What could cause group outliers?

[koja]

#1 ,Parallax issue in scope is one I seen a lot when I used to let folks use my range,wide range power scopes can be picky.folks eye doesn't line up with scope,scope hieght, stock comb,etc #3 crown,lap the crown,#4 barrel fouling,carbon ring before throat.Scope is in a bind from uneven action (remy)scope bases needs bedded or shimmed,crap inside bolt around firing pin,stock bedding.
Brass issue,try different brass or ammo,Federal is the most consistant ammo.Try a different shooter.Check your scope mounting first, then try another scope,Check for carbon ring and scope issues.I've caught myself not wanting to admit a $2000 NF scope has an issue,now on every new scope or one thats been sitting since last hunting season,I run the turrets back and fourth a couple revolutions.

 

[koja]

Oh btw,I shoot a 28 nosler, 17" handgun,caseful of retumbo,ES is 10 ish, 1" @355 yds,bipod prone,"oh that ball of fire"hardly any muzzle flash.Randy Wise beat rifles in ELR with a handgun, 33 nosler 16" .Length of barrel ain't got nothing to do with flyers.

 

[Greyfox]

Not much to add with the comments of load/barrel conditioning suggestions.
With the grouping characteristics(flyers/large groups) the OP has described I would initially check the rifle. For me, more often then not the culprit have been one of these:
-Overheated-light barrel
-defective scope
-barrel crown damage/imperfection
-loose, or defective scope mounts…..insure the base screws are not interfering/extending in the upper bolt channel.
-loose bipod-front rest or other interferences causing intermittent bounce.

 

[Culpeper]

 

[MW204]

Are you sure you're not canting the rifle on the ones that are off?

 

[Teri Anne]

In a hunting gun.... don't let barrel get warm.....
I shoot the same target 2-5 days in a row.
1 shot... only
With dirty barrel.....

Like most others I do not have a range out my back door so shooting one shot a day is way beyond a pain in the butt. I also shoot and practice a lot for competition, mostly across the National Match Course which involves continuous slow fire as well as rapid fire shooting. One shot out of a cold barrel is not something that works for me, as well as many others. Whether one wants to believe it or not, a good rifle will shoot 5 shots in 50 to 70 seconds and hold a 1 MOA group or maybe a bit less. The question is, "What is a good rifle?" Just about all manufacturers make rifles that are capable of 1 MOA with the proper amount of attention to detail. Most rifles come off of a production line and are touched by any variety of people and machinery along their way out the door as a finished rifle. With many there are either defects in materials or workmanship that will affect how it shoots. Quality control between manufacturers varies.
I like tinkering. I buy rifles both new and used then work on making them accurate. I do this by checking and seeing what the manufacturer missed or messed up when putting it together and correcting them. This can be either simple or a long and involved process which I won't discuss here. If anyone is interested PM me and I will gladly explain how I go about this to you. By the way, those of you that cherish that one cold barrel shot somewhere along the way should probably check to see what happens on the second or third shot, just in case you miss on that first one. The results could be interesting.

 

[skipglo]

Are you using a muzzle break? If so....remove it and try again!

 

[Randal Rosenberg]

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 have a Remingtion 700 in the 6.5l55 . The rifle never did group well . The best was a 3 shot group at 100 yards off the bench at 2" work with loads for over 3 years and this is the best it would do . Also I am a Benchrest shooter and have all the good stuff . One day I was talking to Hammer bullets and he told me give them a try with a load he pick out . So I did and the first three shot gave me a 1" group so I played with it and with a hot load it is now doing 3/8 " five shots at a 100 yards . Love it and this is my hunting rifle . YOUR BULLET SEATING AND POWDER HAS A LOT TO DO WITH THIS . GOOD LUCK .

 

[SuperBruce]

Good luck !

Thank you.

And thanks everyone for the tips. I still haven't gotten out to test seating depth but if that's not it then it's probably just not a good bullet-barrel combo. This rifle, while not the best, can consistently print small(er, it's not a match rifle by any means) groups in my hands with other loads so it is unlikely to be only me or only the rifle. I've tried these bullets with other powders (TAC, H4895, Varget) and it's been inconsistent (at best) across the board. I haven't tried varying seating depth yet because I have to load them so far from the lands as it is but I'll give that a shot and if not just move on to a different bullet.

@Randal Rosenberg , this rifle shoots hammers really well (3/4 MOA or less is the norm out to 500 yards) and those are what I use for hunting but I'd like an affordable range bullet to practice with. Hornady bullets are very reasonably priced and have been great for me in other calibers (and the 125 SST over TAC is amazing in this rifle) but I might just have tried a bad combo this time.

 

[nksmfamjp]

Is this a 4 shot group at 100 yards? I'm assuming yes.

Is this a 308? I'm assuming yes.

Is this a bolt gun?

What is TS 15.5?

Since you ruled out the gun throwing fliers…..That would immediately make me go back to the load?

Pressure: you are at 2590 from 18". Hornady is running 175's at 2600 from 24" bbl.

Jump: Where are you at? My first attempt with this bullet would be 0.03". Then I would try 0.06".

Bullets: Have you tried something which has a MV from 2700 - 2900fps?

Dispersion or Flyer: You say flyer. Have you tried shooting 10-30 shots? You may decide it is more likely just dispersion.

Try 20 shots at about 2400 fps and report back.

 

[jensenj71]

I had a new Kimber that would randomly throw a flyer during load development. Wasn't always the 1st or last shot. Sometimes it would throw 2 in a row. Sometime it would shoot 5 without a flyer. I tried different powders and different bullets. It would shot 0.5MOA and then randomly throw one.

Turned out that the front action screw bottomed out on the barrel just before tightening down the stock. It was close enough that the bedding was limiting the play, but there was a little play.

 

[RegionRat]

Thank you.

And thanks everyone for the tips. I still haven't gotten out to test seating depth but if that's not it then it's probably just not a good bullet-barrel combo. This rifle, while not the best, can consistently print small(er, it's not a match rifle by any means) groups in my hands with other loads so it is unlikely to be only me or only the rifle. I've tried these bullets with other powders (TAC, H4895, Varget) and it's been inconsistent (at best) across the board. I haven't tried varying seating depth yet because I have to load them so far from the lands as it is but I'll give that a shot and if not just move on to a different bullet.

@Randal Rosenberg , this rifle shoots hammers really well (3/4 MOA or less is the norm out to 500 yards) and those are what I use for hunting but I'd like an affordable range bullet to practice with. Hornady bullets are very reasonably priced and have been great for me in other calibers (and the 125 SST over TAC is amazing in this rifle) but I might just have tried a bad combo this time.

Some good points in this post.

You have started gaining the experience to know how to evaluate this bullet against the background of what this system does with better ones.

You also realize that there is a trade-off between the cost of those better ones versus the trigger time you get from lower-performing and less costly ones.

There is a value to troubleshooting a particular barrel with a "known good recipe". It can help eliminate you or the gun on a given day. By the same token, it can stop you in your tracks and force you to troubleshoot the barrel or gun before wasting more ammo.

Go ahead and spend some time with exploring the effects of tuning parameters like seating depths, but be honest with yourself and be prepared to spend enough shots to convince yourself. Consider this same exercise with the 175 SMK if you want to see how this gun does or does not respond to seating depth changes and different bullet designs.

Learning the ropes of internal ballistics using an affordable standard match gun is valuable when it comes time to develop a load for a carry gun. I say this because only some of the system's modes respond to load tuning, and some will suck no matter what we do.

Once we learn this with a heavy section match barrel and with good match bullets, we transition you to a carry barrel (sporter) with hunting bullets and school starts all over again because there are now modes that can respond to load tuning in an amplified way compared to a match gun, but you have also learned that some of the adjustment knobs have no real effect. Some bullets and guns will never shoot small.

The difference in methodical learning with heavy match barrels and sporter barrels, is you learn to abandon a bad bullet (or any component) much sooner.

 

[rdr59]

I've had loads do the same thing. Do a seating test .003 incriminate. Make about 9 loads. You will see a pattern small big small big. It has almost always gave me a more consistent load. Plus you get to shoot more and probably learn something. Thanks.

 

[SuperBruce]

I've had loads do the same thing. Do a seating test .003 incriminate. Make about 9 loads. You will see a pattern small big small big. It has almost always gave me a more consistent load. Plus you get to shoot more and probably learn something. Thanks.

That's the plan, roughly. I made a batch of rounds as long as the mag allows and will take my hand-press with me to the range and shorten by 0.003" increments until I find something or run out of ammo.