Making M855 More Accurate? PART 1

Since the adoption of the service round M855 “green tip” and its use in combat we have heard all manner of complaints about it.   Usually it’s about  its accuracy and terminal performance with the terminal performance  problem being exaggerated  in carbines.   I have read what feels like millions of times, how the older 55gr load M193 is more accurate and  has better terminal effect.    I don’t have much to say about the terminal performance of either round at  this time other than to mention that over the years I have used both of those rounds to kill various animals from varmint size to even putting down a few wounded deer. Always with a carbine.  I observed the M193 was less effective than the M855 for whatever that is worth.  but  this time we are talking about the accuracy.

Military ammo  meant for general issue isn’t made to be match ammo. It just isn’t practical in several ways and because of that the ammo is not  as accurate.     I have run across some pretty good lots of M855 though, and it got me thinking.  Can M855 be improved with what I have at home?  How hard would it be to improve it with just some  careful  measuring ?

I grabbed a handful of of M855 I had left from a lot I bought around 2010 that turned out to be unusually accurate. The ammo in this case was real Lake City M855.   This is some of the same batch I used when I shot the Colt A2 out to 1,000 yards.  I set to work taking the ammo apart with a bullet puller in my hand loading press. The RCBS bullet pulling set is priceless for this use.

 

I got the bullets pulled then I figured out what the powder charge would be using the original powder.    I have no idea what the factory mil-spec powder really is and for what I intended, it didn’t really matter.

I weighed and measured the bullets and set aside projectiles that were as close to each other as I could find. I also made some measurements on the cases  I ended up cleaning them up a little with a chamfer  and wasted time seeing if I could sort brass  by any other method.       Before re using them I cleaned up the bullets by removing the water proofing sealant and re-seated the bullets into the cases with more uniform powder charges.   Now it is just a matter of going to shoot them and see what happens.

5 thoughts on “Making M855 More Accurate? PART 1”

  1. Most ammo for this this type of contract will use what is know as “canister powder” – developed for this contract specs, often not available to the public.

    One of the things that will affect accuracy in ammo like this is the crimp of the case mouth into the cannelure. The tension of the case on the bullet will affect starting velocity because a tighter crimp will retard the bullet moving out of the case, which will tend to increase pressure over a round where the bullet moves easily out of the case.

    Second, the steel core being slightly off-axis can cause runout on the bullet as it spins its way downrange. This sort of bullet error is why the modern match bullets that are winning competitions are solid copper.

    Lastly, the primers used have some effect on the consistency of how the powder lights off and the resulting pressures. The primers used in mil-spec ammo will have harder cups, to avoid slam-fires.

  2. Once upon a time I loved picking up the 8# jugs of WC844 for about 2/3rds the price of its more consistent sibling, H335. I haven’t seen any in appreciable amounts since the pulled down components dried up.

    I did this very thing a number of years ago although with bullets and components of unknown lot origins. I sorted bullets based on weight and then by base to ogive length. It was like an odd beer pong game gone awry with plastic cups lined up across the coffee table each sharpie’d with a weight or other measurement on it.
    After all was said and done they did shoot notionally better but for the effort put into it I felt it was beyond diminishing returns. For all the extra sorting work a box of Hornady 68gr with cannelure is still just too easy. Still fun though as most reloaders like to tinker on such things. I’ll be looking forward to see what your results are.

    • you are right, And I even told Howard the other day I knew what the result of all this effort was going to be even before I shot them, and it is just as you experienced. I also am loading just the bullets into commercial components just for kicks. I will have the Part 2 of this up before sunday I’m hoping

  3. The old M-24 SWS was supposed to come with a Lee Hand Press reloader and dies to remanufacture 7.62×51 NATO Ball. The whole SWS was built on the SF Guerrilla Warfare mindset (this is why it came with back up match grade irons, still sniping the enemy while you wait for a replacement scope to come in the next resupply bundle). The next level of SOTIC was supposed to go into this type of reloading and other subjects like improvised suppressors. The class was shelved for some reason. Group SOTIC classes used to teach this subject of reloading along with what NATO ammunition was good and what was junk. The easiest way is to separate the components into groups of three, Group A is spot on the spec weight, Group B is under the spec weight, and Group C is over spec. All the other hand loading TTP’s will apply.

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