lets talk effective distance for caliber/bullet weight

[Tac]

I have been shooting distance for a few years now and was in a discussion on caliber/bullet weight and accuracy at distance. This last weekend we went out and were shooting at 1320 yards we noticed that the 6.5 creedmoor was having a hard time hitting the large sillouette and we swaped to the 338 lapua and hit it. I was curious what the effective accurate range that should be expected for different rounds?

Lets have it.

[PRDATR]

Well I believe the BC plays into it a  lot at extreme ranges. I believe the 1000 yd new world record set with a 6mm  was a tad over 1" for 5 shots.

[Tac]

ok so lets add high bc heavy end for caliber and add that to it 

I have done some research and it seems that all the southwest national guys in the open class seem to choose 284 winchester. 

[Big Browns]

This is a very subjective question.  Each gun will have different max ranges depending on velocity, BC and weight.  Without specific information it's almost impossible to know the max effective range on any specific gun. 

 

Lance is the best person to answer these types of questions!!!!!! 

[Jnj13]

6.5CM or 338 lapua? Quite a difference. There are people all over youtube shooting steel plates with a 6.5CM at a mile. I shoot that round and at 1320 yards would have over 650" of drop. More MOA than my scope can handle. I'm sure the 338 magnum can shoot that distance. It's a cannon! In fact the 338 is the caliber Chris Kyle used on his 2100 yard longest confirmed kill.  

I suspect the 338 drop would be double that of the 6.5CM though. So it's on the scope. The CM is flatter and faster.

[Mike S]

Up to the point where the bullet becomes unstable, likely in the trans sonic range, it pretty much boils down to the shooter.

[Tac]

the transonic speed is a good explanation of and happens with my load about the distance that i,m questioning.

the drop on the 338 is 562.2 inch and the 6.5 is 683.6 inch  that is right at the end of the dial up on my scope to rifle thats why i didnt try and shoot at a mile due to running out of adjustment on the scope. I need to add some angle to the mount to accomplish a mile.

I have been succcesful with both these guns to the 950 yard area i just wanted to see how far i can stretch my abilities. and 1320 was the end of adjustment that both my scopes were able to do and it was a good test of my abilities. 

 

[Zeke-BE]

Depends on your scope too.  My athlon cronus was able to get me 1,364 yards maxed out on a 20 moa rail with a 6.5 CM.  Then on top of that i have some more MOA marks to go off too if needed.

[Jnj13]

Tac, I’m curious now. what are the ballistics for your 338? 

[Tac]

mv of 2629 bc is g1 .7890 bullet weight is 300 gn 

[Dan]

On ‎9‎/‎24‎/‎2018 at 4:49 PM, Jnj13 said:

6.5CM or 338 lapua? Quite a difference. There are people all over youtube shooting steel plates with a 6.5CM at a mile. I shoot that round and at 1320 yards would have over 650" of drop. More MOA than my scope can handle. I'm sure the 338 magnum can shoot that distance. It's a cannon! In fact the 338 is the caliber Chris Kyle used on his 2100 yard longest confirmed kill.  

I suspect the 338 drop would be double that of the 6.5CM though. So it's on the scope. The CM is flatter and faster.

My 338 edge has  a drop of 468 in at 1300 yrds with a 300 gr berger  .818 bc   with muzzle velocity 2850  energy at 1300 yrds is 1684 ft lbs  The 6.5CM is not in the same class of the 338.  You also would have almost triple wind drift as a 338 shooting a 300 gr berger.  The 6.5 is NOT even close to a 338 at 1000 yrds velocity or energy. At 1300 yrds  my 338 drop 38ft.  your 6.5 drop 54ft.   26ft difference  So it is not faster or flatter at longrange.   Like comparing a bb gun (6.5) to a 22 long rifle (338) 

 

 

 

 

 

 

 

 

 

 

[lancetkenyon]

I have shot a lot out past 1300 yards.  With everything from my 6.5SLR pushing a 140 HVLD @ 2850, to a 7RM pushing a 180 Hybrid @ 2996, to a .300RUM pushing a 230 Hybrid @ 3068, to a .338 Edge pushing a 300SMK @ 2820.   

My 6.5SLR is deadly accurate out to 1500 easily....on a calm day....on steel and rocks and stupid ground squirrels that inhabitnone of the areas I shoot.  But I would never shoot at anything else living other than a jackrabbit or coyote at those ranges.  That bullet/speed puts it subsonic at about 1580-1620 yards depending on conditions.  I have shot it @ 1771, but those hit not only become more erratic, but much harder to see impacts for corrections.

I think a lot of errors you are going to see over 1300 yards are wind induced.  Even a 2mph difference will change POI (from 3mph to 5mph) almost 24" difference in drift, from 23" to 47".  And that is if it is consistent.  Swirling winds will push it all over the place.  And winds change direction and speed across 3/4 mile easily.  Meaning very hard to judge all aspects of it.  Tailwinds induce less drop, headwinds induce more drop, full value winds push left or right, etc.  Plus, you still have spin drift at 1300 to account for.  And your zero better be perfect L-R.  And your ballistic inputs.  And your velocity better have single digit ES and SD.

A .338 Edge pushing a 300 Hybrid @ 2900 is going to have far less drift at 1300 yards.  That same 5mph 90° full value wind only pushes the bullet 29" vs 47" with the 6.5mm 140.  And at 3mph, only 13". So about half what the 6.5 140 drifts.  That is a huge difference.

Just because a bullet has a high BC, a lighter bullet is still going to drift more than a heavy high BC bullet.  Takes more force to move the higher mass.  Making a .338LM a much better ELR candidate than a 6.5CM.  The 6.5CM definitely ups your wind reading game though, and far cheaper to shoot for practice.  

 

[Big Tub]

https://www.chuckhawks.com/myth_busting_calibers.htm

 

[lancetkenyon]

Sorry Big Tub.

Copywright 2009.  No inclusion of hand loads, or high quality bullets.  And ridiculously low claims.  Saying a .260 is only good for a 500# elk out to 75 yards is asinine.  And saying you need a .338RUM for a large moose @ 300 yards...…..stupid.

But then again, we were talking about shooting steel, accuracy at 1300 yards, etc., not so much hunting.  Even though I use shooting steel as hunting practice.  I would not use a 6.5CM on anything other than coyotes @ 1300 yards.  Not even a Coues deer or javelina.

In all honesty, I have my own criteria for hunting.  1800fps minimum on target, regardless of bullet type/brand/construction, and 1000ft/lbs of energy for deer-sized game and down, and 1500ft/lbs for elk/bear that exceed 300# live weight.  But, even though I have several rifles that are fully capable of taking big game @ 1000+, I have personally never shot big game over 662 yards.  Coyotes though....if I can see em', I will send lead at them.

[lancetkenyon]

On ‎9‎/‎24‎/‎2018 at 4:49 PM, Jnj13 said:

I suspect the 338 drop would be double that of the 6.5CM though. So it's on the scope. The CM is flatter and faster.

You have it backwards. 

6.5CM w. 140 class bullet will be 2800-2900 average.  Let's say 2850 because that is what my 6.5SLR shoots and I already have all that input into my ballistics program.

.338 Edge w. 300 class bullet will be 2850-2900 average.   Let's say 2850 to make it even. 

Drop is comparable out to 400, then the .388EDGE spanks the 6.5CM in ballistics.  Especially with wind drift at drop at 1300 yards.  

1700 yard comparison:  2000' elevation, 59*F, 10mph 90* wind

6.5CM w. 140 Berger @ 2850fps: drop 1273" (20.8MIL/72MOA), drift 197"

.338 Edge w. 300 Berger @ 2850fps:  drop 940" (15.4MIL/53.5MOA), drift 126"