# Working up a load



## goatchze (Aug 1, 2006)

Well, I'm back from the Czech Republic now and back to working on some loads for my rifle. Most of you saw the previous threads I've made about the various bullets I'm shooting now. If not, you can check them out here and here. (Thanks for all the input in the past).

I wanted to start off with my "go to" round. This is the round where I will be zeroing my rifle and is really the most versatile of the group that I have. It's the 129gr Hornady SST.

I wanted to start from scratch, so I did just this. Looking at the charts that came with my sizing die (perhaps not the best reference), the minimum charge was 38.2gr of H4350 and the max was 41.5gr. I wanted to start wide and narrow it down later, so I loaded 5 cartridges each of 38.2, 39.2, 40.2, 41.2. 

I tried my best to hold everything else constant. The brass was Norma and had been fired once. I went ahead and ran the body sizer just to make sure everything was SAAMI, and then I ran them through a neck-sizer. CCI Bench Rest primers were used. Seating depth was exactly the same for all 20 rounds (0.020" off the lands). I trickled in every round with the scale to keep the powder measure as exact as I could.

The weather was good. Sunny skies and next to no wind. Temperature was in the 90s, humidity was high (I was in a river bottom).

I fired each group into its own target, waiting 4-5 minutes in between shots for the barrel to cool. Before starting I fired a couple of factory rounds so that my first shots would be from a warm (not hot) barrel. After running through all 20 rounds I plugged the numbers into an Excel spreadsheet I had made to view the results. The Excel sheets attempts to reproduce the expected normal distribution from the sample group. The taller and skinnier the graph, the better the group. Here they are:











Looking at this graph, it seemed that 40.2gr would be the best starting point. However, the 41.2gr group seemed to have an outlier. Plus, the graph didn't' seem to make much sense to me; other than the one stellar curve, which was due to a small 5 shot sample, there didn't seem to be any overall pattern. So what if I threw out that one shot? If I used 4 shots and tossed what I thought was an outlier, I got the following graph:











Now things are starting to make more sense. I see a trend where increasing the charge, hence the velocity, is improving the grouping. Since I had to "rig" the results a bit (smaller samples make for tighter groups), I wanted to retest both 40.2gr and 41.2gr. So I loaded up 20 more rounds, 5 each at 40.2, 40.7, 41.2, and 41.7. Firing these rounds produced the following graph:










This seems to agree with the graph before. As I increase velocity, the groups get better and better. Still, these were 5 shot samples; I've got 10 shots at two points now (40.2 and 41.2), so what do they say? Do they agree with the previous two patterns that I need more velocity for tighter groups with this bullet and gun? Here are the composite curves with all 10 shots for 40.2 and 41.2 (since the sample size is larger, I did not feel I needed to omit the "outlier"). I get the same trend; a little higher velocity results in a better group. Omitting the "outlier" shifts the 41.2 group to the left.










Velocities were 2500fps (StDev 20 fps) at 40.2gr and 2600fps (StDev 28 fps) at 41.2gr.

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So here are my questions; #1, does everyone agree with my analysis here? What am I forgetting or getting wrong? The sample sizes aren't the greatest, but this isn't final. I've got everything filed away on the computer here and I plan to just continually add to the data. It's just a start.

#2, my die set says that 41.5 is the max load for this bullet, but I know I've loaded 43gr before (and I get about 2800 fps). I've seen some people (online) loading up to 44gr. From Hogdon's website, they have 125gr and 140gr bullets listed. Linear interpolation gives me a "max load" for 129gr of 43.7. Since the grouping only got better as velocity increased (and never seemed to decrease), I would like to take it a little further. What are your thoughts on going up higher and what are the signs of "overpressure" that I should look out for on the brass?

By the way, 44gr is the physical maximum amount of H4350 I can get into the brass with the 129gr bullet, resulting in a "compressed" load. I measured this out on Sunday.


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## B-Money (May 2, 2005)

try using a geometric mean to smooth your outliers.


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## Ernest (May 21, 2004)

I don't understand why you are going thru any of this. 

Buy a load manual! Now, not later. Now. 

Then, load from min. to almost max. at .5 jumps. 

Find the tightests groups. Reload x5 and reload that charge +/- .2 grains x5 each. Shoot. 

Find the tightests groups. Verify by shooting those loads again x10. 

Then, start playing jump/jam games or messing with primers. 

Velocity, SD, and all that stuff don't mean nothing if it will not shoot tight. Even then, the verticle spread associated with a decent SD in velocity don't mean jack til you get 200 yards plus. 

My suggestion - stop playing with the toys and graphs and the data. Buy a manual, and start discharging more rounds. Shoot more, graph less.


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## THE JAMMER (Aug 1, 2005)

Bob Lee Swagger couldn't have said it better himself.

THE JAMMER


Ernest said:


> I don't understand why you are going thru any of this.
> 
> Buy a load manual! Now, not later. Now.
> 
> ...


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## goatchze (Aug 1, 2006)

Ernest,

Thanks; you're describing exactly what I did (except I started with 1gr increments, then went to 0.5. Next will be 0.2 or 0.1) The graphs are no different than reporting group size; they're just a better representation of the group "tightness". They don't really take any longer than measuring with a ruler and have a bonus of helping me keep up with all the different shots fired and learn more about the gun and different loads. I fully intend to shoot more. (I guess I don't have to report back here everytime I do something though).

Besides, I'm an engineer. I like graphs and numbers and it gives me something to look at/think about while not shooting. I travel often and can only shoot on the weekends; guess I'm just overly excited about perfecting these loads. Just trying to be thorough!

I do have a load manual, two actually. But they're both older than the caliber I'm shooting which wasn't released until 1997. That's why I've been relying on the Lee load data and the Hodgdon load data from their website. It seems (or seemed) a bit silly to buy a whole new manual for those couple of pages. I could be wrong though.


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## THE JAMMER (Aug 1, 2005)

If those are the "couple of pages" that you are actually using, seems pretty prudent to spring for the manual. You're an engineer. If you wanted to learn about nano technology, would you use a 1950 textbook?

Certainly nothing wrong with "reporting back here." That's what the forum is for- for us all to learn from one another. I do like the graphs though.

THE JAMMER


goatchze said:


> Ernest,
> 
> Thanks; you're describing exactly what I did (except I started with 1gr increments, then went to 0.5. Next will be 0.2 or 0.1) The graphs are no different than reporting group size; they're just a better representation of the group "tightness". They don't really take any longer than measuring with a ruler and have a bonus of helping me keep up with all the different shots fired and learn more about the gun and different loads. I fully intend to shoot more. (I guess I don't have to report back here everytime I do something though).
> 
> ...


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## goatchze (Aug 1, 2006)

THE JAMMER said:


> If those are the "couple of pages" that you are actually using, seems pretty prudent to spring for the manual. You're an engineer. If you wanted to learn about nano technology, would you use a 1950 textbook?
> 
> Certainly nothing wrong with "reporting back here." That's what the forum is for- for us all to learn from one another. I do like the graphs though.
> 
> THE JAMMER


Ha ha, true, true. The guys here at work still harass me when I bust out my Dad's 5th Edition of Perry's handbook (printed in the 70s). Most stuff doesn't change that much, but some of it does. This is my problem!

Which manual would you guys recommend? I've just put my hands on the required parts of Sierra's 5th edition (which of course only contains Sierra bullets). I'm thinking Lyman?


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## THE JAMMER (Aug 1, 2005)

If you're serious, get them all: sierra, hornady, nosler, barnes, speer.


goatchze said:


> Ha ha, true, true. The guys here at work still harass me when I bust out my Dad's 5th Edition of Perry's handbook (printed in the 70s). Most stuff doesn't change that much, but some of it does. This is my problem!
> 
> Which manual would you guys recommend? I've just put my hands on the required parts of Sierra's 5th edition (which of course only contains Sierra bullets). I'm thinking Lyman?


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## CoastalOutfitters (Aug 20, 2004)

the sierra manual, usually the 2nd load back from the "green" load is almost always a good one , go .5 gr. above and below and you will be very close.

neck size your brass
clean flash hole
br or magnum primers
set your headspace for the round to the chamber
weigh ea. powder charge


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## goatchze (Aug 1, 2006)

*Nodes*

Well, I've gone through a few more rounds now. I've tested at 0.5gr increments from around the minimum load up to about maximum load. These are all either 5 or 10 shot groups.

The graph below shows the mean distance between any two shots for a given load (not the mean distance from the center of the group). I dont' know if this is indicative of the two "nodes" or not, but clearly there seems to be two ranges which the gun likes more (and one more than the other). Just thought it was interesting, especially the hic-up around 42!

I'm going to go back over the 43gr range with smaller increments (either 0.1 or 0.2), will choose one, and then try to confirm. The excel "curve smoothing" makes the minimum look like it's around 42.8, but 43.2 has been my tightest group so far. Unfortunately I wasn't paying attention and I ran out of bullets! More are on order now.

It will be really interesting if I see something similar with other bullets (95gr VMax is up next!)


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## THE JAMMER (Aug 1, 2005)

_I'm going to go back over the 43gr range with smaller increments (either 0.1 or 0.2), will choose one, and then try to confirm. The excel "curve smoothing" makes the minimum look like it's around 42.8, but 43.2 has been my tightest group so far. Unfortunately I wasn't paying attention and I ran out of bullets! More are on order now._

*See all that money you're saving by reloading. LOLOLOL*

THE JAMMER


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## goatchze (Aug 1, 2006)

THE JAMMER said:


> *See all that money you're saving by reloading. LOLOLOL*
> 
> THE JAMMER


Ha ha ha! You're right. You'll laugh, but I ran out of H4350 this saturday too! I'm going to need bigger stockpiles I think. I was lucky and squeezed the last grain from the container; I think I had about 0.2 left over!

Went back out on Saturday to repeat what I had done previously, but this time with a different bullet (one that I have plenty of for the moment). I tested the 95gr VMax from min load (47gr H4350) to max load (49.7gr H4350). Cartridge length was set same as before, same primers were used. New Norma brass was used.

Conditions weren't as favorable; it was a little gusty. I got smart and set up flags between my table and the target (one at the table, one half way, and one at the target). It was suprising how much the wind could vary over 100 yards! I could see the far target's flagging through the scope, so I would try to wait until I didn't feel much breeze at the table, and when the down range flagging was barely moving I would take a shot.

Here are the results. I thought that it was interesting that this graph has a similar shape as the graph posted for the 129grSST, the only difference being that the minimum load performed better for the 95grVMax. (Note: The velocity on the minimum load, 3100fps, was higher than the velocity for the max 129SST load of 2800fps).

Here's the graph:










So it seems that my rifle, so far, likes fairly hot loads. Here are the results from the 129 and 95gr next to each other:










In this graph, the first point is the "minimum" load and the seventh is the "maximum". The rest are evenly spaced between the min and max.

Next weekend I'm leaving for another trip, so I probably won't get any more shots in until the 4th (I might make it out on the 28th, we'll see)

Even though the "book" max is 49.7, I think I'll try easing it up to 50gr 0.1 at a time. There was no evidence of over-pressure; no cratering of the primer or anything else. In fact, other than my markings, I couldn't see much difference between the min and max load brass after firing. What are your thoughts/advice on this?


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