel Defense barrel needed 1.8 mil of elevation, and 1.2 mil of Left windage for it's setting. The BCM I left the elevation at 0, then dialed in 1.2 mil Right windage it's settings.
The M-193 was shot last week, the 50gr Varming and 77gr Noslers were shot this morning.
One of the rifles, as shot.
image by
Photographer Pilot, on Flickr
The Results:
First, let's start with the M193
The BCM's groups were:
3.666"
3.462"
3.520"
Average 3.549
The best group:
BCM M193 by
Photographer Pilot, on Flickr
The Daniel Defense groups were:
3.471"
2.576"
3.957"
Average 3.334"
The best group:
DD M193 by
Photographer Pilot, on Flickr
Prior to shooting the AE Varmint and 77gr Noslers, I shot 2 5-shot groups with my Larue Stealth using the 77gr Nosler handloads. That way the test wouldn't be shot cold. The groups measured 0.848 and 1.061"
American Eagle Varmint
The BCM Groups:
1.870"
2.148"
2.601"
Average 2.206"
The best group
BCM American Eagle Varmint by
Photographer Pilot, on Flickr
The Daniel Defense Groups:
2.466"
0.970"
1.940"
Average 1.792"
The best group:
DD American Eagle Varmint by
Photographer Pilot, on Flickr
Nosler 77gr Handloads
BCM
1.734"
2.258"
1.684"
Average 1.892"
The best group
BCM 77gr Nosler by
Photographer Pilot, on Flickr
Daniel Defense:
2.504" 1.501"
1.199"
1.054"
Average
1.585" 1.251"