Question regarding "Maximum Loads"

[WalkAbout]

Hello,

I'm new to reloading and recently got started with a Hornady L'n'L progressive press. I'm really enjoying it and shot my first 15 rounds of reloaded ammo yesterday, and immediately came home and loaded up 85 more. When I was buying everything, I purchased a Hornady digital scale to measure my powder loads with. It seems to be working ok, but really just OK and not Great. My measurements seem to vary from .1-.3 grains on the same load each time. There are no fluorescent lights in my work area, and its as level as I can hope to get it. I calibrate it often, and have been getting by since I started at the Minimum load with the intention of working up. The load I'm using for .45 calls for 6.0-6.4, grains of powder, with 6.4 being the max load. Thats not a huge window, and I was wondering if powder manufacturers leave some sort of safety window in their load data, say 8-10% or something like that on either end of the load data. Don't get me wrong, I'm not asking if anyone thinks its safe for me to load 6.5 grains of powder. I'm asking if for some reason I measure a load out to 6.3 trying to work up and it actually measures out to 6.5, am I going to blow my hand off because my digital scale was off 2 tenths of a grain? Or at 6.5 would you just start to see signs of too much pressure on the brass? Keep in mind, this is just plinking ammo and not match stuff.

And yes, a new beam scale is definitely in the works come a few paydays from now. I would like to continue loading in the meantime however, as long as its safe to do so.

Thanks for any help!

b

 

[Walkalong]

Many powders will vary plus or minus .1 gr when thrown from a measure. No big deal. Adjust the measure so it does not throw over 6.5 and you will be OK. You should be starting at 6.0 though, not 6.5.

Me, I would adjust it to through an average 6.1 (low of 6.0 and high of 6.2) and try it.

 

[A and O]

In addition to walkalongs post I've been told, read or heard that the major Powder Manufactures have a plus or minus 5% margin in their specs for each Powder they produce. Over or below 5% the the whole lot of Powder is discarded. Sort of like die lots in carpeting, very difficult to get a perfect match up. This is a major reason why I buy 32lbs of 223 Powder at a time. Work up some great loads and then shoot it up consistently for several years.

As far as throwing charges, using the above at below max it's no big deal. When working up loads I do so in .2 or .3 increments and almost always find the sweet spot at just over the mid point. +/- .1 or .2 or .3 really does not make that big of a factor. I'll probably get thrown in the grinder for what I just wrote but it works for me and don't sweat what I consider to be small variances. We live in an imperfect world. Some day I'm going to buy some commercial ammo and weigh the components. I'll post when I do with my findings.

 

[ArtP]

If I understand you correctly, you're comparing what your thrower will throw and checking it on your digitl scale, right? If one of those two device are off, it's almost certainly the powder thrower. The thrower measure by volume (for speed). It's pretty common for a thrower to be off .1-.3 grains and it will depend on the type of powder, some powder meters better than others.

I also practice what A & O does, that is I load at close to max load and accept that I might get .2 grains over load. I just consider those +P rounds if they do exist and also know there is some built-in safety in the recipes. If what the book said really was the absolute maximum, I would just back off .3 grains. I am also shooting a modern gun that is known to stand up to very powerfull rounds.

To check your scale, weigh a bullet. Power cycle the scale, re-calibrate and keep measuring the same bullet. Once you're convinced your scale is accurate, then you can check for yourself to see how close your powder thrower is.

 

[lwknight]

When I first started reloading a long time ago, I would set my max load 1/10 under the max just to be safe incase I would have went over by 1/10 and blow my self to kingdom come with blood and guts everywhere.
I finally figured out that even if I had gone over by 1/2 grain , nothing discernable would have happened.

Your OAL will have more affect than slight powder variation. If you check several references , you will find a lot of loads vary greatly. Be careful. Work up slowly and pay attention to details.

Fast forward , today I have wildcatted and pushed limits often. I must caution that it takes a lot of study and experimenting to safely go where no man has gone before.

 

[Randy1911]

shot my first 15 rounds of reloaded ammo yesterday, and immediately came home and loaded up 85 more.

Now we've got you hooked and landed in the boat there's no looking back now.

In regard to your scale, digital scales are very sensitive to the slightest air movement (air conditioner vents, cieling fans or even a open window. Beam scale are not so sensitive. What powder are you using? Ball powders like W-231 measure very accurate. Some stick powders like most IMR's vary quite a bit. For just plinking I see no reason to go over half way higher than half way to max. I mean it is not like you are hunting and need all the knock downpower you can get. I have tried digital scales and just don't care for them. I like my balance beam scale best. Call Hornady, 1-800-338-3220, they have great customer serice.

The max load in the book is just a guide. You may reach max load lower or higher than the book. That is why you work up a load. Remember, their data is based on their componets and equipment.

 

[Walkalong]

The max load in the book is just a guide.

Perhaps for an experienced handloader, but not for a new reloader. In that case, the max is the max. These guys in the labs with pressure equipment are looking out for us. We should be grateful we have so much great data to go by these days.

 

[Fatelvis]

A simple test to check the repeatablity of your scale, is to put a check weight (or any other object) on the scale and remove it several times. If it reads the same weight every time, or veeery close to it, you're good to go!

 

[NCsmitty]

It seems that your powder measure is not dropping consistent charges with the powder you are using.

The work around is to drop a lower charge, so it won't exceed your target load, and trickle up to it.

I trust my beam scale and my Lyman #55 measure to throw consistent +-.1gr for all my loads, rifle and pistol.
The argument that .3gr either way doesn't matter, is for some, close enough.

That doesn't fly for me, because it is a variable that I can control in the quest for accurate, consistent ammo.

If you are happy with what I call sloppy loads, it's not going to bother me.

You really should not work so close to maximum, with a wide variable range of powder drops that you are finding.

As Walkalong mentions, "the max is the max".



NCsmitty

 

[Tilos]

Throw 10 charges and weight them, together, the average is the average thrown

That powder measure came with 2 different powder spindles, make sure you are using the pistol(smaller) powder spindle.

 

[WalkAbout]

Wow thanks for all the replies. Answers that bring more questions are the best ones for learning I guess.

What powder are you using?

I'm using Hogden Universal powder and following the recipe posted on their site for 185 grain JSWC bullets with 6.2 grains of powder and a federal large pistol primer if memory serves me correctly. Everything is written down, but its in the basement and I'm lazy at the moment.

Your OAL will have more affect than slight powder variation. If you check several references , you will find a lot of loads vary greatly. Be careful. Work up slowly and pay attention to details.

Are you saying that my OAL should vary with different loads, or that an over or under seated bullet depth will pose more of a problem than 2 or 3 tenths of a grain of powder? I checked the OAL of my finished rounds and they are within the specifications listed in the Hornady reloading manual.

A simple test to check the repeatablity of your scale, is to put a check weight (or any other object) on the scale and remove it several times. If it reads the same weight every time, or veeery close to it, you're good to go!

I've thrown a load of powder into a shell, tare'd the scale with the provided metal cup thingy (thats a technical term!), and weighed the same charge 3-4 times. The same charge will weigh between 6.1 and 6.3 grains. I'm not sure if the fact that I pick it up then place it at a slightly different spot on the scale effects it or what, but the same load will occasionally weigh differently over repeated measurements. Calibrating the scale with the provided 100 gram weight passes every time. I'm assuming at this point that this is the pitfall of working with a digital scale.

Thanks again for all the help guys. I truly appreciate it.

B

 

[Shrinkmd]

I've had good success with my Hornady powder measure. I use the smaller pistol chamber and the micro adjust stem. After weighing 10 charges in the pan, I will then prime up 3 pieces of brass, and then run them through and keep dumping the powder into the pan to double check. Sometimes it sticks on the Powder Cop die or using the press is different than just clicking the powder measure.

With the microjust seater I can get loads to exactly what I want. Of course reality changes the powder dumps along the way, but it feels good to know that you just weighed out 10 charges from brass you might have otherwise seated a bullet on top of, and seeing that the combined total is right on the money, 10 times the single charge you were seeking for.

 

[azar]

I've thrown a load of powder into a shell, tare'd the scale with the provided metal cup thingy (thats a technical term!), and weighed the same charge 3-4 times. The same charge will weigh between 6.1 and 6.3 grains...I'm assuming at this point that this is the pitfall of working with a digital scale.

Yes, it is a pitfall of a digital scale. At least, a pitfall of a cheap digital scale. You have to look really, really closely on the specs claimed by the scale manufacturer. A manufacturer will claim that the scale is accurate to 0.01g (grams) and in the same breath they claim they are accurate to 0.1gr (grains) as well. That's really stretching the truth. Here's why.

0.01 grams = 0.154323584 grains
0.1 grain = 0.006479891 grams

If the maximum resolution of a digital scale is 0.01g, then it's really only accurate to +/- .154 grains. That's closer to 1/6th of a grain accuracy and not 1/10th of a grain like we are expecting. In order for a scale to be accurate to 1/10th of a grain, it needs to list accuracy to 0.006 grams (or lower). It's a bit easier to see why you fluctuate between 6.1gr and 6.3gr with that "accuracy" on the scale isn't it? None of the cheap digital scales marketed toward reloaders have that accuracy. Honestly they closer to 0.2gr of accuracy than 0.1gr.

I've done a little research on digital scales and have found a few that run $70-$90 that will give that level of resolution. Here's my comment from a similar discussion:
https://thehighroad.org/showthread.php?t=533512&p=6619176

Looks like the price has gone up about $20 on the MAC-20! Too bad, that was a great buy.

 

[qajaq59]

Be careful. Work up slowly and pay attention to details.

And keep a notebook of what you are doing.

 

[WalkAbout]

azar- Thats the pretty much explains why I'm seeing what I'm seeing. Thanks for the info. I'll definitely be purchasing a beam scale in the coming weeks.

b

 

[coloradokevin]

I've definitely found that my powder thrower only throws approximately what it is supposed to drop at any given setting (mine usually throws light). As you load more ammo, you'll get a feel for what your powder measure is doing, and how you might want to adjust it for consistency at the charge weights you are looking for.

I might be on the anal-retentive side of this equation, but I typically drop at least ten charges when I first fill the powder hopper, just to get it cycling (these charges just get dropped back into the hopper). I figure that doing so allows the powder some time to settle into the thrower, so that my charges are more consistent when I start loading.

Anyway, I usually weigh every few rounds, just to verify that I'm staying in spec. For target shooting I usually choose a mid-range load, and don't worry too much about the +/- 0.2 grain issue. Mid-range loads seem to preserve brass life better, perform more uniformly, and they use less powder.

Just my $0.02

 

[KBintheSLC]

Adding an extra 0.1 grain is a roughly 1.5% charge increase on a 6.4g load. Depending on the powder you are using, this will increase peak pressure by upwards of 5%. This is probably not enough to blow your gun apart, but should still be avoided for obvious reasons.

To answer your question, it appears that most load data publishers do not intentionally leave a buffer above the max load. For example, the max load for one of my powders calls for 5.0g. If I add another 0.1g to that, I will be about 1200 psi over max SAAMI specs.