Precision rifle FAQ- how to true your ballistic coefficient (BC)

One of the most important yet overlooked items to do when shooting long range is trueing the ballistic coefficient of your bullet. While bullet manufacturers offer ballistic coefficient information on the various bullets they produce, that may not always be the exact BC for your specific setup. In this video we will review the process of trueing the BC of your bullet to your specific setup and conditions. This step is an absolute must do if you are shooting at distances of 600-800yds and beyond.
Instagram: mountainsmulletsmerica
Gear details
Rifle
- Pristine action
- MDT XRS chassis
- Outlier 6.5CM 16" barrel
- Timney 2 stage trigger
- Ottercreek labs .30cal Hydrogen L suppressor
Optic
- Arken EP5 5-25 scope
Ammo
- Ally munitions 135 atip load
00:00 Intro comments
01:09 Gear Review
03:45 Explanation of the process
07:18 Ballistic app setup
10:11 First rounds- 1000yds
11:53 Correct BC in ballistic app
13:15 1265yd data check
15:25 Shooting summary comments
16:37 What did we see in this video?
19:04 Closing comments

[@berteisenbraun7415]

Best long range shooting channel on the Web! YES I DO BELIEVE IT!

[@coltcomphbar]

I agree. He has helped me a lot

[@ebosspt]

Your story telling is as consistent as your shooting. You've managed expectations and deliver on target again and again. Nice work.

[@mitchh931]

Retired Army veteran here, I've learned more about marksmanship from you than I did during the entirety of my military service. I truly appreciate the incredible attention to detail and thorough explanation you provide.

[@EagleEyeShooting]

Presented very well and dig the target footage. Few things I would like to share as a fellow long range shooter. Scope height over bore plays little effect to calculated adjustments. At best, it will interpulate about a tenth. MDT did a video on this also. The first step one must do before relying on ballistic data is to do a tall target test up to your longest target engagement. Ensure your at 100m to see if any scope tracking error is shown. The EP5 is a great scope, but I personally have found a few tenths error past 12 mil on multiple scopes. Kestrel has this compensation as Zero offset. Adjusting BC as shown here will true up the distance your shooting at, however, this does not compensate correctly for your particular rifles and load trajectory. What will happen is distances half the range and closer will have shots impact above the target. It is essential to test at all effective distances. Ballistic solvers like the one shown here will get you close but unfortunately lack the ability to adjust to your rifle and load trajectory. It will get you close, but ultimately you will have to build a D.O.P.E chart with matching DA's Ultimately, this is where a Kestrel is an essential tool with its ability to Cal (MV) at the distance your rifle and load hits transonic. (Must be within 10% of distance). The Kestrel will replot the trajectory to better match your rifle and load. BC adjustments should only be done when you can interpulate exact velocities at targets with muzzle velocity

[@RebaDerChi]

you remind me of a young Alan Jackson. good stuff!

[@MountainsMulletsMerica]

Man this is great! Interesting fact about me…. Like Alan I also grew up on the chattahoochee

[@alangriffith5823]

Great video! One thing which is majorly wrong. At time 8:36, you enter 15.0 for "Velocity Variation". Your entry will change your MV 15 fps with every 1 deg F up or down. Example, reduce your shooting temperature 10 deg F from your Zero temperature and your MV will output 150 fps slower. This number, for factory ammo needs to be determined by shooting a sufficient size string at both your zero temp and then later at a higher or lower temp. For reloaders you can enter a fairly close Vel Variation based upon the powder you use. Example. Varget = .19 fps/1 deg. A great temp insensitive powder. A great powder which IS temp sensitive is Rel 15 = 1.52 fps/deg. These "estimations" can be found by Googling "powder temperature sensitivity chart". Other than this, great video!

[@akhomer]

These videos are clear, concise, and accurate. The format is great and the editing is spot on. I have a feeling the channel will continue to grow!

[@realsavour]

Hey man - great videos. BCs changes based on your bullet, but also depending on many other factors. You NEED to watch the Hornady podcasts about 4DOF and Zero Angle.

[@MountainsMulletsMerica]

100% will check this out…. First I’ve heard of it so can’t wait to see what else I can learn!

[@mitchellb1535]

​@MountainsMulletsMerica I would LOVE to see you try 4DOF! The podcast explanation made it sound very interesting to me. I highly recommend giving it a look!

[@realsavour]

@@MountainsMulletsMerica Would love to know how you're doing on this! Let me know.

[@nilescoyote4829]

Great informative video on trueing BC based solvers. Have you tried using any of the solvers that use the specific bullet your using and doppler radar derived drag curves like Hornady 4Dof or Applied Ballistics PDM's and CDM's? If you haven't I think you'd like what you find. A great explanation of what Hornady 4Dof is and how profiles are built can be found both on youtube and their podcast on pobbean and Spotify is episode #49 "why use 4Dof" The accuracy of the above two solvers compared to solvers that use a BC value from a G1 or G7 standard model is quite an amazing leap forward. I've been using them for the past 6-7 years in PRS competition and we wouldn't be scoring where we do today if we didn't have 4Dof and AB.

[@charlesmckinley29]

Thank you for not only explaining what you did but WHY you did it. Then you proved it worked.

[@veracitysolutionsllc]

Good video. I would add that people should be aware of truing in wind and aerodynamic jump. At those distances it doesn’t take much wind to affect elevation and one could be truing off bad data that could be significantly off on another day.

[@MountainsMulletsMerica]

Great point and I’m annoyed with myself that I didn’t think to mention this in the video. While the wind doesn’t change the theory or the process, like you say it could slightly change down range performance so always best to do something like this in as little wind as possible

[@veracitysolutionsllc]

@@MountainsMulletsMerica definitely a solid video. I wouldn’t worry too much about it. I’d hope those interested enough in long range would have an understanding of AJ soon enough and a little sense to know zeroing or truing in bad conditions can cause issue.

[@Mike750200]

Two and a half mils wind (with an amazing BC) at 1200 yards and making it look easy. Wonderful content. Thanks sir

[@christianlarson6708]

Taking me to school!! I love it! Great knowledge delivered very well and easy to understand/follow. Thanks for your efforts!

[@JeremyElliott]

Maybe this is a generational thing, but as I watch your videos, I have to keep fighting back a bit of surprise that I am being taught so much about long distance marksmanship by Richie Cunningham.😊 Seriously, I love these videos. Good work!

[@MountainsMulletsMerica]

Haha this is great! I’m embarrassed to say I had to look up Richie Cunningham when folks first started making this type of comment 😳😳

[@johnoldman5877]

Great tutorial! If you're going to shoot at distance, you absolutely need a chronograph. You can't just go by the velocity number on the box as that will not be the actual number from your rifle. The AMU also uses 10 rounds or more when collecting velocity data. I like to use a 10 round sample. I use a Labradar and Applied Ballistics. The calculators are very much garbage in - garbage out, so make sure your inputs are accurate. It will save you ammunition and time.

[@calangel]

I use two chronographs: a barrel mounted MagnetoSpeed and a tripod mounted light based or radar based chrono placed at a laser range finder verified distance. Record all weather conditions. Record near and far velocities. Use JBM ballistic's calculator and derive a BC. I've verified the BC of Hornady's 75gr ELD-M with this method. G1 .460 vs Hornady's advertised G1.467, which is within statistical variation of one gun to the next.

[@nicinterlagos4515]

Excellent instructional video. You are crushing it. Never an unnecessary word or unsubstantiated opinions. Great work earning your success. Keep at it.

[@ryanglass3570]

Great info thanks!

[@mikecrowley4275]

Loved it!!!

[@leroybarnhill3495]

Love this channel!

[@GetMeThere1]

I would have enjoyed seeing both charts (with each of the BCs) side by side, to see holdovers at all ranges -- including the differences at shorter ranges.

[@brianqually2212]

Thanks for the demonstration 👍👍

[@westtexas3041]

Thank you for the outstanding video. I will define trying this soon.

[@benjaminbrown1179]

Great vid!

[@jaredandrews379]

Definitely helped me out! Thanks for posting!

[@mikeTyson329]

Great video, keep it up!

[@mr_mongo7228]

Very educational thank you for sharing!

[@gregoryjackson6166]

Great job! Your video confirmed that I was on the right track. Thank you! G.Jackson, MSGT/USMC, Ret.

[@Hav_Nfun]

Very helpful and well explained, thank you for the great content 🇺🇸

[@simonjohnborg]

Best and most precise description I’ve ever come across. Well done. Impressive results from a 16” barrel. I would love to see a video made on the same easy step-by-step method shown here, on how to program a Kestrel 5700 Elite. Keep up the good work.

[@shamusarms5476]

Great video as always!

[@michaelcall1857]

Excellent video! IMO, instructional content is the most interesting.

[@jimlerum]

Nice job. Very informative video. You’re giving a lot of shooters new horizons.

[@badberttube]

Thank you for the master class sir!

[@stevedavis5349]

Just what I needed! Thank you!

[@MountainsMulletsMerica]

Really cool to hear you found value in watching!

[@juanherrera2672]

Easy pease. Good video

[@Puggernaught24]

Great video

[@willo7734]

great info! Thanks for putting together quality content as always.

[@MountainsMulletsMerica]

Appreciate the continued support! I’m trying to grow this channel so I’ve got a ton of new videos in the works. Hope you’ll stay tuned!

[@jasonrad9332]

Good stuff!👍🏻👍🏻

[@kevintowell415]

Terrific BC lesson, I have learned a lot!

[@austinjones9970]

Great explanation. Thank you

[@Capt4Edwards]

Love the content! I'm new into long range shooting and the way you broke this down made it very easy to understand!

[@kellbob4726]

Very Practical your a good instructor I learn tips on all your updates. Thanks

[@shaneciccarelli-palmer2962]

Idek I did not know about this topic, thank you for introducing this valuable branch is shooting to me!

[@ES-so5oc]

Dude you videos are top notch! Rock on!

[@MountainsMulletsMerica]

Thank you! Appreciate you taking the time to watch!

[@mattthompson83]

Best explanation I've seen on trueing out a rifle, thanks!

[@danecker6108]

So helpful! Thanks man

[@MountainsMulletsMerica]

Awesome to hear you found value in this one!

[@GH02T406]

The zero wind noise in his mic with the wind blowing hard is impressive.

[@MountainsMulletsMerica]

Crazy awesome performance out of a $25 Amazon microphone

[@scottupatree3356]

Good info !

[@firstimeshooter6590]

Ima go and save this video. Very informative.

[@stephendebord9953]

Great video, great rifle. This is the sort of thing that has pulled me into wanting to shoot well.

[@derekmcmurry]

great video

[@Runningmancs]

Great video! Getting into precision style shooting myself truing my app data has been a game changer.

[@tonyrebo9862]

Very concise and helpful content as usual! My 6.5 CM will be a happier with my trigger work :)

[@jbsack]

Best long range shooting video on the web. Thank you

[@theboatshoptb]

Thankful you have started to create more content. You make everything easy to understand for those of us trying to understand the fundamentals of long range target shooting! Thanks for taking the time to share your knowledge!!

[@darinmislow9022]

Really great video, thank for sharing your knowledge and know how.!!

[@MountainsMulletsMerica]

Appreciate you taking the time to watch! Really cool to hear you enjoyed this one

[@coltcomphbar]

Currently my favorite channel to watch. By far.

[@brianstillion2062]

Best channel ever.

[@danulman8837]

Great job at presenting excellent information in an easy to follow manner. I enjoyed watching and verifying all of the things I’ve done truing my long range data. I also use Shooter and really enjoy it and find the windage portion of the software to be very user friendly and accurate when computing drift.

[@greatdane3343]

Awesome video and fantastic shooting mate! 👍 👍 I love the instructional content backed up with a practical (and skillful) demonstration. Hopefully someone will sponsor you for a shooting mat so you and your rifles dont have to keep rolling around in the dirt! 😆 Keep it up mate. Great stuff!

[@ledeni012]

Well done, dear colleague! I will recommend this video to all my LR friends as the most informative guide - how to check BC! Well done!

[@diligentefforts8172]

Best vid out there 👌🎉

[@MountainsMulletsMerica]

Thank you! This one ended up longer than I had hoped but wanted to make sure I thoroughly covered the topic.

[@MagnumMuscle1000]

Before adjusting B.C. you must make sure you have the environmental conditions entered correctly (density altitude and temperature) as well as scope height and shooting angle.

[@TMFShooting]

Great Info , thank you , Great Stuff 💯💥💥💥💥💥💥💥

[@webanon]

Nice work as always. That microphone is great in those Palose winds too.

[@grantjamrock3812]

Best all around channel!

[@MountainsMulletsMerica]

Thank you! Really appreciate the support!

[@NoMatureContent]

I appreciate the effort you've taken to edit in the camera angles. Thats no joke.

[@ut_punkn1859]

Great information

[@GTMGunTotinMinnesotan]

I love that the wind was 1 Milllion miles per hour haha. Great content and explanation.

[@randalljeffs7272]

Best long range channel on YT

[@Samc6127]

I’m just now getting into ballistic calculations, and this really helps. I’ve heard my friends talk about trueing, but haven’t had it explained to me.

[@jackamelung8705]

Quality video..Thank You

[@MountainsMulletsMerica]

Thank you! Glad you enjoyed it!

[@What___1931]

Another helpful video. We should start calling you professor!

[@MountainsMulletsMerica]

Haha let’s not get carried away. Really cool to hear you’re finding value in watching!

[@joshgoetz8879]

Great info, would love to see some content on cant impacts and high angle shooting as well!

[@rockylongbrake1703]

🎉great content!

[@MountainsMulletsMerica]

Thank you!

[@jorgerodriguez-wv4ul]

I live in camifornia. I don't even shoot or hunt.. I found ur video really informative and interesting.

[@u4ia4040]

Very good explanation , i think this is applicable on every Balistic calculator . i use this feature on strelok , the devil is in the details and i myself was not aware about the 1400 fps speed range where BC really starts to count . as always great Video and greetings from Belgium

[@Matt-dd3cw]

This guy brings the goods, best long range shooting content on the internet

[@MountainsMulletsMerica]

Really cool to hear you’re enjoying my content! Lots more just like this on the way so hope you’ll stick around.

[@blackout9814]

I appreciated the explanation on how and why to true the BC in shooter app. Until now I only adjusted the MV to "true" the app

[@DoubleGrape944]

Hornady is notorious for inflating their BC numbers so the adjustment that you had to make checks out for sure.

[@recklessjunkie]

I think I have the same Sunwayphoto tripod. I love it.

[@RockDog101]

Great video. Living in a suburb of NYC, the longest target range that I have access to is only 300 yards. But when I move to a free state, I hope to stretch my Bergara out to 1,000+. Either way, very engaging content.

[@Dave-ck8cf]

Wow 😮!

[@davephilpott4543]

Thank you for this video. Many people would consider it "too complicated" to mess with BC, but as we can see the app makes it simple and it really pays off. For those folks without a chrono, it would be great to find out your comments on best estimates on fps adjustments, based on what you see.

[@spartan7.628]

Hey, love the video, BUT recheck that fps variation setting you set to 15. You told the app that that setting for the ammo is 15fps per DEGREE. That's not velocity variation from the chrono but velocity variation per degree of outside temperature!

[@Persuasian338]

Does a mount with a built in MOA (30 moa base in my case) affect height over bore? Chamber vs muzzle height? Or any idea how that affects bullet flight path when it comes to close and far zeroes?

[@21psd]

This is a good question. I wondered the same, exactly where to measure sight over bore using that base. I would think at the muzzle is best but how would someone calculate this?

[@MountainsMulletsMerica]

This is a great question and not something I’ve ever thought about…. My initial opinion is it likely doesn’t make a difference but I don’t have any hard data to base that opinion on. That’s one of those things to me that’s a lot of time and energy to think about and likely won’t make a noticeable difference in downrange performance

[@GB-zi6qr]

If I may add to this discussion. I'm running a 6.5 Grendel with a level scope mount. With 123 ELD-M's and a 200yrd 0, I'm getting just under 2" high at 100yrds. MV is 2470 per Magneeto Speed. Would a 20 MOA base change that? I'm wanting to use this for my general purpose all around rifle. Seriously thinking about building a CM for long range fun.

[@charlesmullins3238]

Boy those 135a tips fly so good..my best 3 of my life were with n560 from my 6.5prc and I can’t tell where 1 center impact vs another is…honestly looks to be a .264” hole slightly and I mean slightly opened up..I need that app back as I used it yrs back and forgot about it…hornadys does good but shooters a lot simpler..love that blaster and more you use that arken more I like it…see if you can borrow a vortex lht 4.5x22 as it’s high on my list for my carbon waypoint…local shop has one for $1700 which ain’t cheap but my other ones are zco840 and s&b pm2 5x25 ..just love the good stuff..thanks man…matt

[@taylorpestana1809]

Cool note from Geoballistics. There is a trueing setting that makes life easy. just input the trueing distance and bam. done.

[@DonaldReynoldsII]

Awsome u have pit me to work and i wil use shooter app

[@TheHoriznLine]

Can you make a video on how to true a bdc and sight it in. Every bdc on a scope is for a specific velocity, barrel length, ammo. A lot of people don’t realize that your bdc more than likely will not line up even if sighted at manufacturer recommended distance

[@MountainsMulletsMerica]

100% this is on my to do list. I won’t be able to make it happen until after first of the year though so stay tuned! Relatively simple process once you understand the concepts and have a ballistic app to use for data

[@TheHoriznLine]

@@MountainsMulletsMerica thank you, so much, an acog or lpvo would be awesome because most people have one or the other

[@mikesoehren5889]

Awesome content. I have been watching for a while and I'm loving the tips and tricks. What App are you using? Mine was just removed from the app store and they forced an update so I can no-longer use it. I'm looking for a good app to replace my old one.

[@carniv0rous]

Th Thanks that was awesome...plz do a similar one for 308 175gr smk

[@distantgi]

Very respectable instructional video, good work! I know that you mentioned the 600 yd and in not being affected by the BC truing, but could you run through the motion for target at 400, 600, 800 etc to compare dope to the ballistic software just for general reference? And possibly how to write a dope card for different environmental/temps?

[@desertdwellers7294]

I found this interesting. I would have thought that the BC the manufacturors give would be exact but I have problems with my BC calc. at longer ranges and have adjusted the muzzle velocity to compensate. But it doesn't help when the distance changes. So I'm going to try this. Hopefully it works.

[@MountainsMulletsMerica]

The bc provided by the bullet manufacturer is very close and directionally correct but there are many factors that influence the exact bc for your specific setup. You’ll have decent results running the bc provided by the bullet manufacturer but if you really want to improve your performance you need to true as shown in this video. Can’t wait to hear about your results when you get your rig trued up.

[@desertdwellers7294]

@@MountainsMulletsMerica, thanks for the info. I'll let you know next time I get out long range.

[@novicereloader]

Nicely done. Both the shooting and the teaching are very good. I'm curious to know how much variation you see between different rifles. Does one rifle change the BC of a given bullet significantly and the next leave it almost as published?

[@imeprezime1285]

Usually, BCs published by manufacturers are higher than observed IRL and LR shooting. Would be interesting to try truing BC for 7.62x39 mm 400, 600 and 800 yards

[@shauntucker5145]

i love you channel. I would love to know what could be expected out of a factory rifle instead of something like this that is so custom. barrels are easy enough to replace but when you start saying 900+ for all the actions, they end up being cost prohibitive.

[@Quality_Guru]

I’m not a PRS shooter, but I’m enjoying watching your channel. I struggle to get a precise grouping on my AR rifle, primarily because of how I have the rifle stabilized at an indoor range. Which Arca Rail and Ball head would you recommend to ensure my rifle is locked on tight? I already have a sturdy inexpensive tripod.

[@GB-zi6qr]

If I may, a few things I've done to my "Entry Level" AR. 1) Tighten up the interface between the lower and upper receivers. I used small pieces of crating tape. 2) install a free float hand guard. This sounds more simple than it is. I did use a mandrel to true the front face of the upper receiver where the barrel extension makes contact. For removal and installation of the barrel I also bought the Giessle reaction rod. The bad news. After all of this the rifle still only shoots 1.5" groups at 100yrds. I did say it's an entry level rifle. I did manage to improve the groups by 0.5". On another AR rifle with a better quality barrel I'm getting 1" groups. This rifle also has a muzzle break, the entry level rifle doesn't. Can it be done? Yes. Is it easy? Honestly that depends on your definition of what is easy and difficult. Wishing you the best of luck in your endeavors.

[@Quality_Guru]

@@GB-zi6qr Thanks for the intel.

[@maxcopple8187]

1100+ yards with factory ammo and a 26" barrel. I need to practice more.