Are My Expectations Too High?

[Doom]

I can’t shoot prone but bench and bipod I get <.5 MOA on my bolt guns for 5 shot groups, but my Daniel Defense M4V7 was more like 3 to 4. I had someone who shots AR regularly shoot it and it was about 1.5. He noted in my case I was overgriping the pistol grip. After he noted it I got down under 2. Changed the grip to a Magpul K2+ which was more vertical like my bolt guns and what a difference. More like 1 MOA. Not saying that’s your particular problem but having someone else shoot it may help diagnose the problem.

 

[KellenQ]

Really excellent advice above. I would do the following - in order:

1. Check everything is tight, scope not touching the barrel, etc.

2. Get a couple of boxes of good quality ammo. FGMM, IMI Razorcore, ADI 69 gr. and maybe Hornady Match. XM 193 is in the best case 2 MOA ammo. M855 is generally worse.

3. Upgrade you stock trigger. LaRue MBT is an excellent trigger at a good price. Also hard to go wrong with a Geissele.

4. Work on your fundamentals. Just because you can shoot a bolt gun well doesn't mean you can shoot an AR15. Be sure you are getting behind the gun exactly the same way each time. Load your bipod. Follow through.

Assuming everything is tight, your disappointing results (and they are disappointing) is probably a combination of you and your ammo. Getting match ammo should get you down to about 2.5 MOA. The rest is up to you. Sub 1.5 MOA should definitely be achievable with your set up. And if you refine your technique and got a good barrel, you could certainly see 1 MOA.

I love my MBT triggers. IMO it is better than the G2S for less money. You can get better triggers, but not at that price point.

 

[SomeJerk]

100 yards prone using a 11.5” barrel Bushmaster with about 10,000 rounds down the barrel. Shooting 55 grain Remington FMJ. Using an EOTech without a magnifier and using a grip-pod for support.
I guess you could start here when comparing.

 

[iktomi]

Upper and lower have a bit of slop to them (how much does that matter aside from fit and finish? All the accuracy happens in the upper, correct?)

Upper an lower fitment are extremely relevant for precision. The gun and shooter move collectively before the projectile is in free flight. Repeatable precision demands that they move in a repeatable way. Sloppy receiver fitment is not conducive to repeatability. But this is an issue in refining sytems that are already much tighter than the group you posted.

The good news is that your zero appears to be centered in your dispersal...

If I had to take one guess based on your descriptions (other than straight up broken shit like a barrel that slipped through QC or a broken scope), my first guess would be barrel extension torque. Something is consistently moving shot to shot, but your group is centered. What could cause this uniform dispersal?

(Other possibility is super jacked ammo. Steel core projectiles are not inherently uniform, and if the lot has horrible concentricity, you might find an entire mag of 'fliers'.)

 

[RUTGERS95]

Upper an lower fitment are extremely relevant for precision. The gun and shooter move collectively before the projectile is in free flight. Repeatable precision demands that they move in a repeatable way. Sloppy receiver fitment is not conducive to repeatability. But this is an issue in refining sytems that are already much tighter than the group you posted.

The good news is that your zero appears to be centered in your dispersal...

If I had to take one guess based on your descriptions (other than straight up broken shit like a barrel that slipped through QC or a broken scope), my first guess would be barrel extension torque. Something is consistently moving shot to shot, but your group is centered. What could cause this uniform dispersal?

(Other possibility is super jacked ammo. Steel core projectiles are not inherently uniform, and if the lot has horrible concentricity, you might find an entire mag of 'fliers'.)

definitely not the case imho. I've had tight and slop and slop were my most accurate ones. Provided of course it's not real slop but a little is fine. If I recall correctly, Stoner wanted a touch of slop. Like all things, it's a matter of degree

 

[ttp675]

Disclaimer: Yes, I'm a decent shot. I've shot well under 1MOA with my bolt gun from the prone. Yes, this was my first AR build, but I'm pretty competent and handy so I feel like I assembled it to the best of my abilities.

Context: Put together my first AR this past year. 14.5" Criterion CORE barrel, Brownell's BCG, DSA upper, Steiner T5Xi 3-15. It has right around 200 rounds on it right now. Shot 77gr S&B at like 3MOA, and this photo is from today with Freedom Munitions reman SS109. Sharpie for scale, but it's like 4.5MOA.

Now, this rifle was never meant to be a dedicated precision platform. I wanted a good general purpose rifle that I could stretch into whatever role I needed it to be. I tried to be as realistic as possible with this rifle. I wanted 1.5MOA with match grade ammo. S&B isn't exactly the epitome of match grade, but I thought it would perform better than it did.

Blaster ammo: My expectations weren't exactly high, but 4.5MOA doesn't really cut it for me.

I should probably order some FGMM or something good for absurd prices and see how it performs before I do anything drastic, but if that doesn't do it do I just tear down and rebuild the thing?

But maybe my expectations were too high?

View attachment 7826447

ThIs are not so good result, it should be better than this.

 

[cbbryan]

I would expect better. I’ve heard great things about the Criterion barrels and I’m considering using them for an 11.5 build because of the 1:8 twist.

These are the groups I got from my build. I tested 9 different ammunitions at 100 yards at my local range. The pictures are of the 5 shot group from each ammo. Then a picture of the rifle followed by my less than stellar 50 yard zero on the bullseye targets using 55gr ammo. The rifle wasn’t cleaned before shooting the groups and has close to 500 rounds through it, maybe more, with about 10 percent being suppressed. The rifle is a 14.5” Geissele Super Duty complete upper, SilencerCo lower, CMC lpk, Geissele SSA-E trigger, and a Sig Sauer Tango MSR 1-6x.

 

[iktomi]

I've had tight and slop and slop were my most accurate ones.

How accurate?

Over how many different loads?

Shot in field conditions?

Stoner designed a system that can be used for high standards of precision with great success.

I suspect maximum precision was not his design intent.

There are lots of reasons a guy might want slop in a gun.

Repeatable precision is probably not one of them.

That said, the upper would have to be falling off the lower to be responsible for the OP's group....

 

[PDXGS]

Like others have mentioned, AR fundamentals are,well, fundamental.
I'd suggest putting a 1" black or red paster dot on that IPSC target or use a 1" grid sight in target.
Also as others have said, try shooting off of a sand bag up front. Cheek weld is important and can be odd on an AR with an optic.
I spent many years shooting DCM/High Power matches and had an occasional gun shot poorly but most of the time it was me.
Stupid shit like that last cup of coffee or improper sling use.
Receiver slop is just a distraction IMHO. I like a tight fit...who doesn't?! But I've run a number of tests with and without an Accuwedge and seen no effect on accuracy...again, it was me.
Triggers matter too.....I prefer a Geissele to a GI trigger but a broken-in GI trigger should give decent results.

Any chance that you can post a pic of your rig?

 

[ThePewLifeChoseMe]

Assuming there isn't any human error (shooting gas guns isn't always exactly the same as shooting a bolt gun), there's still a lot more to consider. Try a variety of match ammo. Different weights and bullet types, by different manufacturers. I would also expect better results, but those 62gr SS109 rounds are the worst to guage a barrel's ability.

 

[the monk]

Assuming there isn't any human error (shooting gas guns isn't always exactly the same as shooting a bolt gun), there's still a lot more to consider. Try a variety of match ammo. Different weights and bullet types, by different manufacturers. I would also expect better results, but those 62gr SS109 rounds are the worst to guage a barrel's ability.

Completely agree with this. Every barrel has its own personality. You and your buddy may get the exact same barrel but they may like different loads. I generally try 6 or 7 match loads of different weights to see what the gun likes and go from there. The holy grail is one that likes them all.

 

[Bubs]

I believe Milspec on 855-3.5" and 856-4.5",they both suck-blaster ammo

 

[Riskyjim]

The below three shot group was 100 yards from my Lead Sled by my 10.5" 7.62x39 Build - Ghost Guns Upper, Spikes Tactical Lower- Aero Internals (Handstop replaced with a forward grip per my state statutes to conform to "other" weapon status) -1-8X Primary Arms ACSS scope with a Hiperfire Designated Marksman Enhanced duty Trigger after dialing it in at 25 yards. I was using off the shelf Russian122gr HP TulAmmo. Your groups should be better than they are.

 

[Snuby642]

I have had poor results at times with gas guns.

The only times my results were like yours, were (in order) ---

Loose scope mount / buis.
Internally broken scope .
Purchased defective re-man ammo.

You have tried a couple different types of ammo, no joy.

I suggest that you get a friend and thier ammo to shoot a couple of groups and consider the difference between thier gun and yours, shoot thiers and compare results.

If your results are measurably crappy compared to your friends have him watch you shoot and offer advice.

A decent shooter using a bargain barrel could easily expect 2 moa without high winds and a steady bench.

An upgrade in trigger is easy and you don't have to spend much if you have a standard parts kit trigger in it.

The difference between a bargain basement barrel and mid grade is huge, and once you shoot 1 1/2 to 1 1/4 with a cheap one it's maxed out.

It's the scope usually first problem and you don't have to spend a fortune at shorter ranges it just has to be tight and not broken.

I have pissed a lot of ammo down range due to scope problems.

 

[912173]

For what it's worth, I had a very noticeable improvement in accuracy after I bedded my barrel extension into the upper receiver. This was a seekins enhanced upper with a white oak barrel shooting match ammo. I went from 1 moa being the best I could do, to routinely shooting 1/2" -3/4". I'd always heard about it making a difference and for me it really did.

 

[RUTGERS95]

How accurate?

Over how many different loads?

Shot in field conditions?

Stoner designed a system that can be used for high standards of precision with great success.

I suspect maximum precision was not his design intent.

There are lots of reasons a guy might want slop in a gun.

Repeatable precision is probably not one of them.

That said, the upper would have to be falling off the lower to be responsible for the OP's group....

sub moa
multiple but prefered heavier weights
oh now it's up to field conditions but ok I'll play, wasn't in the sandbox but various ranges with various positions
yes he did and he did not design it to be a tight fitting upper and lower to maximize reliability and accuracy
incorrect, he designed to be have precision capabilities hence the straight look and bolt move design
agree and disagree

I don't think anyone is suggesting the upper and lower have that much slop for the OP here however, it's most likely a barrel issue given his lighter weights groups so instead of heavy, try lighter then assess. Could be his barrel nut is over torques as well as your point on the glass. Could be a few things but barrel seemed to shoot lighter weight better

 

[Brettdec]

If somebody brought that rifle to my bench, I would:


1. Clean and scope the bore for defects in the crown, chamber, rifling, throat or gas port.
2. Confirm the twist of the rifling.
3. Inspect the feed ramps.
4. Cycle rounds through the chamber and check for damage/concentricity
5. Check all torque specs including barrel nut, gas block, forend, etc..
6. Confirm setup and performance of the optic. (this is a long list - torque specs, parallax, tracking, bell clearance - just to name a few)
7. Shoot test groups (single loading each round on a calm day from sandbags) with ammunition from lot #s proven to shoot MOA or less.

If groups remain worse than 2 MOA (from a shooter proven capable of sub MOA groups). I would,

8. Swap the optic, BCG and lower from a proven sub MOA rifle and re-test.

In the unlikely event that the problem persists after this process, I would:

9. Remove the barrel from the upper receiver and inspect for fitment issues. If none are found, I would Email the results of the process to Criterion. If no response within 3 days, I'd give them a follow up call.

If no satisfaction, I'd try a different barrel. If results prove better than 2 MOA, I would share that result with Criterion (probably my fellow marksmen too). If the problem persisted after barrel replacement and I couldn't identify a reason, I'd apologize to all concerned. Then, I'd give up up rifle building and buy a complete upper.

In my experience, I've found accuracy problems can stem from ANY variable. Ammo and optics mounting issues being the most common, but eccentric chambers, throat issues and bad crowns DO happen too. These can be difficult to spot. Considering the value of ones time and ammunition (perhaps even life, with the OP's rifle), a pragmatic approach is best.

 

[MarkLeupold]

Alright, little update here: Ordered some IMI 5.56x45mm 77gr, might get to shoot this weekend. Next weekend for sure.

Checked scope mounting: all seems good. 15 in-lbs on ring screws and 45 in-lbs on crossbolts (Spuhr mount). The rifle is completely painted, like I said before, so it's got the equivalent of witness marks on the whole thing. Nothing has moved as far as I can tell.

Optic was on another rifle before this and it tracked and held zero reliably, so I want to say that's a known good. It's been sitting in its box for the last couple years.

Cycled some rounds through the rifle manually. Nothing there but some normal scuffing on the bullet from the feed ramps.

Inspected the feed ramps and nothing stood out to me, though I'm not 100% sure what to be looking for. I was mostly checking for roughness or burrs, which they have none.

The sloppiness in the fit of my upper and lower is just enough that you can feel the receivers move in your hands. It isn't what I'd deem as "excessive."

Handguard hasn't moved, though I found something curious when checking over it.

QD sling mount:

Gas block:

There was clearance here, like 3-4mm, but it appears that there was contact at some point in time. I've moved that sling mount and removed my light for the time being just to try to eliminate some more variables.

Haven't checked barrel nut torque (again, BCM handguard gonna be a pain, and I need to get a vise and a workbench). If the issues persist, I'll do a full teardown on the upper and check things there. Probably would let Criterion know at that point too, just to open a line of communication with them. They don't have an accuracy claim, but I'm sure they'll try to help me out.

I'll be dry firing in the meantime if anyone needs me...

 

[Molon]

I believe Milspec on 855-3.5"

The accuracy specification from the US mil-spec for M855 (MIL-C-63989C) states that the average vertical standard deviation and the average horizontal standard deviation shall be “no greater than 1.8 inches at 200 yards using an indoor range.” The accuracy testing is conducted using machine rested, bolt-action, heavy test barrels.

There is also a 600 yard accuracy specification for M855, that is greater than the mathematical equivalent of the 200 yard specification.

 

[bfoosh006]

In for the next round of precision shooting.

It will be interesting if some part was bonking the gas block... and "possibly" causing that large of a group.

 

[MarkLeupold]

In for the next round of precision shooting.

It will be interesting if some part was bonking the gas block... and "possibly" causing that large of a group.

I'd honestly love if that's the issue, but I'm not convinced that mark is from shooting the rifle. 3-4mm of clearance seems like a LOT of barrel whip at the gas block

 

[rottenruger]

Disclaimer: Yes, I'm a decent shot. I've shot well under 1MOA with my bolt gun from the prone. Yes, this was my first AR build, but I'm pretty competent and handy so I feel like I assembled it to the best of my abilities.

Context: Put together my first AR this past year. 14.5" Criterion CORE barrel, Brownell's BCG, DSA upper, Steiner T5Xi 3-15. It has right around 200 rounds on it right now. Shot 77gr S&B at like 3MOA, and this photo is from today with Freedom Munitions reman SS109. Sharpie for scale, but it's like 4.5MOA.

Now, this rifle was never meant to be a dedicated precision platform. I wanted a good general purpose rifle that I could stretch into whatever role I needed it to be. I tried to be as realistic as possible with this rifle. I wanted 1.5MOA with match grade ammo. S&B isn't exactly the epitome of match grade, but I thought it would perform better than it did.

Blaster ammo: My expectations weren't exactly high, but 4.5MOA doesn't really cut it for me.

I should probably order some FGMM or something good for absurd prices and see how it performs before I do anything drastic, but if that doesn't do it do I just tear down and rebuild the thing?

But maybe my expectations were too high?

View attachment 7826447

Strange, I've never thought to try MOA targeting with my AR's, I put the silhouette man downrange and blast away, and if my shots are all center body mass, I'm happy.

But NOW I'm not happy, gonna have to check them out for X-spot targeting. Problem is, I don't have the glass on them for that purpose.

What kind of optic are you running?

 

[rottenruger]

Strange, I've never thought to try MOA targeting with my AR's, I put the silhouette man downrange and blast away, and if my shots are all center body mass, I'm happy.

But NOW I'm not happy, gonna have to check them out for X-spot targeting. Problem is, I don't have the glass on them for that purpose.

What kind of optic are you running?

Oh, you've got Steiner? Then, yes, I'd be disappointed too.

 

[supercorndogs]

That pretty close.

 

[MarkLeupold]

That pretty close.

The BCM is pretty slim internally. Around where the gas tube goes into the block, I'd bet there's only about 3mm of clearance either side, maybe less...

 

[supercorndogs]

I would go shoot it, I wouldn't be surprised if you found your gremlin.

 

[Brettdec]

Good detective work... You may have just saved yourself from a big headache.

 

[TonyTheTiger]

The BCM is pretty slim internally. Around where the gas tube goes into the block, I'd bet there's only about 3mm of clearance either side, maybe less...

View attachment 7829824

That looks like plenty of clearance.

 

[iktomi]

Good detective work... You may have just saved yourself from a big headache.

Agreed.

 

[Cootis23]

I've got a criterion ultralight 18", it'll still do a .6" or .7" with 69gr adi ammo, ss109 is probably as bad as you can get, get some 55gr fmj. Should be 3moa or less. Good ammo, good trigger and good shooter should get sub minute easily with that barrel (I say this cause I got it and I'm a meh shooter) fgmm, imi, magtech, or creemoor if you're a cmp member are all solid choices for otm

 

[Cootis23]

Alright, little update here: Ordered some IMI 5.56x45mm 77gr, might get to shoot this weekend. Next weekend for sure.

Checked scope mounting: all seems good. 15 in-lbs on ring screws and 45 in-lbs on crossbolts (Spuhr mount). The rifle is completely painted, like I said before, so it's got the equivalent of witness marks on the whole thing. Nothing has moved as far as I can tell.

Optic was on another rifle before this and it tracked and held zero reliably, so I want to say that's a known good. It's been sitting in its box for the last couple years.

Cycled some rounds through the rifle manually. Nothing there but some normal scuffing on the bullet from the feed ramps.

Inspected the feed ramps and nothing stood out to me, though I'm not 100% sure what to be looking for. I was mostly checking for roughness or burrs, which they have none.

The sloppiness in the fit of my upper and lower is just enough that you can feel the receivers move in your hands. It isn't what I'd deem as "excessive."

Handguard hasn't moved, though I found something curious when checking over it.

QD sling mount:
View attachment 7829703

Gas block:
View attachment 7829704

There was clearance here, like 3-4mm, but it appears that there was contact at some point in time. I've moved that sling mount and removed my light for the time being just to try to eliminate some more variables.

Haven't checked barrel nut torque (again, BCM handguard gonna be a pain, and I need to get a vise and a workbench). If the issues persist, I'll do a full teardown on the upper and check things there. Probably would let Criterion know at that point too, just to open a line of communication with them. They don't have an accuracy claim, but I'm sure they'll try to help me out.

I'll be dry firing in the meantime if anyone needs me...

Criterion has a satisfaction guarantee, if youre not happy they'll replace or buy back ( I don't remember their wording exactly so don't hold them to my deal, but customer satisfaction is important to them). Also could be gouged from loading bipod, try bags, I can flex thin handguards like that enough by hand, so a bipod definitely will ( depending on how much you load it obviously)

 

[Tillerup!]

Alot of great post here... Definitely try better ammo.. Try some Black Hills or Sierra Match or better match grade (77gr). Or something you shoot in another rifle that performs well for you!
Take it apart and recheck head space .....barrel nut torque...heck, make sure your torque wrench is calibrated if it can be or do side by side comparison with a different wrench (might not be achieving optimum torque)
And, Kellenq...now I'm "wondering" about my AR10 build since I also am using the Criterion Barrel...let me know that works out.

 

[Molon]

But NOW I'm not happy, gonna have to check them out for X-spot targeting. Problem is, I don't have the glass on them for that purpose.

While higher magnification certainly makes sighting easier, it is not a requirement for obtaining sub-MOA groups at 100 yards from an AR-15 when the barrel, ammunition and shooter are up to the task. The first 10-shot group pictured below was fired from a Noveske RECON at a distance of 100 yards using an S&B Short Dot LE set at 4X magnification. The 10-shot group has an extreme spread of 0.78".

The next 10-shot group was fired from one of my Krieger barreled AR-15s at a distance of 100 yards using Ultradyne back-up iron sights. The group has an extreme spread of 0.71".

….

 

[MarkLeupold]

Alrighty, here we go!

Bought some IMI 77gr Razor Core and headed back to the range this afternoon.

Not the greatest range setup, but it'll do in a pinch. Sat down, warmed up with some dry fire; everything is awesome. Reticle isn't moving when I break the trigger, position feels pretty comfy, I've got the rifle bay to myself.

Shot five rounds of Aguila 62gr that I had laying around. 2.701" group.

Shot five rounds of the Freedom Munitions SS109 that I did last week to keep a baseline. 2.576" group. Not quite as terrible as last week, but probably not outside of statistical deviation.

Shot five rounds of the IMI 77gr. 1.564" group. Got up, drank some water, tried to relax for a few minutes. Sat back down, put five more into the same group, opened up to 1.676". Not too bad.

Shot another five rounds of the IMI, 1.465" group.

So yeah. Probably just don't shoot really crap ammo for accuracy. My brain says, "IT'S NOT GOOD ENOUGH," because that clean ragged hole is euphoric to see, but for this rifle and its purpose, this is very acceptable.

 

[LRRPF52]

Did you make sure your receiver face is square?

Bed the barrel into the upper?

Not sure if those were covered.

 

[Cootis23]

Alrighty, here we go!

Bought some IMI 77gr Razor Core and headed back to the range this afternoon.

Not the greatest range setup, but it'll do in a pinch. Sat down, warmed up with some dry fire; everything is awesome. Reticle isn't moving when I break the trigger, position feels pretty comfy, I've got the rifle bay to myself.

View attachment 7831260

Shot five rounds of Aguila 62gr that I had laying around. 2.701" group.

Shot five rounds of the Freedom Munitions SS109 that I did last week to keep a baseline. 2.576" group. Not quite as terrible as last week, but probably not outside of statistical deviation.

Shot five rounds of the IMI 77gr. 1.564" group. Got up, drank some water, tried to relax for a few minutes. Sat back down, put five more into the same group, opened up to 1.676". Not too bad.

Shot another five rounds of the IMI, 1.465" group.

View attachment 7831261

So yeah. Probably just don't shoot really crap ammo for accuracy. My brain says, "IT'S NOT GOOD ENOUGH," because that clean ragged hole is euphoric to see, but for this rifle and its purpose, this is very acceptable.

I'd say that's pretty decent if you're not super comfortable behind an ar, most of my shooting is closer to that then the .6-.7 I can squeeze out. So I'd say practice more and get someone who is a known subminute shooter and see what they do, and thats better then I'd expect from ss109 typically. If you really wanted to test, a couple more types of match ammo to see what it likes. But there's probably room for improvement with what you have (the 18" i have is chromed too so I'd say sub minute should be doable).

 

[Doom]

Since you are shooting bipod on a hard surface, next time put a folded towel or piec of carpet under the bipod. May help or not but won hurt.

 

[gunsnjeeps]

I didn't answer the pole because I'm not sure how to define Mid Grade. To me Rock River is good, White Oak and Compass Lake better. A $1300, maybe nore recently, Rock River National Match is guaranteed for under .75 MOA with appropriate ammo. When I shoot mine of a bag rather than a sling they are under 1 MOA with MK262 and my hand load copy of it. I have $400 PSA (3 gun and plinker) that runs about 1.5 to 2. If I had read this before you reshoot yesterday I'd say ammo. After the reshoot I'd still say ammo. I haven't shot Razor Core and know shooters who use it for practice and 200 and 300 yards but not 600 yards. On the other hand I also know shooters who shoot it all the time.

My only suggestion would be a bag instead of the bipod, but that is more my lack of bipod experience.

 

[carbonbased]

Take a look at this thread: https://www.snipershide.com/shooting/threads/stress-on-upper.7103453/

I don't know what to really make of it, as I am not a AR whiz. At first glance I was confused (I'm a bolt gun guy). So, I had to read it carefully to tease out what they were talking about (I've never had a barrel off an AR)…but now makes semi-sense. I need to find some pics to really get how handguard forces have an impact on the barrel nut. But I'm sure I missed stuff.

TL;DR (again, I may have missed stuff)
The design of most free-floated AR's barrel nut assembly plus a bipod can induce flex in the system. Especially if the bipod is way far out on the handguard and it can mess with groups (unlike a bolt gun). Some AR's, like the patented monolithic LMT MARS upper, remove that flex. So experiment with using a bag (as others have mentioned) and also try placing the bipod closer to the magwell.

 

[Monstershot]

I posted these results in Molon’s Criterion Core thread. I put the barrel in a LaRue stealth 2.0 chassis, with matching lower and MBT. After doing a few shots to begin the zeroing process for my 1-6 scope I shot these two groups. (Adjusted the scope in between groups.)

69 gr fgmm. The fit between barrel and receiver was tight. 14.5” Criterion Core.

 

[Tiribulus]

a lot of peoples problems start at that interface of the barrel and receiver....

I'm certainly not the go to guy here, but that thought crossed my mind.

 

[gunsnjeeps]

Take a look at this thread: https://www.snipershide.com/shooting/threads/stress-on-upper.7103453/

I don't know what to really make of it, as I am not a AR whiz. At first glance I was confused (I'm a bolt gun guy). So, I had to read it carefully to tease out what they were talking about (I've never had a barrel off an AR)…but now makes semi-sense. I need to find some pics to really get how handguard forces have an impact on the barrel nut. But I'm sure I missed stuff.

TL;DR (again, I may have missed stuff)
The design of most free-floated AR's barrel nut assembly plus a bipod can induce flex in the system. Especially if the bipod is way far out on the handguard and it can mess with groups (unlike a bolt gun). Some AR's, like the patented monolithic LMT MARS upper, remove that flex. So experiment with using a bag (as others have mentioned) and also try placing the bipod closer to the magwell.

Looked at the thread referenced and disagree that a free float casues the receiver to flex. The purpose of a free float tube is to remove stress from the barrel. That is why the sling swivel is moved from the gas block to the float tube. A sling puts more strain on a rifle than using a bipod no matter how much a scope and magazine weigh. If float tubes didn't work that way you would have different zeros for off hand (sling not used), sitting, and prone (sling used to maintain position).

 

[carbonbased]

Looked at the thread referenced and disagree that a free float casues the receiver to flex. The purpose of a free float tube is to remove stress from the barrel. That is why the sling swivel is moved from the gas block to the float tube. A sling puts more strain on a rifle than using a bipod no matter how much a scope and magazine weigh. If float tubes didn't work that way you would have different zeros for off hand (sling not used), sitting, and prone (sling used to maintain position).

So, like I said, I don’t really know where I fall on that debate. But the argument isn’t about free floating, it’s about where the barrel meets the receiver. Proponents of the argument say that the flex occurs in the receiver because many receivers, especially of lesser quality, are thin in this area.

Couple that with the fact that many hand guards attach on the barrel extension, and that’s how the force is transmitted to the receiver, causing it to flex. (I think I summarized this correctly, but check yourself).

I lean to agreeing. Watch the video here: https://www.snipershide.com/precision-rifle/petite-white-black-swimsuits-for-women/ (I know it’s a bizarre URL). Lowlight interviews some Seekins fellow.

 

[gunsnjeeps]

So, like I said, I don’t really know where I fall on that debate. But the argument isn’t about free floating, it’s about where the barrel meets the receiver. Proponents of the argument say that the flex occurs in the receiver because many receivers, especially of lesser quality, are thin in this area.

Couple that with the fact that many hand guards attach on the barrel extension, and that’s how the force is transmitted to the receiver, causing it to flex. (I think I summarized this correctly, but check yourself).

I lean to agreeing. Watch the video here: https://www.snipershide.com/precision-rifle/petite-white-black-swimsuits-for-women/ (I know it’s a bizarre URL). Lowlight interviews some Seekins fellow.

Good video and I can't disagree with his statement about bipods and POI, I have never shot an AR off a bipod. I'm in the trust but verify group and I haven't seen evidence.

What I can say is that over 22 years of Service Rifle competition with 2 Rock River NM uppers and one Brownell's upper and quality parts I haven't pulled a shot off zero with sling tension. I have twisted a factory synthetic stock into a barrel with the same sling though and inconsistantly pushed shots that way.

ETA: all three uppers are Rock River free float tubes and A2 hand guards with standard Delta rings. Clarifying because over the last few years other fore ends are allowed.

 

[carbonbased]

Good video and I can't disagree with his statement about bipods and POI, I have never shot an AR off a bipod. I'm in the trust but verify group and I haven't seen evidence.

What I can say is that over 22 years of Service Rifle competition with 2 Rock River NM uppers and one Brownell's upper and quality parts I haven't pulled a shot off zero with sling tension. I have twisted a factory synthetic stock into a barrel with the same sling though and inconsistantly pushed shots that way.

ETA: all three uppers are Rock River free float tubes and A2 hand guards with standard Delta rings. Clarifying because over the last few years other fore ends are allowed.

Yeah, ya got me?

I’m a just bolt-gun guy with a long pandemic beard channeling The Dude: “AR’s are weird, man.”

 

[smoothy8500]

What I can say is that over 22 years of Service Rifle competition with 2 Rock River NM uppers and one Brownell's upper and quality parts I haven't pulled a shot off zero with sling tension.

Yeah, we put way more tension with a sling than a bipod ever could. Which gets me to blame improper hold and recoil control with a bipod on the bench is the root of most accuracy "problems".

 

[bfoosh006]

The BCM Mk 2 upper addresses upper receiver flex . ( ? )


"Shifting mass from non-critical to critical areas; the BCM Mk2 Upper Receiver reduces barrel deflection and enhances bore tolerances improving barrel alignment, consistency and accuracy.
This enhanced rigidity aids accuracy by limiting barrel deflection from external loads such as a bipod or vertical grip. Also prevents unwanted deflection of moving components, reducing the chance for premature damage and wear of the bolt and barrel lugs which results from misalignment."

And I thought.. the Vltor MUR upper also kinda did the same.

 

[gunsnjeeps]

Yeah, ya got me?

I’m a just bolt-gun guy with a long pandemic beard channeling The Dude: “AR’s are weird, man.”

Now, I have to watch that again this weekend. I had to trim my beard. It was getting caught in my charging handle.

 

[carbonbased]

Now, I have to watch that again this weekend. I had to trim my beard. It was getting caught in my charging handle.

This is the first time I’ve had a serious try at facial hair.

During this winter up here in the White North of Doom, my flowing handlebar mustache was constantly freezing to my rifle stock at the range. My nose breath was forming a little ice rink right on top of the stock, and the beauteous mustachio was dipping in (like in a hot tub) during each firing string. After firing was complete, the hairy little buggers wanted to stay and refused to give up their seats.

Ow!

 

[Snuby642]

Mustash wax ?