I should have mentioned that better here but I did other videos on that...It's 1/2 m*v squared...or m*v squared / 450,240 to translate into ft lbs... some online calculators use a different figure to translate to account for sea level I think so their numbers might be very slightly different but really really close. The calculators on deathbybunjie.com will do a pretty good job of calculating it for you, too. Hope that helps!
@@Deathbybunjie thank you. I found it. A bit disappointed with my results. I am shooting a Barnett Whitetail Hunter STR. After entering all the data, I came in about 45% efficient. I was hoping for a bit better. Thank you for your videos and the great info you provide. Look forward to seeing the next one on bolts.
Don't be disappointed! Crossbows are just inefficient, some more than others but next 2 episodes will offer suggestions to make your crossbow more efficient!
Well, Bunjie is 5.8 pounds advertised mass weight. Bunjie, Jr., is 5.6 advertised mass weight. Not much difference, really. Both have added extra sized stirrups, too. Also, Bunjie, Jr., was all decked out with rubber, maybe making up the difference in mass.
I always like to use a heavy arrow. I think it helps absorb the energy and don’t in words dry fire the crossbow. The energy is transferred into the arrow. So the lighter the arrow the more you are in terms dry firing the bow.
Another helpful calculator would be an arrow drop calculator that starts at 0 yards and shows not only 20 to 100 yards but 1 yard to 20 yards so when you have a 3 yard shot you will see how many inches high that you need to aim because the scope is mounted above the arrow. Your bolt will hit low at very close range. Being prepared for that will give you more ethical shots when you have to finish an animal off.
I didn't know that as a rifle and slug gun hunter, I'm used to having the trajectory fly high before it hits the target at say 50 yards. Very interesting analysis!
@@boomerrangerron the same applies to firearms. From 0 to somewhere around 20 yards your projectile will hit low. Bullets and arrows alike actually cross the line of sight twice during flight
The questions I ask myself are: Do we really need the extra speed? Is it so I can shoot farther to target? Do I need to increase my shooting distance? My answer to myself is no I am being successful. Why would I wish to risk making a poor shot placement? I love the challenge of the hunt and bringing the game into an optimal range. If I want to shoot farther distances I have my rifles.
I do agree...BUT this year watch my 2 shots on deer at 20 and 30 yards...both through those deer before they could react...hard to slow down after seeing that. But I'm not looking at long shots either.
The speed is for what Rich is doing staying in that ethical range of 50 yards in and yes it matters because a deer and its reaction is a problem having a bolt that is fast and heavy to go through the toughest parts of animals with 💯 through and through is what we should achieve not being able to shoot 100 yards or more and wound deer or worse.
@@Deathbybunjie Yes true and my Assassin is 360 fps and a smaller compact head which is very nice, same width as Bunjie jr and as you know gives the advantages of hanging out the blind window to shoot lol ! But that is why I wanted the Assassin for the compact design not really the speed because I do have a Crosman Sniper 370 fps so speed is nice but not a necessity for myself. I do understand tho since Jason is still shooting the Axium and ya slow with big arch lol 😝
Rich, I just know that my Horton Legend XL 175 I bought in 06 and I never (thank god) had a problem with her. My babygirl has taken numerous deer and has gone through three strings and hundreds of shots. I just changed this year from a red dot to a scope. Even though it’s old and heavy and slower,I would not change it for the world. “ALL HAIL BUNJIE” Your friend Dan from Jersey.🗽🦅🇺🇸👍
Bunjie (OB) may have had a couple things going for it. (1) being older, Excalibur may not have known yet how to cheaply make a crossbow so they over-designed it some (beefier limbs?). (2) The extra mass weight of OB helps to absorb energy the way a heavier gun reduces felt recoil.
This is a very illuminating series. My Tenpoint Titan M1, shooting a 504 gr. arrow at a chronographed 325 fps, is roughly 56% efficient. Not a barn burner, but farther away from the bleeding side of the cutting edge. 😄 Can’t wait to see the remaining videos in this series. Keep up the great work, Rich!
I went 2 seasons in a row where my limbs broke on my Excalibur Mad Max. Has anti dry fire, so no issues there. I shoot heavy arrows/broadheads. De-string after season is over and make sure things are snug and tight. But they told me they had some QC issues with manufacturing of limbs. Unfortunately there were still some being distributed, and my replacements were defective as well. All was good this season. Excalibur customer service was top notch and replaced both times after I contacted and sent pictures. Still have two Excalibur’s in my arsenal. No bad feelings.
Very interesting, now for the heavy arrow set ups 😁 This will be interesting as I should receive my extra weights from black eagle next week . Excalibur 360TD micro series
Very interesting I have already Broke a limb on my Killer Instinct Target shooting in the Back yard and the Arrow was seated all the way back. Enjoyed it
I won’t lump all manufactures into this but I believe some are riding the ragged edge on arrow spine/weight. Crossbows limbs aren’t any different than compound limbs as far as excess energy being transferred back into the bow with arrows that aren’t properly spined. Heavy arrows for me
Very good #2. I liked this one very much. Looking forward to the arrow mass video. As I have pointed out (many times) a heavier arrow results in lower lost energy, to the limbs. If you have a 280# draw weight and use a 270# arrow...Pull the trigger and all you will get is a moving arrow. No sound, once the string comes to rest. Nearly 100% efficient. Nothing lost to the bow. No damage to the string. Nothing at all in negative, in terms of damages. Now taking this insane example to realistic end.... The heavier the arrow...The less damages that can be inflicted on the bow. Compounds (anything using a pulley system) such as B3 are far more efficient due to the fact that they use leverage to create additional speed, beyond the limb weights, to which they are attached. Fulcrum principle, simply stated. The total load is always less than total travel. This is what makes traditional bows like the O.G. so inefficient, as they need full travel to match the compounds 80/90% travel. Anyways... The shorter limbs are the larger issue. As was said (1st video) you are attempting to spread the greater load over a shorter distance. Anyone who wants to break something can envision that it's going to be easier to break a short stick with 2X the force exerted as compared to a longer stick with 1/2 that weight. Just spec'd my Scorpyd off the Bunjie Calculator. 82% efficient with my current arrows. :)
You like heavier arrows? Lol...agree on the shorter limbs...that = shorter power stroke and less time to impart energy into arrow. But if you pull em back too far they break...seems Excalibur is going route of shortening power strokes it seems though
Excal is shortening the stroke but increasing the weight. Thats net neutral IMO and you still end up with a short limb which is going to fail faster than a long limb. Excal is attempting to make the blanket longer by cutting a foot off the bottom and sewing that piece to the top. Its funny sad and very stupid. What they need is a new blanket, all together. Carbon laminate and all will be well. Thats my view.
@Lever Action new limbs have new design, we'll see how that works. Fibers entire length. The new 380 has them, same as the assassins. But I think the 380 is the real test...it'll be in more people's hands
My Barnett whitetail pro it’s not super narrow not like the new ones it shoots a little under 400fps. I have had no limb problems. But my Excalibur micro 380 I have had limb problems.
You should be working at a crossbow manufacturer as chief engineer with all the specs you just pumped in my head 😁. It made a lot of sense with the excess energy going back in the crossbow
I used your calculator, my Ravin R29 is 55.54% efficient. I'm glad it's above 50%!! That is with 400 grain bolt and 427 fps. Not sure of it's efficiency with my heavier bolts. Thanks for adding the calculator.
I watched a shooting test on crossbows. The recurve vs. compound. The compounds made 150 to 300 shots the cams started to fail. And the recurve was up in the thousand shots. And still shooting with accuracy. What I like about my recurve is I can change toe bowstring out in the field.
They're all different. I did a podcast with a Friend of Bunjie who got 20,000 shots out of his Compound crossbow on the same set of limbs. Genevieve didn't make 750 on her recurve. Those are just examples but they certainly don't speak for all crossbows of course. They're all different.
Very impressed on your videos. I've been looking at them for quite a while. I've been thinking of going with a crossbow this year well your videos are very impressed keep it up my friend.
Time will tell but don't forget 1. There are other xbows out there that are pretty efficient and 2. There are some things we can do to make each xbow a little more efficient...that's coming up soon
Very interesting video Rich! Can hardly wait to see the next in the series! One thing that Bunjie Jr has going for it over the others is less arrow time on the string or the shorter the power stroke, the more forgiving the bow will be which helps out with accuracy. Very much like a higher brace height in a compound bow vs a lower brace height is generally more forgiving. Keep up the great work man!
BUT shorter power stroke = less time for string to impart energy to arrow, which unfortunately makes it far less efficient. Good video topic here thanks!
very educational video!!! i love the information and in depth research on these crossbows... my very question i was going to ask you about how we can make them more efficient is a subject your going to cover... love it!!! but, I'm still curious about the locations of limb failures? design flaw? weak point at the yoke of the limbs? limb bolts?? Is Reverse draw limbs better compared to traditional compound draw limbs?? very interesting stuff.. keep up the good work and i look forward to the other upcoming videos on this subject..
Ok. That explains why kinetic energy goes up as arrow weight goes up, the efficiency and the amount of time that the arrow is in contact with the string increases. Right?
This was great Rich! You always do such a thorough job of researching your topics! And of course you brought the jury to the courtroom as well! I'd love to see your opinion of the new Bungie and it's reverse draw setup?
Hi, I have a question: when you are calculating kinetic energy that you put in the crossbow you use the formula draw weight x powerstroke but draw weight isn’t constant, you use peak draw weight. Peak draw weight is hold for a few inches in compound crossbows generally at the half of powerstroke and even at max draw weight entering the let off which decreases draw weight. So if you calculate kin incoming and use data about real draw weight for different powerstroke and not peak draw weight then efficiency is slithly higher Thanks in advantage for the help, love this channel ❤
Yep, I mentioned that in the video, and without testing each crossbow and measuring it independently there is no way to calculate those numbers really, but given that they're all on a even playing field we can still calculate the difference between one model to another and that is quite impressive
Rich, fantastic video! This may not be possible....but is there a way (or do any of your contacts have a way) to measure or determine how "close to the edge" a crossbow design is? Or some way to establish a baseline (with today's bows) for bow efficiency vs. limb life? If so, factory advertised speeds, bolt weights, draw weights and power stroke could all be used to gauge bow/limb life before even purchasing a bow. Very interested/intrigued by this. Great job!!!!!
Man I think that's great...up for consideration! I think overall efficiency is a close start. Having a lot of overall leftover energy stresses everything. Second thing to consider would be buying an older model from a manufacturer, not their latest and greatest. The latest and greatest is most likely as close to the edge as they can get. This is a great idea though will think on it!
Very good video yet again. Comparing vertical bows to crossbows is really hard to do. Its also just as hard to compare crossbows to reverse draws. You will notice that there is a major words used in crossbow thats “pulling” the projectile. Reverse draw pushes the projectile this allows for the energy to dissipate away from the limbs. Your shock absorbers also move they are free floating that absorbs probably over 50% of the unspent energy. Many may disagree with me but there is a difference in pushing and pulling. Bunjie 3.0 shouldn’t have any issues. Bunjie 1 the original well lots to consider on that. Wider limbs can take more energy the heavy dacron string could take more as well so dry firing with that string was okay to do. You couldn’t dry fire with the flemish though. Materials and how limbs are made is a huge issue. Composite limbs have a hard time handling this pressure. The mostly fibre glass with carbon fibre, this gives them the reduce weight bit does it ever affect the overall life. Anyways great video cant wait for next week to get the arrow conversation. Great job.
@@Deathbybunjie wow i am really surprised by that. I know if i use the flemish it will destroy my whole front end. The Dacron came clean off every time I dry fired. Maybe OB is the best lol
Good stuff Rich! I believe the vixen was the slowest at the time with a 13 1/2 power stroke. I’m pretty sure In the beginning Excalibur used the same limbs on all their models and just increased the barrel lengths from a 13 1/2 stroke to a 16 1/2 in one inch incriminates to achieve 350fps on their top model at the time.👍😃✌️🇺🇸
All hial bunjie keep the good things going very interesting information almost makes me want to shoot alot heavier bolts to save wear on the limbs and a heavier swacker at the end
24 years ago I purchased the excalibur exomag the one with the carved limbs not the mag limbs that came out right after I purchased mine but to this day its still in perfect working order even a after a couple dry fires Just picked up a mag air and a mag 340 1 dry fire destroyed the poor mag air 😢 Excalibur sorted me out
Man, they sure don't build them like they used to! That is really neat though that you have one with the carved limbs, as long as you can buy strings you can probably hunt with that crossbow LOL
I don't think it is always, but it does transfer more energy with longer power stroke as opposed to greater draw weight. That's a plus. But there are reverse draws that have really high draw weights too, and that changes the efficiency numbers of course. Good question for sure!
Short answer is yes, but theres a lot to it. That "Breaking Limbs" series of videos I did attempts to answer that question. Keep watching those. Some real good discussion of that in Talking woth Bunjie podcast, too. Hope that helps!
The science guy mentioned the energy not imparted to the arrow goes back into the bow, either in the form of heat, or sound. For many years archers have noticed, all bows and crossbows were definitely louder, the lighter the arrow was that was shot out of them. As arrows get lighter and lighter, the bow/crossbow is getting closer and closer to simulating a dryfire and expending more and more of its energy into itself. I am no scientist, but, a heavier arrow, does not seem to show KINETIC ENERGY numbers that are much different than lighter arrows shot out of the same bow/crossbow. What does show a greater significance, is MOMENTUM. Which in terms (for my level of understanding), is a moving object's ability to maintain its velocity, when it meets resistance (heavy bone, for example). This appears to me, is a shift of focus on the efficiency of the bow/crossbow, and moves the efficiency focus to the arrow itself. My guess is, that the heavier the arrow, the higher the momentum, and the more energy that is transferred to the arrow, and as a result, less energy transferred back into the weapon itself.
What do you think about the killer instinct crossbows? Hear alot about their limbs breaking. I've got a new one, the fierce 405 but refuse to shoot it until I get some heavier bolts and broadheads.
@@Deathbybunjie I understand that the curve will be a hysteresis curve ie the load curve differs to the unload curve however it is fairly linear and therefore for the purposes of simple calculation- triangular.the formula therefore must be Max Draw x extension x 0.5. To be totally correct its technically the integral of the curve or simply put the area under the draw force curve. The released energy is the area under the unload curve which is transferred to the arrow and bow system.
@@Deathbybunjie Yes, but you calculated that the energy you put into drawing Bunjie was 211 ft lb. This is out by a factor of two ie. it should be 105.5 ft lb. That would make the efficiency 78.7% which might explain its longevity.
I had a crossbow bust on my foot just a couple days ago , my arm snapped the support arm shot down through the foot bar and pinned my foot. My foot now is doing alright. Key word alright
@@BackyardBroadheads the barnett 380 stalker and I am playing with deathbybunjie's calculator and this X-Bow is retaining alot of energy explaining why when I shoot it, it appears to have a recoil a bit
My flatbow will take a pig with a 100 grain broadhead flying at 150 FPS, so a bolt flying at "just" 300 FPS is PLENTY fast enough. I think a 300 FPS crossbow is about the sweet spot between penetration, accuracy and reliability - generally speaking.
@@Deathbybunjie I think so. Would you say 300 FPS is about the sweet spot for a recurve (broadly speaking)? Be interesting to learn how far they can push compounds before running into a reliability issue. Lastly, while I have you, would you say the additional speed of your compound crossbow has resulted in any changes the in way you hunt?
Do they have a cross bow, that has a dual power, option? Some times i don't want to kill the target, or a small animal injury ? It's against the law to shoot a gun in the city.
Most likely, you left the bow strung in a hot car or in direct sunlight long enough to exceed the temperature of which the epoxy can withstand. 99% of delaminating are temperature related. This temperature is usually in the range of 140-180 *f. Eli eve it or not, you can subject a limb to this temp simply by laying the bow in direct sunlight for 15 minutes. Or in a car on a sunny day.
I have to point out something about efficiency, l have an old Barnett Commando which by today standards is very slow, but it can achieve around 210fps with a 125lb prod or bow using 355 grain bolts, more than enough to hunt with, it can achieve the same penetration as my recurve 45lb bow. So really beyond that, the speed gain is minimal compared to the stress and noice increase as you go up in draw weight. So lets say 210fps-125lb - 305fps-280lb make the math about speed gains vs wasted energy, My point: there is a limit to what the gear can do, and the public need to understand that, no matter how heavy you get, after around 150lb you are just wasting energy, a lot of it, and it often turns into vibration/noice, is it worthy to get all that extra stress and noice for just a few fps? thats up to you to decide, for me it isnt, my crossbow is very quiet since there is very little wasted energy.
Run the calculator, and I bet there's more wasted energy there than you think. Keep in mind, also, that with my deathstalker and it's 150 lb draw weight I can get 400 ft per second with a 400 grain arrow. I'm around 380 with a 442 grain arrow, and well over 60% efficiency. I'm not telling you that to brag or anything, but just a tell you that it can be done. My next video talks about this. Crossbow designs have come an awful long way, and I can also tell you from personal experience that there is a world of difference between 260 ft per second on the Original Bunjie with heavy arrows and 400 ft per second with stock arrows on a more modern crossbow. There's no comparison. One of them is through the deer at 30 yards before they can blink. For all intents and purposes it turns 20 yards into 30. It means a pass through as opposed to a deer running off with an arrow half the time, or a spine shot. For me, that's a big deal!
@@Deathbybunjie indeed, l play airsoft, not archery related, but l see the difference between 280fps entry guns and the 350-420fps pro guns. My point is that not everything is draw weight, there is also a matter of limb geometry and materials used to get the best out of your set up, but even then, there is a limit to what the gear can do and those 400+fps comes at the expense of wear on the limbs, thats why faster crossbows tend to have more limb snaping issues. Hunting with slower setups is possible but it requires more patience and closer ranges, there is a world of difference between 210 fps and 400 indeed.
@@georgeASD yes, you do make a point that I totally agree with, and that is certainly it can be done with slower equipment, keep in mind this channel is named after my 2010 excaliber axiom, a crossbow that went with me to Maryland this year and killed four deer, at 260 ft per second LOL. So I totally get it!
I find crossbows are overbuilt and are not as efficient as laminated regular bow limbs. I think I can produce the same amount of energy as a 150 pound recurve crossbow with a 55 pound laminate bow drawing 30 inches
A 150 lb recurve is not a modern crossbow 😆 you can't touch modern crossbow energy with a vertical bow. But I agree crossbows are generally inefficient in comparison. We did a whole series on that 2 or 3 years ago. Some are better than others, but they not as efficient as compounds for sure.
Interesting issue! I have an early model Ravin R10. You know how narrow that can be. It of course is conventional draw, not reverse. I believe the draw weight is over 250 lbs. that R10 has not had a single issue in 5 years. I’ve taken deer with it and it is in like new condition. I hear stories of people having the blown limbs, strings and cables. Never even the slightest concern of wear on the R10. What to make of this?
@@Deathbybunjie I’m seeing where compound crossbows are more efficient. I also tried it with a 500gr arrow at 302fps and the efficiency went down to 31%
@NEA Bow Hunters yeah...you're touching on next week's video lol...added weight improves efficiency but has its limits. But I'm surprised that early, I figured 500 be good still
You know what I don't believe the fatigue thing really for 1 minute Rick because they shoot the crossbow limbs hundreds and hundreds and hundreds of times before they even put them out on the market for us to buy and I know your daughter hadn't Shot Heard hundreds and hundreds and hundreds of times so I just think it all boils down to is how well the live is made some Lim might have more glue than others some companies go with cheaper products and they just break
