Rifles

The Mythical 50/200 Yard Zero

Ever have someone suggest to zero your rifle at 50 yards because that will provide a secondary zero at 200 yards? Ever heard a broken clock is right twice a day? Let's take a closer look at the mythical 50/200 yard zero.

Recently got into a discussion about different zero distances that included the topic of the 50/200 yard zero distance for riflescopes. This probably the second most common zero distance for a riflescope next to the proverbial 100 yard zero that is often vehemently defended as the ultimate zero distance. While I think the 50/200 yard zero has its merits, I think a lot of folks hold it in very high regard while also holding some misconceptions about it.

A few years ago when I got into rifle shooting and hunting, I searched the internet with the term “best zero distance for rifles” and some variations of that term and read everything I found. Several forums had posts swearing that at 50 yard zero was the absolute best because it always gave you the same point of impact at 200 yards and therefore one could easily engage targets up to 200 yards (and even a bit further) with it without giving much thought to making adjustments. Targets under 50 yards would get a slightly low impact. Targets at a 100 yards would get a slightly high impact. And so on. It’s almost like the folks believed the 50/200 yard zero granted any rifle or cartridge mystical powers to get a good enough hit on any target up to about 250 or 300 yards.

Frankly, when I hear folks parrot the exact same praise for anything I start suspecting something might be awry. Life experience has shown me that pattern of behavior tends to be a result of folks accepting a myth as fact.

So, let’s explore it.

I’m going to start this exploration with what I consider a very common setup: an AR-15 chambered for 5.56 NATO with a typical sight offset of 2.6″ and zero distance of 50 yards. The table below will show the drop experience by a couple of different 5.56 NATO loads in 50 yard increments out to 300 yards.

Projectile
Velocity
BC
50 Yards100 Yards150 Yards200 Yards250 Yards300 Yards
55gr FMJ
3240 fps
.243 G1
0″1.63″2.18″1.49″-0.63″-4.41″
68gr BTHP
2960 fps
.355 G1
0″1.49″1.78″0.76″-1.71″-5.78″
75gr BTHP
2910 fps
.355 G1
0″1.45″1.67″0.52″-2.13″-6.44″

So what does the external ballistic data show us? First, zeroing a rifle a 50 yards doesn’t mean we magically get a second zero at 200 yards. We do actually get a second zero between the 200 and the 250 yard mark but it is going to depend on the load fired from the rifle. That said there is still some truth to the claim that the 50 yard zero can be used to engage a target out to about 250 yards without having to worry much about making an elevation adjustment as long as the target larger than the projectile’s trajectory deviation plus the precision deviation of the cartridge and rifle combination. For example, assuming we can consistently shoot 1 MOA groups with rifle and cartridge at 250 yards the smallest engage-able target with the 75 grain load would be about 4.63″ (2.13″ for trajectory deviation plus a 2.5″ group size) in diameter.

Does this change if the same rifle is zeroed at 200 yards? Let’s find out.

Projectile
Velocity
BC
50 Yards100 Yards150 Yards200 Yards250 Yards300 Yards
55gr FMJ
3240 fps
.243 G1
0.38″0.89″1.07″0″-2.48″-6.62″
68gr BTHP
2960 fps
.355 G1
0.2″1.11″1.22″0″-2.65″-6.91″
75gr BTHP
2910 fps
.355 G1
-0.13″1.20″1.29″0″-2.17″-7.21″

Again, we see that using a 200 yard zero doesn’t guarantee an exact second zero at 50 yards. At the same, the secondary zero is much closer to the 50 yard mark when using a 200 yard zero in comparison to how close the secondary 200 yard zero was when using a 50 yard zero.

There are some interesting and important differences between a 50 yard zero and the 200 yard zero also highlighted by this additional data. First is the trajectory deviation between 50 and 200 yards is much narrower when using a 200 yard zero. This gives me a lot more confidence in engaging targets up to 200 yards without making elevation adjustments. The flip side to this is a much wider trajectory deviation beyond 200 yards.

You might be wondering what a 50/200 yard look like if we use a different rifle and cartridge? Let’s explore that using the external ballistics data of a bolt action rifle chambered for .30-06 Springfield with a sight height of 1.5″ shooting a 178 grain ELD-X Precision Hunter cartridge from Hornady. This cartridge has 0.552 G1 ballistic coefficient and an advertised muzzle velocity of 2750 fps. The table below will include drop data using a 50 yard zero, a 200 yard zero, and 100 yard zero for comparison.

Zero50 Yards100 Yards150 Yards200 Yards250 Yards300 Yards
50 Yards0″0.27″-0.76″-3.17″-7.05″-12.51″
200 Yards-0.79″1.86″1.62″0″-3.09″-7.75″
100 Yards-0.13″0″-1.16″-3.70″-7.72″-13.31″

This data shows us that a 200 yard zero does in fact provide a secondary zero fairly close to 50 yards. Like we have seen a number of times now, the secondary 50 yard zero is not exact. Perhaps more interesting, is that a 50 yard zero doesn’t even come close to providing a decent secondary zero at 200 yards. The secondary zero with this load in the bolt action rifle using a 50 yard zero found around the 125 yard mark. A more subtle, but also interesting thing to note, is that we do get a secondary zero around 60 yards when using a zero distance of 100 yards albeit it’s not a very usable secondary zero.

100 yard zero trajectory

I think it’s important to note that it’s harder to find shooting ranges with rifle shooting lanes that go out beyond 100 yards. As such, I think many folks who hold the 50/200 yard zero with high regard and believe the 50 yard and 200 yard zeros will always line up end up using a 50 yard zero and assume the 200 yard zero will line up.

It is possible to get pretty close to a 200 yard zero while using a rifle zeroing target at 50 yards. However, this requires using a chronograph to get an accurate velocity reading and a ballistic calculator to determine the expected trajectory deviation at 50 yards.

Bottom line is 50/200 yard zeros are very usable for many applications. However, I firmly believe it should be referred to as a 200 yard zero (and actually zeroed at that distance) that provides a usable, but approximate, secondary zero at 50 yards. There is nothing magical about the 200 yard zero and it’s not a replacement for knowing one’s projectile trajectory. Zeroing a rifle at 50 yards and assuming the secondary 200 yard zero will be usable is a mistake. That’s my current opinion (which is outdated after looking at more zero distances and the maximum point blank range concept covered in this other post) based on analyzing a bunch of external ballistic data like the data presented in this post. Your mileage may vary.

2 comments

  1. When I learned the 50/200 it was for M4 and or carry handle iron sights and then Red Dots. Zero magnification. Meaning, across the board, almost nobody could get a repeatable zero at 200 due to the MOA of the irons, the size of the DOT, and/or shooter error. It was a practical, but not mathematical zero. It was advocated as “hold on the nose” POA and your POI would never be under the chin or over the head from contact shot to 200 yards. I never did the math, and thanks to you, I don’t have to. Thank you for this.

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