H-1000 in a 25-06 or 6.5-06

[raktrak]

I've been told H-1000 is a good powder for 6.5-06 and my 25-06. Anybody got load data for an accuracy load thats around 3000 ft with a 115/120 Nosler BT?

[T. O'Heir]

"...I've been told..." Generally means that whoever said it was guessing.
Go here for .25-06 max loads. http://www.hodgdon.com/data/rifle/25-06rem.php

[raktrak]

Thanks for the tip , I was hoping someone had developed a super special combo that would give me a head start on load developement in mine it's been limited to IMR4350. I never ever guess at load data, but before I buy another powder I try to learn from others experience. Last count, I had 14 different powders and 64 boxes of bullets. So I was asking If their experience had been positive or negative.Accuracy loads are what I was looking for. Slow powders like H -1000 and H-4831sc seem to be best,but I haven't used H-1000.



" The one thing in life that doesn't cost us a dime, is being nice to others and not short,terse or self important so I share my Loads for 222,243,25-06,6.5-06,6.5x55,7mmSTW,7mm-08,270,308,30-06,7.5x55,8mm mauser,and 35 Remington also building a 300wsm on a Nesika action so as I develop my 1000 yard loads,I will have that available also."

[Unclenick]

Actually, if you read Rifle Accuracy Facts, by Harold Vaughn, you'll learn that slow powders have an accuracy drawback. It is because the pressure in the tube remains higher further down the tube. As the bullet exits, the jet of gas against the base accelerates it a little further, but deflects unevenly if there is any axial wobble or base squareness error. This causes the bullet to tip slightly and the result appears at the target. The stronger that gas jet is, the bigger the error it introduces. Ergo, higher muzzle pressure is undesirable, all else being equal.

The situations in which slow powders would tend to be more accurate is when fast powder can't get enough velocity to keep the bullet supersonic all the way to the target, or when a particular gun's barrel harmonics happen to favor it. Mid Thompkins uses H4350 in the 6.5-284. If he doesn't like something slower at 1000 yards, there is probably good empirical evidence telling him not to use it.

Nick

[raktrak]

Thanks Unclenick: I'm sure the phenomenon you descibe is a source of problems, but the real Will-O-The-Wisp for me is the problem of Harmonics.Some of the rifles are just plain FINICKY to the point that a .1 grain will make the difference. Some people sell real Barn Burners before they find the "sweet spot". I have found that the problem isn't so bad at 80 to 100 yards, but at 400 its huge,and at 1000 you can imagine. I bought a 222 Rem that shoots 3/4 to 1" at 300 yards at the last gun show. It had bad rings and sorry scope and was poorly bedded. A little floating and relieving the barrel channel,and a new scope did the trick.$300 was a steal for that one.



Blessed is he that understands harmonics for he is revered by the common shooters like me and will surely be sought after by future generations of shooters with the accuracy disease in their blood.

[Unclenick]

Yeah. My M1-A used to make a 1/2" knot at 100 yards with the Sierra 168 gr MK's driven by 41.6 grains of the now defunct Scott powder company's 3031 powder. +/- .1 grains and the knot would open up. The same gun and powder pushing the then new 155 grain MK would not make quite such a tight knot, holding about 1" at 100 yards, but you could load it +/- a full grain without the impact or group size changing at all.

Harold Vaughn graphs the vertical shot displacement due to barrel vibration of a rail gun progressing through .1 grain increments of powder charge. It was a sinusoidal shape. At shorter range, if you load near a peak or a valley of the sinusoid, you get wider load variation tolerance. At longer range, loading on the down-slope gets you compensation for bullet drop change as the charge goes up. This also works for some guns not on rails to compensate for muzzle rise during recoil.

In service rifle matches I was always having to remember to drop the elevation 2 clicks (1 M.O.A.) when I went to sitting position from standing offhand at 200, then move right two clicks in addition to normal come-up when I went to prone at 300. Boots Obermeyer points out that some load combinations are not only good for accuracy from the bench, but prove less sensitive to shooter positions; possibly this down-slope phenomenon.

Get Vaughn's book from Precision Shooting. Given your interest in barrel harmonics, you'll like it. Vaughn is a decorated WWII combat pilot who went back to school to study aerodynamics engineering. He became Aerodynamics Supervisor for Sandia National Laboratories and pioneered aerodynamics for nuclear weapons and sounding rockets and the use of computers for aerodynamic calculations. In his book, he uses instrumentation to measure how harmonics interact with the barrel action and bedding. He also shows the effects of twist rate, barrel torque and numerous other details. It’s a great book by someone who refuses to accept speculation and has the technical background and equipment necessary to prove what is and what isn’t, and busts a myth or two along the way. Highly recommended (by me, anyway; and no, I have no commercial connection with it, in case I sounded a little too enthusiastic).

Nick

[Gewehr98]

And also tried Hodgdon's H-4350 in the same chambering. I got excessive pressures with hard bolt lift, and the ammo turned out to be very temperature sensitive, well before I got velocities comparable to other folk's results with the same cartridge.

I've since gone to H-4831SC, and been very happy with it. No problems running a 120-123gr bullet over 3200fps, and a 140-142gr bullet over 3000fps, regardless of temperature and altitude. Pressure signs on my RWS brass have been nill. Barrel/bullet harmonics seem to be well in tune with each other, my best so far has been an 8" 5-shot group at 1000 yards, but I'm working on tighter.

I'd wager H-1000 would be so slow that you'd run out of case capacity long before you hit the velocity range you'd want in a cartridge like the 6.5-06, almost turning it into a .260 Rem, 6.5x55 or 6.5x57 performance wise.