Extreme Spread Issues

BCBRAD

BCBRAD

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I have been loading for a 300WinMag in a Tikka / Tac for about a year now. Use H-1000 powder and a variety of primers and a 208 A-max. It is used for banging steel out to ~1200 yards. My issue is the extreme spread is in the neighborhood of 40fps, this can produce groups (10 shot) up to 25" at 1000 yards, the ES of 40 gives a 10" handicap at that range. This rifle will produce < 1 moa at 100yds, so mechanically the system is not real bad.
I have found that 75.5 gr of powder with a standard Federal Match primer to be as good as it gets. I have allot of H 1000 on hand so am committed to that.
Question I have is there an amount of powder that will give consistent combustion, I realize this equates to a pressure that H 1000 best operates at, I have yet to find this.
Any thoughts on this are appreciated.

As a side note I have a 223 that has an ES of <10fps and SD of 7.7.
 
Powder burns most efficient at the highest pressure it is designed to operate at.
This is why world class long distance competitive shooters load their rifles as heavy as the individual rifle will handle.
 
How did you develop your load? Did you shoot for groups with increasing powder charges, or did you do a ladder test?

You could try a different primer, CCI works very well for a lot of people.

A little detail on your reloading procedure would be useful. Do you anneal? How many firings do you have on your brass? What scale do you use? etc etc.

In my experience, high ES can generally be traced to one of two things: a step in the reloading process, or that your rifle simply doesn't "like" that combination of components.
 
25" at 1,000 is 2.5 MOA. Not at all bad. However, the amount of powder used has nothing to do with combustion.
Hodgdon suggests a magnum primer with H1000. I'd change primers and quit worrying about velocity spreads. Velocity is not as important as accuracy. Especially for long range target shooting.
 
I shoot a 5 shot group, anneal cases and do the normal 'tricks'. I have low ES with my 223 and 260 Rem following the same procedure as with the 300win. being a larger capacity case I was thinking ES should be at least in line with the smaller cartridges. I have been looking at the 'optimum powder charge' way of doing things and am in the process of getting rounds loaded today ( not a good day for the range as it is very windy here), I have freshly annealed cases, trimmed to 2.610", ultra sonic cleaned and polished, inside case necks polished as well, these cases are necked sized with a Lee collet die, and concentricity is 0.000"-0.001", I have some cases that have been neck turned and some that are not, they are Norma cases. I use an RCBS 10-10 scale, its discernible to one grain of H-1000, ya its a slow way. I will load from 76.3 in 0.7gr increments to 79.9 and see what the chrony tells me. Any insight to this is appreciated.
 
I would think you should be able to reduce that ES considerably.

I use H1000 in one of my 308 Norma Mags behind the 200 Accubond and Partition, and neither bullet shows a double digit ES with the load I am using.
I prefer the WLRM primer. I am not shooting a light load. The 'graph says 2900+ fps at 15 feet.

Regards, Dave.
 
I'm not an expert, so just a thought. I have an RBCS 10-10, and it's a back-up should my digital go down. The accuracy of this scale is +/- .1 gr. So that means worst case scenario, you could experience a 0.2 grain variation from the desired charge weight. The question is "could 0.2 gr equate to a 40 fps ES?" I don't know the answer...

However, my digital scale has a +/- 0.02 gr resolution. This equates to a worst case scenario of 0.04 gr or about two kernels of most powder types. If you're measuring things like concentricity and neck turning, I would consider investing in a digital scale that will reduce the variation in charge weights to a minimum. I use GemPro 250 - available from myweigh in Vancouver for example...
 
I'd try the ladder test with coloured bullets at 500 meters, I believe Mystic Precision has the procedure on his site. Has worked for me everytime I develop a long range load. I don't even look at ES/SD anymore as it doesn't tell the tale like the real world does.
 
Each charge weight has a standard federal match and Winchester LR mag primer. I guess the next move is a good digital scale, but we'll see how this goes.
 
[QUOTEPowder burns most efficient at the highest pressure it is designed to operate at.
This is why world class long distance competitive shooters load their rifles as heavy as the individual rifle will handle. ][/QUOTE]

What he said.
 
Terry Perkins said:
[QUOTEPowder burns most efficient at the highest pressure it is designed to operate at.
This is why world class long distance competitive shooters load their rifles as heavy as the individual rifle will handle. ]
Click to expand...

What he said.[/QUOTE]

Trying to find that pressure :) So I'm going to drive them harder. Or if someone knows that pressure I could back-engineer it through Quickload.
 
sunray said:
25" at 1,000 is 2.5 MOA. Not at all bad. However, the amount of powder used has nothing to do with combustion.
Hodgdon suggests a magnum primer with H1000. I'd change primers and quit worrying about velocity spreads. Velocity is not as important as accuracy. Especially for long range target shooting.
Click to expand...

Another swing and a miss.
 
The problem with putting the blinders on while you stare at the chrono for the answer is that you may miss the load that actually works. I'm not saying that a good LR load isn't going to have a low ES, you need to find a accuracy node at an acceptable ES. Ladder testing does this, and rarely gives a false positive so to speak. I use ladder testing and only check velocity once I have a load that passes the test at 500m then I take to 1000. my spot is 1120yards actually...once here I'm looking to confirm the same vertical deviation that I see at 500m.
 
OK, I didn't get the quote about loading to the tilt, out o my head, or my own experience.
I took it out of the book, The Accurate Rifle, by Warren Page.
In case you don't know who Warren Page was, he was Shooting Editor of Field and Stream Magazine for 24 years.
In 1971 he won his ninth National Bench Rest championship, as well as being a good competitor in long range rifle shooting. Here is a quote from his book on loading for long range rifle shooting.

 
BCBRAD said:
Ya, I do that, 0.010" off 3.990" COL
Click to expand...

Just a quick question on your col. How do you run them that long?
In my 300 ultra mag with a 215 berger is only 3.837 and is 30 thou off then lands. With a 208 amax and 300 win mag there can't be much bullet in the case.
 
I do believe it sounds like you have confirmed the group sizes at distance right?

Im more just tagging in for interest as it seems to me you are experienced at reloading but is there any chance your chrony readings were taken in the bright light of mid day if you did not confirm groups sizes at distance?
 
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