.338 Lapua Short Range Stability?

[Andrevski762]

Quick question about ballistics. I think I've either confused myself or misread what people have been saying.

I've seen several people hint or outright say that the .338 LM isn't meant for 100 yd groups as the bullet doesn't stabilize until _____ (insert range, seems to be 300 yds normally). This doesn't make sense to me.

If a gun is capable of shooting .5 MOA at 500-1000 yards, how is it ballistically possible that it could be shooting worse than this at 100-300? The implication to me is that the paths of the bullets are more erratic at short range as the bullet isn't fully stabilized. But extrapolate this, are people then thinking that somehow the bullets stabilize and magically get back in line with each other beyond 300?

MOA is an angular measurement, so unless bullets are being guided back to line-of-aim it is physically impossible for a group to be smaller (in an angular sense) at longer ranges than shorter ranges, at least repeatably.

Sorry for the rambling nature of this, I am just a very visual person and trying to convey what it is I am seeing in my mind. What is the story behind people saying .338 LM is not so great at 100?

Thanks!

 

[mdavlee]

Re: .338 Lapua Short Range Stability?

I had round holes at 25 yards and 100 yards when I sighted mine in the first time. I've not seen any key holes in the cardboard at distances out to 200. I shoot at steel out farther than that so I can spot the hits easier.

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

Drew, that is a fair question. I've experienced this myself, albeit totally unscientifically, where at 300-400 yards groups were somewhat larger than expected, but then I would get much smaller groups (wrt MOA, not absolute dimensions) at distances past 1000 yards. So having read same claims about 338LM bullets stabilizing with distance, I started trying to understand how mechanically this could be take place.

The only explanation I could see is that after some distance gyroscopic stabilization overcomes some initial very slight wobble, precession, or orientation (wrt flight path) in the earlier distances.

Once the bullet leaves the barrel, gravity and air friction seem to be the only forces acting on the bullet, and maybe gyroscopic effect could also be considered a force. But there is these transitional phase force right as the barrel and bullet depart each other: http://en.wikipedia.org/wiki/Transitional_ballistics
Perhaps the spin stabilization takes a moment to smooth out these initial random variations, and this moment is all it takes to reach past 300-500 yards.

I realize this is a squishy explanation, and there is likely a more rigorous explanation, but I haven't come across any on your question. Would be interested in THE answer if someone had it. Having read Litz book I didn't come across anything as far as I can recall.

 

[George63]

Re: .338 Lapua Short Range Stability?

the bullet comes out of the barrel starts to tumble, remembers that the barrel was rifled, so starts to spin, stabilizes and travels 1800yds before it destabilizes again


there - now I can pull up this same reply every month when this same thing gets rehashed

read the Litz book - he had no good explanation so do not expect any

In statistics they tell you data collected with too small of a sample size (or a host of other issues) is unreliable

so test this using scientific methods, and a sufficient sample size before considering it to be a legitimate phenomenon

As far as this:

"What is the story behind people saying .338 LM is not so great at 100?"

6BR will win BR matches at 100yds - 338 LM will not

 

[CoryT]

Re: .338 Lapua Short Range Stability?

Until someone shoots larger angular groups at close range and a smaller group at long range WITH THE SAME SHOTS (using acoustic targets for example), this remains purely anecdotal.

It's most likely traced to things like bad parallax adjustment, lack of concentration at the closer range, etc., than an actual condition. I for one do not believe the phenomenon exists except in some peoples imagination.

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

I can equally accept Cory's point of view.

 

[Lowlight]

Re: .338 Lapua Short Range Stability?

A 6BR wins because the 338 recoils more, most can't handle it.

 

[frankythefly]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">A 6BR wins because the 338 recoils more, most can't handle it. </div></div>
That and most who shoot the 6br shoot it like this:

vs. most who shoot the .338 Lapua shoot it like this:

Note:I stole the above picture from 6mmbr.com and what is the point of a "light gun"(17lbs) when you are just going to mount it on a concrete bench on top of a 50lbs rest?

 

[one shot ST]

Re: .338 Lapua Short Range Stability?

these are 2 5 shoots groups, Sako .338 LM on XLR chassis, distance 100 m, load scenar 250 N165 90.5 gr, AOL to fit mag.
rainy day

shooting position prone with LRA bipod and rear bean bag

 

[frankythefly]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: davide</div><div class="ubbcode-body">these are 2 5 shoots groups, Sako .338 LM on XLR chassis, distance 100 m, load scenar 250 N165 90.5 gr, AOL to fit mag.
rainy day

</div></div>
Nice shooting! Have you chronograph this load? Some may say it is a factor of velocity.

But I am also curious as I would like to try some of the N165 and the N570 in my Sako as well..

 

[one shot ST]

Re: .338 Lapua Short Range Stability?

yes, with PVM-08 AVG on 10 shoots 905 m/s SD 2.8

 

[Whit]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: davide</div><div class="ubbcode-body">these are 2 5 shoots groups, Sako .338 LM on XLR chassis, distance 100 m, load scenar 250 N165 90.5 gr, AOL to fit mag.
rainy day

shooting position prone with LRA bipod and rear bean bag

</div></div>



Did you have a different bolt handle put on, it doesn't look like a factory bolt knob?

 

[one shot ST]

Re: .338 Lapua Short Range Stability?

I dont't know, the rifle is not mine, I did for him only the zero..

 

[BryanLitz]

Re: .338 Lapua Short Range Stability?

Here's my take on it:
http://appliedballisticsllc.com/epswerve.html

Major conclusion based on modeling:
The phenomenon of smaller angular groups at longer ranges was not disproven. The only thing I've shown is that if the phenomenon actually happens, epicyclic swerve is not the cause of it.

-Bryan

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

Davide, you are getting an SD of 2.8 on a sample of 10 trials? In my experience that is really tight.

I tried 250 and 300 Scenars but settled on slightly better performance for 300 at mile distance. However I had another experienced 338LM shooter suggest the opposite. What have you found?

p.s.
When I have run into the OPs phenomenon of short range stability, it was not at 100 yards where grouping is always <1MOA, but at like 300-400 yards. But as Cory suggests, we can't tell that for those 300-400 yard bad groups that the 100 yard or 1000 yard groups would have been better.

 

[frankythefly]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">Davide, you are getting an SD of 2.8 on a sample of 10 trials? In my experience that is really tight.

I tried 250 and 300 Scenars but settled on slightly better performance for 300 at mile distance. However I had another experienced 338LM shooter suggest the opposite. What have you found?

p.s.
When I have run into the OPs phenomenon of short range stability, it was not at 100 yards where grouping is always <1MOA, but at like 300-400 yards. But as Cory suggests, we can't tell that for those 300-400 yard bad groups that the 100 yard or 1000 yard groups would have been better.
</div></div>

You must remember that he is using metric system. 2.8m/s = ~9.2 fps, still very good. I usually aim for SD of less than 10fps.

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

yeah good point... I am in low to mid teens for SD.

 

[bm11]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">A 6BR wins because the 338 recoils more, most can't handle it. </div></div>I know that this is the case for me. I have recoil anticipation issues that I just don't get with heavy suppressed .260.

I like shooting my 338 and I certainly am not afraid of it, but subconsciously I can't help but flinch.

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

There are exercises to eliminate or reduce flinch... we were trained to have a partner feed our chamber with live and spent cartridges, mostly spent ones, and you keep doing that until your live shots are flinch free. That's after alot of dry firing empty to eliminate flinch. I think it was called the ball and dummy round drill.

Finally we were advised to wear a bit of padding to reduce recoil and tendency to flinch.

 

[psinclair]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CoryT</div><div class="ubbcode-body">Until someone shoots larger angular groups at close range and a smaller group at long range WITH THE SAME SHOTS (using acoustic targets for example), this remains purely anecdotal.

It's most likely traced to things like bad parallax adjustment, lack of concentration at the closer range, etc., than an actual condition. I for one do not believe the phenomenon exists except in some peoples imagination. </div></div>

Totally spot on....

 

[Lowlight]

Re: .338 Lapua Short Range Stability?

This comes down to the <span style="font-style: italic">"Human Element"</span> which is sometimes missing when talking about various effects downrange.

When we talk about things that computers will predict will happen, understand it does not have a way to measure the <span style="font-style: italic">"human element"</span> with that shot. So it is giving you the raw data, we have the ability to skew that data in a big way.

Can you have a shooter that gets 1 MOA Groups at 100 and 1/2 MOA groups with the same rifle and ammo combination at say, 600 yards... of course you can. But like Cory has stated, having it happen from the same shot is something else completely.

Run the shots through two targets at the same time, one close, one far, especially if you think the groups downrange should be better, if they are poor at 100 they are not gonna tighten up at 600 yards. But you can mentally compensate whether you realize you are doing it or not.

In my observations, what I have noted is, people focus too much as what they can see and will subconsciously react and adjust. However take that same person and limit the data being fed to their brain and they will get a different result, sometimes for the better. By limiting the information to the brain, we are no longer reacting to what we see.

You can see the impacts at 100 and not at 600, so holding center and shooting is different from seeing what might be perceived as a flier, hence causing the shooter to react differently. Here is my example, I was Target # 7 :

I held center on this target during a competition, it was a "dirty group" shot at the end of the day. Quartering the target and firing my first shot was clearly low right, and inside I gasped. However I shut that part of my brain down and continued to hold center winning the dirty group event. Had I not shut down my feelings of being off center, I could have easily fallen into mental defeat, as my zero is clearly off center by some distance. But the group held by blocking that out.

I did it several times while competing over the years including at distance, here this target was shot at 600 yards in a 12MPH wind and I won that Group Shot event again,

When looking at this target, there as no way at 600 yards I saw the impacts, I basically made my adjustments and focused on quartering the reticle on target and not what my impacts looked like.

The <span style="text-decoration: underline">Human Element</span> is one of the reasons why, what should be science and work for everyone equally doesn't... We all release the shot at different points and are effected differently by the information we take into our brains.

 

[223ai]

Re: .338 Lapua Short Range Stability?

Frank -

You say "quartering the target". Are you dialing wind at distance on static shots (i.e. the 600 yard target above)?

Best,
JP

 

[Lowlight]

Re: .338 Lapua Short Range Stability?

No, I held wind but I still "quarter" the target based on the wind hold, that just becomes my center, so technically in that case I "1/2'd it"

Mentally I am still quartering...

 

[223ai]

Re: .338 Lapua Short Range Stability?

Got it, thanks.

 

[Starbuck]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frankythefly</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">A 6BR wins because the 338 recoils more, most can't handle it. </div></div>
That and most who shoot the 6br shoot it like this:

vs. most who shoot the .338 Lapua shoot it like this:

Note:I stole the above picture from 6mmbr.com and what is the point of a "light gun"(17lbs) when you are just going to mount it on a concrete bench on top of a 50lbs rest?</div></div>

LMFAO! Seriously, I appreciate this thead because I'm still working up my TRG-42 loads for the Oct 15-18 Gunsite ELR class. This shit is not easy, at least for me, so thanks to all the experienced folks who have weighed in on this...

 

[Km22]

Re: .338 Lapua Short Range Stability?

My .338 shoots better than a MOA at 100 yards. If you're getting a wide variation, does the bullet know it's intended path when it was 1" low or high or left or right at 100 yards... and then suddenly make up the difference at 600 yards?

 

[psinclair]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">This comes down to the <span style="font-style: italic">"Human Element"</span> which is sometimes missing when talking about various effects downrange.

When we talk about things that computers will predict will happen, understand it does not have a way to measure the <span style="font-style: italic">"human element"</span> with that shot. So it is giving you the raw data, we have the ability to skew that data in a big way.

Can you have a shooter that gets 1 MOA Groups at 100 and 1/2 MOA groups with the same rifle and ammo combination at say, 600 yards... of course you can. But like Cory has stated, having it happen from the same shot is something else completely.

Run the shots through two targets at the same time, one close, one far, especially if you think the groups downrange should be better, if they are poor at 100 they are not gonna tighten up at 600 yards. But you can mentally compensate whether you realize you are doing it or not.

In my observations, what I have noted is, people focus too much as what they can see and will subconsciously react and adjust. However take that same person and limit the data being fed to their brain and they will get a different result, sometimes for the better. By limiting the information to the brain, we are no longer reacting to what we see.

You can see the impacts at 100 and not at 600, so holding center and shooting is different from seeing what might be perceived as a flier, hence causing the shooter to react differently. Here is my example, I was Target # 7 :

I held center on this target during a competition, it was a "dirty group" shot at the end of the day. Quartering the target and firing my first shot was clearly low right, and inside I gasped. However I shut that part of my brain down and continued to hold center winning the dirty group event. Had I not shut down my feelings of being off center, I could have easily fallen into mental defeat, as my zero is clearly off center by some distance. But the group held by blocking that out.

I did it several times while competing over the years including at distance, here this target was shot at 600 yards in a 12MPH wind and I won that Group Shot event again,

When looking at this target, there as no way at 600 yards I saw the impacts, I basically made my adjustments and focused on quartering the reticle on target and not what my impacts looked like.

The <span style="text-decoration: underline">Human Element</span> is one of the reasons why, what should be science and work for everyone equally doesn't... We all release the shot at different points and are effected differently by the information we take into our brains. </div></div>

Frank, This is one of the most informative posts I've ever read on this site. Well stated!

 

[Kilmore]

Re: .338 Lapua Short Range Stability?

.338 Lapua mag target shot at 100 yards, shot 1 cold bore, shots 2-5 fired at six to eight minute intervals. Clean impacts on target.

 

[Layton]

Re: .338 Lapua Short Range Stability?

Consistent 7 o'clock hits.

 

[notme]

Re: .338 Lapua Short Range Stability?

Cory,
FWIW - I have seen the human factor affect precision time and time again in varying scenarios. Short range gives the brain more "flexibility" when compared to the concentration and greater precision needed to shoot the longer range. Therefore, the brain focuses more on the smaller inputs necessary to acquire greater precision.

 

[Lt. Arclight]

Re: .338 Lapua Short Range Stability?

Outstanding thread!!Well said.

 

[cali_tz]

Re: .338 Lapua Short Range Stability?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: notme</div><div class="ubbcode-body">Cory,
FWIW - I have seen the human factor affect precision time and time again in varying scenarios. Short range gives the brain more "flexibility" when compared to the concentration and greater precision needed to shoot the longer range. Therefore, the brain focuses more on the smaller inputs necessary to acquire greater precision. </div></div>

this is an interesting statement.

 

[Kilmore]

Re: .338 Lapua Short Range Stability?

Same rifle at 600 yards. Same left side impacts. The lefty flier was the cold bore shot. Maybe if I start carrying my willie to the left my shots will hit right? Just an idea.

 

[bm11]

Re: .338 Lapua Short Range Stability?

Looks like my .338 will shoot at 100 after all. Doing MORE load development yesterday and really took this thread to heart. I found that due to the recoil of the 338, I have to spend much more time on each trigger press to make sure I am not tensed up and adding pressure until the trigger breaks rather than involuntarily jerking it.

Here are the results, note that I had my 250 Scenar zero on the gun (they ended up shooting like shit no matter how hard I tried,) so these impacts are low because they are 300g Scenars:

Measures 0.350" CTC, 5 shot group.

 

[TrapperT]

Re: .338 Lapua Short Range Stability?

I have had no problems with the 300gr Hybrids (or any 300 grain bullet) shooting well at 100 yards. These groups were shot in order (bottom first, then adjusted scope and shot the top group).

And the accuracy has continued to hold well past 1000 yards.

 

[Noel Carlson]

Re: .338 Lapua Short Range Stability?

The points that Frank, and Cory, make are all valid... but non-linear dispersion has been observed under conditions which pretty much eliminate psychological, or statistical variation as a source.

This phenomena becomes more pronounces as caliber increases, which dovetails very nicely with a psychological model. The problem is that, in 50 BMG (for example), all that is needed to supress the effect is to switch from a jacketed bulled, or brass solid, to banded copper. This was noted at a range of 100 yards. The statistical argument is somewhat muted by the fact that the shooter is a multiple year national champion with 1,000+ round sampling in all three projectile types.

The moral of the story is that even after accounting for the legitimate critique given by Frank and Cory, and all the diagnostic simulations, you still have to be willing to believe what the bullet impacts tell you.

Sometimes the right answer is; "I don't know".

 

[jfields]

Re: .338 Lapua Short Range Stability?

I have some recent data points that I thought might be relevant to the discussion. I have been doing load development for a 110BA and what follows are my findings:

This is the target I used to zero at 100 yards after installing a new scope rail. After getting it dialed in on the top dot, I shot three times at the bottom dot to confirm. First two shots were in the same hole. Last shot was .27 inches low. You can see that the last zeroing shot was in the same location as the two that went in the same hole on the target below.

This is a target at 300 yards. I was doing a test to see if I could use some once fired brass that a friend had given me. I wanted to see if I could use my current load in his brass. I found out that his once fired brass was not as accurate with the load I had developed using Virgin Lapua brass. I made five shots with my virgin brass load. I adjusted 1/2 MOA after the first shot. This was not enough, obviously. I am still getting used to MOA vs Mils in my dad's scope. The holes with the box around them measure a little less than an inch. (.95) This is consistent with the 100 yard group at roughly 1/3 MOA.

This target is a 15 inch steel gong shot at 1410 yards. The center hit was the first hit on target. I shot 6 more times and had two more hits. All 4 misses went just off the left side of the target. The wind was not terrible, but would lull to almost nothing at times, causing me to push those shots left. This was my first time shooting past 1000, so I'm guessing a little more experience reading the wind would have kept more on target.

At any rate, for me at least, short range results seem to be translating to the longer distances.

The Weapon. Load is 300 grain Scenars over Retumbo in Lapua cases set .015 off the lands.

 

[V-Ref]

Re: .338 Lapua Short Range Stability?

I 1000% agree with these two posts.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CoryT</div><div class="ubbcode-body">Until someone shoots larger angular groups at close range and a smaller group at long range WITH THE SAME SHOTS (using acoustic targets for example), this remains purely anecdotal.

It's most likely traced to things like bad parallax adjustment, lack of concentration at the closer range, etc., than an actual condition. I for one do not believe the phenomenon exists except in some peoples imagination. </div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">This comes down to the <span style="font-style: italic">"Human Element"</span> which is sometimes missing when talking about various effects downrange.

When we talk about things that computers will predict will happen, understand it does not have a way to measure the <span style="font-style: italic">"human element"</span> with that shot. So it is giving you the raw data, we have the ability to skew that data in a big way.

Can you have a shooter that gets 1 MOA Groups at 100 and 1/2 MOA groups with the same rifle and ammo combination at say, 600 yards... of course you can. But like Cory has stated, having it happen from the same shot is something else completely.

Run the shots through two targets at the same time, one close, one far, especially if you think the groups downrange should be better, if they are poor at 100 they are not gonna tighten up at 600 yards. But you can mentally compensate whether you realize you are doing it or not.

In my observations, what I have noted is, people focus too much as what they can see and will subconsciously react and adjust. However take that same person and limit the data being fed to their brain and they will get a different result, sometimes for the better. By limiting the information to the brain, we are no longer reacting to what we see.

You can see the impacts at 100 and not at 600, so holding center and shooting is different from seeing what might be perceived as a flier, hence causing the shooter to react differently. Here is my example, I was Target # 7 :

I held center on this target during a competition, it was a "dirty group" shot at the end of the day. Quartering the target and firing my first shot was clearly low right, and inside I gasped. However I shut that part of my brain down and continued to hold center winning the dirty group event. Had I not shut down my feelings of being off center, I could have easily fallen into mental defeat, as my zero is clearly off center by some distance. But the group held by blocking that out.

I did it several times while competing over the years including at distance, here this target was shot at 600 yards in a 12MPH wind and I won that Group Shot event again,

When looking at this target, there as no way at 600 yards I saw the impacts, I basically made my adjustments and focused on quartering the reticle on target and not what my impacts looked like.

The <span style="text-decoration: underline">Human Element</span> is one of the reasons why, what should be science and work for everyone equally doesn't... We all release the shot at different points and are effected differently by the information we take into our brains. </div></div>

 

[JL]

Re: .338 Lapua Short Range Stability?

Talking about human element- after trying it in many courses with trainees, I am convinsed that "cold bore shot" error could be called to "cold shooter shot" in many cases.
Many times error can be reduced, even eliminated, by dry-firing rifles several times before actual cold bore shot.

 

[psinclair]

Re: .338 Lapua Short Range Stability?

Cold brain shot is what I call it.....I make my living connecting with cold bore shots.

Concentration, preparation and confidence leads to perfection.

 

[Andrevski762]

Re: .338 Lapua Short Range Stability?

Much thanks to all of you guys, it is great to have a place where one can ask a question and not just get wild theories based on anecdotal evidence but hard facts and experiences from the experts.

 

[GUNZ n AMMO]

Re: .338 Lapua Short Range Stability?

When my coworker mentioned about the .338LM or heavier recoiling rifles can only produce better shot groups at farther distances. Well, it became a heated discussion right away because there's really no clear explanation as to why the bullet behaves that way... The only explanation I can think of is the WIND.... a rifle is only as accurate as the marksman, and mis-reading wind calls affects shot groups down range but heavier bullets compensates for that. It sounds counter intuitive right? LMAO Anyway, for the same concept of "why in the hell a 1.5 MOA shot groups at 100 yards, can produce .5 MOA at 1000 yards? Well, I decreased my 338LM velocity and I shrunk the shot groups at 100 yards from .8 -1.5 MOA at 100 yards to .5 MOA average. I haven't done the 1000 yards yet, but I'll soon find out. But to think about comparing 100 yards vs. 1000 yards the error margin is not even fair to begin with because enviromental factors are a greater issue...

 

[oneshot.onehit]

Re: .338 Lapua Short Range Stability?

I still believe that what happens at 100 is only magnified at 1000 doesn’t matter if it’s a 338 Lapua or a 300 Win mag, etc.

Load development and the 338 Lapua is fairly easy to work with, this is probably why there is such a wide variance in what is accepted for overall accuracy down range.

Anything less than 1500 yards the 250 Scenars and 285 Hornady’s work well in comparison to the 300s the 300s tend to take over past 1500 yards.

My favorite, 300 gr. Scenars
We all have days that you except the shot for what it is, but for the most part my Barrett 338 Lapua Mag will run ½ to ¼ moa from 100 yards and to the extended distances unless I fail on my behalf to run the gun straight



oneshot.onehit