100 yard accuracy not translating at further distance

[Usaf197]

New hiccup for me, hopefully it’s a relatively common occurrence.

BLUF; consistent sub moa 100 group. Very inconsistent hits at 1000. Stand deviations around 12 and acceptable ES. 2 moa target at 1000 (20”)

Any thoughts on where to start for trouble shooting?

Set up: vortex viper 5-25 properly torqued
Aero Solus action
Aero 6mm creed barre
Trigger tech diamond
Krg bravo
Berger 105s H4350

At 1000 I’d be 4/10 for hits on 6 creed and 6.5 I’d be 9/10.

Wondering if anyone has ever had a barrel that just wants to be a 100 yard barrel lol

Always considering myself as the issue but I will also point out I swapped barrel on same action to 6.5 proof and was consistent with it, same targets same day etc


Swapped barrel back and still very inconsistent hits. Also tried 6 creed barrel on another action with no change.

Thanks for any advice

 

[oldrifleman]

So the issue follows the barrel?

 

[Usaf197]

So the issue follows the barrel?

Yes and with multiple loads.

All seem promising at 100 but at 800-1000 it’s inconsistent

 

[oldrifleman]

What twist is the barrel? How many rounds down the tube?

 

[FisherT&C]

Did you true your velocity at 600 and your BC at 1000? The rifle may be a 3-4 mile per hour gun at 1000.

 

[Usaf197]

What twist is the barrel? How many rounds down the tube?

1:7.5 and approximately 400

 

[oldrifleman]

Sounds good, what’s you muzzle velocity?

 

[Usaf197]

Sounds good, what’s you muzzle velocity?

3050 fps

 

[FUNCTIONAL]

Had this happen with 1 particular bullet. Was the tightest at 100 (nearly a single hole) but I couldn't hit a boat at 800+ . Just stopped using the bullet.

You said multiple loads but does that mean charge weights or bullets too?

 

[Usaf197]

Had this happen with 1 particular bullet. Was the tightest at 100 (nearly a single hole) but I couldn't hit a boat at 800+ . Just stopped using the bullet.

You said multiple loads but does that mean charge weights or bullets too?

I’ve used 3 bullets with different charge weights, 1 was 1.5-2 moa at 100 yards. I stopped trying it.

The other 2 grouped great at 100 but bad at distance

 

[OREGUN]

are you missing at 1000 to the left and right or high and low or all over the place?

 

[oldrifleman]

At this point I am leaning towards the conclusion that there is something amiss in the barrel. As to what not sure, maybe @Frank Green has seen this before.

 

[FUNCTIONAL]

I’ve used 3 bullets with different charge weights, 1 was 1.5-2 moa at 100 yards. I stopped trying it.

The other 2 grouped great at 100 but bad at distance

Mind listing the bullets? I'd be curious

 

[Frank Green]

At this point I am leaning towards the conclusion that there is something amiss in the barrel. As to what no sure, maybe @Frank Green as seen this before.

So my random thoughts....

Only tried Berger? If so try a different bullet / different brand of bullet and see how they fly.

Three things guys... bullet, barrel, powder... they have to work together. The barrel might not like the bullet/load.

Just because your SD's and ES are really nice that doesn't guarantee great accuracy. Usually I'll say it does but it's not a guarantee.

Old saying, "short range accuracy doesn't necessarily mean long range accuracy" Do all your long range testing at 500 yards or further. That will tell you if your system is working or not.

Aero barrels are button rifled. Button barrels tend to be more temperamental / picky as to the load and bullet they will shoot. This is due to uniformity of the twist possibly being an issue or bore and groove size dimensions. Your twist might not be a consistent/uniform 7.5 or it could be starting out at 7.5 but have a negative twist and not be 7.5 at the muzzle. I've seen button barrels where the twist was as much as .75 slower at the muzzle.

How is the barrel for fouling?

Does it do it hot or cold or both for the accuracy to go sour/not hold? Again barrel temp as it changes if the blank has a lot of residual stress in it could be wandering/drifting on you.

Are the light/wind/range conditions screwing with you? You reading the wind good? Light conditions not messing with you? Just seen classic examples of this a couple of weeks ago at F class champs. First two days shooters had not ideal conditions... some right away blame the gun/barrel/ammo/bullets etc... but then the same shooters who were struggling the last two days conditions are a lot nicer and with the same set up go from shooting low 190's to shooting high 190's and even cleaning the target.

Scope tracking and holding zero? If it's holding zero at a 100 it should at distance. Have you tried a different scope just to rule it out?

Later, Frank
Bartlein Barrels

 

[jbuck88]

If I understand you are shooting a 20" plate at 1000yds. Your SD of 12 is going to eat up at least 7" of that. Plus 10 for your moa at 100yds target size, you said sub moa so I rounded up.

So now your at a base of 17" before you add in any mechanical, fundamental, or environmental influences. 3" is not a lot to work with at 1,000yds

 

[Frank Green]

If I understand you are shooting a 20" plate at 1000yds. Your SD of 12 is going to eat up at least 7" of that. Plus 10 for your moa at 100yds target size, you said sub moa so I rounded up.

So now your at a base of 17" before you add in any mechanical, fundamental, or environmental influences. 3" is not a lot to work with at 1,000yds

Good point... I forgot about the velocity spread and even though say 15fps doesn't sound like much... it adds up on the target down range.

Also I forgot to mention with conventional style rifling or if the rifling is damaged at all but not causing any bullet failure if it's putting any burrs on the bullet jacket etc..I now have data with a high pressure ammo/high velocity it can cause the bc of the bullets to vary as much as 5%. Didn't happen with 5R rifling.

5% doesn't sound like much and you won't see it bad at short range but extend the range and it will show up on the target.

 

[Usaf197]

Mind listing the bullets? I'd be curious

Hornady 103x
Hornady 105 bthp

 

[308pirate]

New hiccup for me, hopefully it’s a relatively common occurrence.

BLUF; consistent sub moa 100 group. Very inconsistent hits at 1000. Stand deviations around 12 and acceptable ES. 2 moa target at 1000 (20”)

Any thoughts on where to start for trouble shooting?

Set up: vortex viper 5-25 properly torqued
Aero Solus action
Aero 6mm creed barre
Trigger tech diamond
Krg bravo
Berger 105s H4350

At 1000 I’d be 4/10 for hits on 6 creed and 6.5 I’d be 9/10.

Wondering if anyone has ever had a barrel that just wants to be a 100 yard barrel lol

Always considering myself as the issue but I will also point out I swapped barrel on same action to 6.5 proof and was consistent with it, same targets same day etc


Swapped barrel back and still very inconsistent hits. Also tried 6 creed barrel on another action with no change.

Thanks for any advice

It couldn't be your marksmanship ability...........of course not.

 

[Frank Green]

Hornady 103x
Hornady 105 bthp

I haven't shot the 103's at all. This is no knock on Hornady as I do like they're stuff. The 105bthp are a good bullet I'll say out to 600 yards. After that? Brady here has shot them across the course and out to a 1k yards and he struggled with them past 600.

Shoot some 108AMAX's and some 107SMK is what I'd be trying before you give up on the gun.

 

[OREGUN]

Although I tend to think it’s not the equipment, per se, I’d be trying some different bullets.

 

[Usaf197]

It couldn't be your marksmanship ability...........of course not.

I did state that I don’t doubt it could be me lol

Just interesting that a different rifle, or just a different barrel and the issue didn’t exist

 

[Dirty D]

…. Stand deviations around 12 and acceptable ES…

At a class a few years ago at 1200 yards my rounds were bracketing the target 10-15’ long and short, windage was dead on so I threw my Magnetospeed on and was getting an SD of 20. An SD of 12 doesn’t sound like much and isn’t much at 100 yards but is a lot at 1200. The instructor (a retired SOTIC instructor among other things) said that USASOC was really struggling to find ammo vendors that could load ammo with single digit SD’s. Your issue may or may not be your SDs but 12 isn’t helping that far out.

 

[OREGUN]

I’m not sure I put too much faith in the SD argument for missing several feet high and low. If the SD is twelve, 99+% of the shots are within .4 MOA of the average at 1000 yards (+/- 36 fps, using a 109 lrht at 2830 for reference).

We still could learn something from knowing where you are missing. Side to side or up and down?

 

[6brshooter]

I did state that I don’t doubt it could be me lol

Just interesting that a different rifle, or just a different barrel and the issue didn’t exist

And bullet/load....don't forget that important aspect.

 

[FUNCTIONAL]

Try the 107smk .020" off the lands. I've yet to not have a smk shoot exceptionally.

For the transparency it was a hornady bullet that wouldn't hold for me either.

 

[Emerson0311]

What happens between 100 and 1000? A group at 400/600/800 on paper would fill in the blanks.

 

[308pirate]

Standard deviation is useless without the range (aka ES) and the average MV.

Math has this weird thing that works only one way despite opinions to the contrary

 

[Maurygold]

Standard deviation is useless without the range (aka ES) and the average MV.

Math has this weird thing that works only one way despite opinions to the contrary

12 sd is informative enough to know there isnt an SD issue here.

Sounds like a barrel or bullet issue. try a berger

 

[Holliday]

I did state that I don’t doubt it could be me lol

Just interesting that a different rifle, or just a different barrel and the issue didn’t exist

Don’t mind 308pirate. He’s the resident “Science Bitch!!” guy. He takes the “Bitch” part very seriously…….

 

[308pirate]

12 sd is informative enough to know there isnt an SD issue here.

The village idiot proves my point

 

[jbuck88]

Standard deviation is useless without the range (aka ES) and the average MV.

Math has this weird thing that works only one way despite opinions to the contrary

While I agree with you. The SD of 12fps means the average of the shots are + or - 12fps from the average velocity? So i was assuming the 24fps difference in velocity for a average verticle dispersion in inches. We have the average of 3050fps.

The ES is going to give truer vertical spread.

Its been way too long for me to remember, and the younger kids are there yeti math.

 

[morganlamprecht]

68% of shots will fall inside +/- 1sd from the average
96% +/- 2sd
99% +/- 3sd


but i dont think a 12sd is the driving issue either

OP, are you shooting steel? is it square or round? Freshly painted enough to see all impacts? If not, are you properly judging impact locations?

one occurrence that happens to people often is they hit steel so they dont adjust...they may hit with a follow up...then they miss with same hold...may miss again...end up hitting well below what their expected precision "should" be and the only issue is their dope/group isnt centered on the plate...circles and diamond shaped plates make it worse (vs squares) if you arent centered. they actually shoot a decent group, its just only 1/2 centered on the plate...

if shooting at a 2moa circle and your 1k dope is 1/2moa low, your vertical error budget on the low side reduces and wind error budget also shrinks in each direction

hitting more consistently with the 6.5 barrel could simply be from having the dope more accurately centered on the plate

if youre seeing all impacts and are centered best you can manage with the group size youre getting then the other suggestions have already been made above...hard to believe a berger shooting sub moa at 100 wouldnt make the trip to 1k tho...never personally seen that

 

[jbuck88]

Thanks. That's kinda what I remember.

I don't think it's a driving issue. I was just making the point it's helping to shrink the target so to speak. It all adds up at 1000yds.

 

[308pirate]

While I agree with you. The SD of 12fps means the average of the shots are + or - 12fps from the average velocity?

Not even close.

I don't have time to teach basic statistics. But @morganlamprecht did.

 

[LRShooter101]

First let me start by saying that there could be several components that could produce this result, many of them have been mentions here. One that has not been mentioned, bullet damage. How consistently/well your bullet performs further down range, can be impacted on how bad the bullet is damaged as it transitions down the barrel. Given that you are running a "fast" twist at near 3,000 fps, my guess is that the bullet could be sustaining damage. That damage may not significantly impact a 100 yard group, but it can significantly impact long range performance. When the bullet is damaged transitioning through the barrel the damage caused to it (engraving, jacket twisting, etc.) will change the BC of the bullet. That damage may also not always be consistent based on the barrel condition and bullet construction. This means that you are ultimately shooting bullets that have variations in BC. Needless to say a BC variation, like a muzzle velocity variation, will show up more the longer the bullet travels. There is some research/data on this out there, but IMHO this is a poorly understood component of long range performance.

 

[jbuck88]

This is interesting.

So we know the average speed of 3050fps and a SD of 12.

Is it not a close guesstimate to assume? Not perfect, but ballpark numbers.

68% of shots fall between 3038 and 3062fps (~6" vertical)
28% (96%-68%) fall between 3026-3028fps and 3062-3076fps (~12" vertical)

With the first 10" of a 20" target are lost being a 1 moa gun.

So just based on the gun and ammo. For the sake of understanding there is zero wind, fundamentals are perfect and zero mechanical influences

68% of the shots are going to land in a 16" group
28% are going to be between 16" and 22"

Am I way off?

 

[Cody S]

try berger 105 or 109 hybrids, or DTAC 115, or hornady atip. those 4 have been the most consistent forgiving long range bullets and have worked in every 7.5 twist for me, except I've not personally tried the atip yet.
eldm did decent at longer ranges.