Group size at distance

[emp1953]

Not a new shooter, but still learn something new everyday, usually from this forum.....So , my question is....why do some guns shoot 1/2" at 100 yds and 2" @ 500 yds, and another that shoots 1/2" @100 won't hold 5" @ 500 yds ? I know in my case it's probably the loose nut behind the trigger, but curious if it's possible or for that to be a mechanical thing with barrel or load or?. Thanks for any info....rsbhunter

I zeroed my .270win at 200yds then went to a range in Millville NJ that has a 600yd range. I used my ballistic calculator, dialed in the recommended scope dope and fired a round. It hit in a spot that would have killed a deer if that's what I was shooting at. From then on I trusted the calculators dope recommendations on long distance shots at game. My longest shot at game was 605yds but it was perfect. Had I not verified it on paper previously at distance I would not have felt comfortable at all taking that shot. Luckily my scope tracks incredibly well.

 

[Blackhawk]

Not a new shooter, but still learn something new everyday, usually from this forum.....So , my question is....why do some guns shoot 1/2" at 100 yds and 2" @ 500 yds, and another that shoots 1/2" @100 won't hold 5" @ 500 yds ? I know in my case it's probably the loose nut behind the trigger, but curious if it's possible or for that to be a mechanical thing with barrel or load or?. Thanks for any info....rsbhunter

This is an open ended question. One that has too many variables all worthy of discussion
Things like rifle build including barrel, stock manufacturer including fit, placement, glass bedding, Pillar bedding, rifles action and age, use, ( throat erosion happens from shooting over a period), head spacing, tightness of action screws, stock material itself (wood can deform over time if not properly stored)trigger group itself, scope mounts,one piece base ( if one piece does it have a 20 MOA included angle or not) or separate bases, Scope Base to action fit itself, were the rings themselves lapped or epoxy bedded, Scope ring brand as well as construction Scope's name brand and magnification, Mil dot or stedia wired plus all hard ware torqued to correct specs ,are just a few of the obstacles that you may encounter.
I have not even started on your rifles fodder. What brand, what weight,what type of bullet ,etc? You get the drift. You see as one question is answered another one can be brought to bare, hence questions just perpetuate themselves in an endless loop!

 

[26Reload]

It is typically only possible to be more accurate at one fixed distance

I agree with this.....especially with my shooting....first shot at whatever is dialed...after that....close....

 

[Tidus56]

I believe vertical has alot to do with it, my Nephews 6.5x06AI that I put together would cut 1 hole at 100 but would shoot 4" groups at 500 with alot of vertical I changed primers and .5 m.o.a and 1" of vertical.
Theres a reason alot of BR guys I know final tune at 1,000 that they shoot

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

 

[L.Sherm]

Because the seating depth or powder charge didnt seem to get rid of the vertical.

 

[rsbhunter]

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

 

[WildRose]

Not a new shooter, but still learn something new everyday, usually from this forum.....So , my question is....why do some guns shoot 1/2" at 100 yds and 2" @ 500 yds, and another that shoots 1/2" @100 won't hold 5" @ 500 yds ? I know in my case it's probably the loose nut behind the trigger, but curious if it's possible or for that to be a mechanical thing with barrel or load or?. Thanks for any info....rsbhunter

More often it's the shooter, not the gun. In general if the gun is capable of sub MOA accuracy and the load is as well, the issue is with the shooter.

That can vary a bit especially with the small high speed rounds that are more affected by wind but as a rule, if you have the rig and the load, the limiting factor is generally the nut behind the gun.

 

[WildRose]

well there is a phenomenon my dad used to talk about when standing behind a 50 caliber shooting tracers at night. He said that you could watch the tracer spiral outward then back inward toward center several times in it's flight. Just theory but would suspect possible impurities in the actual bullet that might effect the centricity of the actual bullet when spinning

Tracers are inherently unstable because they are losing mass throughout the flight and that loss is not perfectly concentric.

 

[WildRose]

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

All good suggestions/ideas.

The single biggest thing I've done to improve consistency and accuracy was paying special attention to consistent neck pressure. I seat bullets very loosely, just enough so that I can't seat them with finger pressure and apply a very light crimp now.

 

[FURMAN]

I have never built a rifle that groups well at 200 (that is where I initially test) that didn't shoot well at 500 or 1000. I still don't see mathematically how you can get good groups at one range and not the other. I'd have to see pictures

I have development several accurate loads with horrible es and they will not shoot long range period. It makes no difference to me if you don't believe it but it is fact. There are other reasons why a load will shoot good at short range and not long range. If the bullet is not fully stabilized as in not fast enough twist it may shoot accurately at short range and not long range. You will not find a 1000 yard benchrest or flcasser who wins regularly doing load development at short range.

 

[WildRose]

I have never built a rifle that groups well at 200 (that is where I initially test) that didn't shoot well at 500 or 1000. I still don't see mathematically how you can get good groups at one range and not the other. I'd have to see pictures

It is quite possible to have a big swing in ES cause that. You may just be fortunate but with an ES over 40 it not only can affect you in the vertical but it can significantly affect barrel harmonics which can make bullets to screwy things at different ranges.

 

[Mram10us]

I have development several accurate loads with horrible es and they will not shoot long range period. It makes no difference to me if you don't believe it but it is fact. There are other reasons why a load will shoot good at short range and not long range. If the bullet is not fully stabilized as in not fast enough twist it may shoot accurately at short range and not long range. You will not find a 1000 yard benchrest or flcasser who wins regularly doing load development at short range.

I dont believe anything until I see facts. That is normal. No one is saying load develop at short range. I start at 500 for ladder, 300 for seating depth then take it out to 1000 to verify. That is my point though, that after all that, I havent seen a load that groups well at 200 shoot poorly out to 1000. I'll let you know though, cause I am testing a couple rifles tomorrow at 1000 that have not been tested beyond 500.

 

[KY_Windage]

I start at 500 for ladder, 300 for seating depth then take it out to 1000 to verify. That is my point though, that after all that, I havent seen a load that groups well at 200 shoot poorly out to 1000.

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!

 

[Tommo64]

There is simply so much more to wrong at extended ranges. Wind drift, spin drift, differing ballistic characteristics between bullets, etc. But most likely shooter error. The kind of errors that don't show up at shorter ranges yet become magnified at longer ones.