Re: What is the best caliber for shooting 1300 yards?
I love reading Greg's posts. They're always well thought out and well written.
I second what Greg said.
Learning true marksmanship is honestly done on a .22 and, if you're lucky, as a kid. Learning how to properly apply marksmanship fundamentals are so easy to teach on a .22... after somebody learns how to hit consistantly with a .22 then, it's easy to move past that onto your 375,408,338,.50 cal application because teaching on a magnum caliber is something completely different.
Having the fundamentals drilled into you shooting a .22 can never be overlooked. This may not be the sexy answer but, it's an honest one. Hell, shooting off a bipod isn't hard but, if you don't possess the proper ability to plant your face on the same part of the stock, line up the shot correctly, load the bipod and have the proper trigger disipline, follow through and the ability to call the shot then, you're pissing away expensive ammunition and going to be frusterated at the end of the day, IMHO.
And, to answer the OP's original question, I'd buy a rifle of 6.5 caliber.... there are several and all are fantastic for 1300yds. Now that answer is sort of loaded.... You should learn how to hand load your own ammunition for this kind of application. Remember you came to a place where there are a lot of folks here that take this very seriously and, you can't be serious unless you hand load for accuracy, IMHO.
If you are serious about learning how to make 1300+ hits then, you have to have good equipment and, you have to learn how to make that equipment work to the best of it's ability. Even the best of equipment will only shoot maybe 1.5moa unless you load for it.... you can watch those groups go from 1.5moa down to .25moa or less based on what the rifle wants to shoot. Actually, there are many loads that will do better than 1.5moa BUT, when you actually work up loads, you will find that the worst ammo for your rifle will go all the way out to about 1.5moa and get back to .25moa or even smaller when you find the correct load for it.
You will find, for example, when shooting at 1000yds... you'd think a 1.5" group at 100yds would transfer to 15" at 1000yds but, that's not true. Because the bullet is in the air for about 1.6 seconds, that 15" group you'd expect will go to 25" and that is if you are a good wind caller.
So, you'r half inch group really ends up being about a 10" plate on most days at the 1000yd range and that is when you load for it.
The good news in all of this is that everyone here is very helpful.
If you don't want to hand load for now, buy a 308... if you have cash and can afford it, buy the 6.5 of your choice and there are a few really good guys that sell custom loads for pretty much anything you want to buy. The 6.5s are all great calibers, they all reach pretty far out and are about the most economical in terms of cost to shoot them... so, 260rem, 6.5 creedmore, 6.5x47 Lapua or even the 6.5x284 if you are a speed demon. I shoot a 300wm most of the time but, the 6.5s do just as well and don't burn all the powder I do.
I'll give the OP the thumbs up for this... you do decide on the application for which you're shooting then, you find the bullet, then you find the rifle.
The application is the important thing. Frame what it is you're trying to do first.. then find what will work best for you. There are so many things to weigh. Cost... cost of barrel life, cost of projectiles, cost of brass and powder... they all count for something. If you want to know what the best cartridge for 1300+ applications with no regard for cost, contact Dave Viers at Viersco... he'll hook you up with a 375VM that will shoot a 375gr pill at 3500fps and you can extend that 1300yds to 3000+.