AI AT Elevation issues at 1000yards?

[B52engmech]

So after a few matches, im noticing my AI AT in 308 is having some elevation issues... my load is 190 gr smk, 43gr varget, cci br2 primers, nosler brass, 2.85 oal. The bolt for the quickloc is torqued to 65inlbs as I got the best repeatable POI at that setting. My SD and ES for that load is 3 std and 8 es. Honestly I'm not sure what it could be. Could it be the clamp in the quickloc system just getting stretched at that torque spec? I'd check every bolt on the rifle and they are all nice and tight.

 

[TheBigCountry]

What’s an elevation issue?

 

[b6graham]

what sort of elevation issues? up and down? just up or just down? random or consistent?

also SD and ES can't be the same value just an fyi

 

[diggler1833]

By elevation issues, are you referring to vertical stringing (impacting high and then low) on the target?

 

[B52engmech]

what sort of elevation issues? up and down? just up or just down? random or consistent?

also SD and ES can't be the same value just an fyi

Sorry yeah I typed this up half asleep. Fixed it.

 

[Frank Green]

Is the POI changing at short range also?

Try a different scope?

Long range... what are the light, environment conditions? Was it just that one day or is it doing it on different days? Wind... tail wind, head wind?

 

[B52engmech]

So after a few matches, im noticing my AI AT in 308 is having some elevation issues... my load is 190 gr smk, 43gr varget, cci br2 primers, nosler brass, 2.85 oal. The bolt for the quickloc is torqued to 65inlbs as I got the best repeatable POI at that setting. My SD and ES for that load is 3 std and 8 es. Honestly I'm not sure what it could be. Could it be the clamp in the quickloc system just getting stretched at that torque spec? I'd check every bolt on the rifle and they are all nice and tight. View attachment 8412755

The issue I'm having is at between 500 and 1000 yards my elevation changes up and down between half a minute to a full minute.

 

[B52engmech]

Is the POI changing at short range also?

Try a different scope?

Long range... what are the light, environment conditions? Was it just that one day or is it doing it on different days? Wind... tail wind, head wind?

Wind is 80% of the time is left to right. Always the same time of day. From 8am to 1130am. I've tried different scopes. From my march 2.5-25, to my nx8, and nxs. All the same poi changing. And 500-1000 yards

 

[morganlamprecht]

if the quick lock was the issue youd see it at any/every distance

ive ran my AT quicklock at 65 in lbs since 2014...no issues, and i know of 5+ others the same

the quicklock would be the least of my concern

 

[b6graham]

mirage?

how are you confirming the elevation? is this on steel during a match and/or from a prop? or prone slow fire?

is the elevation off a consistent .2 at 500, .4 at 800 etc? or is it shot to shot high then low?

 

[TheOE800]

Recoil management?

 

[Frank Green]

Wind is 80% of the time is left to right. Always the same time of day. From 8am to 1130am. I've tried different scopes. From my march 2.5-25, to my nx8, and nxs. All the same poi changing. And 500-1000 yards

Got it! Just need to rule stuff out one thing at a time.

So.... how many rounds on the barrel?

How many rounds fired in between cleanings?

Any fouling issues with the barrel? If your SD's are that low and velocity is consistent I'll say no but have to ask.

 

[B52engmech]

mirage?

how are you confirming the elevation? is this on steel during a match and/or from a prop? or prone slow fire?

is the elevation off a consistent .2 at 500, .4 at 800 etc? or is it shot to shot high then low?

Slow rate of fire, prone. 5 shot strings at steel . And no not consistent at all with it being off.

 

[B52engmech]

Got it! Just need to rule stuff out one thing at a time.

So.... how many rounds on the barrel?

How many rounds fired in between cleanings?

Any fouling issues with the barrel? If your SD's are that low and velocity is consistent I'll say no but have to ask.

Barrel has 250 rounds down the barrel. I clean every 75 ish rounds. And no fouling issues. Scoped it and it's a beautiful barrel.

 

[hafejd30]

What’s your group during load testing look like? Could that be just what the ammo has for a vertical dispersion

What Frank Green said above would be my next thoughts

 

[Frank Green]

Barrel has 250 rounds down the barrel. I clean every 75 ish rounds. And no fouling issues. Scoped it and it's a beautiful barrel.

Well then I'll say we rule out the barrel and scope.

Unless you have muzzle crown damage (double check the edge of the crown)... which could effect accuracy but won't effect your SD's... then it's something mechanical going on somewhere....but what?

I'm running both a 308win and a 6.5CM barrel on my AIAT.... no issues with anything.

You talk to AI at all?

Just throwing mud at the wall now to see if anything sticks.

Later, Frank
Bartlein Barrels

 

[Secant]

An SD of 3 will not equal an ES of 8, so I’m assuming you are using pretty small samples. I’d shoot 7-10 rounds on paper at 100 yards then do the same at distance while chrono’ing all rounds.

 

[kthomas]

I know people hate hearing this, but...

The issue could very well be with the shooter. Specifically, your rear bag technique/fundamentals. .308 certainly has enough recoil to really exploit any flaws, especially if you aren't using any muzzle device to help mitigate recoil.

I too experienced vertical issues with my .308. It wasn't the equipment or the rifle, it was my technique, which had gotten pretty lazy after thousands of rounds of 6mm and 6.5mm cartridges. You can get a way with a lot in those cartridges that can present issues with .308 and larger.

I corrected this issue by correcting my technique. This was through adopting @Enough Said's rear back technique, specifically what's outlined in this article: https://www.snipershide.com/precision-rifle/the-taylor-was-here-rear-bag/

This may be what's happening to you:

You have become accustomed to compromising the rear bag in search of an outcome. The buttstock often sinks in the rear bag when you should be adjusting your bipod legs higher as we move down range. You create an angle with the bag in the form of a “hinge” created by leaning the rear bag fore or aft. That hinge gets exploited by recoil and the butt stock sinks at the shot. You have not achieved a proper relationship between the buttstock and your shoulder because you have been compromising. that vertical stringing you sometimes have? Well, there you go. That vertical stringing you sometimes have… well there you go.

 

[blindspotter]

Based on the TP video I'd say fundamentals and rifle/bipod/bag setup would be the first things to examine. You may want to consider higher rings and a higher setting on the bipod so you can get more rear bag under the buttstock. Not saying that's definitely the issue just something to look at.

 

[B52engmech]

An SD of 3 will not equal an ES of 8, so I’m assuming you are using pretty small samples. I’d shoot 7-10 rounds on paper at 100 yards then do the same at distance while chrono’ing all rounds.

Here's my last from just fouling the barrel before a match. I said 3 and 8 because it was the average out of my last 15 shot group

 

[B52engmech]

Well then I'll say we rule out the barrel and scope.

Unless you have muzzle crown damage (double check the edge of the crown)... which could effect accuracy but won't effect your SD's... then it's something mechanical going on somewhere....but what?

I'm running both a 308win and a 6.5CM barrel on my AIAT.... no issues with anything.

You talk to AI at all?

Just throwing mud at the wall now to see if anything sticks.

Later, Frank
Bartlein Barrels

Haven't talked to AI yet. It won't be for awhile before I can get back out to the range. I plan on switching barrels to see if I have a problem with the factory walther barrel as well. But then again that changes alot of variables to include load data, barrel twist, and even barrel contour. And I might just try a new bag as well

 

[B52engmech]

Based on the TP video I'd say fundamentals and rifle/bipod/bag setup would be the first things to examine. You may want to consider higher rings and a higher setting on the bipod so you can get more rear bag under the buttstock. Not saying that's definitely the issue just something to look at.

Yeah, never been a fan of not having something to apply pressure against with the bipod. And the way it was set up, there was somewhat level ground. Haha. Wasn't ideal. But at regular matches we shoot off of a deck that has a 2x4 we can apply pressure with the bipod.

 

[Chris1972]

Odd man here. I’d say your flirting with stability issues with that bullet and velocity.

 

[jbuck88]

We all know the wall is at 800yds for the 308win. So shooting past that is impossible.

But for under 800yds. Looks like your stability should be ok. Your barrel looks like it is marked 1/10 not 1/12. And based on your ballistics you should be Trans sonic just past 1000yds. So should effect anything sub 800yds.

I am going to punch the easy button and say recoil management. Your only talking .5 to 1 moa shift up and down. That's not that much. If I shot a group at 1000yds with .5moa of vertical I'd be happy.

 

[Nik H]

Haven't talked to AI yet. It won't be for awhile before I can get back out to the range. I plan on switching barrels to see if I have a problem with the factory walther barrel as well. But then again that changes alot of variables to include load data, barrel twist, and even barrel contour. And I might just try a new bag as well

Have you tried shooting FGMM 175 grain to see if it produces the same result?

 

[Shoots 700's]

what size targets? Can you hold the .3 tenths difference? Mirage?

 

[B52engmech]

Have you tried shooting FGMM 175 grain to see if it produces the same result?

I can't get factory gold medal match out to 1k yards here. No where close to being accurate. My older 1/12 twist barrel got the 155 palmas out to 1k yards perfectly fine. Been considering going back to it

 

[B52engmech]

what size targets? Can you hold the .3 tenths difference? Mirage?

1 moa targets at 1k yards and .5 moa targets at 1k yards

 

[Shoots 700's]

10 and 5 inch plates at distance is sporty. Can the rifle hold MOA or better all the way out?

 

[308pirate]

I know people hate hearing this, but...

The issue could very well be with the shooter.

Nah there's no way it can be that....LOL

 

[308pirate]

I can't get factory gold medal match out to 1k yards here. No where close to being accurate. My older 1/12 twist barrel got the 155 palmas out to 1k yards perfectly fine. Been considering going back to it

Any acknowledgement that it could be your skill that is lacking?

 

[FUNCTIONAL]

1) try a different bullet. Shot 130gr eldm bullets in my 6.5x47 extreamly well but fell apart at 700 and further. Some just don't want to work in some guns

2) are you loading the bipod consistently? That could effect your elevation even with everything else being perfect.

3) you said between like 8 and 1130. In my experience that is the time when mirage starts coming around. With mirage typically starting mild, a little gust of wind could be laying it down and taking away the issue and then when wind lays down you have it again. Would explain the inconsistencies.

@Frank Green I knew you were a special man of culture...running an AT.

 

[Nik H]

I can't get factory gold medal match out to 1k yards here. No where close to being accurate. My older 1/12 twist barrel got the 155 palmas out to 1k yards perfectly fine. Been considering going back to it

Very strange...

I have shot my AT with its original barrel (LW 1:12 twist) using FGMM 175 to 1,000 many times without any issues. Now I have a 26" 1:10 twist and it is even better. I admit that it isn't as easy as shooting 6.5 CM to that distance but to say FGMM is not accurate enough is ridiculous.

I am sorry but at this point, I would focus on your fundamentals versus thinking it is anything to do with the rifle.

 

[Nik H]

Any acknowledgement that it could be your skill that is lacking?

Exactly

 

[Shoots 700's]

What speed are you running the 190's Again, I think its the shooter and expecting to consistently hit a .5 moa target

 

[trophyhunter]

What kind of groups do you get at 100, 200 or 300?

 

[Frank Green]

I can't get factory gold medal match out to 1k yards here. No where close to being accurate. My older 1/12 twist barrel got the 155 palmas out to 1k yards perfectly fine. Been considering going back to it

Twist has nothing to do with it.

The only thing where the twist is important is that it is fast enough to stabilize the bullets you are shooting.

You can shoot the 155's thru an 11 twist or a 10 twist and will be just fine. Your spin drift might be a tad more than a 12 twist but that's going to be it.

 

[TheOE800]

Recoil management?

 

[NoLegs24]

Did you just reply to yourself?

 

[TheOE800]

Did you just reply to yourself?

this shit was solved 10 posts in

 

[Rio Precision Gunworks]

So, pretty easy to figure out if this is a non shooter issue. And you can do it at 100yds.

Fire 20rnds using a chrono that isn't attached to the barrel. Do it in strings of 3 or 5 shots and don't let the barrel get ridiculously hot.


Report back with picture of the group with something to reference size (grid or a ruler next to the group) and the average velocity and SD for the 20rnds.

 

[Rio Precision Gunworks]

Also, you shouldn't need anything to press the bipod into. That statement alone likely means this is a recoil management/fundamental issue.

 

[diggler1833]

I know people hate hearing this, but...

The issue could very well be with the shooter. Specifically, your rear bag technique/fundamentals. .308 certainly has enough recoil to really exploit any flaws, especially if you aren't using any muzzle device to help mitigate recoil.

I too experienced vertical issues with my .308. It wasn't the equipment or the rifle, it was my technique, which had gotten pretty lazy after thousands of rounds of 6mm and 6.5mm cartridges. You can get a way with a lot in those cartridges that can present issues with .308 and larger.

I corrected this issue by correcting my technique. This was through adopting @Enough Said's rear back technique, specifically what's outlined in this article: https://www.snipershide.com/precision-rifle/the-taylor-was-here-rear-bag/

This may be what's happening to you:

^This issue was solved with post #18 above.

I've done it too. Cheap rear bags with decent fundamentals, or good rear bags with mediocre fundamentals will induce the same thing...vertical stringing.

Relaxing or tightening the grip on your rear bag plays a role in the recoil impulse (specifically the downward motion of the butt end of the stock/chassis), and the more recoil present the more the effect will be. It isnt a lot...probably .5 - 1 MOA's Worth as most if the recoil is rearward. Not all of it though.

If no bags are used and the rifle is shot tightly slung...then it's a breathing issue. I doubt that's what we're seeing here though.

 

[FUNCTIONAL]

@diggler1833 @kthomas my only issue with just blaming position is he said it only happens from 8-1130am. If he's hitting after that it sounds more like an environmental consideration he's not accounting for.

Possible it's a combo but the timeframe leads me to environmental.

 

[Rio Precision Gunworks]

I missed the part about the timeframe. It's very possible that he zero'd the rifle in a part of the day that had far different lighting conditions.

Environmental lighting is something thats is very overlooked but is the culprit of a lot of "weird stuff."

 

[Emerson0311]

I missed the part about the timeframe. It's very possible that he zero'd the rifle in a part of the day that had far different lighting conditions.

Environmental lighting is something thats is very overlooked but is the culprit of a lot of "weird stuff."

I read that this was the time he was at the range, not that shooting later in the day was more accurate.

 

[FUNCTIONAL]

I read that this was the time he was at the range, not that shooting later in the day was more accurate.

That's possible too.

This is going to end up like a tootsie pop.... the world may never know.

Need more input from OP.