I'm worried about barrel life with a 243 Win. From what I can gather a 243 will give an accurate barrel life less than 2000 rounds. 260 Rem gives maybe up to 3000 rounds, and 308 will probably do better than 5000 rounds. I don't know; the first I saw those numbers was in the last few days.
I don't do a whole lot of shooting, but I don't want to have to rebarrel any more than necessary.
If you feed a calculator accurate data it will do amazing things. . . .
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Yes, that is what I have done. Ten years ago I was doing well to get the range correct, so atmospheric calculations were just academic practice for the day when I would get a good (optical) rangefinder. Results now are just amazing. I can meaningfully account for temperature variations, and then make single-shot hits that I would have missed otherwise.
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If you plugged in the published BC and took those numbers to the range you would miss a 4' target. That said you cannot base a caliber choice on calculations. Imagine plugging in the published BC for the 178 AMAX and comparing it to a poular 7mm rem mag load, the calculator would tell you the 7mm would blow the doors off the 300 RUM when in reality, in the "real world" the 300 RUM would leave the 7mm rem mag in the dust with the 178 AMAX. The 308 is the same way there are bullets available that will give a 7-08 a SERIOUS run for its money, despite the fact that "on paper" the 7-08 blows the 308's doors off. [img]/ubbthreads/images/graemlins/wink.gif[/img]
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I think I see what you are saying. I am an engineer by trade (I design water systems) so I see the abuse of hyper-accurate calculations all the time. With hydraulics, the numbers are not to be trusted completely, but calculations and computer modelling are the best estimates available. You will never be "right on" with a hydraulic model except by accident. However, trying to design a complicated treatment or pumping station by "eyeballing" it is much less likely to get any kind of good results. I think it is the same with ballistics: the results you get from fictitious, i.e., uncalibrated, bullet launches is just an estimate. Still, I think it is the best estimate available.
With water and with shooting, you can't just try something and see how it goes. In both fields that method of decision making is cost- and time-prohibitive.
Also, one needs a healthy dose of proportional sense. If you are comparing wind drift at 1000 yards between two imaginary loadings, the difference between 11 MOA and 10 MOA is essentially meaningless. But if you are comparing one cartridge that models at 11 MOA to another that models at less than 8 MOA, then probably you have a good basis for a decision.
With me and this rifle, I will gather information as well as I can, then have the one built that I think will work best. I won't know for sure how well it works till I start shooting it, but that is a fact of life in design.
I scrapped the 105 amax idea once I found the 95 grain Bergers shot better in my rifle and had a better bc and blew critters up just as well.
I ran them out to a little over 1500 yards at 11,000 feet on a chuck hunt this summer and they did exceptionally well even in a 15 mph wind.
I have shot 6" 5 shot groups at 1200 yards at 5000 feet.
I am blown away by the distance this short little package can give! And the best part is that you can keep shooting at more targets because it doesn't heat up the barrel near as fast as say a .243. [img]/ubbthreads/images/graemlins/wink.gif[/img]
Location: The rifle range, or archery range or behind the computer in Alaska
Re: Need Advice on Caliber
I think maybe you missunderstood me when I said to stay away from the calculators. I didnt meen dont use them for rifles and loads youre familiar with. Calculators have a valuable place in LR shooting. I meant you cant always compare cartridges with a calculator unless you have had first hand experiance with those 2 calibers. Such as comparing the 6mmBR to the 308 Win. For example, I spent more time than I care to admit looking at ballistics on paper, or on a calculator, ect...and I always said to myself the 308 is the LAST round I would ever use for a long range rifle. I had to have a 300 wby or 30-378 based on ballistics on paper...until I owned a 30-378 wby and a 300 win mag and then tried the 308. Will always own a 308. Never again a 30-378! Both the 6mmBR and the 308 have good qualities and both would most likely fit your needs. Just try not to look to hard at "ballistics on paper". You may like the performance of the 308, but might hate the recoil, the list of comparisons could go on for a while.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
After a few years in long range shooting I too have to agree with meichele about cartidges. You can have the best balistically proven cartidge in the world and if it is not consistant or you don't have confidence in the gun, it doesn't do you squat. I have killed more ground hogs out to 700 yards with my .223 shooting 75 a-max than anything. Had the most one shot kills and sometimes, I hate to admit the most fun with. I love the big cool guns but the more I shoot the more the .223 comes out and my 30-338 laupa imp stays home. Buy a gun you can shoot and feel good with. I agree a 260, 7-08, .223, or a BR would fit your needs. Hope you have fun with your project.
Speaking of guns that are fun to shoot but don't hold up on paper, I got started on this path with a .22 rimfire. I put a shim under the rear mount of the Unertl on the free rifle I used in competition and shot out to about 300 yards. I shot match ammo out of a 28" barrel with a muzze bigger than a quarter. No need to wear ear protection with that rifle.
When I had short days in community college I used to take it out to the local silhouette range (Pe Ell, WA) and spend the afternoon doing that. Lots of fun.