Poor accuracy from my recent build (Kreiger barrel)

[bhoges]

I built this rifle over the summer. I tried Federal match ammo as well as several reloads. I was expecting groups of 1/2 or better. Im getting about 7/8 to 1inch groups. Keep in mind Im shooting off a Bald Eagle rest with a 20x Razor scope. All the components are high end and Ive have a fairly good track record building upper. 20 plus this year. The upper/lower are DPMS, Jewell trigger, Aadmount, Vortex Razor, Yankee Hill guard, Kreiger 20inch barrel. Everything is torqued and can't see any issues. Where should I begin?

 

[Brasscow]

What chamber?

Try it without the brake?

Try 24gr of rl15 or varget behind a 77smk loaded to mag length?

 

[bhoges]

Min Spec 223 1/7.7 twist. Its a stock Kreiger match barrel. My loads shot the same as Federal match so I no its not the ammo. I had zero wind today and my 260 shot a one hole group. Maybe Im asking too much for a gas gun?

 

[lte82]

Maybe because that gun is "illegal" where you live? ;-)

 

[lte82]

Min Spec 223 1/7.7 twist. Its a stock Kreiger match barrel. My loads shot the same as Federal match so I no its not the ammo. I had zero wind today and my 260 shot a one hole group. Maybe Im asking too much for a gas gun?

No, you aren't.

Here's my Krieger barreled AR15 groups from today. I am the reason it doesn't shoot bughole / one-hole groups, not the gun.

 

[soter1]

After measuring our little "P - Ps"... Bhoges - Provide more information then just "Federal match and a hand loads". If your working for a sub 1/2 MOA gun your going to need to spend time developing or finding the proper load for you. Have you chrono'd to check velocity or jump? Whether it be factory or hand load you need to cancel out the variables. Keep in mind the twist but spread out between 62 - 77 Grn match rounds and see what works best. Nothing wrong with that.

 

[bhoges]

As far as loads Ive tried target with 69gr Sierra and Win 748 with the same bullets. The reason I used Federal match 69gr is that it pretty much shoots lights out in every 223 Ive used it in. I figured that if it shoots the same as my reloads its one thing I can count out. My loads used Lapua brass, Federal match primers, and Sierra bullets. Ive tried other factory ammo as well with similar results. I believe I did chrono some loads a few months back Ill need to dig up the stats. Im going to try to stay with magazine length so I have never tried playing with oal.

 

[Biggy]

As an above poster said, try it without the brake/comp, check the crown and make sure sure not to not over tighten whatever muzzle device you install.

 

[TheGerman]

After measuring our little "P - Ps"... Bhoges - Provide more information then just "Federal match and a hand loads". If your working for a sub 1/2 MOA gun your going to need to spend time developing or finding the proper load for you. Have you chrono'd to check velocity or jump? Whether it be factory or hand load you need to cancel out the variables. Keep in mind the twist but spread out between 62 - 77 Grn match rounds and see what works best. Nothing wrong with that.

This.

I made the mistake of assuming, years ago, that a load I used with great success would work with the same results in another rifle of the same caliber, same barrel length, etc.

It didn't.

I had to redo my load development and the differences between what the 2 rifles like, for roughly the same results, is not even close.

 

[soter1]

Could be the break/device but that is usually a generic answer and usually not the case. Unless the crown was bad from the git-go, any type of muzzle strike or crown marring would produce a much worse group then what the OP photos indicated. I;m thinking its in the loads and/or chamber/head spacing.

I am my no means even close to an expert but I do see these problems on a daily basis working where I do. Then again, 3/4 MOA is pretty good, relatively speaking.

 

[bhoges]

Ill try the brake first. The crown is perfect. Crowns really don't matter anyway. I know guys believe its very important. They are a few write-ups on rifles with destroyed crown that shoot fine. My buddy and I did a test with a 300 cutting the barrel down from 24-16 in to record velocity drops. We used a hack saw at the range and the groups were very consistent. It was pretty damn funny. I even bore scopes the barrel to check the gas point hole and that didn't have any burrs. Guess it will take time. I swapped the bolt/carrier too with no difference.

 

[soter1]

Crowns are arguably one of the most important parts of the barrel. That's one reason why counter-bores are so popular for jacked up crowns? Either way, I doubt it has anything to do with the muzzle...

 

[bhoges]

I swapped the scope to my 308 along with the mount. It worked fine. Several loads I used were all proven high power loads. I might even break down the rifle again and reinstall the barrel. I know some guns are a bitch to tune.

 

[hdbiker1]

At one point, I tried some of the proven high power loads and found that most are usually moa loads or just slightly better. My CLE Kreiger (20" 1-7) liked the 69 SMK using the Sierra accuracy load (25.3gr Varget) and 24.1gr of N140 for the 77 SMK, all using LC brass and GM205M primers. But you should either do a ladder test or the OCW method to find the load for your barrel. My 77gr load has done quite a few .5 moa 10 shot groups, but on average about .75 moa or less.

 

[redneckbmxer24]

So you've only tried one bullet (69gr SMK)? Try a different bullet, maybe the barrel just doesn't like it. Try some 77's. Also try a different powder. Varget, RL15, and PP2000MR will all work well with that weight range.

Just because it's worked for you before doesn't mean it will this time.

 

[Why1504]

I think the problem is your load. My 223 prefers 77g Burgers. But, I had one other thought:

Did the barrel come with a matched bolt? You could also check the headspace.

 

[Sterling Shooter]

OP,

I'd suspect your control of rifle is inconsistent from shot to shot. Your rest is promoting the error, masking muscular exertion, undermining proper adjustment of NPA, and allowing for divergent angle/arc between line of bore at rest and line of bore at bullet departure.

The bottom line, while others here believe your problem to be the rifle or loads, unless the rifle is broken and/or the ammunition defective, all error originates from shooter inconsistency. Start your analysis of error with this fact: the bullet ALWAYS goes in the direction the barrel is pointed. This means your strikes on the target indicate where the barrel was pointed; and therefore, your error is about movement of the gun, perhaps from poor trigger control, and/or poor position, sight misalignment, or failure to adjust sight to counter for wind and weather.

You would do better to post in the advanced marksmanship section. Although the advice you have received so far is from those who mean well and are sincere they appear to have limited knowledge, that's to say they no nothing about shooter/target analysis.

One more thing, unless you have a chronograph to reveal ES and SD you can not meaningfully appraise any load. Therefore you would be wise to simply shoot some factory match and reorient your results to the concept of marksmanship rather than to quality of gear.

 

[Bill Larson]

Unless you have looked at barrel with a bore scope.... you don`t know what you are pushing bullets thru.... anymore I won`t start on a blank without at least looking at it with a scope......slugging a suspisious one.

 

[Hogstooth]

Take off that brake, try that first, I think you will be surprised!

 

[TexasMade]

If you have the open center reticle razor scope I have found it hard for me to shoot better than half inch. I shoot better with a normal crosshairs

 

[soter1]

You would do better to post in the advanced marksmanship section. Although the advice you have received so far is from those who mean well and are sincere they appear to have limited knowledge, that's to say they no nothing about shooter/target analysis.

OP, go have 3 of the best long gun shooters or maybe a distinguished shooter fire your gun. If the groups tighten up the conjecture from the Oracle may be right and my limited knowledge on this skill set needs to get trained up in the advanced marksmanship section.

 

[bp7178]

That brake mounted with a crush washer would be my first guess.

Second would be headspace on the upper end. Try just bump sizing your brass instead of full-length sizing.

 

[LRRPF52]

The upper/lower are DPMS...

Your upper needs the face squared. No way you are going to pull the best accuracy from a Krieger from an out of square receiver face.

Trouble shoot from your foundation outwards. I wouldn't even think of putting a Krieger in a low-end receiver without squaring the receiver face. You went all out on all the components except the receiver set. You might consider getting Seekins, Mega, or a Precision Firearms billet set to match the quality of the other components.

Address the upper receiver squaring issue at least, bed the barrel extension if you're going to stick with the DPMS upper, and see what happens.

 

[Tx_Flyboy]

OP,

Your approach is all wrong. Your problem is clear as day...you've done no serious load development and expect a load that happens to shoot well in one rifle to shoot well in your other rifle. Seldom does a single load do well in ALL rifles.

You need to find a load that works in YOUR rifle.

I would wager there is nothing wrong with your rifle. Ignore the advise from people asking you to change this or that about your barrel, receiver, etc.

Perform a proper load development (i recommend OCW), use a rest that takes away as much human input into the process as possible (lead slead DF, etc) and only then can you legitimately claim to have accuracy issues.

Not trying to be a dick, but BTDT, and all it took was some effort into load development, and my 1.0-1.5 MOA rifle (with FGMM and other "high-end" ammo), became very consistent sub-moa shooter.

 

[smschulz]

I would look more at load development.

 

[LRRPF52]

You can develop the load all day long, but if your rifle's foundation, i.e. the interface between the barrel and the receiver, is out of square, that dog won't hunt.

Ask any of the reputable rifle builders who are known for accurate upper receiver and rifle builds, and they will all agree that a square upper receiver face with a true extension tunnel is a starting point.

Let's say the OP does some OCW, but continues to get fliers. What will you tell him then?

Eliminate the foundational variables, then do some OCW. Chances are 999 out of 1000 that the DPMS upper does not have a square face. Without a square face, the barrel will settle erratically with each shot, and the next will be fired on a different foundation.

Also, for the barrel length the OP is using, it is standard practice among hi-power an accuracy nazi shooters to bed the extension in the upper, especially if there is all kinds of slop like you see on low-end, mass-produced upper receivers.

We've been through this before here, and the forum member took two rifles that were hovering around 1 MOA, and turned one into a repeated sub 1/2 MOA gun with 5rd strings, and the other a consistent sub-3/4 MOA gun (with a barrel that had no accuracy guarantee at all).

A Krieger deserves a solid, square upper receiver with tight extension tunnel. Would any of you drop a Krieger into a factory Rem 700 action without blue-printing it, then expect 1/2 MOA?

The bolt face should be squared as well. These are just tip-of-the-iceberg accuracy formula steps I'm talking about. The gas block should be bedded as well, if it's a set screw model.

If it were mine, it would get a slightly under-sized upper tunnel in a Precision Firearms, Seekins, or Mega billet set, trued face check, and I would temp-fit the extension by freezing the barrel, and heating the upper. The bolt would be from someone I trust, trued, lapped, ejector radiused, bolt face polished to a mirror, extractor tuned, lugs de-edged, extension polished and de-edged, firing pin hole slightly chamfered, extractor shelf ledge chamfered, gas tube to key interface centered, and a clamp-on gas block installed with balanced fastener torque.

Then I would run the usual checklists on:

* Gas system
* Recoil system
* Fire control
* Magazines
* optics mounting


Then I would load OCW round robin in 3 batches of the same ladders, and head to the range. I doubt any factory ammo would touch it unless I was in a pinch, and then I would use Mk.262 77gr Mod 0, then Hornady 68gr BTHP.

Using that 68gr BTHP load in a Krieger-barreled AR15 built by a guy who followed the accuracy steps I mentioned above, I am able to shoot 2.5" at 600yds with his rifle, at the tail end of dusk. Freaking gun is unbelievably accurate.

Here's the rifle in question:

 

[1SMALLJOHNSON]

Cast the chamber and look for any alignment errors.

Make a lap of the muzzle, and pass it through the barrel, feeling for any tight spots, spots that are tighter than the muzzle.

Either are signs that something is wrong internally.

If both of these "pass the test", then start looking for signs of scope movement.

If those pass the test, then look for "things" that are inadvertently or inconsistently touching the barrel.

If that passes the test, then look to the load. Does the specific load perform in other guns?

 

[bhoges]

Two things. Yes I have done load development. Its not like I tried only a few loads. Ive used at least 4 factory loads and worked up several reloads. The brake doesn't have a crush washer. PWS comps are indexed with washers of different sizes. Its not on too tight. As far as the front of the receiver no I haven't squared it yet. My friend is a smith and he did a test with and without squaring an AR upper. He found no difference at all. The scope and mount function fine they have been run on my 308 which shoots less than 1/2 moa. Ive shot 2.5 inch groups at 500 yards with that scope. There is a comment on my rest. Bald eagle is what I use for my bench rest rifle. Its as steady as they come. I shoot bench rest as well. Im going to try a different bullet and see if it fairs better. Ive eliminated most of the variables that I can.

 

[LRRPF52]

Is your smith friend a renowned accuracy AR15 builder, because I can name half a dozen shops that are right off the top of my head who all will say that the receiver face being squared is a starting point for an accurate upper.

JP
GA Precision
WOA
Precision Firearms
Alexander Arms
LRP

Square the receiver face and bed your extension at the least. It can't hurt. Then see what happens. You haven't eliminated that variable. Everything else is mostly squared away. I would also Red loc-tite your gas block once you have squared the receiver face.

 

[bhoges]

Is your smith friend a renowned accuracy AR15 builder, because I can name half a dozen shops that are right off the top of my head who all will say that the receiver face being squared is a starting point for an accurate upper.

JP
GA Precision
WOA
Precision Firearms
Alexander Arms
LRP

Square the receiver face and bed your extension at the least. It can't hurt. Then see what happens. You haven't eliminated that variable. Everything else is mostly squared away. I would also Red loc-tite your gas block once you have squared the receiver face.

Ill do it this week. Like you said it can't hurt thanks. Not a renowned builder but a Marine. Pretty close in his mind!

 

[LRRPF52]

Most gunsmithing schools will teach blue-printing as a standard, and it involves squaring the receiver face, truing threads to the bore line, lapping bolt lugs into the action, polishing bolt faces, chamfering firing pin holes, tuning ejectors, locking down anything that has the possibility of being loose that shouldn't be, etc.

Anyone with a rudimentary understanding of physics can see the logic behind making sure everything is square, loads are balanced in the longitudinal axis (the line that goes down the length of the rifle), and everything is as symmetrical as possible when supporting the barrel.

The USMC Quantico armorers do all this and more to the rifles they build, even to the point of welding things in place that they don't want coming loose.

 

[scharfschutze762]

Two things. Yes I have done load development. Its not like I tried only a few loads. Ive used at least 4 factory loads and worked up several reloads. The brake doesn't have a crush washer. PWS comps are indexed with washers of different sizes. Its not on too tight. As far as the front of the receiver no I haven't squared it yet. My friend is a smith and he did a test with and without squaring an AR upper. He found no difference at all. The scope and mount function fine they have been run on my 308 which shoots less than 1/2 moa. Ive shot 2.5 inch groups at 500 yards with that scope. There is a comment on my rest. Bald eagle is what I use for my bench rest rifle. Its as steady as they come. I shoot bench rest as well. Im going to try a different bullet and see if it fairs better. Ive eliminated most of the variables that I can.

Im the third person to reccomend you too try it without that brake now. Ive had accuracy issues with that particular brake and so have others.

 

[Accusource8541]

If you have money and time and want the most accurate rifle you can get, then go ahead and try all of these gunsmithing ideas that are above. They certainly shouldn't hurt anything as long as the person knows what they're doing. Otherwise, start with the cheapest and quickest alternatives. A very little bit of load development may do the trick without spending much money at all. I have the same barrel that you have in a cheap Stag Arms upper and it shoots about half MOA with 77SMK and a couple different powders. Would I like to square the receiver face and bed this and that? Sure, why not. Would it make it more accurate? Probably. But it is already pretty damn accurate and I would rather spend the money on ammo. I am certainly no expert when it comes to gunsmithing but it seems like it makes more sense to me to just start with the cheapest and easiest possible variables and work through them first.

 

[bhoges]

Well I have access to the tools and its free. Ill do it this week and hope to try it on Sunday. Thanks for the advice.

 

[kl7883]

silly question.....but have you retorqued the barrel nut? in my experience i find at least half my ars need the barrel nut retorqued after the first 50 or so rounds.

 

[bhoges]

silly question.....but have you retorqued the barrel nut? in my experience i find at least half my ars need the barrel nut retorqued after the first 50 or so rounds.

No Ive never checked it. Ill let you know this week if it was still good. When installed it was at least 40in lb.

 

[hdbiker1]

Wow. I hope it was more then that.

 

[ACPjunkie]

How many total rounds through the barrel? Sometimes it takes a little time for a good barrel to 'settle' and start to really shine.
Ensure a square fit between the upper and the barrel extension and make sure your bolt head spaces to the extension correctly.

Good luck

 

[tipper]

all error originates from shooter inconsistency, inch lbs is not enough try foot lbs.

 

[Sterling Shooter]

This thread amazes me, most all contributors have a mindset that error is about a defective rifle, of course it may be, but the reality is unless the barrel is actually loose, error is most likely about the shooter's inconsistent control of the rifle. Remember all error originates from inconsistency. If the rifle is not loose then it would be wise to review the fundamentals with emphasis on SMOOTH trigger control.

BTW, a standard load for accuracy testing: 25 grains of H335 under a Sierra 53 grain flat based bullet in fresh Winchester brass, sparked with Winchester primers. Shooting the 77 grain bullet which requires more attention to consistent recoil resistance would not be what I'd be initially shooting at SR to appraise anything. It's a more difficult bullet to shoot well simply because it is heavier.

 

[BERTMAN77MK2]

Wow! This is getting more entertaining than Netflix. Am anxiously awaiting the end results!

 

[gqllc007]

The reason most people are addressing the rifle is because the OP says he can shoot well....He is telling everyone to remove user error from the equations...he knows how to shoot...otherwise your suggestions are valid.....I had the same thing happen to me...I had a LMT MRP CQB that would not shoot better than 3-4" at 50 yards....I spoke with LMT and they said "user error"....I can shoot .5-.975 MOA all day long at 100 yards as I have been a bench shooter since 6 years old with a range in my basement...I am 52 now....I know how to freakin shoot...needless to say the LMT is gone

This thread amazes me, most all contributors have a mindset that error is about a defective rifle, of course it may be, but the reality is unless the barrel is actually loose, error is most likely about the shooter's inconsistent control of the rifle. Remember all error originates from inconsistency. If the rifle is not loose then it would be wise to review the fundamentals with emphasis on SMOOTH trigger control.

BTW, a standard load for accuracy testing: 25 grains of H335 under a Sierra 53 grain flat based bullet in fresh Winchester brass, sparked with Winchester primers. Shooting the 77 grain bullet which requires more attention to consistent recoil resistance would not be what I'd be initially shooting at SR to appraise anything. It's a more difficult bullet to shoot well simply because it is heavier.

 

[Tx_Flyboy]

Sterling Shooter is correct...as always.

I'm not convinced the issue doesn't lie with the shooter or his loads.

If you look at the loads he put up, the POI is consistent, meaning (no scope, mount, or rifle issue!!!)

It boils down to two(2) things:

1. Shooter
2. Load.

I'll also point out that the shooter has written "i've performed load development" yet provided

1. absolutely no insight as to what he believes load development to be.
2. No pictures of the loads that he shot.
3. Pictures of how his rifle is set up to perform load development.
4. No information re his load development strategy.

All we have are pictures of two 5-shot groups with FGMM (which arent consistently sub-moa in every rifle).

I'll bet all the crap advise he's gotten about squaring this, and tightening that will amount to nothing.

 

[2Shots]

OP,

Your approach is all wrong. Your problem is clear as day...you've done no serious load development and expect a load that happens to shoot well in one rifle to shoot well in your other rifle. Seldom does a single load do well in ALL rifles.

You need to find a load that works in YOUR rifle.

I would wager there is nothing wrong with your rifle. Ignore the advise from people asking you to change this or that about your barrel, receiver, etc.

Perform a proper load development (i recommend OCW), use a rest that takes away as much human input into the process as possible (lead slead DF, etc) and only then can you legitimately claim to have accuracy issues.

Not trying to be a dick, but BTDT, and all it took was some effort into load development, and my 1.0-1.5 MOA rifle (with FGMM and other "high-end" ammo), became very consistent sub-moa shooter.

Agree here. My recent AR build was with a wylde chamber wilson 20" Once I found the load combination it shoots great, but the powder changed it a lot. CFE223 shot like 1.5moa, 8208XBR shot .5 with both Hornady 75Amax and BTHP.

 

[Cobracutter]

Your upper needs the face squared. No way you are going to pull the best accuracy from a Krieger from an out of square receiver face.

Trouble shoot from your foundation outwards. I wouldn't even think of putting a Krieger in a low-end receiver without squaring the receiver face. You went all out on all the components except the receiver set. You might consider getting Seekins, Mega, or a Precision Firearms billet set to match the quality of the other components.

Address the upper receiver squaring issue at least, bed the barrel extension if you're going to stick with the DPMS upper, and see what happens.

Was coming here to post exact same thing. What/where did you get your upper from?

Putting a kriger on a upper with rough ass barrel threads and reciever face kind of defeats the purpose. DPMS is not known for quality componets. Buy a quality upper and rebuild the gun.

 

[Cobracutter]

The reason you ensure the equipment is GTG is to eliminate variables. In a perfect world we would all have unlimited resources , including time and money.

We also cannot be there to "prove" its a shooter or load issue.

Tackling build deficencies lets the shooter narrow down the problem and focus his time and energy where it needs to be....

Even if he find a load that works well, does that mean the gun won't shoot loose or other loads will shoot well (which could/should with a propperly speced and built rifle)?

 

[bhoges]

Man are my shooting skills in question. If I had a few rifle that shot poorly I'd understand. You guys need some targets with screamers to believe I can shoot and load? Rough crowd. I keep hearing I'm using fmj. I use only bthp or BT in my rifles. I've shot this rifles off a bipod, machine rest and bags. One thing for sure is I can shoot.

 

[nuclear_shooter]

Man are my shooting skills in question. If I had a few rifle that shot poorly I'd understand. You guys need some targets with screamers to believe I can shoot and load? Rough crowd. I keep hearing I'm using fmj. I use only bthp or BT in my rifles. I've shot this rifles off a bipod, machine rest and bags. One thing for sure is I can shoot.

I wouldn't take offense. Nobody here knows you personally (I assume) or has seen you shoot.

While its easy to say your can shoot, anybody on the internet can claim that. They can even show amazing targets (but who knows if they really were shot at 100 yards). Not trying to say you're not as good as you say, just explaining why its been questioned, and why you shouldn't be offended.

One final thought, every rifle has different ergonomics, so if you shoot great with one it might take awhile to get up to that level on another. Don't know what you normally shoot, but its a thought.

 

[pupdawg]

Man are my shooting skills in question. If I had a few rifle that shot poorly I'd understand. You guys need some targets with screamers to believe I can shoot and load? Rough crowd. I keep hearing I'm using fmj. I use only bthp or BT in my rifles. I've shot this rifles off a bipod, machine rest and bags. One thing for sure is I can shoot.

Don't take offense to others questioning your personal abilites. I have been guilty of blaming everything but myself many times before but NOT anymore. When I was "troubleshooting" (pun intended) I used to systematically isolate things one at a time when accuracy results on target were shortcoming.

I used to:

1) Go over the assembly. double check/triple check.
2) Go on forums and ask technical questions
3) Change the load, try different bullets/ powder/primer/case
4) swap scopes with a known good one
5) Torque barrel nuts to EXACTLY 44lbs cause thats what this armorer or that armorer said. (I'm just kidding)

I don't do most of that anymore. Yes I run over the checklist just to double check but when I have a rifle that just isn't working the way I want it to... I TAKE MYSELF OUT OF THE EQUATION and get another good known shooter to shoot it. And then maybe another. I let all kinds of people shoot my rifle all I ask is that they try their best. I'm not talking a couple groups either, at least 4 or 5 five shot groups. You'd be surprised how many of them shot better than I did, on that gun. Sometimes the results were the same, then I'd go down the checklist with equipment/assembly then onto load dev.

You seem to have turned every stone. Did you or did you not let another known good AR15 shooter get on the trigger? Note also I put "AR15" shooter, please don't have some guy that only shoots bolt guns get on it cause this is a different horse. Until you can answer that question (maybe post the results?) not sure what else needs to be said that wasn't already said.

Use factory match ammo like FGMM 69's or 77's or maybe blackhills stuff when isolating issues with consistency/accuracy. HTH

ETA: Who chambered the barrel? I don't know if that was asked?

 

[TheGerman]

Before you disassemble everything or go spending money, I'm still going with:

1 - Work up different loads for this specific rifle (as I mentioned before and why)

2 - Follow through is actually more important on a gas gun than on a bolt. While good follow through is great on both, you'll notice it more on a gas gun because, for the lack of a long technical explanation, there are a lot of things moving around between the time you pull the trigger to when the bullet leaves the barrel. Bad follow through is exponential on a gas gun due to this. My suggestion is simple; keep your head still and on the exact spot on your stock before/during/after firing and have the trigger pulled all the way back at least 2 seconds after firing.