As the title says I'm looking for opinion on the load choice for my 300 mag. I built up loads from min being 66 grains to max being 70 grains. Grouping was fun and interesting but my 2 best of 5 are very bottom and very top of loads. According to my manual the 66 g is 2990 ft/s and the 70 g is 3130 ft/s now I'm trying to decide to go with comfort or speed. The riffle is primarily hunted and not likely to be shot much over 200 yards and 300 is probably the max. Thanks for the constructive input
looking for opinions
- Thread starter zeddy32
- Start date
140 Fps difference when the max range is 300m doesn't amount to much.
Especially when it's so close to factory spec.
Before I bought a chronoghraph I would have loaded up 5 cases with 70gr and observed how well they held up over 5 or 6 reloads.
Especially when it's so close to factory spec.
Before I bought a chronoghraph I would have loaded up 5 cases with 70gr and observed how well they held up over 5 or 6 reloads.
Zeddy IMR 4350 and IMR 4831 will usually group very well with 180 gr bullets in a 300 Win. Would be nice to know what size groups you obtained with every powder charge you tested. How much time did you allow for your barrel to cool between shots?? Were the first 2 or 3 shots close together and the last ones "walking" up or sideways? or did one shot go to one spot then the second shot go to a spot a couples inches one way or the other. Did the third shot go back close to the first shot and the fourth shot closer to the second shot ....... ? You didn't mention how deep you were seating the bullets. Often smaller groups are obtained when the bullets are seated out as far as possible (without touching the rifling) yet still function through the magazine.
The velocity that the book gives isn't much more than a guess at what it will produce in yours. 2990 fps with 66 grains sounds pretty good at first glance (Nosler book, right?) and is faster than some factory loads, but I've got another manual here that gives 2805 fps with the same charge. Which is right? Might be either one, or none.
Backing off a load for reduced recoil is a valid choice, and 2800 fps isn't likely to bounce off a deer's hide at the ranges you mention. Still, it would drive me nuts not knowing whether I'd made a .300 into a 30-06 by accident, on purpose or at all.
If it were me I'd be shooting the hot load, but then again the only reason I shoot magnums is to make bullets go faster.
Backing off a load for reduced recoil is a valid choice, and 2800 fps isn't likely to bounce off a deer's hide at the ranges you mention. Still, it would drive me nuts not knowing whether I'd made a .300 into a 30-06 by accident, on purpose or at all.
If it were me I'd be shooting the hot load, but then again the only reason I shoot magnums is to make bullets go faster.
FWIW, the standard Wimbledon Cup .300 Winchester Magnum load for years used something like 68.5 to 69 grains of IMR 4350 with a 190 Sierra. This normally produces speeds of around 2,900 with match barrels.
The Nosler reloading manuals are excellent, but Nosler seems to be a bit optimistic in their velocity figures -- by about 100 fps or so.
According to my Nosler Manual, 70.0 grains of IMR 4350 is listed as the most accurate load with that powder and a 180 Partition. In the real world, that should be getting you about 2,950 to 3,000 -- just about perfect.
You are correct that there will not be any practical difference between the top and bottom loads with that bullet out to 300 yards. Frankly, a .308 with a 180-grain bullet can do the job on a moose at 300 yards, so you will be fine whatever load you choose.
I think you should load up 10 rounds each of your top and bottom loads and shoot a 10-round group at 200 metres, taking LOTS of time to pace out your shots over a couple of hours.
I would choose whichever load is the most consistent and accurate and stay with it.
You talk about "comfort vs. speed". Frankly, there won't be much recoil difference between the top and bottom loads that you have listed. As to speed, I would expect that 4 grains less IMR 4350 will probably lose you around 150 fps. If your top load is, say, 2,975, then your bottom load will be about 2,825, give or take. Probably not enough to worry about -- even for shooting longer than 300 yards. For these reasons, go with the load that is most consistent and accurate and forget about the rest.
The Nosler reloading manuals are excellent, but Nosler seems to be a bit optimistic in their velocity figures -- by about 100 fps or so.
According to my Nosler Manual, 70.0 grains of IMR 4350 is listed as the most accurate load with that powder and a 180 Partition. In the real world, that should be getting you about 2,950 to 3,000 -- just about perfect.
You are correct that there will not be any practical difference between the top and bottom loads with that bullet out to 300 yards. Frankly, a .308 with a 180-grain bullet can do the job on a moose at 300 yards, so you will be fine whatever load you choose.
I think you should load up 10 rounds each of your top and bottom loads and shoot a 10-round group at 200 metres, taking LOTS of time to pace out your shots over a couple of hours.
I would choose whichever load is the most consistent and accurate and stay with it.
You talk about "comfort vs. speed". Frankly, there won't be much recoil difference between the top and bottom loads that you have listed. As to speed, I would expect that 4 grains less IMR 4350 will probably lose you around 150 fps. If your top load is, say, 2,975, then your bottom load will be about 2,825, give or take. Probably not enough to worry about -- even for shooting longer than 300 yards. For these reasons, go with the load that is most consistent and accurate and forget about the rest.
The only thing to 'go for' is accuracy. Comfort and speed don't matter. Well, maybe comfort, but not at the expense of accuracy.
Suspect, like p-17 says, 70 g 3130 ft/s is optimistic. Hodgdon shows 71.0 as max at 2974 FPS out of a 24" 1 in 10 barrel. And 66.0 at 2,746 as the start load. Not something to worry about, though. Manuals vary a bit. Anyway, load for accuracy not velocity.
Suspect, like p-17 says, 70 g 3130 ft/s is optimistic. Hodgdon shows 71.0 as max at 2974 FPS out of a 24" 1 in 10 barrel. And 66.0 at 2,746 as the start load. Not something to worry about, though. Manuals vary a bit. Anyway, load for accuracy not velocity.
It sort of depends. Nosler's data was shot out of a Lilja barrel and a minimum chamber. If you are running a custom chambered match grade barrel you stand a very good chance of matching or exceeding their velocities. If you have a sloppy chambered factory barrel you might not get within a mile of their speeds. I've got rifles that beat their top speed and do it with Nosler's starting load.
This is the truth, right here!! Custom barrels and minimum SAAMI spec chambers often get higher velocities with less powder than do Factory offerings, which tend to be on the more "generous" side.
I have a custom 308 Norma Magnum, with a nice snug chamber in a custom barrel, and with identical loads, it delivers 150 fps more velocity than does my factory rifle so chambered.
Needless to say, I get away with somewhat less powder for equal performance in the custom unit.
This is why a chronograph is a valuable tool. You can actually KNOW what your velocities are in YOUR rifle with YOUR load. Otherwise, it may not even be a close guess.
Regards, Dave.
