Causes of flyers?

[Swamp Fox]

Not necessarily a cast boolit question, but I’ve been working up some loads for a rifle. I’ve got a few acceptable loads, and one that seems great, except for the occasional flyer. The rifle generally will shoot around 2” groups, but one load I’ve tried will give 3 holes touching then a couple random rounds 4” away. Everything else seems good, all loaded to with in a couple thousandths of the same length, very consistent velocity.

What causes the flyers?
Is it just barrel harmonics with a particular load that a rifle doesn’t like? Seating depth? Is there a place to start with fine tuning it to make a good load or should I just move on?

[Winger Ed.]

After the normal precautions--
Maybe weigh out the batch of bullets, and be sure the barrel's crown is good/polished.

[challenger_i]

After following Ed's advice...

Assuming you sort your brass to the same weight, head stamp, trim length and, hopefully, lot number, I would recommend annealing your cases and try the loads again.

[Shopdog]

Hmmm, there's a reason quality barrels cost what they do. So if you're pushing a factory barrel,especially one with a sporter profile, much past 3 shots.... well, as much as it pains my frugality to say it,you get what you pay for.

Are there some factory barrels that can be outstanding,of course. What is,or are your chances of getting one? I'd say one in a hundred on varmint profiles and maybe half that for thinner profiles.

On cast; how well,and how efficient(quickly) you can make effective changes in your process "should" allow you to keep ahead of the curve. Meaning,if you're stuck with say one sizer die.... one top punch.... one mould... You see where this is going?

The ability to experiment plays a tremendous role in the search for accuracy. Seating depth is critical IME. Seating *"straight" is right there with that. Annealing then becomes part of the conversation. Powder burn rates,and a bunch of other fun things to try.

*Seating straight; cast is grippy,real grippy. So make darn sure the boolit is as straight as possible, before it hits the seating die. They don't self correct like a harder JB. This same effect shows up in the chamber. Where a jacketed bullet will get right with the bore centerline,cast if presented to the leade in the chamber is misaligned... well,it just isn't gonna get any better. Nope,it's going to get worse.

So,seating on the press... and seating in the chamber are two areas that leave something "on the table".

You need to have fun. If it becomes that 4 letter word.... WORK.... Well,you're in for a rough ride. The very best of luck with your shooting.

[dverna]

Hmmm, there's a reason quality barrels cost what they do. So if you're pushing a factory barrel,especially one with a sporter profile, much past 3 shots.... well, as much as it pains my frugality to say it,you get what you pay for.

Are there some factory barrels that can be outstanding,of course. What is,or are your chances of getting one? I'd say one in a hundred on varmint profiles and maybe half that for thinner profiles.

This is easy to check but boring.

Fire 2-3 shots and wait 10 minutes for the barrel to cool.

[fenderman57]

Had that trouble with a 223,30-30 and ball powder, switched to a magnum primer and that cured it.

[waksupi]

If cast bullets with conventional lube, I would guess lube purging. If jacketed bullets, check diameters with a micrometer. Clean copper fouling from the bore.
If those aren't the problem, there is nothing wrong with the barrel, it is a bedding issue.

[oldleadhead]

If all else being equal perhaps it's the technique of the person driving. Look for variables there, especially "breathing"...

[Larry Gibson]

Not necessarily a cast boolit question, but I’ve been working up some loads for a rifle. I’ve got a few acceptable loads, and one that seems great, except for the occasional flyer. The rifle generally will shoot around 2” groups, but one load I’ve tried will give 3 holes touching then a couple random rounds 4” away. Everything else seems good, all loaded to with in a couple thousandths of the same length, very consistent velocity.

What causes the flyers?
Is it just barrel harmonics with a particular load that a rifle doesn’t like? Seating depth? Is there a place to start with fine tuning it to make a good load or should I just move on?

If you've got "acceptable loads, and one that seems great" there's nothing wrong with the rifle that needs correcting. As for the "occasional flyer" with those loads if not caused by you then it's probably caused by a defect in the bullet. Solution is to properly weight sort the bullets. I've posted how to do properly weight sorting so you may find it using the search function.

As to the "one load I’ve tried will give 3 holes touching then a couple random rounds 4” away". That obviously is just a bad load. It's most likely caused by inconsistant ignition and burn of the powder used or the bullet is being pushed too hard/fast. Since you haven't told us the cartridge used, the rifle used, or any specifics about the load or cast bullet used it's difficult to guess which is the problem. More detailed information would be helpful?

[MostlyLeverGuns]

It is probably not the barrel. It is surprising how ugly a barrel can look thru a bore scope and still shoot very well. Like waksupi said, bedding is probably the problem. Getting the barrel clean, really, really clean before load development helps a lot. Sometimes just changing powders without cleaning can cause poor grouping. Many older ball/spherical powders leave a hard residue in the barrel if not cleaned after shooting(Bl-c2,others). Changing bullet type cast, jacketed, PC can cause accuracy issues. STRAIGHT cartridges make a big difference.

[Kraschenbirn]

Not really sufficient info provided by the OP. Rifle? Caliber? Barrel length/profile? Specific boolit info? Load data...like powder, charge weight, primer, etc?

So far as a barrel problem...once upon a time, I owned a pre-64 M70 'Featherweight' in .270 Win (I'd [probably read too much Jack O'Conner in those days.) that would put the first three rounds under a half-dollar then began to wander as the barrel heated up. Tried everything we could think of: trigger job, bedded the receiver, floated the barrel, diddled with different powders and bullet designs to no avail. Finally just gave up and settled for what it was...a darned effective coyote killer. The point being that, sometimes, you just got to accept what is and live with it.

Bill

[Gewehr-Guy]

I have examined a lot of my bullets that were shot into large snow piles used as backstops. Some have revealed voids in the sides of the castings, even after examining them before sizing. I think they could be the cause of a random flyer, so now all my bullets are weighed.

[popper]

Read an article a while back from a professional ballistician (Mil, etc). He got to talking about bullet yaw in the barrel. Due to expansion of the barrel and bullet entrance problems. Not much we can do about it other than measuring bullets and letting the barrel cool. Bad crown usually gives and off 'target' but still a group. Could be bedding.

[Shopdog]

Anyone who makes their own H&I style sizer should be conversant in their "leade" in.

Translated; the literal degree of taper that is machined near the top, has a marked effect on the self centering action of that stage of sizing. Another place this taper shows up...is if you make a nose sizer.

A master, plain ring gage for instance will have the inside corner "broke" or relieved as a matter of manufacturing. You can make nose sizing ring gages too. This relieved edge is what I'm referring to. OK,here's where it gets tricky to describe compared to... if you see/doing... there will be a certain taper angle that for the given example,that will be obviously better at self centering. What that angle is; each mould,each bullet,will have NOTICABLE preference. Think more in terms of, a little, a lot, or a whole lot. IOW's small,medium,and large. Versus me spouting off particular degrees...minutes,and seconds.

An automotive example; simply put,a three angle,sometimes 4 angle valve seat. It ain't a small matter.

Once you've seen it on the bench,this centering phase starts to explain why chamber designers have different approaches. With this in mind,I do "think" over the years the JB benchrest crowd have sorta agreed on certain chamber leade angles? Could be wrong but since I don't shoot JB's... it don't really effect me,haha. Cast is definitely ahead of the curve here for about a dz reasons. Alloy,mould specs, sizing,yada. We're not burdened with the $$$ to change bullet profiles.

Sorry for the novel.

[Shopdog]

Further; "well if a little taper is good,a lot of taper has to be better"

Well,it depends. Yes if the dang bullet is a mile long (low drag high bc bullets obviously come to mind,and sorta explains why they're currently in "fashion")... but we don't have long bullets sometimes.

But there's a funner way to look at too much,or too long of leade in. Once you get past a certain taper... remember we're trying to self center not,just make things easier. Too much leade angle is diminished returns because of that length. The bullet stops self centering cause you're taking too long. The bullet stops centering and starts yawing.

Goldilocks liked her porrage "just so". You could say,here honey take this hot porrage and let it cool. Well no,she's hungry now. She can't wait for it to cool. And that other bowl(short leade angle) ,dang that's to cool and the microwave broke last week so give me that just right bowl. So it is with leade angles... and how they self center. Too long may not exhibit the same reaction as too short/abrupt but there is a reaction. You need to find your Goldilocks.

[country gent]

Are the fliers in the same order of firing? Ie always 4and 5 or random in the group? it may be an issue with stress in the barrel and its heating up. You might try firing the group slower like one round every 2-3 minutes to allow the barrel to cool and normalize between shots.

[HATCH]

Flyers can be multiple different things or even a combination of different things.

Are you using a bench rest to hold the rifle perfectly still?
If you shoot outside, is there any wind?
Powder drop - what are you using?

For max consistency you want to load the same head stamp cases using an automatic powder drop and do it all on a single stage press.

There are so many variables.

Funny story, My father owned (i now own) a Remington AAC bolt gun in 300BO.
On a clean bore the rifle would not group. It still shot acceptable with groups sizes less than 2 inches at 100 yards.
But after the fourth or fifth shot the group size would reduce to less than an inch.
Now before someone says the barrel heated up, he could shoot 3 shots then a week or so later shot more and the group size would reduce.
Or he could shoot all the same day.
The bullets were cast 220 grain lead coated with hitek black.
They were loaded on a dillon 550.

[Swamp Fox]

Some more info for the people that were asking. This is on a savage 99 f, so it has the thin barrel that is bad to heat up. Generally this particular one tends to start drifting left as the barrel heats up, but I try to shoot and give it a minute or two then shoot another, letting it cool completely between loads. The crown looks fine to me but I’m no expert on that. What do I look for? Shooting off of bags but not an immobilizing rest. The receiver itself is on the bag so that the forearm isn’t pressing against the barrel. Brass is all annealed, bullets are all Speer hot core 150 grains. Every powder charge was weighed before loading. The brass was not sorted by weight or manufacturer, but neither were the other loads that didn’t have flyers. They seem to be random in the shot string.

Based on what I’ve seen so far I can sort the brass out, and may try a different bullet. I may also try cleaning the barrel of copper fouling, but seems like that could go either way. Seems it can be most anything and there’s a lot of variables.