270 Zeroing Question

[JeffDilla]

I'm taking my new 270 to the range on Sunday to get it zeroed so I can finish out the last couple weeks of deer season with it. I bought a couple boxes of Hornady Superformance 130 gr SST factory loads upon the recommendation of friend. The trajectory chart on the box claims that 1.2" high at 100 yards will give a 200 yard zero.

My question is, at 1.2" high at 100 yards, approximately where would this put me at 25 yards and 50 yards? Admittedly, trajectory and ballistics are a little outside my realm of complete understanding. I did read the thread about the 50 yard zero for the 308 but am still left a little confused. Any help or suggestions would be appreciated.

Thanks.

 

[ironworkerwill]

You can use a ballistic calculator to figure it like the one at JBMballistics.com. Also you'll need to know how high the scope is off the bore center to center.

 

[rcmodel]

.270 Win?
.270 Weatherby?

The 130 SST has a ballistics Cofficient of .460.

Your scope height is 1.5" or close to that.

Depending on barrel length, your velocity is about 3,000 FPS, if it's a 270 Win?

Plug those numbers into the Hornady ballistic app,
http://www.hornady.com/ballistics-resource/ballistics-calculator

And it says:
200 yard zero.

25 = -.7"
50 = - .2"
75 = 0
100 = 0
150 = -0.9"
200 = -3.0"
250 = -6.4"
300 = -11.1"
350 = - 17.4"
400 = - 25.3"

rc

 

[ontarget]

I don't know why the ammo mfrs put the tables on their boxes. There are way too many variables involved. I guess they would be good enough to get you on paper but I am afraid a lot of people use that chart as the gospel and never really shoot their gun at those ranges to check the actual performance.

 

[ironworkerwill]

Amen, there is no substitute for actual bullet holes in paper.

 

[JeffDilla]

Thanks for the replies. I attempted to use the JMBballistics calculator and entered all the info I could but there were a lot of terms and variables I was not familiar with.

rc, Thanks for the info. It's a 270 win, I should have specified. The Hornady box states the muzzle velocity is 3200 fps. I measured the height of the scope and it appears to be 1.5" over the bore, or pretty dang close, at least. The barrel is 22".

I understand that there are too many variables to consider, I guess I'm really just trying to get a rough estimate of where that bullet would be at 1.2" high at 100 yards.

The areas I hunt don't offer many opportunities for long shots, 25-75 yards would be typical, but 100-200 isn't completely out of the question, so I'd like to have that availability.

I do plan on shooting various distances at the range on Sunday out to 250 yards and will confirm where the bullet is on paper at each, but like I was saying, I'm just hoping to get a rough estimate of what to expect for the shorter ranges.

 

[rcmodel]

1.2" high at 100 yards will give you and approximate 190 yard zero.

It would be less then 1/2" high at 50 yards.
And less then an inch high at 75 yards.
1 1/4" high at 100.
1/3 inch low at 200.

rc

 

[jmr40]

The Superfromance ammo will be closer to 3200 fps than 3000. Don't sweat the details too much. I zero all of my rifles as close to dead on at 100 yards as I can, (308, 3006 and 300 WSM). None of them are more than 1/2" above or below my line of sight from 50-130ish yards. Perfect for shooting through brush and still less than 2" low at 200 yards. Even out to 300 yards I can still hold high on the back and get hits on deer size game with no hold over. Beyond 300 yards some hold over is necessary, but it doesn't get complex until you start shooting at 500 or farther.

I'm not a fan of zeroing high at short range in order to get less drop at longer ranges. It just complicates matters at close range where most shots are taken and offers virtually no advantages at longer ranges. The practice is becoming much less common with todays flatter loads, better optics and range finders.

 

[Geno]

rcmodel:

Hornady's SuperFormance SST exits the barrel at 3,200 FPS. Ergo, I set my zero at 300 yards for the open bean fields in Michigan. I did a screen shot of the ballistics from Hornady's site below.

Geno

 

[Gtscotty]

I'm the opposite of jmr40, I like to use the MPBR method of sighting in. My 140AB load is sighted 2.5 in high at 100yds, 1.7 in high at 200 yds, and 3.5 inches low at 300 with a standard, center poa and a decent shot, any medium game in that range is toast. I actually shot these at the range first, then messed with BC in the Hornady ballistic calculator to match my measured velocity and targets at each range . The Hornady program has matched my range results with .270 and 30-06 pretty well out to 300 yds, so I'd say you can put your numbers in there and at least get a ball park. The only real wild card you'll have is that you don't have an exact velocity, if it were me I'd probably estimate 3100 fps with your 22in barrel and the Superformance ammo.

 

[rcmodel]

rcmodel
Hornady's SuperFormance SST exits the barrel at 3,200 FPS.

Exits what length barrel??
They don't bother to say.

But you can bet your fuzzy bunny slippers it is longer then the OP's 22" barrel!!

rc

 

[JeffDilla]

Thanks for the info. rc, that Hornady calculator helped a lot to give me some numbers to play with before going to the range on Sunday. I realize there a lot of variables to consider but I have a much better idea of where I want to be to start out and then take it from there. Much appreciated.

 

[Geno]

rcmodel:

Odd, I thought Hornady was running 22" barrels for the test, but you are correct, test barrels were 24". At this link:

http://www.hornady.com/support/faqs/ballistics-data

They claim a 25 to 35 FPS lost in velocity per 1" of barrel reduced barrel length. I re-ran the ballistics with a starting muzzle velocity of 3,150 FPS, and it only changes the 300 yard zero by 1/10th of an inch +4.1" versus +4.0".

Geno

 

[Geoffo]

The 270 shoots so flat that you can use the published trajectory figures with confidence for hunting purposes. Same with all of the common rifles we shoot today, barrel length will make a small difference but you won't notice it for hunting. For me I always zero a flat shooter like yours at around 1.5" high at 100m, you'll get the most out of a 270, it's easy to aim low or dead centre at 25m to 150m. Out at 300m you could still aim dead centre or just a few inches higher than dead centre to kill a deer. Much easier than trying to guess holdover above an animal out at 300m, if you zero at 100m

 

[GooseGestapo]

For simplicity, sight the .270 at 50yds. Check, correct at 100, go hunting.
Start at 25yds, 1" low to "get it on the paper" (I bore site by removing bolt and aligning bore on target at 50-100yds, correct scope to match bore). Then fire one shot at 25 yds. Correct to approximately 1" low. Fire one shot at 50 yds, correct to zero. Fire 3 shot group at 100yds.
You want a .270 ~1.5" high at 100 for 200 yd zero, ~7" low at 300.
My experience suggests Superformance 130 will get ~3,100fps from 22" bbl.
my warmish 130's from 24" bbl run 3,100 from 24"bbl, but much more accurate than Superformance. (55.0grn H4350, Nosler 130grn CT B.T., or Sierra 130 GK @3.300"oal). Kills deer like lightning. For elk, a Hornady 140 or 150 Interlok is hard to beat!

 

[ku4hx]

Once I got mine set where I wanted it at 100 yards, I just backed up the target holder to 50 and then 25 yards and shot test rounds. Nothing like actual real world data.

 

[ku4hx]

I don't know why the ammo mfrs put the tables on their boxes. There are way too many variables involved. I guess they would be good enough to get you on paper but I am afraid a lot of people use that chart as the gospel and never really shoot their gun at those ranges to check the actual performance.

One did it so now they all do it. At best it's just a guide with only marginal real world application. But it does give Bubba braggin' rights.

 

[Sav .250]

A lot of other factors come into play here.

I`d start at 25 yds and work my way out. Sighting in a weapon is not rocket science.

 

[CoalTrain49]

Once you do the calc use the cheat sheet feature on the Hornady website. You can sight in at 100 yds and use your scope adj to click in the moa grads to shoot at what ever distance you want past your sight in range. Just tape it to your stock or laminate it and attach it to your coat zipper. I think that's how snipers do it. They take a range reading and dial it in. Takes out all the guess work.

 

[jrdolall]

In your situation, which is probably pretty close to how I hunt in Alabama, I would just have it dead nuts on at 100 yards and forget about it. Back when I was hunting peanut fields and often took 250-350 yard shots I would site in at an inch high at 100 yards. Shooting at a deer sized animal there is no need to adjust your POA within 200 yards. No need to worry about a 1/2" difference if the deer is at 75 yards or 150 yards, just point and click.
I never used a 270 very much as I normally hunted with 30-06 but, within 200 yards, there isn't enough difference to cause a problem at all. If you need to reach out to 250 yards and beyond then knowing ballistics and distance becomes critical.
If you feel the need to be prepared for longer shots then by all means do a proper zero and you will feel more comfortable at longer distances. I have a Rem 700 in 30-06 that is zeroed for 200 yards but I haven't used it on a hunt in several years.

 

[loose noose]

On my Remington 700BDL in .270 Winchester that I bought new in 1972, I took it down to the range, after bore sighting it in, and started firing at 100 yards. Note; I was using Remington 130 grain Core-Loct factory rounds. After shooting 6 rounds I had it dialed in using a Weaver 3X9 scope with medium rings. I put 3 rounds in the 2" bull w/i an inch or so of each other. Keeping that zero I shot my first big Mule deer at 75 yards and the bullet hit right where I was aiming under the left front shoulder. The next big game animal I took the following year using the same rifle and ammo, was a pronghorn, at nearly 300 yards aiming at the base of the neck the bullet smashed thru the right front shoulder and the animal collapsed.

The moral to this story is like was stated earlier, nothing left to calculations is perfect, so the best rule is actual shooting at the range, and being able to read the wind. Especially in that 300 yard Pronghorn shot. I later took a small bull elk up in Colorado using the 150 grain hand loaded Remington Core-Lokt at slightly over 100 yards looking directly at me in a fire break. Again the rifle was sighted in at 100 yards and I held right at his chest and hit right where I had aimed. He too dropped right down.

 

[JeffDilla]

Great info. Thanks all.

 

[gamestalker]

Just to clear up a possible misconception, zeroed and sighted in are two completely different functions, I'll explain below.

To better describe what this means, it's a process in which you first chrony the load, then starting at around 200 yards, you find the point in which POI is no longer above the last dead center sight in. So in other words, if when sighted in at 200 yards, if you move the target out say another 20 yards, and POI is now higher than at 200 yrds, then turret adjustment must be once again made to sight in at that distance. Then if I move the target out another 10 yards, and it's still producing a higher POI, then I continue the above process until the optic is actually zeroed.

Now if one were to sight their high powered rifle, .308, .270 win and such at distances closer than 100 yrds. distances out beyond the sight in distance of say 50 yrds. will be seriously flawed. And I wouldn't be surprised if anything under 50 yards would even be physically possible to achieve. A .270 running a 130 gr. bullet at 3000 - 3100 fps is going to shoot excessively high at 100, 200, and possibly even beyond that if sighted in closer than 50 yards. The center bore to optical center line is roughly 1.5" on an average scope mounting system. This is because most scopes don't have enough adjustment range to allow for such extreme reticle movement.

GS

 

[J-Bar]

I love my Ruger #1 in .270 Winchester. I've lost count of the number of deer I have taken with it. It is sighted to hit a little over 2 inches high at 100 yards. Measuring tenths of an inch...forget it.

When I see a deer within 300 yards, I put the crosshairs in line with the front leg, and hold halfway between the bottom line and top line of the animal, and squeeze the trigger. Most drop in their tracks. A few have run less than 50 yards. One of the mysteries of life is why anyone would use something other than a .270 Winchester to go deer hunting.

Back to the tenths of an inch thing. Your accelerated breathing and heartbeat when you aim at a deer will negate any precision obtained when sighting in to tenths of an inch. And if your breathing and heart rate aren't accelerated when you are aiming at a deer, why are you hunting?

I took my most recent whitetail about 6 hours ago. With my .270. Broke his neck at the shoulder blades at 150 yards. He dropped in his tracks. My pulse is almost back to normal.

 

[gamestalker]

I'll second that notion J-bar, the .270 win. is THE deer slayer rifle of all time, IMO.

I've killed more deer, elk, antelope, and countless other animals with a .270 than with any other rifle. As far as 1/10th inch variables and such, when I punch paper, I punch paper, and when I hunt, I hunt, and never the two shall meet. A well placed kill shot has little correlation to a 1/2" group on paper @ 200 yds..

GS