Ideal M4A1 Ammo Choice

[K. Knight]

Tonight, PV1 Reynolds and myself verified some very useful information I collected.

We were told to use the base game "5.56mm 30Rnd Mag" and "5.56mm 30Rnd Mag Tracer" by Bohemia Interactive. However, these bullets do not match up with the range echelons on the M150 RCO. Out to 400m it's accurate, but the 500m and 600m markers hit about a foot or more low.

I Googled the various other ammo types and found that the "5.56mm 30Rnd M855A1 (No Tracer)" and "5.56mm 30Rnd M856A1 Red Tracer" rounds are the ones currently in active duty. In PV1 Reynolds' and my trials of the different magazines, we found that these rounds matched up perfectly with the range echelons on the M150 RCO at ranges of 200, 400, 500, and 600 meters. It has a flatter trajectory and reaches the target much quicker than the "5.56mm 30Rnd Mag" rounds, making hits on moving targets much easier to achieve.

We also tested the rounds on four different missions and found them to be highly effective against infantry targets, requiring only one or two rounds to kill.

Don't take our word for it; compare them yourself. You will not be disappointed.

http://imgur.com/a/BAeLT

[SGT (Ret) B. Carter]

Interesting. Not sure how far they go in modeling the ammunition in ARMA. Not sure what round is in the standard mag. Did you do any testing with the other types of ammo? 

Perhaps the standard mags hold M193 Ball.

Here are the supposed real life ammunitions and some pros / cons

M193: 55gr - higher velocity.  Less stable over longer ranges.
M855: 62gr - has SS109 steel penetrator. For better penetration of barriers. Sails through soft targets.
Mk318: 62gr - OTMRP -  Open Tip Match Rear Penetrator.  Light front with heavy rear provides stable flight at longer ranges. Rear penetrator provides better barrier penetration as well.  Adopted by USMC
Mk262: 77gr - OTMRP - Adopted by Army and SOCOM - Provides harder hitting barrier blind round from shorter barrels. Provides more stabilized accurate round for SPR (accurized rifles with longer barrels - i.e. Mk12) at longer ranges.

Would be interesting to see which round works better in which weapon at different ranges.....assuming the characteristics are modeled in ARMA.

[CW2 (Ret) O'Neill]

Keep in mind that the M4s, M150 optics, and the M855A1 ammunition all come out of RHS, therefore it makes sense that they match up the best.

Realistically, a standard M4 should be point target effective at 400-500m and area target effective at 500-600m. Any distance beyond that, you're just wasting ammo. Using the standard BI 5.56mm ammunition as we have been, I have never had any major problems with hitting targets until over 600m as I realistically should. However, I use the Aimpoint or the Aimpoint w/ 3x magnifier depending on the mission. I don't like using the ACOGs.

Now, in terms of the most effective ammunition, I believe the Mk318 SOST is the most effective form of ammunition within our mods.

If you're having difficulties hitting targets using standard BI 5.56mm ammunition in your M4 with a M150 optic, I have 3 suggestions. One, get some range time and practice to push through the deficiencies you're experiencing. Two, use a different optic and get some practice with it until you find one you're effective with (insure you're using an optic inside the 506th official arsenal). Three, send it up your CoC that you would like the M855A1 ammunition to be added to the official arsenal and your Platoon Sergeant can try to requisition them.

[K. Knight]

10-4.

CPL Carter, yes we did test the other magazines, and the M855A1 and M856A1 Tracer were the superior rounds as far as accuracy and time to target are concerned. Indeed, you are correct, they are the armor piercing rounds, which would explain their effectiveness against infantry contacts. If I'm not mistaken, PV1 Ramirez killed a guy through a wall.

I'll do some more testing in a private server with the ballistic path enabled, and report future findings here, as well as send it up the chain.

Thanks for reading.

[K. Knight]

Just wanted to add that I noticed the M855A1 mags are in the back of the Humvees by default.

Did some extensive testing on an offline map with ballistic paths enabled and found the close range penetration was identical to the base game mags. However, the downrange velocity/penetration carried much further with the M855A1 rounds.

[K. Knight]

Update:
I went and tested the M16 with the M150 RCO with the Bohemia Interactive 5.56mm 30rnd Mags, and they matched up perfectly at every range. There was some inconsistency at longer ranges with the RHS M855 and 856 rounds, so I'm guessing they're just glitched. Made a bug report on the RHS forum, and it seems that they are looking at it already.

It makes sense that the M16 would match up and the M4A1 would hit a bit low considering the M16 has a 20" barrel and the M4 has a 14.5". I've been scratching my head on this one, but the answer is clear now. This thread can be deleted

[C. Wallace]

The RCO has 2 different versions in real life. One for the m16, one for the m4. Obviously if you use an m16 RCO on an m4, your impact deviation will be off, especially at longer ranges. Not sure if RHS took that into account.

[J. Hammac]

The RCO has 2 different versions in real life. One for the m16, one for the m4. Obviously if you use an m16 RCO on an m4, your impact deviation will be off, especially at longer ranges. Not sure if RHS took that into account.

Perhaps experiment with the AN/PVQ-31A and TA31 that's also included. There might be a slight almost indiscernible difference in them.

UPDATE: Jumped into a quick mission for some informal testing. The AN/PVQ-31A, M150, and TA31RCO are identical in performance to 200m (the range I was testing at). Ammunition at that range is also identical. The one variable that differs is in the rifles from what I saw.

The M16A4 has great accuracy with all three ammo types and optics.
The M4A1 (PIP and Block II included) was less accurate but had the same POI as the M16A4.
The Mk.18 Mod.1 had a considerable POI drop with all three ammo types and optics.

It would appear the ROF increase and reduction in length and weight is countered with a reduction in range or both accuracy and range even out to 200m. Though I imagine the unit rarely uses the Mk.18, it is still a point to note if utilized and should be weighed against other options accordingly.

[Treyum]

The unit only uses the base M4A1 Models. Anything Block 2, Mk.18 or M16 is strictly prohibited in official unit operations. That being said, those rifles are extremely commonly used in fun ops and in patrol ops servers. Thanks for the information.

[CW2 (Ret) O'Neill]

Friendly reminder that we have both the BI 5.56mm ammunition and the Mk318 ammunition in the official arsenal box. I use the 318 and have never had a problem hitting or suppressing targets at any range under 600 meters.

Additionally, I've found that the differences from which rifle, optic, and ammo are best suited for marksmanship are so minute that really if you play with any rifle, optic and ammo for an hour, you'll easily be able to compensate for those minute differences.

[K. Knight]

Thanks for that, Sergeant O'Neill. Today I threw another 2500 rounds downrange and these were my findings.

http://i.imgur.com/dOXVoM2.jpg

I drive out to a building Northeast of the Patrol Ops base and shoot until I find what range the various bullets are impacting relative to the echelons on the M150 RCO. All shots are taken from a prone position, taking a breath with left shift, exhaling, then firing. All ranges were confirmed with a rangefinder then checked extensively for consistency.

It seems the Mk318 is good until 500 meters, then begins hitting higher and higher probably due to a flatter trajectory. The Mk262 matches the echelons perfectly out to 600 meters, then shows a slight variance in relation to the 700m and 800m echelons, landing at 750m and 900m respectively. Lastly, the BI 5.56mm Mag proved to be less accurate than initially perceived, landing 50-60m short of every echelon, and 25m short of the 800m mark. If I was forced to choose between the BI Mag and the Mk318, the Mk318 would be the clear victor based on its accuracy when engaging point targets within 500 meters.

On a side note, the last four rounds in the Mk318 and Mk262 magazines are tracer rounds, informing you when you're about to run out.

On the 5.56x45mm Wikipedia, it's stated in regard to the Mk262 that, "Apparently it is superior to the standard M855 round when fired from an M4 or M16 rifle, increasing accuracy from 3–5 minutes of angle to 2 minute of angle. It appears that this round can drastically improve the performance of any AR-15 platform weapon chambered to 5.56 mm. Superior accuracy, wounding capacity, stopping power and range have made this the preferred round of many special forces operators, and highly desirable as a replacement for the older, Belgian-designed 5.56×45mm M855 NATO round. In one engagement, a two-man special forces team reported 75 kills with 77 rounds. The Mk 262 has a higher ballistic coefficient than the M855 of 0.181, meaning it loses less velocity at long-range."

Almost 10,000 rounds later, and I'm still not satisfied. I plan to do more testing when I have time.

Until then.

[Goldberg]

Don't forget about the M855A1 magazines that's available via RHS.

[K. Knight]

Are those approved for use? If they are, I can add them to the diagram.

[Goldberg]

As far as I'm aware they are.

[CW2 (Ret) O'Neill]

Are those approved for use? If they are, I can add them to the diagram.

Last I checked, there are only 3 forms of M4 compatible ammunition in the official arsenal box, the Bohemia Interactive 5.56mm ammo, the BI 5.56mm Red Tracer ammo, and the RHS Mk318 5.56mm ammo.

Unfortunately, it's not exactly specified what type of ammo the BI 5.56mm magazines are but I would believe they're based off either the Mk318 or Mk262 rounds since Arma 3's storyline is based in 2035 and mostly everything is "futuristic" or advanced by our modern standards.