Accuracy trouble shooting an AR15

[DPRoberts]

Does anyone have a checklist they go through when troubleshooting an AR that just won't shoot?

I've covered most of the obvious stuff like properly torquing mounts, rings, barrel nut, flash hider, etc, making sure the barrel is actually free floating and putting another shooter behind it, but it seems I need to delve deeper. The most recent troubling discovery is that the gas tube contacts the barrel nut regardless of the position its in. Even after removing a bit of material from the nut, (nothing drastic) the tube wants to rest on the top of the nut. I'm unable to find whether that is detrimental to accuracy or not.

Currently the rifle does around 1.5 moa consistently with handloads or match factory (I've tried pretty much every popular .224 bullet). Oddly, it performs pretty similarly with m855, go figure. I'm not looking for it to compete with my bolt gun, but I'd like to get a dependable 1 moa from a rifle with a SS match barrel.

Anyone have any ideas?

Specs are:
Spikes upper and lower
Rainier arms match 16" 1-8" twist 223 wylde barrel (regular match not Ultramatch) only about 200 rounds down it so far.
Troy TRX extreme rail
A2 flash hider
Vortex Viper 2-7x32 in a Larue SPR (cranked down tight)
Geissele ssa-e
other bits and bobs

 

[kvwpwr]

Re: Accuracy trouble shooting an AR15

Keep practicing.

 

[Russ D]

Re: Accuracy trouble shooting an AR15

Try not wrapping your thumb around the pistol grip. I have great results with a wide variety of Ar's all shooting 55 grain Vmax hand loads with 27.0 grains of Varget. All of my Ar's from custom to factory guns can shoot 1 moa with this load and me shooting at 100 yards.

 

[sic65stang]

Re: Accuracy trouble shooting an AR15

What reloads are you shooting? Specifically what bullet and grain? IMO that barrel will like something heavier than 55.

 

[BOL556]

Re: Accuracy trouble shooting an AR15

Are your groups going up and down and right to left or are they all over the place. You could also check the tracking of the rifle scope or try a different scope all together. Like someone said above if your not use to shooting the AR platform shoot more and the groups will get smaller. I kinda had the same problem if that the case going from AR to bolt gun. When I went to the bolt gun my groups sucked for about the first 400 rounds but now they are getting better.

 

[jwb47]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sic65stang</div><div class="ubbcode-body">What reloads are you shooting? Specifically what bullet and grain? IMO that barrel will like something heavier than 55. </div></div>

negative on that . my 1-7 colt 6940 shoots 52 grain hornady amax bullets just as good as it shoots 70 grain barnes bullets .

are you using a flash hider or a muzzle brake and are they installed correctly? if so try a different optic

 

[dixiejarhead]

Re: Accuracy trouble shooting an AR15

try 75gr loads. bullet design plays just as big a part as weight with these guns. If the patterns are inconsistant - make sure barrel is tightened to proper torque specs. Too much or too little and it won't group.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Russ D</div><div class="ubbcode-body">Try not wrapping your thumb around the pistol grip. I have great results with a wide variety of Ar's all shooting 55 grain Vmax hand loads with 27.0 grains of Varget. All of my Ar's from custom to factory guns can shoot 1 moa with this load and me shooting at 100 yards. </div></div>
I've experimented with a few different grip holds and trigger positions including not wrapping the thumb and 90* trigger finger. Nothing really made much of an impact. Obviously I'd never completely rule out shooter error, but I (and other shooters) have been getting such consistently poor groups I'm inclined to think there's another factor. Shooter error usually manifests in really poor coupled with occasional really nice groups in my experience.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sic65stang</div><div class="ubbcode-body">What reloads are you shooting? Specifically what bullet and grain? IMO that barrel will like something heavier than 55. </div></div>
Ive tried hornady 68 and 75gr bthp over Tac and Varget as well as several factory loads in 69 and 77 SMK. I'm pretty discouraged in my quest for the magic bullet it likes.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HAVOC615</div><div class="ubbcode-body">Are your groups going up and down and right to left or are they all over the place. You could also check the tracking of the rifle scope or try a different scope all together. Like someone said above if your not use to shooting the AR platform shoot more and the groups will get smaller. I kinda had the same problem if that the case going from AR to bolt gun. When I went to the bolt gun my groups sucked for about the first 400 rounds but now they are getting better. </div></div>
A typical group generally has more vertical dispersion than horizontal, no doubt partly due to the typical AR chin weld. The scope tracks well but it has occurred to me that it might be a little too low power for reliable load development. I'm not a great gas gun driver but I have put better 1000 rounds through this rifle on the previous barrel. The biggest frustration is the lack of accuracy gain I've seen replacing the chrome lined gov profile barrel. It seems logical to me to expect that increasing the mechanical accuracy of a rifle should bring down group size even if shooter error is a factor.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jwb47</div><div class="ubbcode-body"> are you using a flash hider or a muzzle brake and are they installed correctly? if so try a different optic </div></div>
Rifle has an A2 flash hider torqued to 20 ft/lbs. Its vertical and correctly torqued but I don't know if there is another factor to look for here.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dixiejarhead</div><div class="ubbcode-body">If the patterns are inconsistent - make sure barrel is tightened to proper torque specs. Too much or too little and it won't group. </div></div>
Barrel nut is torqued to 45 ft/lbs but I have tried 30 and 70 to see if I saw a difference.

I really appreciate the help so far guys. I've put a lot of cash and effort into this rifle I'm still hoping that I'll be able to work it out.

 

[spr1]

Re: Accuracy trouble shooting an AR15

Lose the A2. The closed bottom has a negative effect on accuracy. Put an A1, an AAC Blackout, Vortex, or Surefire FH on it and watch the groups shrink.
Years ago I had an HBAR that would shoot 1.5 moa, I removed the A2 and installed an A1, the groups dropped 8" vertically and the group size was sub-moa.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

OP,

My AR for Service Rifle competition is built I think as good as it gets, since I've shot many groups close to zero dispersion with it using irons from sling supported prone position. On a typical 20 round for record string of fire on the MR-31 target I can hold close to a 1/2 minute, producing cleans with double digit X-counts. I mention this since so far you've gotten some advise which is simply ridiculous.

What's important is a good barrel, clean breaking trigger, alignment of parts i.e. gas tube/barrel nut, and, perhaps, proper torque on the A2 flash hider. A drill rod can be used to index the barrel nut, and the use of a peel washer will solve any problem when indexing the flash hider that would possibly cause the muzzle to flare.

Remember, although you could have a multitude of problems all problems originate from two arenas: inconsistency and incorrect compensation for the effects on trajectory.

When the rifle and ammunition are no longer suspect of being inconsistent you should direct your analysis to the principles of marksmanship, position consistency, and proper sight adjustment.

One more thing, a good barrel is difficult to understand unless you are a really good shooter to know what you've got. Until you're shooting HM scores at LR you might want to trust in someone like Frank White at CLE for a good barrel. I've had Frank turn all of my Service Rifle barrels for over a decade. I've yet to get a bad one.

Also, regarding barrel torque, using a barrel nut wrench fitted to a torque wrench you could just about have the nut indexed properly at less than specified torque, or you could exceed torque specified for a properly indexed nut. This is where finesse and abandonment of specified torque is prudent. That's to say, you may want to get it tight and then back off to get the nut to index. that's the way I do it.

 

[Niles Coyote]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: spr1</div><div class="ubbcode-body">Lose the A2. The closed bottom has a negative effect on accuracy. Put an A1, an AAC Blackout, Vortex, or Surefire FH on it and watch the groups shrink.
Years ago I had an HBAR that would shoot 1.5 moa, I removed the A2 and installed an A1, the groups dropped 8" vertically and the group size was sub-moa. </div></div>

Never thought about that. I will have to try it.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Niles Coyote</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: spr1</div><div class="ubbcode-body">Lose the A2. The closed bottom has a negative effect on accuracy. Put an A1, an AAC Blackout, Vortex, or Surefire FH on it and watch the groups shrink.
Years ago I had an HBAR that would shoot 1.5 moa, I removed the A2 and installed an A1, the groups dropped 8" vertically and the group size was sub-moa. </div></div>

Never thought about that. I will have to try it. </div></div>

Just buy a peel washer. The peel washer assures proper indexing of the A2 Flash Hider where it will not be an accuracy factor.

 

[Temp9]

Re: Accuracy trouble shooting an AR15

If you want to see if it's the flash hider, just pull it off and shoot with the muzzle naked. Also, overtorquing your flash hider can kill the accuracy. Something to do with stressing the muzzle or something.

Also try giving your barrel a real good cleaning. The first handful of rounds through a new barrel tend to foul it more than usual (hence the birth of overblown break-in procedures). If you haven't cleaned your barrel yet, I would give that a try.

It sounds to me you may have a barrel issue, seeing as how you were shooting your original barrel just as well as this one. If you can't figure this out, send the barrel back to Rainier. They'll take care of you.

ETA: A great load for 16" barrels is 24.6-24.7gr Varget, Nosler Custom Competition 77gr, Federal FGMM SR Primers. It gives me an average of about .7" 5 shot groups at 100yds with my Rainier Ultramatch 16". This is a hot load, so work up to it in your rifle.

 

[317millhand]

Re: Accuracy trouble shooting an AR15

Is say that 1.5" isnt TOO BAD with a 16 inch barrel, but I have seen factory Rock River guns with 16 inch Wyle barrels shoot at MOA or below. Yours should be no different. If you have access to another scope, try that as well. Atleast to rule it out.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

Alrighty, looks like I have a couple things to try for my next range session. I'm going to:
Fully clean barrel
Remove flash hider
Different scope (after trying old scope with no flash hider)

Does anyone see a problem with blocking my gas port (flipping my gas block upside down) to eliminate variables of gas tube alignment and the typical gas gun driving errors? Essentially I'd be turning it into a straight pull bolt action.

 

[Temp9]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DPRoberts</div><div class="ubbcode-body">Alrighty, looks like I have a couple things to try for my next range session. I'm going to:
Fully clean barrel
Remove flash hider
Different scope (after trying old scope with no flash hider)

Does anyone see a problem with blocking my gas port (flipping my gas block upside down) to eliminate variables of gas tube alignment and the typical gas gun driving errors? Essentially I'd be turning it into a straight pull bolt action. </div></div>

Good luck! Most of the "difficulty" in driving a gas gun doesn't come from the cycling action, but rather the increased lock-time from the trigger. A bolt gun only has to drop a striker, which moves all of about a centimeter. AR's have a lock-time that's about 10x longer, if I recall correctly. Gas tube alignment shouldn't be an issue unless it's really binding up, which you could see visually. But if you're still set on disabling the gas system, I don't see any problem with flipping the gas block. Make sure the set screw (if applicable) isn't damaging the gas port on the barrel.

Also, make sure you use good cleaning procedures. Use a bore guide, quality rod, etc. Check out LoneWolfUSMC's videos on Youtube for a very good tutorial on cleaning precision rifles.

 

[Irish Bacon]

Re: Accuracy trouble shooting an AR15

Practice Practice Practice

 

[spr1]

Re: Accuracy trouble shooting an AR15

Forget the gas block......

 

[TripleD]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">OP,

My AR for Service Rifle competition is built I think as good as it gets, since I've shot many groups close to zero dispersion with it using irons from sling supported prone position. On a typical 20 round for record string of fire on the MR-31 target I can hold close to a 1/2 minute, producing cleans with double digit X-counts. I mention this since so far you've gotten some advise which is simply ridiculous.

What's important is a good barrel, clean breaking trigger, alignment of parts i.e. gas tube/barrel nut, and, perhaps, proper torque on the A2 flash hider. A drill rod can be used to index the barrel nut, and the use of a peel washer will solve any problem when indexing the flash hider that would possibly cause the muzzle to flare.

Remember, although you could have a multitude of problems all problems originate from two arenas: inconsistency and incorrect compensation for the effects on trajectory.

When the rifle and ammunition are no longer suspect of being inconsistent you should direct your analysis to the principles of marksmanship, position consistency, and proper sight adjustment.

One more thing, a good barrel is difficult to understand unless you are a really good shooter to know what you've got. Until you're shooting HM scores at LR you might want to trust in someone like Frank White at CLE for a good barrel. I've had Frank turn all of my Service Rifle barrels for over a decade. I've yet to get a bad one.

Also, regarding barrel torque, using a barrel nut wrench fitted to a torque wrench you could just about have the nut indexed properly at less than specified torque, or you could exceed torque specified for a properly indexed nut. This is where finesse and abandonment of specified torque is prudent. That's to say, you may want to get it tight and then back off to get the nut to index. that's the way I do it. </div></div>

GREAT post Sterling shooter! You've ruined it for everyone. Shooting is supposed to be mythical voodoo where no advise is bad advise!

Brakes Flash hiders- I often loctite them on (with red) & no washers leaving a gap. I like the post about changing from an A2 & the possible influence created by uneven gas venting. It only makes sense. Brakes generally loose accuracy if they are biased unequally, conversely, when not, they often help.

The point of that not being bad for a 16" barrel.... Shorter barrels are fundamentally more accurate due to being factually more rigid. Sight radius isnt an issue since you're using a scope.

I'd venture to say you got a crappy barrel.

 

[Niles Coyote]

Re: Accuracy trouble shooting an AR15

I am not in the OP shoes and have been happy with the accuracy I have been getting form my 18” FN barrel, But... I am a sucker for improvement as long as it doesn’t brake the bank and a Vortex has now been installed on my barrel and torqued to 20 foot pounds. I had a A2 on there and it was torqued more than 20 but properly indexed, so we shall see what tomorrow brings.

If my groups improve, Great! If they stay the same, Great! I will report back with what I find. Durring load work up this upper has been shooting moa and under with the best loads around .5moa at 100. My last upper didnt have a muzzle device and its favored load was tighter still.

I also put a better grip on. That may help a little as the aftermarket grip I had on there, while better than the factory, still left much to be desired in the consistency dept when I would set myself up for a proper 90 degree trigger press. This one fits my LG/XL hands better giving a little more support for proper indexing.

I will say, I'd be very happy if the above improvements get rid of the crazy fliers that I had a hard time explaining on some loads.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

Where did you get the idea that a 90 degree "trigger press" was proper? You might want to try a firm high handshake grip, which places the trigger finger straight off the trigger. Then, place the finger on the trigger where it rests comfortably.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Where did you get the idea that a 90 degree "trigger press" was proper? You might want to try a firm high handshake grip, which places the trigger finger straight off the trigger. Then, place the finger on the trigger where it rests comfortably. </div></div>

Just to be clear this is what I was referring to. Pic was posted by LowLight in a past thread and is from the "Trigger School" SH training vid. Seems to be a pretty widely accepted technique especially for gas guns.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

That's not a gas gun, and what you say is widely accepted is not fact. I'd suggest you go to the USAMU's web site and see what the best AR shooters on the planet have to say about AR grip and trigger finger placement.

 

[Scottmilk9]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">That's not a gas gun, and what you say is widely accepted is not fact. I'd suggest you go to the USAMU's web site and see what the best AR shooters on the planet have to say about AR grip and trigger finger placement. </div></div>

Sterling, can you point to where the info is? Ive been saying same thing for a while, but don't have any hard evidence to back it up and would like to know what the AMU says.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">That's not a gas gun, and what you say is widely accepted is not fact. I'd suggest you go to the USAMU's web site and see what the best AR shooters on the planet have to say about AR grip and trigger finger placement. </div></div>

Sterling, can you point to where the info is? Ive been saying same thing for a while, but don't have any hard evidence to back it up and would like to know what the AMU says.</div></div>

I don't know how to get you to the link; but, you can take my statement to the bank, which is from current USAMU SDM training text. Following previous text is this statement: "The purpose of proper placement of the firing hand on the pistol grip allows the trigger finger to be pulled straight to the rear without disturbing sight alignment". This method works for most scenarios where accuracy is paramount. It is not technique proper for CQB scenarios.

 

[eracer]

Re: Accuracy trouble shooting an AR15

I happen to believe that the stiffness of an upper receiver contributes to accuracy. Spike's cast receiver is not so stiff (and probably not perfectly machined at the critical receiver face.) They're not bad uppers (I have a couple of them.) But for a 'match' gun I'd look at getting a VLTOR, Sun Devil, MEGA, or Ranier machined billet receiver.

I'm not so sure the stiffness of the lower is as important, but a matched set wouldn't be a bad thing.

(Of course there are much more important factors to consider, but if you are looking to squeeze accuracy out of a match gun, then having a good, stiff upper/lower can help.)

Just my two cents.

 

[oneshot onekill]

Re: Accuracy trouble shooting an AR15

I've posed the question about increasing AR accuracy recently to some very knowledgeable people on the subject. Sterling Shooter's information matches up with what I've learned except for one thing that he didn't mention that I've found to significantly reduce the group size on my AR's... Lapping the receiver face. There's a tool you can get from Brownells or probably any online store like Brownells. Lapping the receiver face insures a perfectly aligned mating between the barrel and the receiver. May not make a difference for you but it certainly helped my AR's reach their accuracy potential. Oh, and by the way, the AR's I've done this on are all Spikes Tactical. FWIW...

 

[Tx_Flyboy]

Re: Accuracy trouble shooting an AR15

DP,

I would only listen to what Sterling shooter said if I was in your shoes.

The fact that you are consistently getting 1.5MOA out of the gun no matter what you shoot tells me it may be the operator...no offense intended.

What you havent told us is how you shoot your groups. Do you shoot in a tacticool fasion (Bipod & ball of your non-shooting hand or even no rear support)? Or do you properly supportthe rifle (front and rear bags or rests)?

How many shots are you firing for each group?

How fast are you firing the groups? You should give the barrel enough time to dissipate heat and not heat up too quickly.

It's not your scope/scope rings as your groups will show a wide dispersion greater than 1.5MOA.

Why dont you tell us a little more and we can get to the root of the matter...my money is on your technique and execution.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tx_Flyboy</div><div class="ubbcode-body">DP,

I would only listen to what Sterling shooter said if I was in your shoes.

The fact that you are consistently getting 1.5MOA out of the gun no matter what you shoot tells me it may be the operator...no offense intended.

What you havent told us is how you shoot your groups. Do you shoot in a tacticool fasion (Bipod & ball of your non-shooting hand or even no rear support)? Or do you properly supportthe rifle (front and rear bags or rests)?

How many shots are you firing for each group?

How fast are you firing the groups? You should give the barrel enough time to dissipate heat and not heat up too quickly.

It's not your scope/scope rings as your groups will show a wide dispersion greater than 1.5MOA.

Why dont you tell us a little more and we can get to the root of the matter...my money is on your technique and execution. </div></div>
I don't doubt Sterling Shooter's advice at all. My normal natural grip and trigger pull follows the guidelines he brought up pretty closely. I just mentioned the 90* trigger finger, not wrapping thumb, etc to say that I had tried a couple different techniques that are sometimes recommended for shooting gassers.

Also I would never rule out shooter error, but I have been seeking a possible hardware problem since I've experienced such a small amount of accuracy gain since swapping out the chrome lined barrel for match. My comment about how it shot surplus ammo was probably a little misleading. I meant to emphasize my surprise that it shot surplus so well not that I'm getting the same groups with all ammo.

My current process for load development and 100 yard groups is 5 shots slow fire off a bipod and rear bag form the bench. I know bags or a rest would be ideal but I don't have access to one. I don't have a specific wait period for cool down between groups but I'm sure its sufficient since I usually use that time to check targets, shoot the bolt gun, or fill out my log.

I'll be heading out this weekend to see if I've either fixed anything with my tinkering or if anything I've learned in this thread has stuck between my ears. You guys even have me rooting against my shooting ability. It's so much cheaper to fix me than a rifle.

Many thanks to all posters

 

[Mike_in_FL]

Re: Accuracy trouble shooting an AR15

I have a question for you regarding your Geissele trigger. Are you aware that they specify setting up the trigger with over travel? In other words the sear breaks, the rifle fires and then your finger travels through slack before stopping it's movement.

I would try stripping all the copper out of the barrel as suggested. You never answered the question about trying another scope or mount. You've also made the comment "chin weld". You need to temporarily add something to that stock if you don't have a good cheek weld.

 

[Tx_Flyboy]

Re: Accuracy trouble shooting an AR15

DP,

I believe i may have isolated your major issue...the bipod.

I initially thought my savage VLP in .243 was an occasional sub-MOA rifle...until i forgot my bipod and had to shoot off bags at the range. That day, i turned in multiple sub-moa groups with a variety of factory ammo (i dint reload at the time), and proved to myself that the rifle and shooter are capable.

With bags, you can set the rifle on the front bag(s), and squeeze the rear bag until ur scope's reticle lines up perfectly on the target. If you do this right, the rifle will stay on target there without muscle tension...all you have to do is control your breathing, and gently squeeze the trigger straight back and follow through.

It is very difficult to get this kind of consistency from a bipod...again, at least for me.

I have tried shooting my rifles with a caldwell & harris bipods and get the same results (seated position)...over >1MOA with occasional sub-moa groups. I dont shoot with a bipod anymore.

I know there are people capable of turning in outstanding groups with bipods...i'm not one of them. Bipods never provided the stability and consistency in followup required to get sub-moa groups...at least for me.

If a bipod is a must for you, i would strongly recommend the sinclair bipod or any of the bipods the F-class shooters use...(you wont find a harris or other tactical bipdos in widespread use amongst the top shooters).

Now, about your handloads;

what loads are you using?

have you done extensive load development?

It is not unusual to have scatter nodes that produce 1.5moa or worse groups.

My advise to you is to pony up $30 for a set of front and rear bags at Academy or your local gunstore...one of the best investments you'll make and it will save you money when doing load development.

 

[Sterling Shooter]

Re: Accuracy trouble shooting an AR15

I too think the bipod can be a problem. It's no doubt a steady rest but not necessarily a steady support. In addition, the shooter may be determining the height of his position with what he perceives is proper when using the bipod which is not as ideal as determining height by the natural bone supported relationship between shooter, gun, and ground when the stock has been brought to the head rather than the head to the stock. With bipod too low, the position can bring about perspective of aim issues which may be seen as vertical grouping. A position built on bone alone and then supported with sandbags of a height which complements the need will also eliminate the need for a rear rest, helping the shooter to recognize stockweld and butt to shoulder consistency. A position cognisant of these and the other 3 factors of a steady position assures maintenance of recoil resistance shot to shot which helps the shooter hit where aimed at distance. BTW, the position I have described places the non firing hand on the forend. This too helps get consistent control over the rifle from the time the trigger is pulled to the time the bullet clears the bore.

 

[Frank]

Re: Accuracy trouble shooting an AR15

Don't get hung up on the "match" barrel. Match is just a word that is frequently put in front of something to make it seem better. Most of us think of Kreiger, Hart, Obermyer, Brux, Bartlein and a couple other brands when we say match/target grade barrels. Some use the word to describe the contour more so than the inside of the barrel which is the important part. My last lower tier match barrel took approx 1000 rounds before it started shooting good. My upper tier(see list) barrels put the first 5 shots into a little knot, and continue to do this with most any load with a good bullet and appropriate burning rate powder for caliber/bullet weight.

 

[TonyAngel]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> I happen to believe that the stiffness of an upper receiver contributes to accuracy. Spike's cast receiver is not so stiff (and probably not perfectly machined at the critical receiver face.) They're not bad uppers (I have a couple of them.) But for a 'match' gun I'd look at getting a VLTOR, Sun Devil, MEGA, or Ranier machined billet receiver.</div></div>

I really don't know what this is about and the poster should really check his facts before he posts such things because it can lead some down the wrong road.

As far as I know, Spike's uppers are milled from a milspec 7075 forging. There ain't nothing wrong with their receivers.

DP, I feel your pain because I went through it. I've found, in the end, that all good barrels are capable of MOA accuracy with ammunition that they like. In most cases, the barrels I've tried liked more than one type of ammunition as well.

First, shooting an AR precisely is difficult, relatively speaking. You have a lock time that is a lot longer than that of a bolt gun to contend with, so follow through is very important.

If you are shooting off of a bipod, I'd suggest going to front and rear bags. Shooting off of a bipod is a skill in itself and requires practice to perfect the proper form and technique.

If I was you, I'd look at a few things. First, did you break the barrel in? If not, you could have an accumulation of copper fouling at the throat. Clean the barrel using a good copper solvent and see if you get a ton of blue on the patch.

The second thing I'd try, as mentioned above, is to use a good front rest and rear bag. For accuracy, the name of the game is consistency. Doing it the same way, every time and this includes the cant of the rifle.

The third thing I'd try is getting access to a scope with more magnification. I know that there are some guys that just plain have the discipline, trigger control and awareness of what their body is doing to shoot well with open sights or a low magnification scope.

I am not one of those guys. If I can't see it, I'm not thinking about it. What I'm talking about seeing is my respiration pattern, the effect of my heart beat, etc. With a bigger scope, you can see all of that and its effect on your sight picture.

For me, when I was shooting my precision rig and a 10X Nightforce scope, the best I could do was around MOA at 100. With a 22X scope, my groups dropped to under MOA at 100 and it was pretty consistent.

For your purposes of just seeing what the rifle is capable of, you really don't need a good scope. All you need is something that will hold zero with glass clear enough to be able to see the target in good weather.

Once you confirm that your equipment is not the problem, then you can concentrate on honing your skills with your chosen equipment.

As for cranking down tight on that LaRue mount, don't do this. Adjust it as per the instructions. Any tighter and you're going to do a job on that upper.

 

[salmonaxe]

Re: Accuracy trouble shooting an AR15

I have one instance where a low profile gas block impinged on my rail during recoil. Rifle shot terribly. Low pro was a clamping type so it barely fit. Troy TRX is a really small and flexible rail. With bipod pressure I wonder if your gas block is touching.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

With so many recommendations for switching to bags I broke out my cordura stash and sewing machine and put some together. Tomorrow I'll be hitting the range hoping to see a difference.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body">I have one instance where a low profile gas block impinged on my rail during recoil. Rifle shot terribly. Low pro was a clamping type so it barely fit. Troy TRX is a really small and flexible rail. With bipod pressure I wonder if your gas block is touching. </div></div>I was checking into this yesterday and and while the rail clearance is sufficient, there was a contact mark on the bottom of the gas block where my bipod adapter had contacted the gas block. This was pretty disconcerting since I've previously checked to make sure there was space in between, but I'd never been able to eyeball it while loaded. I removed some material so there's much more clearance now.

I also took a few hours this morning to put together some of the most painstakingly consistent reloads I've ever loaded for an AR. I never bother sorting components for AR, but this time I did and discovered an alarming variation in the ogive length of my 68gr bthp hornady bullets (midway blems. These are the bullets that I have done the most extensive load development with and have based a large portion of my accuracy assessment on. In sorting them I found that the bullets sorted into 2 consistant groups .005" apart measured with a comparator. I'm thinking that a group comprised of a mix of those 2 bullet contours could account for some of the vertical stringing I've seen. I loaded 20 rounds from one length group as well as 20 rounds of 75gr over my previous most successful powder charges.

So tomorrow I'll be testing: Front and rear bags, ditching the bipod that might have been ruining my free float, sorted bullets of 2 different weights, and emphasizing following through. Changing 4 variables at once makes this officially the worst scientific test ever but if I see an improvement I'll be thrilled.

 

[TonyAngel]

Re: Accuracy trouble shooting an AR15

DP, with the exception of the rimfire benchrest competitions that I shoot, I do all of my shooting exclusively from a bipod. It isn't that hard, you just need to do it right. I'd suggest that you spend the money and watch the training videos offered by Sniper's Hide. They are quite informative and can serve to be a solid platform upon which to build your skills.

 

[hlee]

Re: Accuracy trouble shooting an AR15

Sterling Shooter, in another set of posts, you describe the proper grip as firm "like shaking a youngster's hand" with the webbing of your hand firmly placed as high on the grip as the gun will allow. This jibes well with what I found on the USAMU training videos on YouTube. However, in those videos it appeared that the instructor was speaking about combat shooting. How does the grip of an AR platform rifle differ between precision long range and combat shooting?

I am not now, nor have I ever been, a member of the military. I am just a guy that started shooting with bolt guns that now owns an ar10 looking to get information on precision shooting with this platform. Thank you.

 

[DPRoberts]

Re: Accuracy trouble shooting an AR15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TonyAngel</div><div class="ubbcode-body">
I really don't know what this is about and the poster should really check his facts before he posts such things because it can lead some down the wrong road.

As far as I know, Spike's uppers are milled from a milspec 7075 forging. There ain't nothing wrong with their receivers.

DP, I feel your pain because I went through it. I've found, in the end, that all good barrels are capable of MOA accuracy with ammunition that they like. In most cases, the barrels I've tried liked more than one type of ammunition as well.

First, shooting an AR precisely is difficult, relatively speaking. You have a lock time that is a lot longer than that of a bolt gun to contend with, so follow through is very important.

If you are shooting off of a bipod, I'd suggest going to front and rear bags. Shooting off of a bipod is a skill in itself and requires practice to perfect the proper form and technique.

If I was you, I'd look at a few things. First, did you break the barrel in? If not, you could have an accumulation of copper fouling at the throat. Clean the barrel using a good copper solvent and see if you get a ton of blue on the patch.

The second thing I'd try, as mentioned above, is to use a good front rest and rear bag. For accuracy, the name of the game is consistency. Doing it the same way, every time and this includes the cant of the rifle.

The third thing I'd try is getting access to a scope with more magnification. I know that there are some guys that just plain have the discipline, trigger control and awareness of what their body is doing to shoot well with open sights or a low magnification scope.

I am not one of those guys. If I can't see it, I'm not thinking about it. What I'm talking about seeing is my respiration pattern, the effect of my heart beat, etc. With a bigger scope, you can see all of that and its effect on your sight picture.

For me, when I was shooting my precision rig and a 10X Nightforce scope, the best I could do was around MOA at 100. With a 22X scope, my groups dropped to under MOA at 100 and it was pretty consistent.

For your purposes of just seeing what the rifle is capable of, you really don't need a good scope. All you need is something that will hold zero with glass clear enough to be able to see the target in good weather.

Once you confirm that your equipment is not the problem, then you can concentrate on honing your skills with your chosen equipment.

As for cranking down tight on that LaRue mount, don't do this. Adjust it as per the instructions. Any tighter and you're going to do a job on that upper. </div></div>

I've received excellent information and advice from everyone in this thread, but you sir deserve a fabulous prize for calling the low magnification problem.

On a whim I shot my last 2 groups at 50 yards to see if I saw a performance increase with a better view of the target. The results were 2 groups measuring .35" and .28" center to center putting me comfortably sub moa. It seems that despite the fact that my previous shooting with the AR felt good, I was unable to repeat my point of aim using a 1 moa crosshair at 7x. Moving the target closer essentially doubled my magnification of the target allowing me the resolution to actually maintain consistency.

Before I shot the 50 yard groups I had also seen a drop in the average size of my 100 yard groups to around 1.25". Shooting with bags and a greater understanding of AR accuracy no doubt were the reasons.

I must admit that I feel a little silly to have my 6 month long headache solved by something so simple. Once again thanks everyone for the lessons and advice. You guys have completely demystified what makes an AR accurate and I'll be a better shooter because of it.

Less thinking more shooting.

 

[Temp9]

Re: Accuracy trouble shooting an AR15

Congrats! It's always nice to see a solution in these threads.