5.56 coal

[cancer]

Thought it'd be interesting to do some measurements on the cartridge overall length of all the 5.56 and .223 I have on hand. Measurements in inches.

IVI (62gr)
2.247
2.246
2.247
2.245
2.246
2.247
2.246
2.246
2.247
2.246
avg 2.246
std dev 0.0007

Federal AE (55gr redbox)
2.189
2.188
2.193
2.183
2.190
2.198
2.197
2.194
2.194
2.197
avg 2.192
std dev 0.0048

Remington UMC (55gr)
2.224
2.229
2.230
2.229
2.228
2.224
avg 2.227
std dev 0.0027

WCC85 (US military surplus M193 55gr)
2.250
2.238
2.244
2.251
2.246
2.254
2.251
2.250
2.254
2.254
avg 2.249
std dev 0.0052

Interesting results. Obviously the QA/QC at IVI is much better than at the commercial manufacturers. The IVI was even from four different years (92, 95, 96 and 98). Federal AE was from two different lots. One with crimped primers and blue paint on primer, the other from non crimped primers, but labelled the same. Remington UMC was from two different lots with different coloured primers. The WCC85 was from the same lot.

 

[Travis Bickle]

Standard IVI 5.56mm ball is very good quality ammunition.

It's regarded as better than most high end commercial ammo as far as consistency and accuracy goes.

Very good ammo indeed!

 

[cancer]

Yeah, IVI shoots very well out of my AR15s. That said, so does the Federal AE, and you can clearly see how the bullets are seated at difference distances into the neck of the cartridge based on inconsistent amounts of the canelure showing. It seems that OAL of the cartridge isn't that big of a deal for precision in an autoloader. That said, I haven't run any of these through my new chronograph yet. I suspect velocities will be more consistent with the Remington UMC and IVI.

 

[Ganderite]

OAL is an important issue to military quality control. A long round would jam a magazine. Military ammo is 100% gauged for OAL. You might find the occasional bullet nose smeared from the gauge.