Max elevation for accuracy - ELR

[Hoffer]

Been going over some numbers and data lately

Just throwing this out there for discussion

I am thinking accuracy goes to **** past 150-180 moa of elevation no matter what the caliber or velocity.
Obviously more FPS or altitude gets you farther out. 150-180 moa seems around 400-600 ft drop for a wide range of larger calibers.
For accuracy I am going with the 36" sq plate past 2000 yards for reference ... so 338 and larger calibers.
Also no wind condition for comparative performance

Any input or ideas?

[kcstott]

I can say, Don't have enough experience beyond a mile, but I'm guessing it's the angle of attack and increased front face of the projectile exposed, creating higher drag that generates instability.

[Hoffer]

Did a quick calculation on 5 rifles
4000 ft alt 150 moa

338LM 2575fps 2800 yards 975fps - Berger300
338 Imp 2900fps 3050 yards 975fps - Berger 300
375 CT 2825fps 3100 yards 990 fps - CE 400
? 3500fps 4000 yards 970fps - CE 400
? 4000fps 4600 yards 960fps - CE 400
? mystery test rifle

Interesting that the target hit speed are all very close no mater starting velocity

[kcstott]

Did a quick calculation on 5 rifles
4000 ft alt 150 moa

338LM 2575fps 2800 yards 975fps - Berger300
338 Imp 2900fps 3050 yards 975fps - Berger 300
375 CT 2825fps 3100 yards 990 fps - CE 400
? 3500fps 4000 yards 970fps - CE 400
? 4000fps 4600 yards 960fps - CE 400
? mystery test rifle

Interesting that the target hit speed are all very close no mater starting velocity

I think that shows more of just how true a velocity retardation coefficient calculation really is and the law of diminishing returns is correct, a difference of 325 fps makes no difference at range,

[Hoffer]

I think that shows more of just how true a velocity retardation coefficient calculation really is and the law of diminishing returns is correct, a difference of 325 fps makes no difference at range,

It does extend the range considerably

[URSA Facilitator]

Been going over some numbers and data lately

Just throwing this out there for discussion

I am thinking accuracy goes to **** past 150-180 moa of elevation no matter what the caliber or velocity.
Obviously more FPS or altitude gets you farther out. 150-180 moa seems around 400-600 ft drop for a wide range of larger calibers.
For accuracy I am going with the 36" sq plate past 2000 yards for reference ... so 338 and larger calibers.
Also no wind condition for comparative performance

Any input or ideas?

Hoffer - I'm missing what you are trying to get at. Are you saying, in some manner or fashion, that you can't get "there" from "here"?

BTW, URSA SoCal has seen 6mm Creedmoor shooters make hits at 2080.

BTW, dispersion around your point of aim is what you appear to be after and only a round target provides that. "Plate" or paper makes no difference.

Define your objective and terms and run the numbers.

[Hoffer]

Hoffer - I'm missing what you are trying to get at. Are you saying, in some manner or fashion, that you can't get "there" from "here"?

BTW, URSA SoCal has seen 6mm Creedmoor shooters make hits at 2080.

BTW, dispersion around your point of aim is what you appear to be after and only a round target provides that. "Plate" or paper makes no difference.

Define your objective and terms and run the numbers.

Just interesting that 5 types of rifles at a certain MOA elevation end up roughly the same velocity at target

Also at the KO2M that elevation would appear to be about the same given the higher elevation of the match. With the caliber of competitors at the KO2M and that is the MOA where the accuracy stopped is my point.

[LynnJr]

Harry
Time to get a 20mm?
I think we need a new term like maximum accuracy range verses Speed or MARS.

[focus]

Hi Harry,

I think Time Of Flight matters. Less shot dispersion due to wind. I ran a 338 at 3500 FPS last year; because, it had the best WEZ prediction. But, I couldn't tame the bullets I used. Random BC variation drove me nuts.

So, far those 400 CEs seem to be cooperating. We'll soon see.

Cheers,

[Hoffer]

Hi Harry,

I think Time Of Flight matters. Less shot dispersion due to wind. I ran a 338 at 3500 FPS last year; because, it had the best WEZ prediction. But, I couldn't tame the bullets I used. Random BC variation drove me nuts.

So, far those 400 CEs seem to be cooperating. We'll soon see.

Cheers,

True

Updated with TOF

338LM 2575fps 2800 yards 975fps - Berger300 TOF 5.8
338 Imp 2900fps 3050 yards 975fps - Berger 300 TOF 6.1
375 CT 2825fps 3100 yards 990 fps - CE 400 TOF 6.1
? 3500fps 4000 yards 970fps - CE 400 TOF 7.4
? 4000fps 4600 yards 960fps - CE 400 TOF 7.4
? mystery test rifle

Maybe with heavier bullets TOF can be extended, but it does not work for the 50 guys at the moment