Making a square peg fit a round hole, at long range
Sept 27, 2022 19:28:37 GMT -5
mwd8722, deathray, and 3 more like this
Post by Kyle on Sept 27, 2022 19:28:37 GMT -5
As hunting season approaches and everyone starts making their way to the ranges, various shooting topics get discussed on the message boards. One of the most popular this time of year is Ballistic Coefficient or BC as commonly referred to for short. In a NUTSHELL a bullet's BC is a numerical value that expresses how well it is able to maintain its velocity compared to a theoretically perfect, 1.000 BC model projectile. Just as there are many types and shapes of bullets, there are many Ballistic Models that projectiles are compared against for their BC numerical expressions.
The shooting industry has tried to keep things relatively simple over the years in terms of assigning or rating a bullet's BC. Ballistic apps, rangefinders, custom made elevation turrets all have been primarily based on either the G1 or G7 ballistic models. Shooters that have used ballistic apps with these models over the years have noticed and been instructed to either increase or decrease muzzle velocity to make real world shots conform to a ballistic app generated shooting solution, trueing. Some shooters increase or decrease the BC to achieve the same "trueing". Trueing may be a good practice if there is reason to believe a chronograph is not reading correctly or if the shooter believes their optic is not graduated correctly, such as 1 MOA adjustment moving impact 1 MOA on target. Nonetheless, input data is being altered in an attempt to duplicate real world shooting on paper.
Referring to High Performance muzzle loading projectiles - In general altering inputs for G1 BC or Velocity in a ballistic app will give the shooter a somewhat close chart to go by for Zero to 400 or 500 yards and distances in between, where the shooter is trueing to make the app and the real-world impacts to closely mimic one another. However, more and more shooters are seeking to get the most out of their equipment, making longer shots and expecting higher level of precision shot placement. Trueing for much longer distances, using an app as a stand-alone method, is a setup for failure in my opinion. Sure, the shooter will be able to get a close distance and a far distance to align in an app and on paper by truing. distances in the middle will likely not match tic for tac.
In my opinion why there is such a discrepancy between real world shooting impacts on paper and generated ballistic app data is that for years we have been told to make a square peg fit a round hole. The G1 or G7 ballistic models do not match the actual proportions of many of the bullets we are shooting, definitely not the AccuMax or Aeromax series. Most devices on the market are based on the G1 and G7 models and use algorithms based on those models to provide shooting solutions. As stated, if one is shooting close to medium range, 0 to 4 or 500 yards, trueing will deliver ok results. Trying to exceed that is where actual bullet trajectory will not match a ballistic app if the bullet does not conform to the proportions of the used ballistic model.
Take these things into account when you are spending time at the range zeroing your rifle, developing drop charts or using sophisticated equipment such as Kestrel to make tic and tac match. Below is a representation of what bullets would actually look like if they matched the 1.000 standard for each model. I hope this brings things into perspective. Who else believes that the Aeromax and AccuMax more closely resemble the G8 ballistic model? Apps do exist, Bullet Flight M and Ballistic AE to name a couple that have the G8 algorithms. Brian Litz has made great progress with custom drag models in Applied Ballistics. One day I believe that apps will be made more user friendly for shooters to create their own drag curves and models for making those longer shots.
Left to Right Ballistic Models: G1, G2, G5, G6, G7, G8, GL
The shooting industry has tried to keep things relatively simple over the years in terms of assigning or rating a bullet's BC. Ballistic apps, rangefinders, custom made elevation turrets all have been primarily based on either the G1 or G7 ballistic models. Shooters that have used ballistic apps with these models over the years have noticed and been instructed to either increase or decrease muzzle velocity to make real world shots conform to a ballistic app generated shooting solution, trueing. Some shooters increase or decrease the BC to achieve the same "trueing". Trueing may be a good practice if there is reason to believe a chronograph is not reading correctly or if the shooter believes their optic is not graduated correctly, such as 1 MOA adjustment moving impact 1 MOA on target. Nonetheless, input data is being altered in an attempt to duplicate real world shooting on paper.
Referring to High Performance muzzle loading projectiles - In general altering inputs for G1 BC or Velocity in a ballistic app will give the shooter a somewhat close chart to go by for Zero to 400 or 500 yards and distances in between, where the shooter is trueing to make the app and the real-world impacts to closely mimic one another. However, more and more shooters are seeking to get the most out of their equipment, making longer shots and expecting higher level of precision shot placement. Trueing for much longer distances, using an app as a stand-alone method, is a setup for failure in my opinion. Sure, the shooter will be able to get a close distance and a far distance to align in an app and on paper by truing. distances in the middle will likely not match tic for tac.
In my opinion why there is such a discrepancy between real world shooting impacts on paper and generated ballistic app data is that for years we have been told to make a square peg fit a round hole. The G1 or G7 ballistic models do not match the actual proportions of many of the bullets we are shooting, definitely not the AccuMax or Aeromax series. Most devices on the market are based on the G1 and G7 models and use algorithms based on those models to provide shooting solutions. As stated, if one is shooting close to medium range, 0 to 4 or 500 yards, trueing will deliver ok results. Trying to exceed that is where actual bullet trajectory will not match a ballistic app if the bullet does not conform to the proportions of the used ballistic model.
Take these things into account when you are spending time at the range zeroing your rifle, developing drop charts or using sophisticated equipment such as Kestrel to make tic and tac match. Below is a representation of what bullets would actually look like if they matched the 1.000 standard for each model. I hope this brings things into perspective. Who else believes that the Aeromax and AccuMax more closely resemble the G8 ballistic model? Apps do exist, Bullet Flight M and Ballistic AE to name a couple that have the G8 algorithms. Brian Litz has made great progress with custom drag models in Applied Ballistics. One day I believe that apps will be made more user friendly for shooters to create their own drag curves and models for making those longer shots.
Left to Right Ballistic Models: G1, G2, G5, G6, G7, G8, GL
