Longest flattest trajectory

[cavedweller]

This is perhaps totally Field Target methodology related "or not". I really enjoy setting up different air rifles and diligently creating dope charts based on actual shots from a bench on a clear day - I always like to compare my trajectories with StrelokPro. To date the flattest trajectory I’ve found in the .177 cal is with JSB 10.34’s moving at 880 fps. I’m shooting flat in 3 different guns from 21 yards to 42 yards. The 4th gun, a TM1000 is shooting jsb13.4 heavies for comparison here. One gun, my Steyr HFT, is basically flat from 25 yards to 40 yards but had a very minimal drop out to 55 yards.
Q? What’s your longest flattest “verified” shooting gun/pellet combo? Please include the weight and brand of pellet and the speed you’re pushing it at.

@RScott I recently adjusted my scope - reduced the height by removing 1/2" pic risers and the following is the result for the Daystate Revere... the pic above left to see before and after:

 

[elh0102]

I believe you will find that the scope mounting details will skew your numbers. The actual trajectory is simple math, and the physics will not vary. A pellet of a certain weight and diameter, fired at a specific velocity, will fly the same from any rifle. (That's not totally accurate, as barrel dimension and twist rate will have an effect.) But, the height and angle of the scope will result in different POA vs. POI relationships.

 

[cavedweller]

I believe you will find that the scope mounting details will skew your numbers. The actual trajectory is simple math, and the physics will not vary. A pellet of a certain weight and diameter, fired at a specific velocity, will fly the same from any rifle. (That's not totally accurate, as barrel dimension and twist rate will have an effect.) But, the height and angle of the scope will result in different POA vs. POI relationships.

Do tell….. more!

 

[cavedweller]

I believe you will find that the scope mounting details will skew your numbers. The actual trajectory is simple math, and the physics will not vary. A pellet of a certain weight and diameter, fired at a specific velocity, will fly the same from any rifle. (That's not totally accurate, as barrel dimension and twist rate will have an effect.) But, the height and angle of the scope will result in different POA vs. POI relationships.

I’m not following completely - the scope shouldn’t have much to do with a given trajectory? The scope only provides for aim points and zero? But every gun with a given pellet and a given speed should result in a predictable and repeatable trajectory? My example is the four guns I’ve set up most recently have different scopes set at different heights but are yielding similar flight paths.

 

[Spartan]

Highest speed coupled with highest BC (stable flight being assumed) will give the flattest trajectory every time. It's that simple.

Projectile weight, barrel details, scope height, etc., are all irrelevant if only looking for flattest trajectory.

 

[Airgun-hobbyist]

Good question. I am always looking at the ballistics in Strelok Pro as well. The flattest trajectory for me is going to be the new heavy ZAN .30 caliber 56 grain pellets running at 895 fps. I set up the scope zero on everything at 40 yards so there is about half the pellet's diameter of hold-under at 32.5 yards. It's flat within half an inch from 16-49 yards, and roughly an inch from 10-53 yards.

 

[iAMzehTOASTY1]

Depends on your zero?
I've zerod at various distances (from 5-100yards)
Short distance would be flatter, no?

 

[Airgun-hobbyist]

I’m not following completely - the scope shouldn’t have much to do with a given trajectory? The scope only provides for aim points and zero? But every gun with a given pellet and a given speed should result in a predictable and repeatable trajectory? My example is the four guns I’ve set up most recently have different scopes set at different heights but are yielding similar flight paths.

This is true. You should notice a slightly different amount of distance and hold-under based on the speed and weight, coupled with a slight variation in the line of sight in relation to the pellet's path based on the scope height. All mine air rifles zeroed at 40 yards, shooting pellets or slugs, are still within a few yards and about .200" in hold-under around 30+ yards of each other. It is the longer ranges, past 50 yards, that really make a difference in drop based on speed and bc.

 

[Spartan]

Yall are talking about two different things. POI v. Range and Drop v. Range. One is relative to the scope, the other is relative to the muzzle. If one is talking about "flatness of trajectory" that is a projectile's flatness relative to the muzzle. Perhaps that's opinion, but it is the widely accepted standard of the term that I know.

 

[Airgun-hobbyist]

Yall are talking about two different things. POI v. Range and Drop v. Range. One is relative to the scope, the other is relative to the muzzle. If one is talking about "flatness of trajectory" that is a projectile's flatness relative to the muzzle. Perhaps that's opinion, but it is the widely accepted standard of the term that I know.

I am, and thought it was clear enough in my posts to understand that the heaviest .30 caliber ZAN 56 grain pellets were the flattest, because of the higher bc. The scope being zeroed at 40 yards allows for the flattest line of sight out to about 50 yards, for a fairly flat point of impact.

 

[JimNM]

Gravity is constant. "Flat shooting" is a self deceptive reference to POA vs POI vs gravitational acceleration. All things will accelerate at the same rate. Drop a pellet from the same height as a horizontal barrel shoots the same pellet and the two will strike ground at the same time, assuming level ground.

The higher the angle between line of sight and pellet launch angle, the steeper the approach to the point of incidence where POI and POA intersect, aka: Zero. The steeper angle means less time (and distance) where the POI and POA coincide.

Scope height over bore has a major impact on the relationship. Put the numbers into your favorite program and chart it out.

 

[Franklink]

Pheww! Talk about overcomplicating the situation.

Original post here seems to be in reference to a sub20fpe field target gun. Distances would be 10-55 yards. Since distances are not given in regular ft, and laser rangefinders are illegal, the widest possible "zero" is a desirable feature. The phrase "flat shooting" commonly used to refer to a wider zero range, compared to other options.

What OP is getting at, is that with a 20fpe limit, certain pellets have a larger zero range than others. His example was the 10.34s at 880.

For 20fpe field target, there's really only a few combinations that are realistic to use, the primary ones seen in competition are:
.177/10.34 under 930ish fps
.177/13.34 under 821 fps
.20/13.73 under about 809fps.

Of course there's other semi-reasonable options, like the .22/13.43 or the .177/16.2, but those are rarely seen, mostly b/c they fall short of the three most used combinations, for some reason or another (less wind resistance, VERY pronounced rainbow trajectory, etc).

Ultimately it comes down to faster/flatter versus heavier, loopier, within reason. You don't see anybody shooting in the extremes, like a .177/8.44gr @ 1030fps or a .22/18.13 @ 704fps, because it's either too fast for the pellet weight, or such a pronounced rainbow trajectory that there's no wiggle room built into the range estimation (again, where the "flatness" of the trajectory comes into okay).

As OP stated, the flattest REALISTIC combination that I've played with is also the .177/10.34s. I like em even better up around 915-925fps, from a polygonal rifled barrel. Pure magic for the field target game, and with a good barrel, almost an unfair advantage.

 

[FelixS]

Using my favorite resource for most things in life, caveman logic:
1. I would think that fps at a given projectile caliber and weight would be the same across the board, regardless of the gun.
2. Height of the scope will give you differing vantage points of a given trajectory, see my sketch.
3. Lighter and faster projectiles will be flatter up to the point where speed affects stability, thereby distort the trajectory.

My 2 cents.

 

[cavedweller]

I believe you will find that the scope mounting details will skew your numbers. The actual trajectory is simple math, and the physics will not vary. A pellet of a certain weight and diameter, fired at a specific velocity, will fly the same from any rifle. (That's not totally accurate, as barrel dimension and twist rate will have an effect.) But, the height and angle of the scope will result in different POA vs. POI relationships.

Imagine a air rifle held in a vice with no scope, imagine that air rifle is fully charged with each pull of the trigger, then imagine you are viewing the pellet’s trajectory from a side view - the pellet will rise and fall according to physics and environmental conditions; it will have a beginning to its apex and an end, at which point the pellet will begin its descent. None of this is determined by the (non existent scope); Ballistics and mathematics yes. Does this make sense or have I lost my mind at 4:30 am?

 

[cavedweller]

Depends on your zero?
I've zerod at various distances (from 5-100yards)
Short distance would be flatter, no?

Nope

 

[cavedweller]

Pheww! Talk about overcomplicating the situation.

Original post here seems to be in reference to a sub20fpe field target gun. Distances would be 10-55 yards. Since distances are not given in regular ft, and laser rangefinders are illegal, the widest possible "zero" is a desirable feature. The phrase "flat shooting" commonly used to refer to a wider zero range, compared to other options.

What OP is getting at, is that with a 20fpe limit, certain pellets have a larger zero range than others. His example was the 10.34s at 880.

For 20fpe field target, there's really only a few combinations that are realistic to use, the primary ones seen in competition are:
.177/10.34 under 930ish fps
.177/13.34 under 821 fps
.20/13.73 under about 809fps.

Of course there's other semi-reasonable options, like the .22/13.43 or the .177/16.2, but those are rarely seen, mostly b/c they fall short of the three most used combinations, for some reason or another (less wind resistance, VERY pronounced rainbow trajectory, etc).

Ultimately it comes down to faster/flatter versus heavier, loopier, within reason. You don't see anybody shooting in the extremes, like a .177/8.44gr @ 1030fps or a .22/18.13 @ 704fps, because it's either too fast for the pellet weight, or such a pronounced rainbow trajectory that there's no wiggle room built into the range estimation (again, where the "flatness" of the trajectory comes into okay).

As OP stated, the flattest REALISTIC combination that I've played with is also the .177/10.34s. I like em even better up around 915-925fps, from a polygonal rifled barrel. Pure magic for the field target game, and with a good barrel, almost an unfair advantage.

@Franklink - Well - damn - I’m upping my fps on the next ten guns I set up! Urban myth that the 10.34’s destabilizing above 890?

 

[cavedweller]

Using my favorite resource for most things in life, caveman logic:
1. I would think that fps at a given projectile caliber and weight would be the same across the board, regardless of the gun.
2. Height of the scope will give you differing vantage points of a given trajectory, see my sketch.
3. Lighter and faster projectiles will be flatter up to the point where speed affects stability, thereby distort the trajectory.

View attachment 357181

My 2 cents.

thinking

 

[cavedweller]

I am, and thought it was clear enough in my posts to understand that the heaviest .30 caliber ZAN 56 grain pellets were the flattest, because of the higher bc. The scope being zeroed at 40 yards allows for the flattest line of sight out to about 50 yards, for a fairly flat point of impact.

I get what you’re saying but I’m not buying it because your scopes line of sight has nothing to do with a pellets predictability at a given speed. @Franklink said it best. Besides that the question is about flattest longest trajectory using what pellet at what speed.

Q? What’s your longest flattest “verified” shooting gun/pellet combo? Please include the weight and brand of pellet and the speed you’re pushing it at.

 

[cavedweller]

Gravity is constant. "Flat shooting" is a self deceptive reference to POA vs POI vs gravitational acceleration. All things will accelerate at the same rate. Drop a pellet from the same height as a horizontal barrel shoots the same pellet and the two will strike ground at the same time, assuming level ground.

The higher the angle between line of sight and pellet launch angle, the steeper the approach to the point of incidence where POI and POA intersect, aka: Zero. The steeper angle means less time (and distance) where the POI and POA coincide.

Scope height over bore has a major impact on the relationship. Put the numbers into your favorite program and chart it out.

I like what you’re saying but I’m much denser than air. Because this is not about POI or POA; rather this is about beginning of trajectory apex to end of trajectory apex. Here's the thing... high school physics was wasted on me because i was wasted on MaryLou's budding body. However, i believe you are speaking about "angle of incidence". These 3 pictures highlight what i am getting at:

 

[cavedweller]

I like what you’re saying but I’m much denser than air. Because this is not about POI or POA; rather this is about beginning of trajectory apex to end of trajectory apex. Here's the thing... high school physics was wasted on me because i was wasted on MaryLou's budding body. However, i believe you are speaking about "angle of incidence". These 3 pictures highlight what i am getting at:
View attachment 357184
View attachment 357185View attachment 357186

The first pic shows two diff pellets out of the same .177 Daystate Revere, the 10.34 and the 13.43
The second pic shows a comparison between two different rifles with same pellet jsb 10.34
The third pic is a Custom Benji showing a pellet from 10 yards all the way out to 55 yards these shots were taken by a new shooter so he had to double up a few times as he didn't trust his finger pull.
In picture #1: Note how the JSB 13.43 pellets behaved out of the same gun shooting with the exact at same tune (settings) which caused the Pellets to be moving much slower or around 819 fps as opposed to 880 fps. They destabilized much quicker and had a much shorter APEX and in the end, they had a greater angle of incidence at the POI.