Originally Posted By: HidalgoOriginally Posted By: tugboaterOriginally Posted By: HidalgoFor whatever reason, my rifle (6.5) prefers 4064 with the 120s, but it does shoot H4350 well with 130-140 bullets.
Did you try H4350 with your 120's?
Yep. Couldn't get it to group as well. It was a tad faster, but the accuracy wasn't as good.
This is not a bad example of what I am going to say.
Generally the heavier bullets in any given caliber perform better with a slower burning powder than a faster burning powder. WHY?
With a heavy for caliber bullet, the slower burning powder has rounded or more gentle curve to it. This helps and allows for the bullet to reach a better velocity than a fast burning powder. The faster burning powder in the heavy bullet is sharp and peaks very fast. It's like the powder has fissled out before it had time to get the big bullet really going.
Part of the reason we have the magnum powders for the large magnum calibers.
Let's remember this. The only things we have in this game that are constants are the weight grain of the bullet, and the caliber. The rest are all variables. This includes velocity, powders, primers, COAL, all of which can be changed to achieve a different result.
As far as amounts of powder in each case, a 75% to 100% Usually gives the better results. BUT this is not set in Stone. The one example that comes to mind rather quickly is the 500 S&W using 12 grs of Titegroup and a 440 grain bullet. This load works well in most examples of handguns and rifles.
But getting back to a varmint rifle, I have even found that a few compressed loads give better results and I am not afraid to use them, as long as they are within safe pressure parameters. Ex: Using RE19 w/ 140 grain in a 260 That load is safe and good in my rifle and is in the Nosler book. 3 shots 1 holes at 100 yards. 18" barrel so I have to stop and let it cool before proceeding.
Another thing I wanted to touch on was rifle twists. Most times a faster rifle twist will allow one to use a slower velocity, and still get good results. The opposite being a slower twist most times will give good results with faster velocities. Look at the 22-250 1-14, and 1-12 and a 223 w/ 1-12 , 1-9, and 1-7 Pages upon pages can be written about which combo works best.
Last thing are burn rates, they cannot always be relied upon to give the best results. Sure they can be a guideline, but too many additives are added to the powders that give each one it's own characteristics. The other thing is the materials in which each powder is manufactured. Ex: Most powders base are some nitro cellulose and nitro glycerin the nitro cellulose made from wood or paper. But Vhitavouri claims that their nitro cellulose is from cotton. Is this better? It is supposed to be,, But, I will let you and your pocketbook decide that.
Now with all that info hopefully you can decide on what powders you want to try for the given caliber and bullet weight. Hopefully I have not confused anyone, and explained this in a simple manner.
The IMR 6064 was the go to powder for many years in the 22-250 it is still good. But we also have a lot of other powders out there now, and with different bullet combo the list can be rather long. May I suggest get at least 100 of the bullets you want to shoot, and several powders that you think will work and try 1-3 of each load. I have a list of several loads for the 50 gr, and the 55gr Noslers and the 55 gr Hornady. And I had a lot of fun doing all of this.
added I load for accuracy not for speed, but get them as fast as I can, as long as they group well.