great read john...even though i knew most of this...it was great to re-read it....and learned something new....i had no clue that leupold would swap out reticles for @225 bucks or so....i have a vx7 and will be also doing this as well....thanks for the ''heads up''
It's a cut-and-paste, but I thought it was explained better than what i was about to write...
The units of density are mass divided by volume (m/V). Density will increase if either mass increases while the volume remains constant or if volume decreases while mass remains constant.
Density of air will vary as the temperature and moisture content in the air varies. When the temperature increases, the higher molecular motion results in an expansion of volume and thus a decrease in density.
The amount of water vapor in the air also effects the density. Water vapor is a relatively light gas when compared to diatomic Oxygen and diatomic Nitrogen. Thus, when water vapor increases, the amount of Oxygen and Nitrogen decrease per unit volume and thus density decreases because mass is decreasing.
The two most abundant elements in the troposphere are Oxygen and Nitrogen. Oxygen has an 16 atomic unit mass while Nitrogen has a 14 atomic units mass. Since both these elements are diatomic in the troposphere (O2 and N2), the atomic mass of diatomic Oxygen is 32 and the diatomic mass of Nitrogen is 28.
Water vapor (H2O) is composed of one Oxygen atom and two Hydrogen atoms. Hydrogen is the lightest element at 1 atomic unit while Oxygen is 16 atomic units. Thus the water vapor atom has an atomic mass of 1 + 1 + 16 = 18 atomic units. At 18 atomic units, water vapor is lighter than diatomic Oxygen (32 units) and diatomic Nitrogen (28 units). Thus at a constant temperature, the more water vapor that displaces the other gases, the less dense that air will become.
You may be familiar with the concept that moist air is less dense than dry air. This is true when both have the same temperature or when the moist air is warmer. Said in another way, air with a greater percentage of water vapor will be less dense than air with a lesser percentage of water vapor at the same temperature. Often people erroneously believe that moist air is denser than dry air because very moist air is more difficult to breathe than dry air.
Man, this forum is full of good stuff..........I have been reading a lot about various compensations (angle, distance, wind) particularly watching the videos on NSSF. In the last video I watched he talked quite a bit about wind compensation calculations based on .308, which is what I will be shooting once it gets here, but how do I find info on different calibers? Thanks in advance, D
Being a new guy here that's right where I went, "For the New Guys". Excellent thread and great post John! The knowledge and information here is amazing. Just purchased a Remington 700 SPS Varmint in .308 but still have to wait 5 more days, I'm in CA, before I actually get to keep it. First order of business is to have it converted to a box magazine. Then a bi pod. any recommendations for a bi pod anyone? Optics will be a Shepard 618 V2. It was recommended by a friend at Quantico. We'll be moving to either Spokane or outside Boise in the very near future where there will be plenty of opportunity for long range shooting. Can't wait! Thanks for any and all help as it is appreciated!
First check in post, semi-long time silent member though. I too would like to thank you all for the wealth of knowledge and wisdom on this site. About 2 more years to retirement and then hopefully I get my time back to spend doing some of the things I have been putting on hold. Getting my feet wet in the long game being one of them.
What's positively amazing is how much has changed since the OP 12 years ago. Look at how many companies are either gone or largely irrelevant. Look at the current "go to" choices that weren't even around back then.
Well Boys, here she is. Her name is Mavka. She has been in the works for a little over a year. Started with a CZ452 .17hmr, moved up to a Tikka T3 .223, and finally a Springfield M1A NM w/ Douglas Barrel and a few other tweaks. I would like to thank all of you for your help and support into my transition in building a custom rifle. This forum community is one of the best I have ever been in. So many old dogs here with the knowledge that young pups Seek to learn. Thank you all!
specs: Manners MCS-T2A Elite Carbon, Badge Ordnance M-5 Comp DBM, Bartlein 1:8 5R SS 6.5CM, Jewell HVR Benchrest, BT Atlas Bipod, APA lil'Bastard, SPUHR SR-4000 Seperate Rings, Steiner Military M5Xi 5-25x56mm MSR. R Bros Rogue Action, Smithed by Travis Ridel.
My goal is to start attending my local monthly matches for the next year and enter my first major event in 2019. Look forward to meeting some of you in person.
P.S. I am in the market for a Range Finder, Kestrel w/AB, Chrono, Spotting Scope, Single Stage Press w/ 6.5CM Dies, tripod w/Saddle
I think the folks here understand that I post mostly for the new guys. At least that's my aim. I am a core adherent of KISS, and have made it the work of going on two decades here to stick with factory gear and try to find the most economical way to decent accuracy. I'm no champion, I just love to shoot, and don't believe in trying to do anything but my best. I deeply respect the folks here who get into the really complex and exquisite approaches to the various disciplines. I just don't have the means or the temperament to treat shooting as an obsession. It's recreation for me, and I get my smiles one at a time. i won't prognosticate here, I just invite folks to keep an eye out for my posts and make up their own minds.
I have been reading on and off here for a few years. I thought I had registered in the past but I was unable to login so I registered again. This is great site and I appreciate the opportunity to learn.
The wealth of information and experience shared by you fellows is greatly appreciated. I've learned so much in a short amount of time. Now it's time to put it to practice.
Thank You to all for your generosity.
Great post to read. I was so glad when I found the page had parted ways with scout. Wish all my stuff from original page transferred over but I’m mainly glad to have access to all the info this page has to offer
Thanks for all the great info guys! I've been a recreational shooter out here in the Southern Nevada desert my whole life but want to start to take it a step further with precision rifle shooting. I'm currently building up my first semi-custom rifle for extended range shooting. Any tips or advice on parts or accessories would be greatly appreciated! I look forward to learning a lot. Thanks again.
Since this topic came back up after Scout, many of the original links to excellent info have ended up broken. Hopefully their authors will see this post and be able to fix them.
There is a new, good book out there by Ryan Cleckner. I have purchased and repurchased this book to give to my shooting friends well over a dozen times. If there's better, I haven't found it yet.
I strongly agree with having a shooting partner. Both of you should be familiar with Cleckner's book and its contents. The best part about having a shooting partner is that each of you can be a coach for the other. An additional educated pair of eyes will help you immensely, and you can return the favor.
That additional pair of eyes can help you out with your safety, too. Not just about making mistakes, but by watching your back.
Most of us can get so wrapped up in what we're up to that we can lose track of our surroundings. That can be dangerous.
For example, my shooting club is within a mile or two of the Arizona/Mexican Border. We are constantly being warned that there are smugglers and other infiltrators literally as close as the far side of our berm some days. I flatly will not go there shooting alone.
My shooting partner has been in a neck brace since a motorcycle accident back in early January, and I have not been to the range since. We still don't know when he's getting rid of it. So, with the dearth of serious shooters in the area, I sit on the back bench.
What I will not do is bring a couple of thousand dollars of gear all alone to a remote location just this side of the border, put my hearing protection on, and start attracting all comers with gunfire, with nobody to watch my back.
As an Old Vietnam Era guy yet new here living in the Peoples Republic of California now, where I get dirty looks for what I ware in public I personally love to see the younger guys and gals shooting! I have recruited one grandson and hope to work on my youngest granddaughters (3 of them) here in CA. I have real hopes for one of them.
My first post - great info guys! One of the things I need to do is keep a log book. That will be the next thing I make or purchase. I'll also start keeping a log of the case prep and load development. I hope to meet some others in the vicinity of southeastern Wyoming.
Great information especially on the natural point of aim. I served as a special agent after the Corps and attended numerous training classes and shooting seminars and never heard NPA discussed. I am glad for the what the Marine Corp taught me and I have carried that through my life. I served as a range instructor with my agency and taught NPA and body alignment.