Wife's Elk Arrow Trajectory

[treillw]

Some of you may remember reading this thread talking about arrows and broadheads for my wife.

Broadhead and Arrows for Weakling Wife

Title is a wife approved joke - don't get mad at me. 😬 Much to my delight, my wife wants to archery hunt this year. She got a great deal on a Diamond Infinite Edge and really enjoys shooting it. We just started shooting more seriously a couple of months ago. She is up to 39 pounds and has...

www.rokslide.com

Since then she has gotten a PSE Bandit NXT, is up to 46 pounds, and draw length is set at 26.5 inches. I've had people tell me to use everything from 300 grain arrows to 600 grain arrows for her to elk hunt. I figured we just need to get some heavy points and test things out for ourselves. I did the testing yesterday and got some intriguing results. I figured some of you might have been down this road before, so I'd see what you think. Here are the drop results:



Observations:
• A couple of the numbers don't make sense and I will have to re-shoot those (highlighted in red).
• Arrows are Gold Tip Expedition Hunter 3555 and might be under-spined for some of these points.
• It's interesting that the 505 and 530 grain arrow drop the same.
• I would expect to see more of a drop as weight increases at 30 yards - but maybe that is just because I'm not a robot and the human error is more significant than the effect of changing tip weight.
• The groups at 40 yards are pretty tight. Wind picked up on arrow 3 and might be some of the reason for the craziness?
• I need to shoot these through a chrono and get some speeds.

Any other insights?
Any tools to make my data more useful?

Thanks!

 

[Billy Goat]

Is adjusted drop the difference from the lightest arrows I take it?

I'd recommend sighting in each arrow at about 30 yards. Shoot that same pin at distances inside and outside of that. That's where I feel like trajectory comes into play, it's if you are off by 3 or 4 yards because the animal walked up or came closer. Use that to determine what is acceptable trajectory. A shot that you know the exact distance isn't a big deal, assuming it's within your range.

 

[Whiskey_Fish]

Is adjusted drop the difference from the lightest arrows I take it?

I'd recommend sighting in each arrow at about 30 yards. Shoot that same pin at distances inside and outside of that. That's where I feel like trajectory comes into play, it's if you are off by 3 or 4 yards because the animal walked up or came closer. Use that to determine what is acceptable trajectory. A shot that you know the exact distance isn't a big deal, assuming it's within your range.

I think this is a really good suggestion. I’m struggling to articulate the reasoning but I also thing that somewhere in the process of adjusting the drop to a baseline you skew the data. Comparing a hold over/under from 30y every time could be done as a percentage difference and might be eye opening. MPBR for your bow in essence.

Edit: I’d also consider removing the group size and only look at the vertical component of the group. Might be easier to interpret those red boxes that way.

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[wildwilderness]

I think you are over thinking it a bit! Also the tune is going to be way off, which will also affect where the arrow impacts. For example I just changed some things up on my set up. - went from #68 dw and and a 480gr arrow and 29.5" dl to #70, 450 gr arrow and 30" dl (switched release) After re-tuning the bow, I only gained, 4 fps, and was hitting LOWER.

So you never know exactly what will happen as you tweak the set up. If you want a more objective comparison just shoot the chrono with the various weights. That will give you be best estimate of trajectory. The conventional wisdom will be in the middle of the extremes- for elk, with that bow, build an arrow that is properly spined/tuned between 400-500 grains!

 

[Billy Goat]

Shoot at a horizontal line. Don't worry about spread, it will be easier to hold on a single plane.

 

[Billy Goat]

I think you are over thinking it a bit! Also the tune is going to be way off, which will also affect where the arrow impacts. For example I just changed some things up on my set up. - went from #68 dw and and a 480gr arrow and 29.5" dl to #70, 450 gr arrow and 30" dl (switched release) After re-tuning the bow, I only gained, 4 fps, and was hitting LOWER.

So you never know exactly what will happen as you tweak the set up. If you want a more objective comparison just shoot the chrono with the various weights. That will give you be best estimate of trajectory. The conventional wisdom will be in the middle of the extremes- for elk, with that bow, build an arrow that is properly spined/tuned between 400-500 grains!

Something has to be wrong with your Chrono or setup. You don't drop 30 grains, add 1/2" of draw and two #'s and only gain 4 fps. On my bows 30 grain is 7-9 fps. Every pound is about 2 fps. 4-5 fps for 1/2".


I have often used heavy point weights to play with heavier arrow setup. Tune isn't as critical when you don't have wings on the front of your arrow. It's not a good evaluation once you get past 50 yards. But I have duplicated things to 45 later with a properly spined hunting arrow, in comparison to an underspined heavy tipped practice arrow. Biggest thing is arrow diameter skewing things.

 

[wildwilderness]

Something has to be wrong with your Chrono or setup. You don't drop 30 grains, add 1/2" of draw and two #'s and only gain 4 fps. On my bows 30 grain is 7-9 fps. Every pound is about 2 fps. 4-5 fps for 1/2".

The chrono is very old at the club. The bow is a 2017 Carbon Defiant 34" with the current setup as described its getting 282 fps on the chrono. Its shooting bullet holes through paper. I didn't test the fps before I made the changes, but iirc it was in the mid to upper 270s last year. I will have to go shoot at 100 yds and see how the trajectory really changed. Just got it tuned up.

 

[sndmn11]

FWIW my wife is shooting around a 550gr arrow, 50#/25", and can get to 60 yards on her fast eddie. She also wouldn't even consider any shot at game past 20 yards without being ranged, and likely none past 40 yards period.
The downside to this is there is less margin for range estimation errors which may be common in hunting. The upside is that it has taught her to be very critical in her shot process for shooting in between pins, and that extreme focus mindset I think has accelerated her learning as well as transferred over to rifles.

 

[Billy Goat]

The chrono is very old at the club. The bow is a 2017 Carbon Defiant 34" with the current setup as described its getting 282 fps on the chrono. Its shooting bullet holes through paper. I didn't test the fps before I made the changes, but iirc it was in the mid to upper 270s last year. I will have to go shoot at 100 yds and see how the trajectory really changed. Just got it tuned up.

Somewhere I have written down what a carbon defiant turbo was doing. Had one 29" drew 72#. Had it cooking with light arrows. I think it put a 411 grain arrow around 305 fps.

 

[treillw]

Is adjusted drop the difference from the lightest arrows I take it?

Edit: I’d also consider removing the group size and only look at the vertical component of the group. Might be easier to interpret those red boxes that way.

Sorry for the confusion. I didn't move the sights at all for the testing. I just shot the bow as it was and figured I could adjust everything by subtracting out the drop at 20 yards to effectively "zero" the bow. Everything shot low, so I used the same philosophy with "adjusting" all of the 30 and 40 yard shots as if those pins were zeroed at those distances as well - as they would be.

The group size only considers the vertical distance. I just put that in there as a sanity check - seeing those 6" and 7" groups, I know I can shoot better than that and need to redo those.

 

[treillw]

it's if you are off by 3 or 4 yards because the animal walked up or came closer. Use that to determine what is acceptable trajectory.

Yeah, I'm kinda struggling to know how to interpret this data haha. That might be the thing to do. It's hard to quantify what is acceptable.

Eventually were going to come up with something and then just have he go shoot a bunch and see how it works for her with pin gaps and misjudging yardages, etc.

 

[treillw]

I think you are over thinking it a bit!

Who? Me?? Nah!

 

[treillw]

If you want a more objective comparison just shoot the chrono with the various weights. That will give you be best estimate of trajectory.

How do I go from velocity to trajectory? Some sort of calculator I assume?

 

[treillw]

FWIW my wife is shooting around a 550gr arrow, 50#/25", and can get to 60 yards on her fast eddie. She also wouldn't even consider any shot at game past 20 yards without being ranged, and likely none past 40 yards period.
The downside to this is there is less margin for range estimation errors which may be common in hunting. The upside is that it has taught her to be very critical in her shot process for shooting in between pins, and that extreme focus mindset I think has accelerated her learning as well as transferred over to rifles.

Good info. Is she using pins at every 5 yards?

How bad would the train wreck be if she misjudged 25 yards as 30 yards?

One good thing about elk is that they are big targets. I think 16" is the conventionally accepted size of the vital area. That does allow for a good bit of vertical error....

 

[sndmn11]

Good info. Is she using pins at every 5 yards?

How bad would the train wreck be if she misjudged 25 yards as 30 yards?

One good thing about elk is that they are big targets. I think 16" is the conventionally accepted size of the vital area. That does allow for a good bit of vertical error....

Yes, she does have 20, 25, 30, 35, 40-60.

She needs to be within 5 yards AND execute a precise shot to stay in the 8 ring within those 40 yards. I do think that your data supports you have to change weight 75+ grains in these low poundage/short draw scenarios in order to see a meaningful difference in trajectory.

Her first archery hunt will be this year for doe pronghorn.

I built her arrows as I did because I figured numerous pass throughs and clean harvests have happened with darned near identical arrow speed and mass, and you'd be hard pressed to find a trad guy shooting significantly less mass.



Added* she started off with 3 pins spaced every ten yards and did fine, bit has gained a lot of confidence with better results going to 5 pins.

 

[sndmn11]

To be frank, I think if we did it again we would do the two pin fast eddie. This would force a measured distance to be picked, therefore reminding to measure, and eliminate the range estimation hiccup.

 

[treillw]

I built her arrows as I did because I figured numerous pass throughs and clean harvests have happened with darned near identical arrow speed and mass, and you'd be hard pressed to find a trad guy shooting significantly less mass.

Just curious; what are you referencing with the numerous pass throughs and clean harvests? Trad guys?

 

[sndmn11]

Just curious; what are you referencing with the numerous pass throughs and clean harvests? Trad guys?

Yes.

 

[treillw]

About how much energy do their bows make? Any clue?

 

[Billy Goat]

Mine do about 35-37 ke.