How to work up a new load

18 February 2002, 17:42

<rickdm>

I am very new to reloading, but after buying the equipment and reading everything I could get my hands on, I think I am ready to work up my first loads. I want to work up a load for a 140 gr. Partition for a 7mm STW. I am trying to figure out where to start. The Nosler and Hodgdon manuals list this load with IMR 7828 ranging from 74gr to 80gr of powder. Since I will load these at home and take them out to the range I am trying to figure out where to start. Load 6 cartridges for each load in 1 gr intervals? Do I start at the bottom and load to the middle (following the Nosler numbers), or start in the middle and load to the top (following the Hodgdon numbers)? The possibilities seem endless, I will have to replace the barrel by the time I finally get it sorted out ;-)

Any suggestions on how you approach this would sure be appreciated.

Rick

18 February 2002, 19:13

<PaulS>

rickdm,
Start at the lowest listed load. work your initial loads up at .5 grain (or 1% of the maximum listed load) increments until you find a small (or the smallest) group or ANY signs of pressure. NEVER exceed the maximum listed load. You will probably find that groups grow and shrink with different charges. When you find a smaller group in the trials then work around that group in smaller increments to find the smallest group repeatable. Then you can play with your seating depth to fine tune your load for it's best accuracy.

PaulS

if you have any questions you can E-mail me at:
paulstephens2@attbi.com

------------------
stay safe and live long!

18 February 2002, 19:34

Pyrotek

rickdm,
I start from minimum and go up, a larger window for load finding...and always tighten the scope before any testing, use a steady benchrest.

Usually I start looking for a powder that is known to burn clean, consistent, and match the case capacity. There may be more than 1 powder that fits this category...

Then I choose the one that is the slower burning, it allows you to approach higher loading density.

Pick a bullet type you want to use, start with one that is reputed for good results.
generally the bullets are seated as deep as the caliber(.22's are seated .220" deep, .30's are seated .300", not a hard-and-fast rule but it's a start)

Now as you load, you change powder weight...
for example : 41grn, 42grn, 43grn, 44grn.
if loads are not accurate, try the middle numbers : 41.5grn, 42.5grn, 43.5grn.

If they still are not accurate, try a different powder or bullet and start over.

But if an accurate load is found, alter the powder charge or bullet seating depth a little up and down, see if it can be more accurate, for example 43.5grn is found to be accurate, but 43.4grn may be even more accurate if you ever tried.

That's how I explore the loads. Some people use BOSS, instead of tuning loads for the rifle, they tune the rifle for the load, they work fine but takes the fun out of reloading if you ask my opinion.
Pyro

19 February 2002, 03:22

<Whitespider>

Rick;
Here post I wrote on another board concerning pressure signs and maximum loads, but it applies to working up a load also.

The problem with visual pressure signs is that by the time you see them pressures are probably way to high already. The trick is to use as many things as possible to determine where the max load is for your rifle/load combo is. Primer appearance, bright shinny spots on the case head from the ejector/extractor cut outs on the bolt, sticky extraction, case seperation, heavy recoil, abnormal muzzle flash, blown primers, shot shell like groups on target are all see/feel/hear indicators that can also be caused by other things than pressure. But if pressure is the cause, it is way over max. I use case head expansion and a cronograph while keeping an eye on the see/feel/hear indicators. When working up a load and shooting over a cronograph every increase in powder charge usualy will give about the same increase in bullet speed. If the next charge up gives a larger than normal increase in speed you are probably over max, back off. If it gives a smaller than normal increase than you have reached a point where it is not doing any good to go higher and you are probably over max anyway. Eratic bullet speeds also indicate a problem with the load or powder charge. At the same time I'm watching the crono I'm measuring case head expansion, I like to use cases that have been fired with at least two full pressure loads and if I can measure 0.0001" expansion at the point just in front of the extractor groove than I back off. Also if bullet speed is a lot more than factory loads or what the reloading manuals show I begain to look real close at all my indicators. I personaly believe that a cronograph is the one most important tool you can use to finding max loads. One more thing that helps alot is expeareance with the rifle and powder your using, you learn certain things about each and can begin to predict results. Hope this helps and I hope I didn't make this sound to difficult, it realy is an easy and quick process once you do it a few times.
Good Luck

[This message has been edited by Whitespider (edited 02-18-2002).]

19 February 2002, 03:40

John Frazer

quote:
Originally posted by rickdm:
Since I will load these at home and take them out to the range I am trying to figure out where to start. Load 6 cartridges for each load in 1 gr intervals? Do I start at the bottom and load to the middle (following the Nosler numbers), or start in the middle and load to the top (following the Hodgdon numbers)?

My first recommendation would be to load just 3 at each powder increment. That should be enough to tell you what velocity you're getting and whether pressure is excessive (I judge by velocity, measuring the "pressure ring" and external indicators like sticky bolts, the more clues the better!) and will leave you fewer bullets to pull with the loads that are too hot.

Second, if you haven't loaded for this rifle before I would start at the lowest figures and work your way up in 1 gr. increments.

With experience you may learn that a given rifle can handle bigger charges -- I have one .30-06 that has never shown any sign of excess pressure with any book maximum load, and another that has to stop a grain or two earlier.

John

19 February 2002, 03:53

tom holland

quote:
Originally posted by rickdm:
I am very new to reloading, but after buying the equipment and reading everything I could get my hands on, I think I am ready to work up my first loads. I want to work up a load for a 140 gr. Partition for a 7mm STW. I am trying to figure out where to start. The Nosler and Hodgdon manuals list this load with IMR 7828 ranging from 74gr to 80gr of powder. Since I will load these at home and take them out to the range I am trying to figure out where to start. Load 6 cartridges for each load in 1 gr intervals? Do I start at the bottom and load to the middle (following the Nosler numbers), or start in the middle and load to the top (following the Hodgdon numbers)? The possibilities seem endless, I will have to replace the barrel by the time I finally get it sorted out ;-)
Any suggestions on how you approach this would sure be appreciated.
Rick

I agree with everyone comments starting with the low and going to the high. If your rifle is sighted in. I would only load three rounds for each load as your barrel will get alittle hot and cleaning between each test load will help. Becareful on playing with the seating depth. If you have a factory round use that as a guide to what depth to seat the bullet. Sometime on recoil a round will move forward in the magazine. Most hunting groups are done with a 3 shot group. I would go up one gr at a time and try and keep it simple to start with. Try and find one powder and stick to it and I agree you can wear out a barrel testing too much to find the "perfect" load. I started out with a nosler manual years ago and with the new type mag rounds out now the loads should be pretty good. Well good luck!
Tom

19 February 2002, 03:59

<Boyd Heaton>

Start at the lowest listed and work up.A half grain of powder in a case that big will not make much of a differance.I use H870 in mine.And I went up a full grain at a time.I think in a case that big it is a waste of powder to go up a half grain at a time.Start low.And when you get close to max look at your cases for sign's of pressure.

------------------
I HUNT LONG RANGE.AND YES I USE MATCHKING'S.

19 February 2002, 05:09

<Oldmodel70>

Rick, select a powder that you can't get enough of into the case to get your self into trouble. Years ago when I was new to reloading, an oldtimer gave me that good advice. I was loading for a 30-06 at the time, and the old guy suggested a case full of H4831 and a 150 grain bullet. Also in my 218 Bee, drop a case full of IMR 4198, seat a 45 gr. Hornet bullet, and shoot. Using a case full of the proper, slower burning powder for the cartridge, and the standard bullet weight, not some very heavy bullet, you are not so likely to get in over your head. Some reloading manuals, such as Lyman, and Hodgdon indicate which loads fill the case, or are compressed. Grant

19 February 2002, 08:18

<rickdm>

Thank you for your insights. I guess there really is no way around starting at the bottom and working up in 1 grain increments. My frustration is that the starting load for the Hodgdon manual is the max load for the Nosler manual, that makes the spread very wide. Just loading three bullets for each load makes seems like a good place to start. I have played a bit with the bullet seating depth, but it seems that the magazine depth and not the lands are what sets the depth.

It also sounds like I am going to have to get a chrono to figure out what the loads are doing. I have monitored the case expansion for the brass that a friend loaded up for me, and the area in front of the belt expanded by .0045. This was with a pretty mild load, does that seem OK?

Thanks,
Rick

19 February 2002, 09:31

<Whitespider>

Rick;
If as you say the starting load for Hodgdon is max for Nosler, better back off your starting load to what Nosler recomends.

19 February 2002, 10:10

<10point>

Rick get yourself a reloading notebook and take careful notes when on the range and evalutating your loads.

If you leave powder in your "powder thrower" after a session ALWAYS tape a piece of paper with the "powder type" thats left in the thrower. You'd be surprised at how age can affect the memory.

Most of all take your time and enjoy. Be deliberate, a whole new world of shooting is opening up to you. Reloading is a gas!

And dont be afraid to ask questions, there are some master re-loaders on this forumn.........good shooting..........10

19 February 2002, 10:42

<MontanaMarine>

My process is like this:

1. Decide what the purpose of the load will be.

2. Decide on a bullet/powder.

3. Back off about 10% from max and load 10 rounds each, charge increasing 1 grain at a time until I get to max. (If using moly bullets and slow powder I will go up to 2 grains over max in a 30-06 or 338 Winmag size case.) Then I shoot a 10 shot group with each load. Making sure I do not overheat the barrel. I clean the bore between groups to make everything as equal as possible. Usually the first round from a clean bore is a bit low, about 1 inch, from the group.

4. The most accurate load I then reproduce in 10 rounds lots with bullet seating varying in 1/100th inch per lot from 2/100ths into the lands to 3/100ths off the lands. I Shoot these 60 rounds in 10 shot groups, cleaning between, to see what is best.

5. Try the best load with different primers to see if one is significantly better.

I shoot over a chronograph so I know exactly what the velocity is. Depending on your purpose, your criteria for best load should consider: Accuracy, velocity, extreme spread, and standard deviation.

Good Luck, MM

19 February 2002, 10:48

<BEJ>

I believe this method was posted here some moons ago. Anyway, starting at the minimum listed load, weigh charges in .2gr. increments for each round, i.e. if you start at 48.0, 48.2, 48.4, 48.6, 48.8, 49.0 etc. What happens is that your shots start stringing, then a group, then it moves off again, etc. When you find several rounds that group well, you can focus your next reloading session on the charges that grouped well (usually there are more than one good grouping). I found this method faster and it uses less components.

20 February 2002, 14:53

<rickdm>

Guys, thank you for your input, your insights it just show me how much I have to learn. I made up my first batch at 1 grain increments, four rounds each load. I can't wait to see how they do this weekend.

Do you ever get so far into reloading that you instead of reloading to shoot, you shoot to reload? Seems like it could happen ;-)

Thanks,
Rick

20 February 2002, 16:23

<grkldoc>

BEJ,
I never heard of this method of developing a load before, but the more I think about it this makes very good sense. I have been able to plot group size versus bullet seating depth off the lands. I have found that one obtains a sine wave. This is largly related to barrel vibration. That is bullets exit the barrel at different points in the barrel vibration cycle depending on their velocity. That is, as the barrel vibrates it reaches a maximum amplitude in one direction then changes direction. At the maximum amplitude the relative position of the barrel is changing slowly. Therefore, any bullets exiting near this point would have a similar impact point. Also, because the position of the barrel is changing slowly, small velocity changes here would not show significant change in point of impact.
So, if you slowly increase the charge weight, the velocity will increase. At some point, the timing of the exit will be such that the bullets will start exiting during the maximum amplitude. Because this region of the sine wave is relatively velocity insensitive, several different powder charges will group here. Of course, which velocities group well will be dependent on the seating depth (the distance from the barrel exit). Now I have my next experiment.

Thanks!

20 February 2002, 16:26

rogerinneb

Read the "Chronograph Tech. Article" at:

http://www.shootingsoftware.com/ftp/chrontech.txt

It's very interesting. Actually, all the "bench tips" at the www.shootingsoftware.com site, written by Jim Ristow are very interesting. He's quite a tinkerer. If you use an electronic scale you need to read about his tests--you'll be back to your 10/10 scale before you know it!

He has a nice little rig you can build to load powder and seat bullets at the range, which is ideal for load development. The key is an electronic scale that runs on a battery like the Dillon model.

Roger