Attack of the (M193) Clones, Part Two: M855 Comparison.

This thread is dedicated to Zhukov, for his tireless efforts in improving the signal to noise ratio in these technical forums.







In Attack of the (M193) Clones, part one, we examined the velocity and accuracy (technically precision) of four different M193 clones currently available on the commercial market. In part two, we’ll be examining the velocity and accuracy of four different M855 clones currently available on the commercial market. The M855 clones examined for this article are shown below.

IMI M855





Winchester Ranger M855






Prvi Partizan M855





American Eagle XM855






The obvious difference between the projectiles used in M855 and M193 clones is the weight difference of 7 grains, 62 grains versus 55 grains. The M855 projectile has a FMJ construction but also has a steel “penetrator” in the ogive section of the bullet. This makes the projectile unusually long for its weight, as well as giving it a lower specific gravity. Most, but not all, of the M855 clones have the tip of the bullet painted green.

M855 versus M193 projectiles.





The 62 grain M855 projectile is actually longer than the heavier 69 grain Sierra MatchKing.





Note the steel penetrator in the sectioned projectile below.





Chronographing of the M855 clones was conducted as described in part one, using the same 20” M16A2 barrel. The results are shown in the table below.





Accuracy testing of the M855 clones was also conducted exactly as described in part one, using the same free-floated 16” Colt HBAR fired from my bench-rest set-up at 100 yards. As previously stated, I chose a chrome lined, NATO chambered barrel as the accuracy test vehicle as this is the type of barrel that these clone loads are most likely to be fired from. It is sometimes possible to obtain slightly better accuracy from mil-spec/NATO pressure loads by firing them from an AR-15 that has a stainless steel match-grade barrel with a hybrid chamber such as the Noveske NMmod0 chamber or the Wylde chamber for examples; but you're not going to make a silk purse out of a sow’s ear.


Three 10-shot groups of each load were fired in a row with the results shown in the table below.






Here are the previous accuracy results of the M193 clones along with the M855 clone results for comparison.






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wonderful!

Great review!! The only thing that I regret is that you left out the new PMC 855 ammo that is out there.


On another note, is this Federal XM193 different from the American Eagle XM193 you tested? If not, why the different box packaging?

Thanks!

http://www.cheaperthandirt.com/AMM207-5.html

No.

Thanks for another great test/write up!

I'd definitely side with Molon on this. Just look at the chart- you have an ES ranging from 2.41 to 3.96" at 100 yards. That is absolutely perceptible even without a ruler...

The next bulk-brass ammo I buy will be IMI.

all XM855 round boat tail? or no?

@CG42, if you read about the development of the SS109 projectile, you'll find that a 1/9" twist is the OPTIMAL rate of twist for this bullet, the only reason most 5.56 NATO military weapons have 1/7" twist bbl's is because they want to be able to use the M856 tracer round, which has a ridiculously long projectile for which a 1/6" twist is optimal, and so a 1/7" twist is used as a compromise between the two so that both M855/SS109, and M856 ammo can be used without horrible results. Not horrible, but not ideal either, this twist rate compromise obviously means a little less velocity with M855, and a little less accuracy with M856.

So there's the long answer for you.

Nice thread - thanks. The IMI data doesn't surprise me - it's very good stuff.

That's just ridiculous in length.

Marked as "do not archive". Have you updated your collected posts with this yet?

I bet if Molon received some ammo in the mail he'd test it for you.

I don't think Molon accepts ammo from others for his tests. It might suggest bias.

I hope you will test some plain Lake City 855 to add to the list. Thanks for all your work Molon.