Group size at distance

[sturner]

Tag

 

[Greyfox]

Bryon Litz talks about this in his 1st Edition, Applied Ballistics in Long Range Shooting. Paraphrasing, the angular group size will not stay constant at long range due to the spin/gyroscopic effects on the bullet, and groups could be expected to increase 25%. My own experience with my best shooting LRH rifles/loads with sub .5MOA accuracy is that they can maintain pretty consistent group size between 100 and 500 yards. Out at 800-1000+ yards I'm usually at 1.5-2x of my average MOA group size. My competition rifles at the longer ranges are generally better. This seems consistent with Litz's statements.. Of course, mirage, wind, lighting, parallax, etc. can be factors....and if not at optimum, can(and usually do) degrade consistency further. Just my experiences.

 

[L.Sherm]

What made you decide to change the primer? Was it the ES number or SD? Just a guess? I am curious because I typically start with a primer and stick to it. Thanks for any info

What really opened my eyes to how much a different primer can tune a load was about 12 years ago my nephew brought me a Ruger 338WM to work up a load for.
I have a 338 WM in a Sako L61.
I used the same brand of brass, bullets and powder on his Ruger to start out with was getting frustrated best I could get it to shoot was 1.25- 1.5 groups. I was just about to give up and say well that's all this factory rifle will do.
Read an article about primer change figured what the #### got nothing to loose, changed the primer and it literally cut the group in half I was amazed.
I use the exact same powder, charge, brass, and bullet but I have to use a different primer in the Ruger.
It really opened my eyes to what a primer change can do.

 

[milo-2]

My experience is that whatever they do at 100 is real close to what they do farther out. If it shoots 3/4" at 100, it shoots 6" at 800, assuming no breeze anywhere, of course.

Maybe I just need to shoot more loads!

I'm not going to discount what you see, but in my experience, that is not the way things work.
In a perfect world, every bullet that comes out of a barrel would go in 1 hole, the diameter of a pencil. So when a guy thinks about just how did this become 3/4" at 100 yards. Something in the chain caused it to open up, which is another topic, but a 3/4 moa rifle at 100 will never shoot 3/4moa at 800 or 1K.
The only exception to this may be bigger 338's and larger and personally, I don't attribute this phenomenon to bullet stability either.

 

[KY_Windage]

but a 3/4 moa rifle at 100 will never shoot 3/4moa at 800 or 1K.
The only exception to this may be bigger 338's and larger and personally, I don't attribute this phenomenon to bullet stability either.

Well, don't say "never." This is an 800-yard permanent plate I shot with my factory Rem. 700 7-08 that shoots about 3/4" at 100 yards. The strikes at extreme left and right were put there by someone else before I started shooting. I could see all 6 shots I fired going into the same spot, so we drove down and taped the dollar bill up for reference. I'd call it a 3/4-moa group. There was no breeze at all. The bullets were 162-gr. H Match. I don't have a photo but it shot close to 3/4 moa at 1000. Maybe 1 moa there. I didn't put a tape on it.

What you say makes perfect sense, but it is not what I see. I just don't think we get those perfect atmospheric conditions very often to be able to see how linear our rifles shoot.

 

[rsbhunter]

I am so glad I posted my question....the different theories, knowledge base, and opinions have really shown me that maybe I need to open my thinking to the fact that there are different factors to each aspect of rifle shooting, especially accuracy focused. Please keep posting, you have all given me an early Christmas present....MERRY CHRISTMAS....rsbhunter

 

[KY_Windage]

One thing I think trips up a lot of people when they move out to long yardage is rifle cant. That may not show up at 100 but at 600 you better be very careful to keep your rifle bubble centered.

 

[Rhovee]

I think it depends how load development was done. I have limited distance to test (1-300). Then 1k during the spring/summer. Seems that 5-600 yards a lot of loads can hang in there for equal size at shorter distance. But over that and things can go bad fast. 338's to hold up a lot better than most.

 

[Blackhawk]

Blackhawk, good points, but most rifles capable of .500 and under groups have had the attention to details checked, dealt with and components are of the caliber that are capable of accuracy beyond the off the rack weapon. Most problems associated with poor accuracy at short range you address, normally flyers, non grouping, and erratic grouping are caused by the problems you pointed out. I am starting to subscribe to the theory of shooting at long range to check accuracy, and watching the es and sd to control the vertical...then adjusting components and seating depth to get the grouping I am looking for...The info on this forum is a gold mine....I thank all of you found the replies and advice , rsbhunter

I agree with your logic and my magneto speed V3 chronograph is my best friend . As you pointed out the tighter the vertical string is (E.S.) and the smaller the bullet placement is from point of aim (P.O.A.) the more accurate the load becomes. This is called the S.D.. Other than performing a ladder test(Satterlee) I think it is called, your chronograph is the best way to establish a successful load development.
Simply put as group size diminishes the lower the E.S. and S.D. numbers become. I myself keep working at both these numbers until I'm satisfied with my shot placement. I will start my load development at 100 yards and when I'm content with my numbers move out to 200 yards and beyond. I also carry with me my 3 ring binder which contains all per-tenant data as well as my actual targets which I print off an internet target generator site. At night I plug in my data from the chronograph to a spreadsheet in order to analyze it. This will give me an easy way to record , store , or compare records of previously shot reloads.
At the range I've had other shooters ask me just what I record, and why. To that I reply with what I've already answered above. Couple that with my actual targets and generally people will want to know more by asking questions.
I feel very fortunate to reply as knowledge and my opinion I feel is meant to be shared. This I was taught at a very early age from some very close mentors. What they instilled in me was that knowledge should be shared freely among those who are willing to listen , as there should be no great secrets in life that are kept locked away in a persons mind. Rather information should be freely exchanged with like minded souls. On the other side of the coin it is up to you as a individual to discern whether the information is valid or just so much nonsense.
I truly enjoy this web site, because of the quality of it's subscribers but more importantly the amount of quality information that is freely given.
To that end I wish to thank all of you for your posts, contributions , and time !

 

[WildRose]

I agree with your logic and my magneto speed V3 chronograph is my best friend . As you pointed out the tighter the vertical string is (E.S.) and the smaller the bullet placement is from point of aim (P.O.A.) the more accurate the load becomes. This is called the S.D.. Other than performing a ladder test(Satterlee) I think it is called, your chronograph is the best way to establish a successful load development.
Simply put as group size diminishes the lower the E.S. and S.D. numbers become. I myself keep working at both these numbers until I'm satisfied with my shot placement. I will start my load development at 100 yards and when I'm content with my numbers move out to 200 yards and beyond. I also carry with me my 3 ring binder which contains all per-tenant data as well as my actual targets which I print off an internet target generator site. At night I plug in my data from the chronograph to a spreadsheet in order to analyze it. This will give me an easy way to record , store , or compare records of previously shot reloads.
At the range I've had other shooters ask me just what I record, and why. To that I reply with what I've already answered above. Couple that with my actual targets and generally people will want to know more by asking questions.
I feel very fortunate to reply as knowledge and my opinion I feel is meant to be shared. This I was taught at a very early age from some very close mentors. What they instilled in me was that knowledge should be shared freely among those who are willing to listen , as there should be no great secrets in life that are kept locked away in a persons mind. Rather information should be freely exchanged with like minded souls. On the other side of the coin it is up to you as a individual to discern whether the information is valid or just so much nonsense.
I truly enjoy this web site, because of the quality of it's subscribers but more importantly the amount of quality information that is freely given.
To that end I wish to thank all of you for your posts, contributions , and time !

The sharing of knowledge and experience is what makes this the best forum on the internet relative to our sport.

I've been at this n ow for about 45 years and if I dig around I can learn something every time I click on the site and I'm not the least bit embarrassed to share my own errors and struggles moving along the learning curve for the last five decades.