Have you ever wanted to build a gun that was perfect for you? It has been lingering on my wish list and now I am going to get started. My first thought, “what do I want to do with it?”. My problem is I want to do too many things. I love the focus and pace of bullseye competition with a .22 caliber pistol. I like the intensity of using my 9mm for fast moving and shooting at the range. I feel accomplished when I hit my target at 200 yards. I know for long range folks that is not really far but for a 25 yard shooter, it felt great. I also like a light turkey shotgun for this time of year. And recently, I have been thinking about conceal carry, backpack hunting and longer range shooting.
Because I can do everything and my conceal carry gun, a 9mm M&P Shield, is pretty darn good, I decided to build a 200 yard gun first then one for backpack hunting.
How do you decide what caliber is best?
If you are going to shoot long range, punching paper or hunting, how do you think about the caliber choices? Lots of things ran through my mind, what will go the distance, availability, cost, receiver and barrel options. Although, I have some experience thinking about calibers, I never really spent the time looking at the numbers. I always used someone else’s gun and the caliber was decided by design. When starting with a blank slate, I had some research to do around the basics behind bullets and cartridges. What are the options? What is long action versus short action? Does the shape of the bullet matter? I found an article that discussed both actions written in the fall of last year by Ron Spomer. This article started me on a journey to create the chart you see below. I list the ballistic data for a couple of suppliers with similar bullet weights at 200 and 500 yards. For ballistics, I used the ballistics calculator at gundata.orgfor many of the calibers. I utilized the Hornadyand Federal sites for 6.5 Creedmoor ballistic data. I wanted to make sure I understood the information provided in the ballistic calculators and this great article ‘Common Ballistic Terms You Should Knowin Guns and Ammo gave great explanations. For this project, I pulled the points below around a view of the key metrics:
- Ballistic Coefficient – Basically, the higher the number, the less amount of drag.
- Grain – the mass of the bullet.
- Velocity – measured in feet per second. Velocity is a driver.
- Energy – measured in foot pounds
Velocity is the driver. The energy is proportional to the mass and proportional to the square of the velocity. What this means is, if the velocity is held constant and the mass is doubled, the energy is doubled, however, if the mass is held constant and the velocity is doubled, the energy increases 4 times; Big Deal.
As far as availability, I looked for the number of manufacturers that offer the caliber with inventory available for purchase. The only caliber that was more difficult to find was the 7mm08. I was pleasantly surprised with the availability.
When creating the list below, I picked similar bullet weights for a particular caliber. You can see for 308, I chose to look at two different bullet weights. I glanced at different grain weights for some of the other calibers and decided to stick with the one I found most available. As I narrow in on a cartridge and the exact purpose, I am sure the larger grain weights will come into play.Ballistic DataThis is a bunch of data – what does it all mean? I wanted to make some sense out of it in alignment with my priorities. I care more about 200 yards than 500. I know that velocity is a driver and I am not so worried about re-loading – yet. I remembered a technique for evaluating data that allows you to prioritize what is important. For example, being flat out to 200 yards is one of the more important items so it got a 5 ‘weight’ (highest level) while energy at 500 yards was less important and got a ‘weight’ of 3.Weighted Score
What would you choose?A couple of calibers are bubbling to the top for what I will be doing. How should I decide between the Short Action 6.5 Creedmoor and one of the Long Action Calibers? Should I look to the talked about advantages with a short action, weight, clean burning, increased accuracy potential due to reduced flex. I am interested in your opinion. Please comment on this post and share some of your experience and points I may have missed.
I know I will learn more from the community at large as I walk this journey. I looked forward to sharing the next steps.