got a problem need some help/ideas

Mort98

Member
I have an AR with a 20" stainless barrel with a Wylde .223 chamber, 1 in 8 twist, 5R rifled, scoped with a 4.5 X 14 scope. The gun has always been a tack driver with its preferred ammo. 1/2 MOA when I hold up my end. I reload so I have tailored several different loads to this gun.
All of a sudden it's printing the 1st shot an inch to an inch and a half up and left of the rest of the group. Example: If shots 2 thru 10 are all in a 1" bullseye shot number one will be an inch to the left and about 1.5"s high. All screws are tight and torqued properly with regards to the scope/mount. Very consistently does this. I haven't torn into the gun yet be plan to in the next couple of days. Any ideas on what to look for are welcome. I built the the gun myself so I'm pretty confident that everything is still torqued properly. I will try a different scope before tearing the gun apart.
 
Has anything been added or remove between the time it was grouping well to when it started throwing the first round? IE suppressor, muzzle device, scope, trigger, etc?
I'd start there.
 
Have you changed locations geographically? Like it was fine in the middle of winter in Minnesota, and now you live in South Texas in July?
 
First try single loading a 5 shot group. If no poi shift(all in a group). You will need to figure out why first one off the mag is an issue.
It could only happen when first rd is left or right on top of mag.
Bullet moving in case mouth.
Bullet/case neck alignment getting distorted.
At 100 yards accuracy/repeatability requires wind watching, good bench shooting/ technique and rests(bags bipod)
No lead sled for accuracy testing.
 
I would thoroughly clean and decarbon then shoot a couple foulers and try again before tearing into it. But then i dont know a thing about ar’s as i only own bolt rifles.
 
Nothing added or removed, Same 10rd mag I always use, No geographic changes, Did a good cleaning about 200 rds ago usually go 500 or 600 hudred rds between cleanings, only clean when accuracy starts to drop off, today was the first time this issue has come up, happened all day today, shot about 120 rds 5 or 10 at a time. Barrel was slightly warm even on the first "cold bore" shot. Never had cold bore issues before with this barrel. No bullet creep measured, was shooting at 100yds, little to no wind no lead sled have good set of front and rear bags on a solid shooting bench shot several .5 and .6" groups with two other AR's today. I'm not perfect by any means but way better than to throw the first round that far from point of aim/impact every single time with this gun. Most 5 rd groups with this gun were 1.5 to 1.75 inches first round well out shots 2 thru 5 were between .4 and .7 inches. Shot one 10rd group first shot 1.6" out of group 2 thru 10 were .65". Every single first shot was left and high no matter how hard I concentrated on making a good shot. I'm pretty good at calling my turds and they are rarely that far out of the rest of the group. Felt like I was having a pretty good day with the trigger today.
 
Will definitely try single loading a couple of groups. Great idea, should of thought to do that today. Will also check into the left/right side of the mag too, although it didn't seem to make a difference as I did shoot a ten round group today with the exact same outcome.
Shot 3 other AR's today. Had the normal groups with the 2 other AR's that were in the mix today. Only got out the other two guns to prove to myself that it wasn't me pushing out those first round shots. Have the exact same triggers in most all of my AR's most actually feel a tad bit different but they are very very close.
 
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Cold bore shot.
This was my first instinctive thought

Did a good cleaning about 200 rds ago usually go 500 or 600 hudred rds between cleanings, only clean when accuracy starts to drop off, today was the first time this issue has come up, happened all day today, shot about 120 rds 5 or 10 at a time. Barrel was slightly warm even on the first "cold bore" shot. Never had cold bore issues before with this barrel.

Hmmm I think I have a suspect.... (actually two).....
Tell me how many rounds down the chamber total as best you can guess????
Whom did your barrel?
What did you do to break in the barrel?
 
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Mike-you thinking carbon ring? I'd look at how the gas tube rests in the bolt carrier. Maybe give the chamber a good soak/scrub. Often if it's the 1st shot out of a mag, will trace back to being set off due to the bolt going home at a different speed than when the gun cycles.
 
@Jerryrigged Exactly
That and or maybe copper build up in the throat area.
Which if the barrel has went to "eating" copper the only remedy is to clean the barrel more often. IF you completely remove the all the copper that has started to build up in the barrel throat accuracy will go to :poop:

The idea is if it's there just clean it enough to smooth it out by simple cleaning more often.
(one pass with patch and a little bit sweets 7.62 will tell the tell on copper. The patch will be blue, if so use several patches with CLP or something to clear the sweets out quickly don't let it takeout all the copper. Sweets will take out all the copper when used with a nylon brush /jag patch.)
I am not that advising using Sweets at this point I would say try CLP, Hoppe's #9, or your favorite bore solvent. And clean it until the patch comes out pretty much white.
And then do that after each session.

If the barrel had been cleaned with a regiment of CLP /and or sweets when new after each and every range session versus being treated as if it was a rimfire cartridge. I probably wouldn't suspect as carbon ring or copper. I would immediately go to the barrel nut first then the gas tube being straight as the simplest cause. It may not be the cleaning regiment schedule of the OP that is a problem.

The other thought is if the barrel was installed in the upper without a moly based lube for the barrel nut to upper threads could gall and would allow the gas tube to do as you have described. But even with moly lube it could happen. easy check loosen the barrel nut off the upper inspect the threads on upper and nut re apply moly based lube on the nut and upper install nut and use a torque wrench.
Depending on the nut design the value will differ. I use a indexed nut on all mine (meaning the gas tube passes through the nut, so my values are a bit more than 30 ft-lbs, the exception being the pistol cartridges this are spot on at 30 ft-lbs)
give this a view as a guide


But back to the cold bore shot, every one of my AR's from the NRA match gun (s), Match Service rifle to the SBR (s) regardless of twist (1-14" to 1-6.5"), barrel profiles (straight bull's requiring special dia. gas block and gas tubes, to pencil barrels), lengths (1.5" to 26"), etc all throw a "Cold Bore" shot some exactly as described by the OP. It's not uncommon they all did it since new as well as about 90% of my Bolt guns. My cure is simple fire a fouling shot off target before shooting for groups.
My only reason to mention the carbon ring/copper to the barrel nut/gas tube is because the OP mentioned this is new to him. Other wise I would dismiss it as the "cold bore" shot. It very well maybe that the OP just never noticed it before thinking he just pulled the shot in the past.
 
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Probably 1500 to 1700 rounds thru the barrel. Barrel was installed with Permatex white lithium grease on the threads and torqued to 45 ft-lbs. This barrel was purchased from MDWS and has never been a copper collector, not sure who actually made the barrel. Wouldn't be surprised at all if I have a carbon ring issue. I'll do a deep cleaning first then check barrel nut torque. There doesn't appear to be any issue with gas tube alignment.
 
Personally I would do a good cleaning first. (what I call a good cleaning maybe probably is what you think of as a "deep" cleaning)
leave a coat of CLP in the bore let it sit 3-7days, swab through with patch observe dirty? now patch with clp until patch emerges pretty much white. again leave a coat of CLP.
Leaving CLP in the bore will continually break down carbon layer by layer. Hence the repeat of cleaning the residue out with a patch and jag and reapplying a new soaking coat.

Now if I wanted to do a "deep" cleaning, then I would use J-B Paste bore cleaner with a oil on a jag, then follow with a brush. Important part here as stupid as it sounds stop at 2-3" from exiting the bore. now make two to three passes with a patch and oil to move the abrasive to 2-3" from the muzzle (we are attempting to protect the crown here).
On the last pass a new patch heavily coated with CLP now we exit the bore and pass the muzzle ... REMOVE the jag / patch before retracting the rod back (only exit the crown with patch and jag don't enter the crown). Retract the cleaning rod put the jag with a new patch coated with CLP push through coating the bore remove jag/patch remove the rod. Let the rifle sit the CLP will continue to work at breaking down any carbon in the barrel. before firing again a simple pass through with a jag and patch 1 time will pull out the broke down carbon.
Note : J-B bore paste is a abrasive -- extreme care must be taken otherwise you can destroy the crown quickly hence my statement of exit only via the crown only. USE this method sparingly. And only when needed. Most the times this is not a needed process. If cleaned after a range session you will probably never need to do this.

What I didn't cover was the muzzle device as @SupressYourself stated --- Clean it --- you don't have to remove it although I do and will. I usually have it off when "deep" cleaning a barrel. (it's soaking in hoppes #9 and I'm attacking it with a old toothbrush multiple times until clean)
@SupressYourself thanks for the reminder (LOL you posted as I was typing great catch) and it is spot on
 
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Deep cleaning also means J-B bore paste to me too, always has. Just finished a 2 hr cleaning session for today. Going to borrow a buddies bore scope tomorrow and give it a look. Pretty sure I still have some work to do on it but think I am making progress. Pretty well convinced, at this point, that a nasty carbon ring was/is the problem. Lots of Varget through this barrel!
No muzzle devise buy the way, just a thread protector. Most of my guns just have target crowns but this one is threaded.
 
I don't see a carbon ring only effecting the first shot in a string, unless you are seeing a change in the brass ejection angle along with the poi shift.
A carbon ring is building up over a series of rounds, any issues would worsen until a cleaning. Normally a carbon ring manifests as a pressure change.
 
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My .02- Carbon ring/gas port erosion/crown ding should all manifest themselves with all rounds fired. I'm still leaning towards hand cycled bolt speed vs gun's normal cycle/feeding to close bolt. What is the ONE thing different with shot #1 vs 2,3,4,5 etc?
 


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