Hopefully I'm in the right forum. If not, sorry, moderators please move it as necessary.

I'll be shooting at some longer ranges 300-600 yards in the near future and am trying to see what the heaviest bullet that will stabilize in a 308 with a 12" twist. Typically I've heard 168 to 175 but I've also seen posts on the net somewhere that people were using some 190's and 210's.

I know the 168's will work but just want to see what the heavier bullets do. Eventually I'll be moving to 1000 but that won't be till next year...need to save up for a better scope.

I'm shooting a 700PSS 24"bbl.

Its bullet length, not weight you have to match to the twist, but i bet you already knew this. Berger lists the best twist for there bullets on the website. Sierra will list the twist on some bullets that require a very fast twist. Click the bullet number on the site. Hope this helps.

It's actually length, weight, and muzzle velocity, but length is most important, weight second, and MV the least important.

The JBM calculators include a stability calculator that works well with .30 caliber bullets. Pick a muzzle velocity you will likely achieve with your bullet weight of interest, then change the bullet length in the calculator until the stability result is at least 1.4 for best match accuracy and 1.3 for hunting accuracy, and not over 1.7 for best match accuracy and not over 3.0 for hunting accuracy. Then you will be assured of a good shot at achieving the desired performance level. Note that atmospheric conditions can be factored in as well.

Many match bullets can actually tolerate higher numbers, into the 2's. The upper limit is about not introducing too much bullet wobble due to mass symmetry imperfections, and many modern match bullets are so good that doesn't seem to happen despite spinning a bit faster than is generally considered optimal.

Nonetheless, sticking to the 1.4 to 1.7 criterion, for example, at 2500 fps MV with your 12" twist you can use a 200 grain bullet for target accuracy if it isn't longer than 1.373" or shorter than 1.284". You can use a 180 grain target bullet if it isn't longer 1.324", or shorter than 1.238". Etc. I leave you to calculate your own on the JBM site. The sight also has a partial table of bullet lengths for reference under "lengths" on the menu column at the left.

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Nick

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"First contemplation of the problems of Interior Ballistics gives the impression that they should yield rather easily to relatively simple methods of analysis. Further study shows the subject to be of almost unbelievable complexity." Homer Powley

Your gun should stabilize up to 190. The 175 will preform better for the ranges you are going to be shooting. The down side is all guns don't like the same bullets and powder charges. You will just have to play with the load until you find what your gun likes.

Hey, thanks for the responses guys.

Yea, Sctony, I figured that the 175 would be one of the better contenders, was just hoping that someone had used a 190 load in a remington and I'd have a place to start. Kinda sucks when you get the bullets and powder only to find out what 100 other people know...it doesn't work.

Thanks for the link to the calculator, I'll see what I can come up with.

Looks like I'll be doing some reloads in 190 soon but I'll need a bit of research first. (currently working on some 168's as we speak) Got that itch to go out this weekend.

Have heard great things on Alliant Reloader17 for this class cartridge. I shoot a 7.5x55 Schmidt-Rubin and the guys on the Swiss boards use this almost exclusively now. It's nearly a ballistic twin to the .308 aka 7.62x51 Nato round. The nato is higher pressure, however. Here's alliant's load table:

Seanh, i did some reloading with the 190 smk this past week end. I did the reloads with the powder that i had on hand. Varget, imr 4895 and imr 8208xbr. My test loads were shot through my custom weatherby accumark that has a 27.5 in krieger barrel with 1 / 12 twist topped with a fixed 45 power leupold scope.
The max load i could get with the varget was 44 grains it reached 2568 fps. With 43.5 i got 2521 fps. The best group was .507 moa.
Imr 4895 max load was 43.5 grains with 2603 fps. With 43 grains i got 2577 fps. The best group of that powder was .391 moa.
Imr 8280 max load of 40 grains i got 2486 fps. With 39.5 grains 2466 fps. Best group was .411 moa.
All groups were 5 shots @ 100 yds from my lead sled. I HOPE THIS INFO HELPS YOU OUT.

The title of this thread really confused me. I thought the OP was asking about the 308 1.5" case.

I was trying to figure out how Tony got over 40 grains of Varget into that case w/o blowing something up!

So did I, at first.

I just edited the title to make it a bit clearer.

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MikeG

IF YOU RELOAD WITH HODGDON OR IMR POWDERS THIS IS THE LINK FOR YOU. IT GIVES LIGHT AND MAX LOADS.

data.hodgdon.com/cartridge_load.asp