Loads in different manuals differ 25% for same powder and bullet weight

pinne65

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Hello,

I've just started reloading for 10mm. I have two different loading manuals, Lyman 48th edition and Speer #14. I'm using 180 grain bullets and Alliant Unique as propellant.

Here's the quIRKer, Lyman's min/max loads are 5.8/6.7 grs Unique and Speer are 7.2/8.0 with muzzle velocities 1018/1064 and 1043/1138. Speer uses this propellant weight for either TMJ FN or GDHP and Lyman uses Sierra JHP #8460.

Lyman uses universal receiver 5", Speer S&W M1006 5"

Both use CCI 300. Lyman uses Winchester/Norma brass, Speer doesn't specify

Both manuals say to NEVER exceed max loads. But here we can see that Speer's min load is .3 grs higher than Lymans MAX load.

The only difference I can see is the brand of bullets and brand of barrel used.

I played it safe and worked up from Lyman's min to Speers's min. And was not able to notice any difference in recoil in my Glock 20, (the only way I can judge since I don't have a chronograph, yet), between the two.

I'm to say the least a bit confused. Anyone care to weigh in on this.

/Bjorn
 
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deadeye

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It depends on the firearm used and the extent that they want to be held liable for suggesting. The Lee load says 7.0gr using the 180gr JHP @1,125fps. I have the speer volume 12 and the Lyman vol. 47 and they list the same as yours.
 
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The lyman manual is for cast bullets, probably not listing a jacketed bullet.

Loads differ depending on source, age, and a number of other factors, I know with alliant the loading data they publish on their website is usually very anemic, so I usually go with the sierra manual and cross reference that with still another manual.

The main thing I do as I test a load is to look for signs of excessive pressure, in automatics that can be fairly easy, how far is it kicking your brass out?
 

2gr8dgs

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I have recently got into reloading for this cartridge. I recommend you go over to Glock Talk, look under "gun related clubs" & then the "10mm re loaders forum". there is a TON of good info related to this specific caliber. As far as different load suggestions, My rule of thumb, when there is a discrepancy, is to go with what the powder manufacturer suggest. Not the bullet maker. good luck, Mike
 
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Because of these variations I prefer to use the Powder Manufacturers data that they post online. For Pistol I work my loads up for feel and accuracy not exceeding the published max.

For rifle I work totally off the results on the target and chronograph, letting the fired case tell me if I am at the limit. Sometimes I get pressure signs much sooner than the data would indicate. Hard to lift bolt, extractor marks, or flat primers are telling one to stop even though they haven't reached the max charge level.
 

Mark W.

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ROFLMAO you should try figuring out how to load 30-40 Krag for a Winchester Model 1895. All the books are based on the much weaker 1896 Krag Military bolt action and are under 40K CUP while the Model 95 is good for 46-47K CUP (and actually more since it is also chambered in 30-03 and 30-06) I have found huge variations in loads for the same weight bullet I have found identical loads showing 200fps differences between the books.

I'm to the point where I am about to do my own pressure testing. And I'm buying a Chronograph ASAP
 
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pinne65

pinne65

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Thanks for the info everyone!

The Lyman data is for JHP bullets.

The brass flies about 10'.

I'll check out Glock talk and the Alliant site.

Unfortunately I think I'm pretty inept at spotting signs of over-pressure signs. I've been reloading for 45 Colt/454 Cassull for a while. And the only thing I've noticed is that some of the brass is getting harder and harder to get in and out of the shell holder.

The nickel plated UMC brass I'm using has been reloaded twice. It seems like maybe the extractor will destroy the cases before they start showing signs of over-pressure.
 
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If you are having trouble inserting the case into the shell holder there is a very good chance your loads are not just over pressure but waaaaaay over pressure.

It is pretty much a rule of thumb that a load which causes .0005" of expansion at the base of the case is too much.

As a suggestion, take a new case, load it with your current load, but before firing it, measure the base of the case in the "solid" area just above the rim with a good accurate micrometer. Shoot the cartridge and then measure again. If there is significant expansion in the solid portion, before the beginning of the case walls, then you are too hot. Another quicker method but not as accurate is to take a shell holder to the range with you. "Gauge" your cartridge before firing, getting a feel for the looseness in the shell holder. After firing see if it has measurably tightened up.

If the primers on your fired rounds are totally flat, with absolutely no radius at the edges remaining, that could also indicate you've got the wick turned up too high. I don't rely totally on primers for pressure but they are one sign.

Lastly, if you chronograph your rounds and are seeing speeds way higher than the load data would indicate pressure is probably high too.
 
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The lyman manual is for cast bullets, probably not listing a jacketed bullet.
Lyman's lists loads for both cast and jacketed in their 'regular' book,they do also make a 'cast bullet' guide.
The variances you are seeing is common,and can drive ya nuts.I just load 'middle of the road',and if it's good enough..well,it's good enuff.
I don't care for nickel plated brass,it splits very easily and is harder to run through the sizer die after the 1st firing or 2,as if it work hardens.ymmv on this,but I use yellow brass only.
 
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I like the Lyman manual because of all the data they list...in particular, measured pressure in CUP (especially useful when loading cast lead).

I like Ni plated brass...it makes it easier to identify my own brass at the range and I have no problem getting at least 5 firings per batch. LEO Brass sells it at some great prices. I just bought 1000 cases of .40S&W for $25...
 
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pinne65

pinne65

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I should clarify that brass that's getting hard to get into the shell holder has been reloaded 13 times. It's 45 Colt by PMC. And I'm only loading it min loads. The Remington brass is still holding up after the same number of loads though. As is the Starline. And yes, I should probably retire the PMC brass now.
 
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I should clarify that brass that's getting hard to get into the shell holder has been reloaded 13 times. It's 45 Colt by PMC. And I'm only loading it min loads. The Remington brass is still holding up after the same number of loads though. As is the Starline. And yes, I should probably retire the PMC brass now.
Probably a good idea. Even with light loads the brass does tend to "flow" with the pressures. Some places in the case wall are most likely thinned out and a case rupture is in the near future. 13 times is a fair amount for any case. Of course we would all like more but I consider any of my brass that's been loaded 10 times or more as "paid for".
 
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I should clarify that brass that's getting hard to get into the shell holder has been reloaded 13 times. It's 45 Colt by PMC. And I'm only loading it min loads. The Remington brass is still holding up after the same number of loads though. As is the Starline. And yes, I should probably retire the PMC brass now.
I suggest you retire the entire lot. That's kind of an odd thing to have happen, though. Are you roll crimping? One usually sees the cracks at the mouth, first.

The advice to measure the case is a good one, and right after firing is best. If it doesn't expand too much on a new case then I'd again suspect your brass vs. overpressure.

Chronographs are cheap enough now they are also good tools to have for load development. They help by providing correlating data.
 
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The approach you described is good - check as many data sources as you can, play it safe and work your way up gradually. Most manuals have good photos and descriptions of excessive pressure signs. Taking the time to be safe is always best. Don't lose that habit.

Also remember that powders can vary somewhat from one lot to another. So when you get new powder it doesn't hurt to back off a bit until you're sure it's behaving the way you're expecting. I had a can of H110 once that produced squib loads including one stuck in the barrel using magnum primers, heavy crimp, and near-max charge.
 

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