Fix the flyer?

[Canonshooter]

Upper - BCM BFH ELW 16-inch mid-length
Ammo - Speer LE .223 75 Gold Dot

I've had this upper for years and have been very happy with it (still am). I usually shoot this rifle at 100 yards or less, but today I tweaked my zero at 200 yards to achieve my desired MPBR of about 230 yards.

First 3-shot group at 200 yards measured 1-1/2 inches, the second 3-shot group at 200 measured 1-3/4 inches. With the zero confirmed, I settled down for some 5-shot groups.

What I was finding in 5-shot groups is that the rifle would cluster four in a MOA group or better (like the first two groups), then the fifth shot was WAY out of the group, opening it up to around 3 MOA. It did this pretty consistently, able to get most of the shots in a tight cluster then sending one in five out into left field somewhere. One group at 300 yards clustered four of the shots within 4 inches, then sent the fifth to open the group to 10 inches (about 3 MOA)

I was shooting prone with bags front and rear, squeezing the shots off carefully, so I don't think there was anything I was doing to force the flyers. Other ammo is usually in the 2 - 3 MOA range but doesn't consistently cluster tight groups like the GD ammo.

Question - is there something I should be looking for mechanically that might account for this behavior? Or is this typical of lightweight barrels?

TIA for your insight.

[georgeib]

By any chance, was it the first round throwing the flyer? Any idea?

[ndmiller]

Have someone else shoot some groups to confirm what you're seeing.

[Canonshooter]

By any chance, was it the first round throwing the flyer? Any idea?

No idea, did not have a spotting scope.

[georgeib]

No idea, did not have a spotting scope.How are you loading the first round, charging handle or dropping the bolt using the release? Makes a difference.

I'm order to eliminate first round flyers, you could try shooting the first round off the target and then shooting the rest for the group.

[opngrnd]

I'm willing to bet it's your first shot out of the magazine. I have experienced this myself, I see it a lot when zeroing other people, and I've had conversations with people who shoot far more than I do and believe that the first round of the magazine will sometimes group different. Some people go as far as to test different magazines and see which one does it the least.

[Canonshooter]

Double-tap

[Canonshooter]

How are you loading the first round, charging handle or dropping the bolt using the release? Makes a difference.

Dropping the bolt.

Here's a 300 yard target from today - five in a 4-inch cluster, then one out of the group. Don't know which round went low;


https://i.ibb.co/mNhbrh4/artarget-1.jpg


Rifle in question, optic is a Leupold FX-II Ultralight 2.5x20mm;

https://i.ibb.co/7j48Zjp/rifle-3.jpg

[georgeib]

Dropping the bolt.

Here's a 300 yard target from today - five in a 4-inch cluster, then one out of the group. Don't know which round went low;


https://i.ibb.co/mNhbrh4/artarget-1.jpg


Rifle in question, optic is a Leupold FX-II Ultralight 2.5x20mm;

https://i.ibb.co/7j48Zjp/rifle-3.jpgTry shooting the first round off target, and then grouping the next 5. That'll confirm whether you're getting first shot flyers, as I suspect.

[Canonshooter]

Try shooting the first round off target, and then grouping the next 5. That'll confirm whether you're getting first shot flyers, as I suspect.

Will give that a try, thanks!

It will be a while before I make another range trip so if anyone has any other suggestions, they would be appreciated.

Thanks!

[grizzman]

If 3 round groups are good, then neither of the next two can be the first out of the magazine.

It's very possibly the shooter's technique. Does it matter if they're the first 5 through the barrel, or only after you've heated it up firing others?

[Canonshooter]

It's very possibly the shooter's technique.

Could be, but I'm starting to think it may be that Surefire/Oveready/Malkoff Lego WML I have mounted. ;-)

[ndmiller]

If 3 round groups are good, then neither of the next two can be the first out of the magazine.

It's very possibly the shooter's technique. Does it matter if they're the first 5 through the barrel, or only after you've heated it up firing others?

I was thinking along the same lines, have someone else shoot some 3 and 5 round groups at the same distance.

[Canonshooter]

Going through my (mental) notes;

I remember when I first got this upper I fired a nice, tight 1.2 MOA 5-shot group at 100 yards, then a short time later shot another tight 5-shot group, but it was a few inches lower than the first group. That was with a different scope I was using at the time (a VXR-Patrol), so I think I can rule out a problem with the current scope.

Same thing happened today - first three shots went into 1-1/2" at 200 yards, but were 2-inches low. I dialed-in what should have been perfect compensation on the scope, the next three shots went into a nice tight group but were now 2-inches high.

I wonder if this lightweight barrel walks around a little....

[rjacobs]

Im going the opposite and saying last round in the mag if you are only loading 5.

Gun recoils differently when the bolt locks back.

I have more last round flyers than any others...usually in my 6.5 creed gun which big frame AR's are hard to drive anyway.

Personally the "only" first round "flyers" I have are cold bore shots, but thats to be expected.

[georgeib]

Im going the opposite and saying last round in the mag if you are only loading 5.

Gun recoils differently when the bolt locks back.

I have more last round flyers than any others...usually in my 6.5 creed gun which big frame AR's are hard to drive anyway.

Personally the "only" first round "flyers" I have are cold bore shots, but thats to be expected.Interesting! I had wondered if that could be a possibility, but dismissed it because the bullet has already left the barrel before the bolt unlocks. I'll try to pay attention to that and see if I can duplicate your experience.

[Canonshooter]

I know this sounds crazy, but it's almost as if the barrel is shifting in relation to the upper receiver (and the scope mounted on it). I have no idea how this could happen, but that is what it seems like. The deviation in group spreads is IMO too consistent for the barrel "warping" due to heat.

Last four shots of the day at 200 yards had two distinct groups, each group about .5 MOA separated vertically by four inches. Four shots tells me nothing really, but the pattern is the same.

I may buy an upper receiver rod, remove the barrel, inspect and then re-install it.

[ViniVidivici]

I almost always have a flier, often 2, when shooting groups. Always figured it was me.

I do load the first round by releasing the bolt from lock back, to eliminate a variable.

I can't see how the recoil difference when firing the last round would affect things as the bullet has already left before the bolt moves, but anything's possible within that "voodoo zone" of shooting, right?

This is making me want to load 7 rounds next time I shoot a fiver. Neither the first nor the last shall be on the paper. Will be interesting to try.

Is it a clue, that some barrel makers guarantee their accuracy standards as they do?
Ballistic Advantage's sub MOA guarantee is: best 5 out of a turnbolt, best 3 out of 5 from a semi.

Having someone else shoot the gun will eliminate the shooter as a variable for sure.

[MistWolf]

10 round groups are a much better indicator of precision than 5 round groups

[gaijin]

Im going the opposite and saying last round in the mag if you are only loading 5.

Gun recoils differently when the bolt locks back.

I have more last round flyers than any others...usually in my 6.5 creed gun which big frame AR's are hard to drive anyway.

Personally the "only" first round "flyers" I have are cold bore shots, but thats to be expected.

This. Don't shoot last rd. of group from bolt lock.
If you're shooting 5 rd. groups, use a mag with at least 6 rds. loaded.
Burning 1st rd into berm is not a bad suggestion either.

[Canonshooter]

Went through the rifle this morning checking for anything loose with the optics, but found everything was tight.

Having owned quite a few BCM uppers over the years, I've found all functioned perfectly but varied quite drastically in accuracy (precision). One government profile I had was atrocious and ended up sending it back to BCM, which they credited toward an upper with the 16-inch SS 410 barrel. That was the most accurate upper I ever owned, but I made the mistake of making the rifle way too heavy with my optic/stock/quad rail selections.

This BFH ELW upper is really amazing for it's weight, and all things considered ranks as one of the most accurate, perhaps second only to the SS 410. If I ignore the one-in-five flyers, it's actually very close to the SS 410. Though I'm still open to any other suggestions on what to look for, I beginning to believe that this is simply the characteristics of this barrel. Pinching the barrel to the end of the handguard, a very considerable amount of flex can be seen and barrel harmonics could certainly explain the performance I'm seeing. To put it in perspective, according to the BCM website the 16-inch BFH ELW barrel weighs 22 ounces, the 16-inch SS 410 weighs 33 ounces - the latter is obviously going to be much more rigid.

[TBAR_94]

I’m not an AR accuracy expert but I have done some accuracy testing with other guns. I would try some 10 round groups to see if it’s just a single flyer, or if the groups just open up with more shots. If it is just a first or last round it should be pretty easy to figure out with a spotter.

[Canonshooter]

Having owned quite a few BCM uppers over the years, I've found all functioned perfectly but varied quite drastically in accuracy (precision). One government profile I had was atrocious and ended up sending it back to BCM, which they credited toward an upper with the 16-inch SS 410 barrel. That was the most accurate upper I ever owned...

A new BCM 16-inch SS 410 barrel inbound. :D

Rifle will still weigh south of eight pounds sans WML. If it performs anything like the last one I had, I'll be mighty happy.


https://i.ibb.co/x3g1vDy/recce-1.jpg

[Rifleman_04]

How many rounds through that barrel?

I shot out an LMT barrel and that was the first symptom it showed was a random low flier. Within a few hundred more rounds it would string rounds vertically over about 18" at 200 yds.

edit: Can't remember who said it maybe sinister or F2S mentioned advanced throat erosion is the cause?

[Canonshooter]

How many rounds through that barrel?

Very low round count, definitely less than 1,000 perhaps as low as 500. I think it's simply the characteristic of a lightweight barrel. The fact that it puts 80% of the shots into near-MOA groups indicates that the barrel performs well for a lightweight.

[TMS951]

Load 12 rounds, shoot the first and last round off the target.

Fire the middle 10 rounds on target.

Also quite honestly I'd load up a full 30 round mag and shoot a 30 round group.

[Canonshooter]

Re-barrel complete. I'll see how it let's 'em fly this weekend. :-)

https://i.ibb.co/ph9JDpd/ss410-1.jpg

[TMS951]

Re-barrel complete. I'll see how it let's 'em fly this weekend. :-)



Did you ever do any further testing on the last barrel or did you just walk away from it? I thought you said it was pretty low round count? It didn't seem like you ever confirmed something was wrong with it.

[gaijin]

Load 12 rounds, shoot the first and last round off the target.

Fire the middle 10 rounds on target.

Also quite honestly I'd load up a full 30 round mag and shoot a 30 round group.

Second this, particularly with a LW barrel.

[Canonshooter]

The new SS 410 barrel is performing admirably. After an initial break-in and sighting in, it's holding about 1.2 MOA with my go-to load (Speer LE 75 Gold Dot) with no flyers - this is with a 2.5x scope with the rifle on the bench and bags. Surprisingly the new barrel seems to like XM193, recording one group just over one MOA group and no group larger than two MOA. Target loads with the 77 OTM bullet do better than the 75 GD load, but I don't have much on-hand in those loads. I suspect with the right load and more magnification, this is easily a sub-MOA capable barrel.

Nothing else has changed with the rifle - same optic, and I'm even using the same magazine and the flyers have disappeared. Everything seemed in order when I removed the BFH ELW barrel. But even with the flyers, the barrel was still holding better than 3 MOA, and produced clusters in the 1.25 MOA range. All things considered, really not bad at all for a "pencil" barrel that weighs 11 ounces less than the new one.

Thanks to all for your help and suggestions!

[opngrnd]

The new SS 410 barrel is performing admirably. After an initial break-in and sighting in, it's holding about 1.2 MOA with my go-to load (Speer LE 75 Gold Dot) with no flyers - this is with a 2.5x scope with the rifle on the bench and bags. Surprisingly the new barrel seems to like XM193, recording one group just over one MOA group and no group larger than two MOA. Target loads with the 77 OTM bullet do better than the 75 GD load, but I don't have much on-hand in those loads. I suspect with the right load and more magnification, this is easily a sub-MOA capable barrel.

Nothing else has changed with the rifle - same optic, and I'm even using the same magazine and the flyers have disappeared. Everything seemed in order when I removed the BFH ELW barrel. But even with the flyers, the barrel was still holding better than 3 MOA, and produced clusters in the 1.25 MOA range. All things considered, really not bad at all for a "pencil" barrel that weighs 11 ounces less than the new one.

Thanks to all for your help and suggestions!

Glad to hear it's working out.