Vltor A5 Stock and SBR

AR/M4 AR General Discussion
1

Finally got around to installing my Vltor A5 stock system the other day on my SBR in lieu of the Magpul UBR. My SBR is a self built 11.5" from BCM with an AAC M4-2000 suppressor and 4x32 ACOG.

So today markm and I went out to one of our usual spots to do some testing now that the good weather is in full effect. I didn’t know what to expect and I will say that I was somewhat surprised.

We fired a variety of ammo and used 3 different buffers. To the best of my knowledge we had zero issues with cycling. The ammo used was as follows;

  1. Lake City M855 FMJ.

  2. Hornady 75gr. steel case TAP.

  3. Hornady 55gr. steel case TAP.

  4. Swiss RUAG 55gr. M193 clone.

  5. Markm hand rolled .223 55gr. magic ammo.

It fired very smooth and when doing hammer pairs and controlled pairs I could tell the difference from the previous set up using the H3 buffer.

We also dropped his BCM 14.5" middy upper onto my lower and it ran like a champ. Very smooth and easy to control. However, we did have to use the lighter buffer.

The second part of the test (this is a two for one special) was to test POI shift when using/ removing the suppressor. I know the topic has come up several times in the past so I wanted to share my experience and thoughts. Having said that I am not a mathematician so I’ll let you guys determine how much shift there was.

We started the testing by firing unsuppressed at 50 yards in the prone position using a back pack as the shooters support. I fired a total of ten rounds. This group was fired using Hornady 55gr. steel TAP.

This next group of 10 was fired suppressed.

This group of 10 was fired suppressed using Hornady 75gr. steel case TAP.

This group of 10 was fired unsuppressed.

Summation: I chose 50 yards because I feel that it represents an accurate distance at which a civilian or LEO may engage someone. As you will see the shift in my opinion is small enough that it shouldn’t be a concern.

I may push out to 100 yards next time and see if that makes a bigger difference.

2

I’m very happy with the A5 setup Robb J put on my SBR (Daniel Defense 12.5" upper). I’ve been using a Sprinco “Green” rifle spring and Vltor’s 7 oz buffer. That, combined with an AAC Brakeout, makes it an incredibly smooth recoil and very fast splits out of a Geissele SSA.

I just got some Bob Marvel Custom Gun Oil, which I’ll use to lube the nickel boron BCG. That stuff makes Slip 2000 feel like molasses.

3

Which buffer were you using on the 11.5"? Im juat curious when you went lighter for the 14.5", do you mean you went to the Vltor standard 5.3 oz buffer or tweaked one to go lighter per Vltor’s instructions of switching tungsten and steel.

I’ve run mine with two different SR15’s, one having the smaller gas ports and it ran all ammo fine.

I have a couple SBR builds coming up and I’ll be using the A5 on all of them. This and a T3/BattleComp makes for a great combination and a very fast gun. Glad to see more and more positive reviews.

Looking at your shift, it’s about 3 MOA or a little bit more, assuming there’s about an inch and a half difference in those groups at 50 yards. Since I’m going off of a picture and can’t really measure it from my iPhone, I could be off a bit. Seeing as the shift is elevation only, I wouldn’t mess with it, especially if using an RDS or Acog.

Jonathan

4

Looking forward to following this… I am planning to add the A5 to a 10.5 per Robb’s recommendation.

5

Did yall try any of the different buffer weights in markms auto?

Using the 6oz and colt spring I am very happy with mine now.

6

We tried all the buffers. I can’t even remember which did what. When gunz rolls out of bed he’ll have to post his thoughts.

We were playing so much musical buffers on the A5 and the BCM middy I can’t remember WTF we figgered out. :confused:

7

I believe that we could only use the H3 version as the H4 was too heavy.