stubblejumper

Not at all a true statement.The accuracy of a load is based on many factors and some particular bullets just will not shoot as well as others in a given rifle reguardless of the quality of the rifle or the load development.This applies to all cartridges.not just the large capacity overbore cartridges.

driftrider

I agree with Stubblejumper. 1/2" accuracy or better requires a that almost all of the factors influencing accuracy are tightly controlled to near perfection resulting in a very high level of consistancy. Let's be perfectly realistic here; <1/2 MOA is OUTSTANDING ACCURACY for any gun. That level of accuracy on a consistant basis (one or two lucky groups do not count toward the consistancy requirement) is hard to achieve even with dedicated, purpose-built benchrest guns, let alone a light sporter weight magnum hunting rifle.

A good quality rifle is just the start of an accurate SETUP. Now if you were to say that a custom rifle, with all the accuracy work done to it, should shoot MOST types of ammo into 1 MOA, I'd say that's not unreasonable. But even a great rifle with crappy or ill suited ammo won't shoot up to potential, nor will great ammo make a poor rifle shoot well. BOTH factors have to be matched to each other.

I've heard that the large capacity, over-bored magnums are somewhat finicky, often showing a lot of fluctuation in velocity which is a factory in accuracy. Both because a bullet that is faster or slower, all else equal, will hit higher or lower (respectively), and because velocity and pressure variations also change the harmonics of the barrel, resulting in less than outstanding accuracy.

Mike

Elkhntr04

Well I guess my gunsmith demands a little more from his custom rifles. He won't settle for a 1 MOA, in his opinion that is factory rifle accuracy. He won't ship a rifle off to a customer unless he gets a 1/2 MOA out of it. I guess he just has a different way of looking at things.

Elkhntr04

I am curious what is working best out everybodies RUM. Stubble, I read you have the 300. What is your best load for that. Are you able to get around 3400 fps with it? Anybody else?

bigcountry

Elkntr04, I got .5MOA accuracy with my 300RUM with 89 and 90gr of H1000 and 200gr accubonds. I only get around 2990fps. Fine with me.

Elkhntr04

Bigcountry,

How many different powders did you try? I got some Retumbo to try with the 200 grain accubonds. Have you had any experience with it? Did you try and push it any harder with the H1000? Or did you just try that, had it work and not mess around with it?

bigcountry

Goodness, I have tried RL22, RL25, H1000, Retumbo, and IMR4350 with this 300. Yes, I had good luck with Retumbo, but not as good groups. I think with 200gr I was using 94gr of Retumbo. Didn't Chrono. I got 2.1" groups at 200 yards with this. I like H1000, and besides I got 8lb container of it.

Elkhntr04

Thanks for the feed back. I will load up some Retumbo and see how that works. Then I may try the H1000 and see what the difference is. Thanks again for the info.

stubblejumper

I get 3340fps out of my 300ultramags using 180gr bullets and r-25.Group size averages 1/2" to 5/8".