Norinco CJ 95 ammunition powder and projectile measured weights

[CV32]

Okay i'll contribute. I have a 500 round bag of Hornady 55gr FMJ cannelure that i bought two years ago for a crazy price of $44. I grabbed a handful and pulled out my scale and vernier caliper. So, here are the numbers.

9 - 55gr
6 - 55.1gr
3- 54.9gr
1- 54.8gr
6- 54.3gr

Bean counters can do the variation, percentages etc. What struck me as really weird is that there was no middle ground between the light bullets and normal weight. 0.3grand variance around 55gr then a sudden fall to 54.3 grain territory with nothing in between. The light ones i measured several times to verify i wasnt getting screwy scale reading. Now, diameter every single one of them came out to be 0.2235" No variance. Mind you my Mitutoyo caliper reads in 0.005" steps, a proper micrometer would probably give us more precise number. Quality, i've never come across any weird 55gr FMJ's from Hornady. I cant say the same thing with their 52gr Boat tail hollow points. Several ones i've come across with exposed lead on the side. Anyways, there some info for you.

Thanks. That is interesting info.

 

[alpining]

Okay i'll contribute.
I have a 500 round bag of Hornady 55gr FMJ cannelure that i bought two years ago for a crazy price of $44.
I grabbed a handful and pulled out my scale and vernier caliper.
So, here are the numbers.
...

Outstanding, thanks. I dropped your numbers into a spreadsheet to calculate the standard deviations, and here's what I got:

Type: Hornady .224" 55gr FMJ cannelure bullets
Packaging: bulk

Sample size: 25

Lowest measured projectile weight: 54.3
Highest measured projectile weight: 55.1
Average projectile weight: 54.84
Standard deviation: 0.316
Standard deviation as percent of average: 0.58%


Compare that with the Norinco bullet weight "standard deviation as a percent of average" value of 0.67%. Not really much better in terms of weight. My next post will show the same variables for a few other types of bullets that I've had the chance to measure.

Your observations about bullet diameter are interesting: Very consistent, which is good. I'll include bullet diameters in future posts. If someone has links to the threads on undersized Norinco bullets, they'd be a great inclusion here, I think.

However, the weight variance in this sample of Hornady bulk 55gr FMJ bullets is very nearly as much as was observed in the Norinco sample. BOTH bullets would greatly benefit from weight sorting if you're looking to improve accuracy. The frequency of those 54.3gr bullets is strange, indeed. EDIT: It's interesting to note that the tendency of the most out-of-spec Norinco bullets was on the low side as well. That would make sorting all that much easier, as you could probably just discard bullets on the low side. /EDIT

I'm not prepared to say that the Hornady bullets are not significantly better than the Norinco bullets, but this data does not support the assertion that they are better. Mind you, consistent diameters is far more important than weights.

 

[alpining]

Some more bullets I had available:

Type: Hornady .224" 55gr VMAX w/o cannelure
Lot#: L6101
Packaging: 100 box

Sample size: 12

Lowest measured projectile weight: 54.7
Highest measured projectile weight: 55.1
Average projectile weight: 54.94
Standard deviation: 0.131
Standard deviation as percent of average: 0.24%


Type: Nosler .224" 69gr Custom Competition HPBT
Lot#: DB07F91
Packaging: 100 box

Sample size: 12

Lowest measured projectile weight: 69.0
Highest measured projectile weight: 69.2
Average projectile weight: 69.12
Standard deviation: 0.0718
Standard deviation as percent of average: 0.10%


Type: Hornady .224" 75gr Match HPBT
Lot#: L6203
Packaging: 100 box

Sample size: 12

Lowest measured projectile weight: 75.2
Highest measured projectile weight: 74.9
Average projectile weight: 75.12
Standard deviation: 0.0937
Standard deviation as percent of average: 0.12%


It shouldn't be much of a surprise to see that the more expensive bullets tend to have better weight consistency. But I was surprised at just how much better it is. The improvement in weight consistency from the Hornady bulk 55gr FMJ to Hornady 55gr VMAX is huge. And the difference in weight consistency between the Hornady bulk 55gr FMJ and pulled Norinco bullets is actually very small. (The 69gr and 75gr bullet data are included just for comparison sake, as you should definitely not simply drop a heavier bullet into the Norinco cartridge without adjusting the powder charge, which would negate the time advantage I'm considering taking advantage of.)

For those less mathematically-inclined: The most useful variable that these data show is the "standard deviation as percent of average". It gives a measure of variability of the bullet weight relative to the average bullet weight. You can compare these numbers directly between types of bullets, and a higher number means greater variability (which is generally bad for accuracy). The difference between lower values here (e.g. from 0.10% to 0.24%) is probably insignificant unless you're really in to precision shooting. The difference between the Hornady VMAX (0.24%) and the Hornady bulk 55gr FMJ (0.58%) is much more significant. It indicates that sorting the more variable bulk bullets by weight would probably be worthwhile if you're trying to improve the consistency (accuracy) of your ammunition.

Similarly, sorting the Norinco bullets might yield better accuracy, especially if the lower weight bullets also happen to be undersized. This will be reported in my next post, where I'll also include the same data for some different Norinco lots and some American Eagle commercial ammunition I have on hand.