What could cause group outliers?

[Derfman]

One more question…do you have the correct twist for the bullet you are shooting?

I'll echo one other cause that someone brought up…parallax. This is one cause that is most often overlooked. It's. Very easy to maladjust your diopter on many scopes by turning it when increasing or decreasing your scope's power. If the locking jamb nut loosens slightly, it will turn. I have done it, with a Nightforce Atacr.

Make certain that your diopter is adjusted properly by putting your crosshairs on target, and moving your eye left, right,up, down, and if the crosshairs do not stay on your target, you need to adjust your diopter.

 

[Lenny Foffa]

I find that when I shoot several 3 shot groups with holes touching the one or two groups with two holes touching and One hole with a space, between the holes, it is me getting tired. Me loosing focus and concentration. Accurate loads, cases segregated by weight , Coal and Ogive all verified and the barrel allowed to cool 2 min or more between shots. Its just me . IMHO

 

[dougduey]

Maybe the attached will help you. They are from the Hall of Fame Benchrest shooter "Speedy" Gonzalez. Google him if you don't know who he is. I'm fortunate enough to have him be my gunsmith, and I always learn something when I drop by his shop. He's a very humble and cool dude, as well as a legend in the firearms & shooting world.

 

[Derfman]

Maybe the attached will help you. They are from the Hall of Fame Benchrest shooter "Speedy" Gonzalez. Google him if you don't know who he is. I'm fortunate enough to have him be my gunsmith, and I always learn something when I drop by his shop. He's a very humble and cool dude, as well as a legend in the firearms & shooting world.

Redding named the "type s" die after him. He designed the die type. Initially it was made for him, and as a special order, but they received so many orders for the die that started producing it as one of their production models. The "S" stands for Speedy. I'm off to the range. He is one of the best.

 

[Creedmoorcarl]

I have what seems like a good load developed using 178 ELDM bullets with TS 15.5 in Lapua brass but I'm experiencing odd fliers. SD is ~10 fps over a large number of loads and velocity is averaging 2590 fps. On average, out of 4 shot groups (odd number but it's how many my internal mag holds so thats usually what I do with this rifle) I'll have 3 making up a 2/3 MOA (or less) group and the other shot is 1.5 to 2 inches away. Sometimes this is 2 of 4 touching, sometimes is just a good group for all 4 shots. This rifle will generally shoot just under 1 MOA groups with a good load: no match rifle but fliers are not the norm. However, it is a bit picky of a barrel: not all projectiles shoot well in it.

I'm inclined to chock it up to one (or more) of a the following causes:

1. These are pandemic projectiles so perhaps I may have a not-so-good batch.
2. My jump maybe in a sensitive spot (only tried one jump so far), although I do check the CBTO on all rounds and they're quite consistant showing a variance of about 1 to 1.5 thousandths.
3. These are just not a good bullet for this picky barrel.

I'm interested to know what more experienced people think. Thanks in advance.

Sometimes I'll drop my load by a half grain or a grain and shoot a 10 shot group letting my barrel cool

 

[dougduey]

Redding named the "type s" die after him. He designed the die type. Initially it was made for him, and as a special order, but they received so many orders for the die that started producing it as one of their production models. The "S" stands for Speedy. I'm off to the range. He is one of the best.

Yes, you are correct. He had Redding custom make them for his custom rifle clients at first. They eventually became too expensive for him to include one with the rifles he built. He told me that Redding called him one day and said they'd like to start producing them since they had a lot of people asking for them. They said we'll call it the "S" die as a tribute to Speedy.

 

[Mike Matteson]

Intresting, and it pays to read. Got the target downloaded and will get them put away here shortly. I'll have to watch next time at the range.
One thing I wonder about is? Why don't people set up and cool there barrels at the range with a CO2 tank and items to cool the barrel with. It would seem to me if you are driving several miles. The cost to set up with tank, regulator would after a short time pay for itself by the cost of gas. If your range is in your back yard that's a different story.

 

[spladi]

I have what seems like a good load developed using 178 ELDM bullets with TS 15.5 in Lapua brass but I'm experiencing odd fliers. SD is ~10 fps over a large number of loads and velocity is averaging 2590 fps. On average, out of 4 shot groups (odd number but it's how many my internal mag holds so thats usually what I do with this rifle) I'll have 3 making up a 2/3 MOA (or less) group and the other shot is 1.5 to 2 inches away. Sometimes this is 2 of 4 touching, sometimes is just a good group for all 4 shots. This rifle will generally shoot just under 1 MOA groups with a good load: no match rifle but fliers are not the norm. However, it is a bit picky of a barrel: not all projectiles shoot well in it.

I'm inclined to chock it up to one (or more) of a the following causes:

1. These are pandemic projectiles so perhaps I may have a not-so-good batch.
2. My jump maybe in a sensitive spot (only tried one jump so far), although I do check the CBTO on all rounds and they're quite consistant showing a variance of about 1 to 1.5 thousandths.
3. These are just not a good bullet for this picky barrel.

I'm interested to know what more experienced people think. Thanks in advance.

Consistency is key, I think, from everything to everything.

 

[RegionRat]

Intresting, and it pays to read. Got the target downloaded and will get them put away here shortly. I'll have to watch next time at the range.
One thing I wonder about is? Why don't people set up and cool there barrels at the range with a CO2 tank and items to cool the barrel with. It would seem to me if you are driving several miles. The cost to set up with tank, regulator would after a short time pay for itself by the cost of gas. If your range is in your back yard that's a different story.

Many folks use various methods for accelerating the cooling of their barrels at the range.

I have not seen CO2 but I have seen folks use spray cans of other refrigerants like the ones we use to troubleshoot circuit boards or spot chill hardware.

I have also seen everything from wet towels, to water or alcohol being swabbed down the bore, to small fans used to force air through the bore, etc..

I use the small battery powered fans for many years to cut down the barrel cooling time on carry rigs when testing at the range. When I remember it, I also bring one to XTC club matches and try to cool the barrel between rapid strings.

I try not to get the barrels very hot and use twin guns to avoid the issue when prairie dog hunting.

 

[Mike Matteson]

I can understand that. I got 2 20lbs tanks, and value to attach to the tanks. I using a clear plastic tubing to a cleaning rod alinement tool to seal off the chamber and go from there. The tanks were $50 each to fill. So it's prices. If noting else I sure can get my beers cold from the kag.

 

[Mike Matteson]

Consistency is key, I think, from everything to everything.

Consistency I agree.

 

[Derfman]

I have what seems like a good load developed using 178 ELDM bullets with TS 15.5 in Lapua brass but I'm experiencing odd fliers. SD is ~10 fps over a large number of loads and velocity is averaging 2590 fps. On average, out of 4 shot groups (odd number but it's how many my internal mag holds so thats usually what I do with this rifle) I'll have 3 making up a 2/3 MOA (or less) group and the other shot is 1.5 to 2 inches away. Sometimes this is 2 of 4 touching, sometimes is just a good group for all 4 shots. This rifle will generally shoot just under 1 MOA groups with a good load: no match rifle but fliers are not the norm. However, it is a bit picky of a barrel: not all projectiles shoot well in it.

I'm inclined to chock it up to one (or more) of a the following causes:

1. These are pandemic projectiles so perhaps I may have a not-so-good batch.
2. My jump maybe in a sensitive spot (only tried one jump so far), although I do check the CBTO on all rounds and they're quite consistant showing a variance of about 1 to 1.5 thousandths.
3. These are just not a good bullet for this picky barrel.

I'm interested to know what more experienced people think. Thanks in advance.

I thought of a few more items:
1. Are all bullets concentric ? Are you using a VLD seating stem? Are you possibly knocking some of them out when loading them into the magazine, or are they getting knocked out going from the magazine to the chamber?
2. As others have mentioned, I too have/have had guns that would not shoot certain bullets. I have a model 700 '06, with a 20" barrel that will only shoot Barnes TTSX bullets with a .133 jump. I have never jumped bullets that far. I also had an old .300 Weatherby that would not shoot boat tail bullets, supposedly because of the huge free bore, and would only shoot Speer flat backs, or Nosler partition bullets.
3. I remember someone at one of the bullet manufacturer's telling me that when he load developed, he kept his powder charge constant and varied the seating depth, but I don't remember how he decided on where to start with the powder. Either way, they are dependent variables that either, when changed, alter case volume, pressure, and Vo.
You might want to try the Berger recommendation, and do 10, 50, 90,
and 130 jumps. 2 different 3 shot groups of each. I am working on this with my RUM and have found some interesting stuff, but I'm not done yet.

 

[5280Reloader]

Listen to the Hornady podcast "your groups are to small" series. You will never look at small groups the same again.

I was going to say the same thing, I listened to that one twice. Still trying to decide how I want to attack the next test day but I like what they had to say. I need to find out how to interpret the 7, 3 shot groups in to one. Have you tried this method yet?

 

[eoperator]

Have you tried this method yet?

I took my 2 most accurate rifles .223 & 6cm that I considered to be 1/3moa rifles, 30rnd groups ended up more like 1.1moa. This explains alot of the "fliers" I thought I had. Also tried several 20rnd groups with different seating depths and charge weights, there was little if any change in group size.

Moving forward a single 3rnd "cherry picked group will mean very little to me. I would be willing to bet the common ".5moa" hunting rifle is truthfully more like 1.25moa