Earlier this month I inquired about whether or not CCI 400's are actually the same primer as CCI 550's - as heard here quite a few times over the years.
Unclenick chimed in with:
I stated I would run a field test; and today, I have the results . . .
Firearm is an AR-15 style sport rifle. 16" (or 16 1/2" maybe?) bbl. 1:7 twist.
Bullet is a Hornady 55gn FMJ-BT with Cannelure (Hornady bullet #2267).
OAL = 2.197" seated and collet crimped at the cannelure.
Case is Lake City "LC 16" twice fired. Trimmed to 1.750" and primer pocket de-crimped.
Propellant is 23.8 grains of AA2230.
10-round samples, both.
CCI 400: ...........CCI 550:
Low= 2759 .......Low= 2766
High= 2848 ......High= 2852
Average= 2813 ..Average= 2815
ES= 88.32 ........ES= 86.71
SD= 23.15 ........SD= 29.18
I would consider that to be statistically insignificant. I would expect two 10-round samples of identical ammo to vary more than that.
I know this doesn't prove CCI 400's and 550's to be the same, but they sure seem to perform pretty darn close.
Feel free to chime in.
Unclenick chimed in with:
. . . Twenty years ago, the lady answering the phone at CCI told me CCI's employees all bought the 400s for both rifle and magnum handguns as the cup and priming mix and its quantity were all the same . . .
I stated I would run a field test; and today, I have the results . . .
Firearm is an AR-15 style sport rifle. 16" (or 16 1/2" maybe?) bbl. 1:7 twist.
Bullet is a Hornady 55gn FMJ-BT with Cannelure (Hornady bullet #2267).
OAL = 2.197" seated and collet crimped at the cannelure.
Case is Lake City "LC 16" twice fired. Trimmed to 1.750" and primer pocket de-crimped.
Propellant is 23.8 grains of AA2230.
10-round samples, both.
CCI 400: ...........CCI 550:
Low= 2759 .......Low= 2766
High= 2848 ......High= 2852
Average= 2813 ..Average= 2815
ES= 88.32 ........ES= 86.71
SD= 23.15 ........SD= 29.18
I would consider that to be statistically insignificant. I would expect two 10-round samples of identical ammo to vary more than that.
I know this doesn't prove CCI 400's and 550's to be the same, but they sure seem to perform pretty darn close.
Feel free to chime in.