Testing the 5.56mm MK318 MOD 0 / 5.56 SOST ammo

The 5.56 SOST  is the ammo currently being used by the USMC and other troops in the GWOT,  it has not been available for the public to buy for very long so I, like a lot of other people have been curious about how it performs. The round was designed to  have better terminal performance and accuracy from short barreled rifles with a muzzle velocity of 2925 fps from the 14.5 inch M4 barrel.  The round is a OTM,  this is important to remember as it is not the same as a hollow point.  It does however, offer up better performance and is barrier blind. The bullet itself has a thick copper base and a lead front end with the usual open tip that results from the process of making the bullet.  Also present are the rings seen around the bullet much like a barnes triple shock X.  A lot of people assumed and still do that the SOST is a barnes solid copper TSX, but it is not.

After getting my hands on some of the ammo I decided to test it for accuracy first. Since the ammo is intended for combat weapons, I chose to use my Colt 6940  with milspec barrel with 1/7 twist. I did put a Leupold 18x target scope on the carbine though so i could get all the accuracy out of it I could.  I fired 2 strings of 5 shots at 1 inch dots and one string of 10 shots of M855 to compare it to the common military load all at 100 yards. It was around 1100 AM , sunny with a  2 oclock 18 MPH wind.

Other then the normal 1st round flyer you usually get from hand cycling the action as opposed to letting the recoil operate and chamber  the next few rounds, the ammo showed some  great potential. The group on the left  was a little worse due to my own bad trigger work and lost concentration on one shot, but still pretty good considering. Now I know some claim  5 shot groups tell nothing, but if you over lay to  strings you get a pretty good idea  and you keep barrel heat down and mirage off the barrel messing with the scope.

After shooting the groups I decided to test out how the round matched the trajectory of the M855 since that is one of the things the SOST round was meant to have in common with the green tip. Out to 300and 400 yards  the SOST did match the BDC of my TA31F  ACOG and zero of other scopes and Aimpoint RDS I had on hand zeroed for the green tip. Also when comparing the position of the groups in relation to the aiming points, you can see on paper that the zero held very close for both rounds.

Now, the real surprise for me, was how good the lot of M855 I shot turned out to be!  Many gun board expurts and gun magazine expurtitions will gladly tell you how terrible green tip is in the accuracy department along with its many other flaws , makes it  slightly more useful then tits on a boar hog. After getting the carbine hot  after some drills using the SOST and playing around, I fired off 10 rounds fairly quickly  with the Colt/18x combo.  The results left me a little surprised, rarely have I seen green tip shot for accuracy  with sand bags, a table and a target scope further then 50 yards. And I do not recall having seen any pictures of it doing as well in a true 100 distance group.  I shot the green tip with all seriousness and the same concentrated effort I did with the SOST and the results were pleasing and a little surprising to me.  I have never taken the green tip seriously  enough for my own needs in the accuracy department so this will indeed lead to more testing of the M855 if for no other reason  then to see if this was a fluke.

Now I do not mean to sound like I think green tip is crap, I have seen some  good performance out of it at longer ranges on coyote size targets and even man sized targets. But on the other hand, I have seen some terrible accuracy from it too. Of course lots and different MGGs have as much to do with it as anything, not to metion the different shoots and the quality or lack of  in the guns used.

Back to the SOST, I think its a pretty good round from what I can tell. It is not MK 262 or TAP 75 gr. But for general issue to everyone, it is an iprovement in my humble opinion.  I have not shot anything living with it yet, but I will. Also, in the next few weeks I will test it though a few “barriers” like auto glass, wood, and wall paneling. Hopefully I will get to shoot through some auto doors as well.  I would not use it in my own house if over shooting is a issue, but I would use it for anything else at this point if you can find enough for SHTF bulk storing. And you have the benefit of practicing/training with M855 and still being able to shoot the SOST without a zero change. At this point I can not say it is better then any MK 262 top load in accuracy, but it is not meant to be, but, it is better then M193 by a long ways and it shows the ability to shoot a lot better the M855 and even if it just matches it in accuracy you still have the benefits of better terminal performance and barrier penetration while still holding together to hit the target behind if power point presentations can be believed. Hopefully my future testing will offer at least a tiny sample to help prove or disprove the new round.

Aimpoint vs. Eotech for the home defense rifle

Both Aimpoint and Eotech are popular reflex optics for the AR15 family of weapons.  Constantly online and there are heated debates over which is the better optic and many people have differing opinions for different reasons.  There is one major reason the Aimpoint should be picked over the Eotech for home defense.  This is the Aimpoints battery life and run time.  An Eotech needs to be turn on before use, and will run 4 or 8 hours before shutting down.  The Aimpoint will run months to years depending on model and brightness.

The Soldier or the police officer when going on duty or starting a patrol has the time to turn on an Eotech.  You don’t know when you might need to use a home defense rifle, and you shouldn’t want to have to turn on its optic before you can use it.  Even worse would be if your battery is dead when you need it.  The new Eotech EXPS3 has a listed battery life of 25 days on setting 12.  The new $400 dollar Aimpoint PRO will run 3 years on 3/4 max brightness.

Back when I owned an Eotech 512, I often found the batteries were dead when I wanted to use it.  I had to store the batteries out of the optic to keep them from draining.  Not only did I have to turn it on before I would shoot, I would have to check during the day that it is still on.  When working at the range, I have seen more then a few shooters day at the range ruined when the only rifle they bought has an Eotech with dead batteries and no iron sights.

If your rifle is a fun gun, get the optic you prefer.  But if you require a reflex sight that is ready all the time, use an Aimpoint.

Ranges Notes

Had a Colt 6920 with a Trijicon TA31-MRD ACOG and a Spikes 5.45 with a TA31-ECOS ACOG side by side at the range today.  Both were zeroed using the 300m point of aim at 25 meters.  Later that day, both were used to shoot at a steel target at 565 yards(about 500 meters).  The Colt using M855 ammo and the ACOG calibrated for that ammo was right on for elevation when using the 500m mark.  However when shooting at 500m with the 5.45 and an identical 5.56 Bullet Drop Chart reticle, the 5.45 corresponded to the 400 meter mark on the BDC.

It was interesting to see how much flatter the 5.45 was flying compared to the same zero at the M4.  I’ve never been able to find good data on the ballistic coefficient of the 5.45 7n6 rounds, or readable info on its trajectory.

Mark Serbu and the BFG-50A

Mark Serbu with BFG-50A

On Thursday I had the pleasure of meeting Mark Serbu and getting to fire a couple of shots through the new Serbu BFG-50A semi-auto .50 cal rifle.  I was already familiar with his products as the Serbu Super-Shorty shotgun is often seen at the local machinegun shoots and in the occasional movie.

Serbu was function checking and breaking in some rifles that his company was getting ready so ship out.  While his BFG-50 bolt action has been on the market for a while, the semi-auto 50A is relatively new.  Firing this .50 was very pleasant, but it does provide bystander with a good bit of blast from its effective muzzle break.  It uses the same mags as the Barrett M82/M107.  Couple of the best things about the BFG-50A is that it is lighter, and cheaper then the Barrett semi-auto .50s.  Sadly, due to high-winds knocking down target frames, we did not get to see how well the BFG-50A groups.  I look forward to seeing more of these at the range.

Thanks to Mr. Serbu for answering my questions and letting me take his picture.  He indicated that he is working on a pistol for his next project.

More information about Serbu’s products can be found at Serbu.com

On Back Up Sights

I have seen many arguments online about the necessity of back up sights on a rifle using optics.  The general concensious seems to be that they are needed on military rifles, but not on civilian rifles.  This is not the case.

In the military people work in teams and are almost never alone.  Should a rifle go down it is not really an issue as you still have many other people capable of continuing the fight.  For the civilian and the police officer this is often not the same.  If someone wakes up in their home and finds the battery dead in their reflex sighted rifle it helps to have iron sights.  However if a Marine’s optics fails, he is only reducing his squads fighting ability by 1/13 its firepower.

So do you need back up irons?  First needs to consider if the rifle is a toy, or a tool for fighting.  If it is a toy, back up sights are not necessary.  If it is a fighting tool, look at its role and how it is set up.  If you are running battery powered optics or magnified optics on quick detach mounts, I would suggest back up sights.  So if you need to use a wrench to remove your optic, back up sights may not be practical for you and you may be better off switching to a different weapon.

“Damn, the batteries are dead.”  Is not an uncommon saying at the range I work at.  Not only among cheap optics with poor battery life, but often about Eotechs.  Batteries discharge, cheap batteries and cheap optics drain even faster.  Even the best optics can be broken.  On the range this is just an annoyance, for the Soldier or Marine it means that their buddies will have to take up the slack.  However if you, as a lone civilian or law enforcement officer, have this happen in the fight, the results can be costly.

I highly recommend back up sights on the individuals fighting rifle.  If you are fighting by your self, being able to keep your weapon in the fight is crucial.

On that note, also make sure to keep your back up sights zeroed.

Condition One and only


This video is a reminder of the results from not being ready for a fight when it happens, and not making sure to always keep your side arm in condition 1.  Not only did the would be hero get shot, but he lost his gun to the bad guys and if they got away its likely they will use or already have used it on some one new.