Diamondback DB-15 Accuracy Problem

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wbm

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Diamondback DB15 5.56 NATO M-Lok, 16" 1-8 Twist
Leupold Mk AR Mod1 6-18x40

Ammunition
Winchester 69gr 223 Match
Clean cold barrel first two or three 5 shot groups are 3-4"
Let barrel cool.
Next series of 5 shot groups are 1-1.5" consistently.

What the heck is going on?!
 
More info would be helpful.
1st outing with the rifle? Have you tried other brands and bullet weights? Is the barrel free floated?

If it's a new rifle, it'll take some breaking in. Standard mil-spec AR 15's aren't the most accurate either.
Try different ammo & weights to see what it likes best.
 
That's why they allow fouling rounds in matches before your sighters and record firing.

Basically, powder (not jacket) fouling builds up to a certain point and sort of gets blown/wiped out on a consistent basis on succeeding shots. Jacket fouling usually gets worse.

Your first shots, the powder fouling probably built up to the worst it's going to be.

The alternative to accepting powder fouling changes is to clean the barrel after every shot, Some bench rest shooters do this,

I did find that one of my M1 Carbines shot better when absolutely filthy than clean. I attributed that to the grunge taking up slack in the tolerances. No grin, no rofl, that's the way it was.

I had a .243 Win with a warped barrel which would walk its shots high and left as it heated up. Allowing it to cool between shots kept the shots in a nice group. I always meant to get cryogenic stress-relieving on it to cure the problem,

Then there's the old adage, "Every rifle is a rule unto itself."

Terry, 230RN
 
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100 yards? I would guess some residual stress on the barrel and heat helps. Going from 4" to 1" is fairly extreme.

More likely, I would thing you get better after a few minutes in it. I'm assuming if your running 1" at 100 yards or more, your probably far above an average shooter, (I see old targets at 100 yards running 3-7" pretty regularly, and thats scoped rifles).

Maybe the time it takes to shoot 15 or so rounds gets you prepared. I KNOW it makes a difference with me. I will shoot 5- 7" at 7 yards on pistols for a few mags before dialing it into single hole-1/2".
 
I think that you answered your own question. The first 2 to 3 five shot groups are open and subsequent groups close up. 1) you are settling in or 2) the barrel is settling in or 3) both you and the barrel are settling in. See what you and the rifle do at a new shooting session when the rifle has not been cleaned - that should narrow down your causes.
 
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More info would be helpful.
1st outing with the rifle? Have you tried other brands and bullet weights? Is the barrel free floated?
Click to expand...

Third outing with the rifle and the barrel is free floated.
Have tried only two other brands and bullet weight...both 55gr....Frontier 55gr OTM and PMC Bronze 55gr.
 
IMHO, most run of the mill ARs are not super accurate. Most are 2moa. I am not sure how much ammo is a contributing factor. Most of my ammo is of the inexpensive 55 or 62gr variety. Usually I just do the best with what I have. For you I would suggest checking some different ammo and making sure everything is still tight, rails, etc.
 
wbm said:
Diamondback DB15 5.56 NATO M-Lok, 16" 1-8 Twist
Leupold Mk AR Mod1 6-18x40

Ammunition
Winchester 69gr 223 Match
Clean cold barrel first two or three 5 shot groups are 3-4"
Let barrel cool.
Next series of 5 shot groups are 1-1.5" consistently.

What the heck is going on?!
Click to expand...
That is unacceptable accuracy. With decent ammo groups should be less that 2 MOA. Check to make sure the bolt moves freely in the BCG and doesn't bind. There could be something else. If the rifle is new I would send it back. Does the bolt seat properly?
 
Clean, Cold barrel is your problem right out of the gate. Once your barrel gets fouled, then it starts grouping OK.
Don't clean your barrel until the groups start opening back up, then foul the barrel with a few rounds before you start shooting groups again.
 
A clean or dirty barrel isn't going to make anywhere near that big a difference. There is a mechanical problem with the rifle. Most likely BCG or bolt.
 
Did not clean barrel and took it out Saturday...same problem. Contacted Diamondback and told them the issue.

BCG does not bind bolt seems to seat properly.

Thanks for the replies!!
 
wbm said:
Did not clean barrel and took it out Saturday...same problem. Contacted Diamondback and told them the issue.

BCG does not bind bolt seems to seat properly.

Thanks for the replies!!
Click to expand...
Did they suggest any possibilities or mention sending gun back in for inspection? Please keep us updated
 
wbm said:
New barrel arrived and installed. No charge. Going to range tomorrow.
Click to expand...

Hopefully your DB15 is better now. 55 FMJ isn't going to give you much better than 2-3MOA but the 69 match should shoot better.

I have a friend with one, it doesn't shoot that great. We were trying to hit a 2/3 Silhouette at 250 yards but had mostly misses.
 
Really appreciate the responses guys.

First off. The barrel was really bad. Smith said he was going to use it as a demonstration of what a really bad barrel looked like.

Range Report: New barrel. Best ammunition used yesterday was. Winchester 69gr Match yesterday. 7 shot group was 1.25".

However. Not So Fast! The first few shots with the gunsmith installed new barrel resulted in 10 to 15" groups! Was shooting Frontier 55gr match. First shot 5" lower left of target diamond. Second shot 6" upper left of target diamond and so it went! Thought about backing over the rifle with my truck but decided against it. Hope that was the right decision.

After ten or so shots it finally settled down. Let the barrel completely cool and then began to shoot the Winchester 69gr with good results. Finally ended with Sig Sauer 77gr Match. Three shot group was 1".

Bottom line? I don't know. Will see. If the DB15 follows the previous pattern, after cleaning the rifle will shoot all over the place at first then settle down to 3-5 inch shotgun like groups. If it does that again I may reconsider backing over it with my truck....what could it hurt?
 
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I mounted a scope and zeroed it in for a fellow. I think it was a D.B. Cheap scope too. I got it in enough for S.D. But it would not be reliable enough for shooting small animals out beyond 50 yards. My neighbor said don't worry about it. He said it will just sit in the closet. The guys not a sportsmen. He's a good friend of my neighbor. I take pride in my work. After my neighbor told me this. I felt a little better.
 
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