What could cause group outliers?

[Shane Lindsey]

Who shoots 30 round groups for hunting? And how many are shooter induced flyers? Didn't watch the video so no context there, but did they shoot said rifle from a vice?

The first two are all that matter. If on separate days, from cold/dirty bores you can shoot .5 minute groups, that is what matters. It takes time to map these shots. I think trying to gather long range data over 30 rounds in one day on a hunting rig, requires this.

If you want a consecutive, 30 round, .5 minute gun, it needs to weigh a ton, not fun for hunting.

 

[eoperator]

Who shoots 30 round groups for hunting? And how many are shooter induced flyers? Didn't watch the video so no context there, but did they shoot said rifle from a vice?

The first two are all that matter. If on separate days, from cold/dirty bores you can shoot .5 minute groups, that is what matters.

Honestly are your 2 shots within .5moa from your point of aim repeatable? Once in awhile doesn't count.

I do agree that 30rnd groups are not practical for most. Take a listen to the podcast I am willing to bet you learn something if you can keep an open mind.

 

[Shane Lindsey]

Agree on learning something.

I map the cold clean/dirty on my rifles. It takes several sessions, but yes, the loads shoot .5 moa for those shots. Those are all that matter to me. This is after all load development is done. Yes I cherry pick the best groups and tweak those to get to this point. That is always done with more than two shots for load dev, but takes time. Light barrels, mirage, blah, blah...Final load development is mapping those first two shots over multiple days.

 

[eoperator]

Being honest with myself I have never owned a hunting rifle that would put 3rnds within .5moa of point of aim (not group size) 100% of the time, excluding shooter induced erorr. If I cherry picked groups I have several that would.

 

[Shane Lindsey]

Good video for helping to manage expectations. Definitely do what he says about testing how you will use it. Hence cold bore mapping over multiple days. Honestly, not ever done it over 10 days (20 shots) but have for probably five.

Guess it's time to start with the ten days.

 

[smokey3]

I listened to that podcast and while I agree with what their point was, it has little relevance on a hunting rifle and a couple of shots at game. Not many animals will hang around longer than that if you miss on the first couple of shots. I also believe the cold bore shots are the most important. If I was competing in PRS, F-class, or 1000 yard benchrest competitions then the larger testing groups would mean much more to me. I have at least 6 rifles that I can depend on to hit where I am aiming for a few shots, maybe not for a 20 shot string but they do fine on targets and low round count and that is really all I need for hunting and scope alignment verification. I belong to a 1000 yard benchrest club however I don't compete, mostly do to time and equipment cost, but I do like to shoot as far as the range allows. The guys on that podcast are competitors in the long range games and the information that they shared is highly relevant to their disciplines and competitors that compete in such, however I find more value in knowing and having confidence in my equipment to give me .5 moa accuracy even if it's just capable of doing it for five shot groups which for what I do is more than sufficient. Everyone has different needs and opinions and that is fine.
Edit to add: I don't find much fun in shooting a rifle that will not shoot a 1/2" group at a 100 yards other than my AR style rifles which a 1 1/2" group is sufficient for me.

 

[JiminAZ]

A bit of thread drift here but another place that this set of observations regarding true accuracy/group size matters is evaluating whether your scope is returning to zero.

Have to admit I've chased a click or two around thinking zero had drifted, when in reality it was just the gun's true variation asserting itself.

 

[eoperator]

I would like to see how many ".5moa" hunting rifles could truthfully hold .5 moa from point of aim over 30 shots on the same target so "cherry picking" is ruled out. This could be done in any cadence and time frame preferred by shooter.

I would bet a VERY VERY small percentage could.

 

[William W.]

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 can't prove it, but on the basis of having pulled numerous bullets from factory, and my hand-, loads, I am convinced that neck tension is the issue. If you machine your brass to a consistent neck thickness, feel free to write me off. I refuse to go through this effort after primer pocket uniforming and flashhole deburring, but my groups have improved noticeably after adding a Brownells expander die to my Dillon loading die group. I prime and load in two operations so my case necks go into this die twice. For sizing, I use a type S Redding die that initially resulted in a number of cases, apparently with thin necks to be over-caliber and tossed.

 

[Mike Matteson]

I can't prove it, but on the basis of having pulled numerous bullets from factory, and my hand-, loads, I am convinced that neck tension is the issue. If you machine your brass to a consistent neck thickness, feel free to write me off. I refuse to go through this effort after primer pocket uniforming and flashhole deburring, but my groups have improved noticeably after adding a Brownells expander die to my Dillon loading die group. I prime and load in two operations so my case necks go into this die twice. For sizing, I use a type S Redding die that initially resulted in a number of cases, apparently with thin necks to be over-caliber and tossed.

I don't follow that. Why would tossed the cases? I would think you change the bushing and size again. If you split the necks then that a different story.

 

[Maol]

I map the cold clean/dirty on my rifles. It takes several sessions, but yes, the loads shoot .5 moa for those shots. Those are all that matter to me.

Yep I agree it is reasonable to expect that and to make it a goal for the Cold bore. I have 2 that are .5 MOA. Consistent neck tension, uniform case volume, primer pockets and flash holes all matter. So does low runout and quality bullets. Those 2 I can count on being .5 MOA every cold bore shot from the bench or prone. Both are money for the 1st 3.

If those 'cold' 3 start to open up they get deep cleaned and then I foul them until the the cold bore shots are back.

I care about 3, 5, 7, 10 round groups, but honestly in hunters I only regularly shoot cold bores then a quick 2 after. All 3 at different adjacent POA and measure distance to POA for each. Then I'm done for the day with that hunting rifle. I shoot 22LR and 223 for training and fun. I may do load development with a new rifle or shoot another that needs shooting after that.

 

[William W.]

I don't follow that. Why would tossed the cases? I would think you change the bushing and size again. If you split the necks then that a different story.

I never said that the necks split. Simply the metal was too thin to size correctly.

 

[LTH181818]

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 had similar experience with a top tier barrel. Had it fluted, after I received it from the manufacturer. After ~60 rounds I replaced with a new barrel. When I think back to that flyer problem and wonder if the bullet jackets could be slipping from the cores.
I prefer hunting and scouting vs. chasing down group sizes. Maybe too quick to pull a barrel. I have had many different bullets come apart..could jackets slipping account for flyers with out us realizing it?

 

[Mike Matteson]

I never said that the necks split. Simply the metal was too thin to size correctly.

I never said that the necks split. Simply the metal was too thin to size correctly.

Then you are not using a type S Redding bushing die. Because you can change the bushing out for a smaller bushing. I have several bushing for my Redding bushing dies. One of my cases has to be sized or step down 4 times to achieve the ID in the neck area I am after. From 7mm to 6mm.
Or you can get a bushing die from Redding and or bushing. Brownell, Midway and other supplies have them and bushing too.
Now what I haven't tried is bushing down to below a .002" ID and using a mandrel to expand the neck back to the .002" for neck tension. I am looking at that and will try it to see if any better grouping come from that. There has been a lot of debate on final size of the neck. Presently I stand on the side of being able to achieve my neck tension by using bushing. I do cut all my neck for thickness to start with. So the the out side of the case are even. That's using new case that never been fired. Once fired cases, that a different story. I believe I would size, and use a mandrel before cutting the necks for thickness. That way I know the uneven neck thickness are to the outside before cutting the necks to thickness.
I am still waiting on is my bullet seater die. For my 6mm/280AI chamber. The die is a blank and has to be reamed for the cartridge. The second rifle being built, I will have the blank seating die before hand. Live and learn.
The other is you have to watch for spring back too. It looks to me that you will have to watch the necks for several days to see what happening with the neck for changes.