I put a new Ballistic Advantage 18" (rifle-length gas tube) on my Precision AR.



I took her out to the range to try some different factory loads to see what it likes (second time out with the new barrel).

Admittedly, I was in a hurry. I tried to not let that affect each shot-break, but it definitely sped up the rounds per minute that went through the barrel.

I went through eight different loads.

At first, the rounds grouped high, but otherwise in a pattern as you might expect.







As I worked through the different loads, the rounds started to string vertically.











I went back and shot another group of Fed. Gold Medal Match and it also strung out vertically, whereas it didn't the first time. I took my time, and put five more rounds through the tube waiting between each shot (I wasn't really 'waiting' between shots before more than just re-acquiring the target, breathing, and breaking the trigger).

This is what I got:



Other than what looks like a flyer, this group looks like the first 69gr FGMM group (which I'm happy about).

How much time do you wait between each shot?

Do you agree that the vertical stringing is the result of the barrel heating up from rapid shooting? Or do you think it was just shooter's error and I'm blaming it on barrel temperature?

Vertical stinging is often the result of firing at different places in the breathing cycle.Thats what I would suspect.

Have you shot it without the can?

What is the progression of the string? In other words do the shots start low and work their way up, or are they random up and down?

That butt stock isn't helping. For now, move it all the way back and adjust the scope accordingly. Plan on getting a precision oriented stock. What are you using for a rear support?

Move the bipod as far forward as possible.

The gun looks out of balance to me, but hard to tell in a pic. Looks barrel heavy.

Inhale, exhale partly, hold it, break. Every shot.

I was not using the can when conducting Ammo testing.

I was shooting five round groups without breaking contact on the rifle. Therefore, I did not look through my spotting scope after each round.  I don't know what the progression was.

I like adjustable length stocks, especially for transport/storage and it is at my favorite setting.

The bipod is all the way forward.

I shot over bags (front and rear) off a bench. Wasn't using the bipod.

I warm my barrel up and keep it warm. I can shoot 30 in a row maybe 4-5 shots a minute without stringing. I can shoot 15-20 shot groups with my 24" AR(6 pos car stock with comb attachment) with no stringing. Bipod and rear bag.

Exhale completely, shoot before the inhale.

Is your scope low enough so you can rest your head on the stock and get a good sight picture?

See what I have to use on mine to get a proper consistent cheek weld.

The scope height is perfect. The Larue SPR-E mount is made for standard comb height.

My vertical is often the stock not in the ideal same position in shoulder and related is natural point of aim (pushing up, pulling down), and trigger control.

Or the barrel and load just aren't working.

Help me understand what a PRS or other stock will do for me? Do you suspect the CTR is moving slightly, or does it just not offer comb height adjustment?

I'm willing to go in for a new stock if you think it would help. I've already thought about it, but I like being able to collapse it to fit in a case or in the safe.

Considering I use an M4 stock on two of my "precision" rifles I don't see how a different stock will help.

Seems to work for me, one barrel is a Wilson Combat other is a Brownells, nothing special.

.223


6.5G