Molon
09-04-10, 14:13
http://www.box.net/shared/static/be91ni0w00.jpg
Snapshots are brief looks at a variety of loads for use in the .223/5.56mm AR-15 platform. A “Snapshot” will include a short description of the load, chronograph data from a single barrel and the accuracy (technically precision) results of one 10-shot group fired from a distance of 100 yards.
The reviewed loads were chronographed from a 20” Colt M16A2 barrel with a 1:7” twist, chrome lining and a NATO chamber. 10-shot strings of each load were fired over an Oehler 35-P chronograph with “proof screen” technology. All velocities listed are muzzle velocities as calculated from the instrumental velocities using Oehler’s Ballistic Explorer software program.
http://www.box.net/shared/static/kyd2aznrv0.jpg
http://www.box.net/shared/static/52xzjapv7i.jpg
Accuracy testing was conducted from my bench-rest set-up from a distance of 100 yards following my usual protocol. The fore-ends of the weapons rested in a Sinclair Windage Benchrest and the butt-stock rode in a Protektor rear-bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was attached to the objective-bell of the scope. Naturally, the wind conditions were monitored using a Wind Probe. The set-up was very similar to that pictured below.
http://www.box.net/shared/static/xo4duzdgtp.jpg
Prior to the firing of the factory loads, control groups were fired using hand-loaded, match-grade ammunition. In every case the control groups had significantly smaller extreme spreads and mean radii than the factory loads tested. As an example, a typical 10-shot group from my Krieger barreled AR-15 firing hand-loads using the 62 grain Berger HP bullet is pictured below.
http://www.box.net/shared/static/3iyz43ukhj.jpg
Nosler 77 grain Custom Competition HPBT
http://www.box.net/shared/static/2n8n8bdn2n.jpg
This ammunition uses Nosler’s 77 grain OTM projectile with a cannelure, loaded in Nosler brass.
http://www.box.net/shared/static/x1m9huhroc.jpg
This load had a muzzle velocity of 2612 fps with a standard deviation of 19 fps. A 10-shot group fired from my Krieger barreled AR-15 had and extreme spread of 0.98” and a mean radius of 0.31”.
http://www.box.net/shared/static/cde6psac15.jpg
American Tactical 5.56 x 45mm 62 grain
http://www.box.net/shared/static/yus2phi0eh.jpg
This M855 “clone” is charged with ball powder, has crimped and sealed primers, asphalt sealant at the case-mouth and utilizes a 62 grain SS109-type projectile. This bullet is a full-metal jacket, boat-tailed, cannelured projectile with a steel penetrator insert.
http://www.box.net/shared/static/ezfdukckva.jpg
The muzzle velocity of this load was 3077 fps with a standard deviation of 21 fps. America Tactical claims that this ammunition “is lot tested to assure less than one minute of angle” accuracy at 100 meters.
http://www.box.net/shared/static/46f1f4m6m5.jpg
A 10-shot group of this load fired from an AR-15 with a free-floated, 20” Colt HBAR had an extreme spread of 4.49” and a mean radius of 1.33”.
http://www.box.net/shared/static/u1nisupaht.jpg
Remington 62 grain HP Premier Match
http://www.box.net/shared/static/e63hje6ie7.jpg
This Remington load is topped with a flat-base, cannelured, 62 grain HP projectile and uses Remington–Peters brass.
http://www.box.net/shared/static/iprft1iol3.jpg
The muzzle velocity of this load was 2897 fps with a standard deviation of 14 fps. A 10-shot group fired from my Krieger barreled AR-15 had an extreme spread of 1.3” and a mean radius of 0.52”.
http://www.box.net/shared/static/ayti251fhp.jpg
COR-BON 69 grain Performance Match HPBT
http://www.box.net/shared/static/ge99n46d59.jpg
COR-BON’s 69 grain Performance Match ammunition is loaded with Sierra’s 69 grain MatchKing. An added bonus with this ammunition is that is uses Lapua Match brass, arguably the finest brass available for reloading for AR-15s.
COR-BON’s website claims that the velocity of this load is 3000 fps from a 20" barrel. From the 20” Colt barrel this load had a muzzle velocity of 2854 fps with a standard deviation of 25 fps. From a distance of 100 yards, a 10-shot group fired from a Krieger barreled AR-15 with .223 Remington chamber and a 1:9” had an extreme spread of 0.88”.
http://www.box.net/shared/static/xt31p1ik08.jpg
Fiocchi 77 grain Exacta
http://www.box.net/shared/static/jiekp0snbq.jpg
This Fiocchi load uses the 77 grain Sierra MatchKing (without a cannelure.) The load is charged with ball powder. From the 20” Colt barrel, this load had a muzzle velocity of 2549 fps with a standard deviation of 16 fps. This is a little on the slow side for this particular category of ammunition, however since this is intended to be a “target load”, velocity is not a crucial factor at shorter distances.
A 10-shot group fired from 100 yards from a Krieger barreled AR-15 with a 1:7.7” twist, had an extreme spread of 0.995”.
http://www.box.net/shared/static/1jbmq3mv7x.jpg
to be continued . . .
Snapshots are brief looks at a variety of loads for use in the .223/5.56mm AR-15 platform. A “Snapshot” will include a short description of the load, chronograph data from a single barrel and the accuracy (technically precision) results of one 10-shot group fired from a distance of 100 yards.
The reviewed loads were chronographed from a 20” Colt M16A2 barrel with a 1:7” twist, chrome lining and a NATO chamber. 10-shot strings of each load were fired over an Oehler 35-P chronograph with “proof screen” technology. All velocities listed are muzzle velocities as calculated from the instrumental velocities using Oehler’s Ballistic Explorer software program.
http://www.box.net/shared/static/kyd2aznrv0.jpg
http://www.box.net/shared/static/52xzjapv7i.jpg
Accuracy testing was conducted from my bench-rest set-up from a distance of 100 yards following my usual protocol. The fore-ends of the weapons rested in a Sinclair Windage Benchrest and the butt-stock rode in a Protektor rear-bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was attached to the objective-bell of the scope. Naturally, the wind conditions were monitored using a Wind Probe. The set-up was very similar to that pictured below.
http://www.box.net/shared/static/xo4duzdgtp.jpg
Prior to the firing of the factory loads, control groups were fired using hand-loaded, match-grade ammunition. In every case the control groups had significantly smaller extreme spreads and mean radii than the factory loads tested. As an example, a typical 10-shot group from my Krieger barreled AR-15 firing hand-loads using the 62 grain Berger HP bullet is pictured below.
http://www.box.net/shared/static/3iyz43ukhj.jpg
Nosler 77 grain Custom Competition HPBT
http://www.box.net/shared/static/2n8n8bdn2n.jpg
This ammunition uses Nosler’s 77 grain OTM projectile with a cannelure, loaded in Nosler brass.
http://www.box.net/shared/static/x1m9huhroc.jpg
This load had a muzzle velocity of 2612 fps with a standard deviation of 19 fps. A 10-shot group fired from my Krieger barreled AR-15 had and extreme spread of 0.98” and a mean radius of 0.31”.
http://www.box.net/shared/static/cde6psac15.jpg
American Tactical 5.56 x 45mm 62 grain
http://www.box.net/shared/static/yus2phi0eh.jpg
This M855 “clone” is charged with ball powder, has crimped and sealed primers, asphalt sealant at the case-mouth and utilizes a 62 grain SS109-type projectile. This bullet is a full-metal jacket, boat-tailed, cannelured projectile with a steel penetrator insert.
http://www.box.net/shared/static/ezfdukckva.jpg
The muzzle velocity of this load was 3077 fps with a standard deviation of 21 fps. America Tactical claims that this ammunition “is lot tested to assure less than one minute of angle” accuracy at 100 meters.
http://www.box.net/shared/static/46f1f4m6m5.jpg
A 10-shot group of this load fired from an AR-15 with a free-floated, 20” Colt HBAR had an extreme spread of 4.49” and a mean radius of 1.33”.
http://www.box.net/shared/static/u1nisupaht.jpg
Remington 62 grain HP Premier Match
http://www.box.net/shared/static/e63hje6ie7.jpg
This Remington load is topped with a flat-base, cannelured, 62 grain HP projectile and uses Remington–Peters brass.
http://www.box.net/shared/static/iprft1iol3.jpg
The muzzle velocity of this load was 2897 fps with a standard deviation of 14 fps. A 10-shot group fired from my Krieger barreled AR-15 had an extreme spread of 1.3” and a mean radius of 0.52”.
http://www.box.net/shared/static/ayti251fhp.jpg
COR-BON 69 grain Performance Match HPBT
http://www.box.net/shared/static/ge99n46d59.jpg
COR-BON’s 69 grain Performance Match ammunition is loaded with Sierra’s 69 grain MatchKing. An added bonus with this ammunition is that is uses Lapua Match brass, arguably the finest brass available for reloading for AR-15s.
COR-BON’s website claims that the velocity of this load is 3000 fps from a 20" barrel. From the 20” Colt barrel this load had a muzzle velocity of 2854 fps with a standard deviation of 25 fps. From a distance of 100 yards, a 10-shot group fired from a Krieger barreled AR-15 with .223 Remington chamber and a 1:9” had an extreme spread of 0.88”.
http://www.box.net/shared/static/xt31p1ik08.jpg
Fiocchi 77 grain Exacta
http://www.box.net/shared/static/jiekp0snbq.jpg
This Fiocchi load uses the 77 grain Sierra MatchKing (without a cannelure.) The load is charged with ball powder. From the 20” Colt barrel, this load had a muzzle velocity of 2549 fps with a standard deviation of 16 fps. This is a little on the slow side for this particular category of ammunition, however since this is intended to be a “target load”, velocity is not a crucial factor at shorter distances.
A 10-shot group fired from 100 yards from a Krieger barreled AR-15 with a 1:7.7” twist, had an extreme spread of 0.995”.
http://www.box.net/shared/static/1jbmq3mv7x.jpg
to be continued . . .