worst accuracy ever

K

kooman

Member
I put together a rifle yesterday that I was going to use for a "beater" or a truck gun, i used a 16" mid gas Anderson barrel. went to sight it in and I couldn't bieleve the results, 10 shots at 110 yards were a foot to around 2 foot apart, scattered all over the place. No its not me, no its not the ammo, had a good optic and mount, all tight, barrel nut was tight, free float handguard. I put a different barrel in the same configuration and it shot fine. so whats the worse grouping anyone has ever seen from a barrel with an obvious problem?
 
check the crown for a burr or something silly.

as you found its barrel related. contact anderson i'm sure they'll want to make it right.
 
Look in the barrel and make sure there is no extra metal hanging down from the gas port hole. Most little ones shoot out in the first shot but you might have a Mt. Everest in there. Just hold it up to the light. Have you run a rod/patch through it? This will always show one.

Greg
Realistically I suspect the crown. If it is threaded perhaps the end of the barrel thread area might have swaged down a tad also.
 
i had a gouged gas port on my first 300 blk barrel - port came right through one of the lands. however accuracy wasnt what suffered. not saying that it cant, just wasnt my experience.

if its a nasty at the gas port, you should likely find copper deposits on your bolt from it shaving the jackets as they pass.

i didnt notice it until about 300 rounds in and my gun started to not cycle normally. i finished shooting my ladder with a single shot AR that morning and when i got home the gas port was plugged solid with copper flakes from jackets getting shredded and the tail of my bolt (near the gas rings) looked like it was copper plated.
 
thanks for the replies, I looked the barrel over and I don't see anything obvious with the naked eye. the barrel seems a little sloppy when fitted into the upper receiver, I don't know if that is normal or not but I don't ever remember seeing one quite that loose before. also after about 20 shots there appears to be a copper coating around the gas port under where the gas block was, not sure what that's about either. I will see what Anderson has to say and go from there. thanks again
 
If the barrel is a loose fit to the receiver, that is most certainly a cause for concern...and likely at least one cause of the accuracy issues.
 
the barrel is 1 in 7 and I was using 50 grain bulletsOriginally Posted By: Foxpro.223What is the rate of twist on the Anderson barrel and what bullet were you using?
 
I realize that combination is not ideal but a 2 foot spread?Originally Posted By: Stu Farishthat's a fast twist for bullets that light. you might have to slow them down a bit to get better accuracy.
 
Originally Posted By: koomanI don't see anything obvious with the naked eye. the barrel seems a little sloppy when fitted into the upper receiver

how did you check this fit between barrel and receiver? where do you feel the sloppy at?
 
I don't ever recall seeing copper around the gas port hole. There's got to be an issue with that sucker. I bet they'll send you a different one without much problem.
 
When you say the barrel is tight. What does tight mean? 35 lbs, 45 lbs, 55 lbs? I once torqued on to 70 lbs before it would shoot.
 
sliding the barrel into the receiver is loose, and once the barrel is seated in the upper I can still wiggle it quite a bit. I tried a different barrel in the upper I was using and it fit like it should. I did stick a dial caliper (i dont have a mic here) on the Anderson and it does measure a few thousands less than others.Originally Posted By: SlickerThanSnotOriginally Posted By: koomanI don't see anything obvious with the naked eye. the barrel seems a little sloppy when fitted into the upper receiver

how did you check this fit between barrel and receiver? where do you feel the sloppy at?
 
well not real sure, I started at 35 and then went to the next notch for the gas tube, probably 50-60 ft lbs, it is a Midwest industries nut/handguard.Originally Posted By: MGYSGTWhen you say the barrel is tight. What does tight mean? 35 lbs, 45 lbs, 55 lbs? I once torqued on to 70 lbs before it would shoot.
 
If the barrel extension is loose or is able to move inside the upper receiver you'll more than likely have accuracy issues.

I would agree that the 50s shouldn't be that wild even in a 7 twist, but you never know as every barrel is different.
 
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The barrel should not wiggle in the upper once the barrel nut is torqued, properly. I would look into the install versus the barrel before you call the barrel manufacturer. The barrel extension likely needs to be torqued more.
 
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if the barrel extension is loose on the barrel, shouldn't that be a problem for the barrel mfg and not the end installer? especially so since this is directly related to headspace for that barrel.


i dont think many folks buy an AR barrel that doesnt already have the barrel installed, and if they do its more than likely a custom grade blank that they're taking to a gunsmith for finishing, and therefore the GS would be responsible for proper installation of the extension.



the op did say that it appeared to be loose going into the upper but that another barrel didnt exhibit the same issues - so its probably a problem with the barrel.

personally i'd say get the mfg involved - maybe even show them a video of the loose fitment, or confirm with them over the phone the correct ID of the barrel extension.

it may turn out to be a tolerance stacking issue - your barrel extension is just a bit small, but within spec & and your receiver is just a bit large, but within tolerance spec - type of thing
 
too light bullet for twist rate, I experienced easily 3" or even bigger groups.

2' not so much. I agree that you're likely looking at something in hardware that is loose where it should be tight.
 
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