Help with my long range shooting

[buckbrush]

I have been shooting and reloading for 15+ years with the last 3 being devoted to long range shooting. I would guess that I shoot 6-700 rounds a year. I started with a 300 Win Mag that I still have. Since then, I have moved up to a 338 Lapua that I have been shooting for the past year. The farthest group I have ever shot was at 775 yards with the 300 Win Mag. It shot a 3 shot group that was a little over 2" and I was amazed to say the least. With my 338 Lapua, I shot a group at 400 yards that was a tad under 2" so I figured that load to be good as well. My ES for both loads is right around 12 fps.

Here is my issue. At 1000 yards out to 1650 yards (the farthest I have shot) my groups really seem to open up. They appear to be over MOA (like 1.5 or more) but really can't be measured since I just shoot at rocks at that distance. This shooting usually happens on nice calm days as well. I shoot with an Appleseed instructor who seems to think my technique is quite good but I have not thrown that issue out just yet. I don't believe recoil to be an issue since both guns are heavy and have breaks. I have quality glass on them (New IOR 6-24x56 and S&B PMII 5-25x56) as well as quality bases and rings. Both guns were professionally built and bedded.

When hand-loading, I don't do anything special like weight sort brass, bullets, etc. I shoot 208 A-maxes and 300 SMK's. I don't turn necks either. I just weigh each charge and seat the bullet and am done.

Am I missing a major reloading step that is causing my long range accuracy to fall off so noticeably at extended distances or do I need more practice?

Thanks.

 

[Tikkamike]

Well the first thing you need to do is shoot paper at those distances and see what you are actually getting. Secondly I would anneal your brass, when you got an ES of 12 fps was that with new or nearly new brass? as your brass work hardens your neck tension will start to vary and your spread will probably increase. Also are you positive you are adjusting ALL of the parallax out of your scope? those are the first things I would check/do. You will loose a degree of accuracy once you become sub sonic. Also the wind variable at that distance could be to blame. as you probably know the wind does a lot of crazy things in 1000-1650 yards and the slower your bullet gets the more the wind affects it.

 

[loosesniper2000]

+1 on all the above from Mike
I'll also add, that the MOA rule is usually good while the bullet is supersonic, once it goes subsonic the bc no longer holds true and wind wreaks havoc on the ballistics. I remember being in the pits pulling targets at 1000yds and seeing bullets smack the paper side ways as they were tumbling. The groups you shot were great but extend the distance and the simple math no longer holds true.

I'll admit it would be nice if it worked out in the field like it does on paper but once a bullet is subsonic it is no longer stable.

 

[Michael Eichele]

Both the above posts offer great info/insight. Just to reinforce what they are saying:

At 1650 yards, I suspect you are getting close to or are at the transonic zone. The 208 has most likely gone to or past it. Your accuracy/stability will suffer. To what degree? Its hard to say. There are so many variables it isnt even funny. Most the variables in this context we are not even aware of.

That said, my two best 3 shot groups at a full 1000 yards (3.5" and 4.5"), all bullets keyholed the target. They all went nose first but at sizeable oblique angles. The funny thing is that from 100-600 yards this load grouped a consistent 1MOA and yet tightend up over distance. There are no hard and fast rules here except that the transonic zone WILL affect all bullets to a degree. Some bullet/twist/velocity combos will react differently. Some will survive and others will tumble. Either way, accuracy will be affected.

Is 1.5 MOA really that bad at 1650 yards? I see plenty of guys at the range that cant keep 2 MOA at 100 yards. I know plenty than can do better than 1.5 at that distance and more that cannot. If youre getting a consistent .5 MOA on a good day and 1 MOA or less at 1K on a bad day, you should be happy.

 

[midwesthunter]

One thing that I would add is since your shooting at rocks you don't have anything constant to aim at. If your aim point veriest a 1/2-1" at those distances your groups will very. But I would definatly shoot some paper and give yourself a solid aim point to see what your really doing.

 

[WildRose]

Good explanations above. I'll add to it however in that the very long VLD bullets are going to begin destabilizing at transonic speeds and the non VLD's with the shorter profile are going to suffer less destabilization at sub sonic speeds but give up accuracy while at super sonic speed vs the VLD designs.

Unfortunately no one has found a bullet that can reshape itself to perform at peak levels at both plus and sub sonic speeds.

A sub MOA weapon and load should be sub MOA at any range as long as the bullet remains super sonic, but after than it's going to open up.

 

[buckbrush]

I anneal every third firing so I don't think the brass is too hard. Thanks for the input so far. I think I will try to hang some targets at 1000 to see what happens.

How much effect does excessive runout have at long range? I've never checked for it.

Thanks.

 

[T3-OleMan]

Good explanations above. I'll add to it however in that the very long VLD bullets are going to begin destabilizing at transonic speeds and the non VLD's with the shorter profile are going to suffer less destabilization at sub sonic speeds but give up accuracy while at super sonic speed vs the VLD designs.

Unfortunately no one has found a bullet that can reshape itself to perform at peak levels at both plus and sub sonic speeds.

A sub MOA weapon and load should be sub MOA at any range as long as the bullet remains super sonic, but after than it's going to open up.

Thanks for that explaination. Talking about just that point in the flight where conversion to sub sonic occurs I would like to learn what we (ya'll) know as to what the good-bad & the ugly is if you are shooting rounds that have: (i.e. something like this..... a FB will be more accurate up to that point, but at that point it will go to hell in a skinny nanosecond...bla..bla ...what ever. Or the opposite...what ever. Even if you can't prove what you believe at that point in the flight please give your best guess, you have been there and I have not.....please I know some of you have gotten into some of these areas. I am wanting to be a spounge on this stuff just because alot of us can learn something from your tests. It might allow us to make a better GUESS which bullet to use in certain situations.
A) FB......

B) BT......

C) RBT......

D) VLD & any thing else......

Thank you for your support. {:>)

 

[snowpro440]

I dont know about all that, but I have been shooting the 300 blkout and testing my own supersonic and subsonic loads and it seems not to have the same reaction as you stated when I get above 1150 fps or so an when they reach my target at 100yds an by then they sure slowed down a bit , they have not keyholed or destabilized ... I cant explain this ..? Could it be the distance ?

 

[loosesniper2000]

I would say that it is the distance. Let's use a spinning top for an example. Once you initially spin it, the top wobbles momentarily then stabilizes (this would be the yaw) after the bullet reaches its maximum distance (remember the top) the destabilization begins to occur. which is similar to the yaw once created outside of the barrel. This explains why heavier bullets sometimes shoot better at longer distances. Also this is why it's important to have the correct spin on the bullet.

To summarize things, once the bullet goes subsonic at extended distances variables affect accuracy at a higher degree when the projectile is running out of steam. That's why VLD bullets tend to do better down range.

 

[WildRose]

Thanks for that explaination. Talking about just that point in the flight where conversion to sub sonic occurs I would like to learn what we (ya'll) know as to what the good-bad & the ugly is if you are shooting rounds that have: (i.e. something like this..... a FB will be more accurate up to that point, but at that point it will go to hell in a skinny nanosecond...bla..bla ...what ever. Or the opposite...what ever. Even if you can't prove what you believe at that point in the flight please give your best guess, you have been there and I have not.....please I know some of you have gotten into some of these areas. I am wanting to be a spounge on this stuff just because alot of us can learn something from your tests. It might allow us to make a better GUESS which bullet to use in certain situations.
A) FB......

B) BT......

C) RBT......

D) VLD & any thing else......

Thank you for your support. {:>)

Mainly it has to do with the front half of the bullet.

At SS speeds the bullet is piercing the air and traveling within a vacum created by the sonic wave generated by the tip. The long thin VLD design allows those bullets to maintain super sonic speeds and stability longer than the more blunted non VLD designs.

At sub sonic speeds lift characteristics come into play.

It's the same reason that early generation super sonic fighters had serious problems at sub sonic speeds. In order to achieve the greatest possible speeds the wings were shortened and swept back in a sharp V design and made ultra thin so as to reduce drag.

Conversely low speed aircraft have a much greater wing area and the wings are straighter giving them much more air to work with.

Many of the early SS fighter prototypes did fine as long as they were accelerating o0r cruizing above the speed of sound but destabilized often to the point of no longer being controllable as they tried to slow back to sub sonic speeds for maneuvering and landing.

Today we get around that with planes that can change the angle of the wings and or make use of flaps for greater maneuverability and stability at low speed.

I'm not a physicist or an engineer so I can't do a very good job of explaining it but I understand the basic principles involved and have seen the results.

Google Bullet design and VLD bullet design and you can find some good articles on the subject.

 

[snowpro440]

Complicated but I see what your saying for a bullet fired from a great distance, but would that would mean my 1100 fps 220gr SMK bullet fired from my 300 blackout should destablize as soon as it leaves the barrel ? Even at 200 yards its still maintaining a decent 3 inch group . This has me questioning things ?

 

[loosesniper2000]

Not necessarily, the bullet you're using has a consistent pattern to it. At that velocity it doesn't see extreme variances. You could use a 22 for example and the results would be similar.
You take an object and spin it at several hundred thousand rpm's. When it slows there's nothing to contain the energy so it will wobble or tumble.

 

[WildRose]

Complicated but I see what your saying for a bullet fired from a great distance, but would that would mean my 1100 fps 220gr SMK bullet fired from my 300 blackout should destablize as soon as it leaves the barrel ? Even at 200 yards its still maintaining a decent 3 inch group . This has me questioning things ?

No your SMK is not a VLD and it's never exceeding SS speed therefore that transition that happens as the shock wave begins to collapse never occurs.

It is a BTHP but not a VLD, it has a much shorter and thicker profile than a VLD of similar diameter and weight.

Compare photos of the SMK and a Lapua Scenar or Berger VLD and you'll see what I mean.