Differences between the loading "bibles"

[hmonnier]

I'm sorta new at this reloading. I notice in comparing the loads for a specific projectile across several of the reloading 'bibles' (Hornady, Lyman, etc), there are deviations in both the min load, and max load numbers. I have no concern with the min load, but wonder "should I take the lowest of the max across the different books" as the max load????
Just curios.....

 

[RC20]

My take is that I get cautious once I hit someones max load.

If its looking fine pressure wise, I will move it up a bit at a time until I hit the highest max load of any of the books.

Technically I understand they use various equipment to test and come up with different results for pressure limits, but some of those can be several grains or more for rifle cases and that seems pretty odd.

Pressure signs are a sticky bolt lift, primers changing from normal and ejector wipe on the back of the case.

 

[TXAZ]

You should worry both about light and heavy.

If you load too light, you can get a squib in the barrel. (which could cause the same results as below when followed up with a second shot)
If you load too heavy, you get a new barrel and best friends at the ER room and possibly a plaintiff's attorney.

 

[Dano4734]

Primers they are using makes a difference big time. My one book had a starting load near a max load. Then someone here pointed out one used mag primers the other two books did not

 

[RC20]

TXAZ: I have never seen a load listed so light the bullet does not readily leave the barrel.

Some powders can get weird pressure pulse at light loads but they don't publish data below certain levels and they know which ones those are.

 

[USSR]

I have no concern with the min load, but wonder "should I take the lowest of the max across the different books" as the max load????

FWIW, I once contacted Sierra (which is known for it's conservative load data) about one of their listed "Max" loads. When I questioned a tech guy about the pressure of said Max load, I was told "Don't know, that's just where we decided to stop". Now, I'm not telling anybody to exceed Max loads, but if you're looking for some scientific basis behind them, you may be disappointed. Just saying.

Don

 

[hounddawg]

you seem to be exercising caution which is good. Book load should be taken with a grain, no make that a entire box of salt. Recently I blew a primer starting at 1 grain above minimum on a load.

A case in point. Recently I started a load workup with H4350 and 142 gn SMK's for .260 Rem. I decided foolishly to start at the middle of the load data since I normally find 2 or three good nodes and I was looking for a long range load.

To make a log story short I blew my first primer due to overpressure. I stopped there and came home and pulled the bullets and weighed the charge of all the reaming loads. Powder weights were good. The primers were ruled out, they were Fed GM match. Double checked the load data at the Hogdon site and it listed 41.5 to 44.5.

I started getting serious pressure signs at 42.5. I looked at the data for the 6.5 CM which has a similar case capacity and then at the 140 gn Nosler data. Both started much lower. I am restarting the load development at 39.0

Lesson learned always get at least two or more sources for any load and use the most conservative for starting loads. If you can only find one published source use common sense and start with the bare minimum

 

[TXAZ]

TXAZ: I have never seen a load listed so light the bullet does not readily leave the barrel.

Some powders can get weird pressure pulse at light loads but they don't publish data below certain levels and they know which ones those are.

I haven't experienced it either RC20, but know someone with a .50 that was working up a load and that happened. Not a good gun to experience a squib in.... (as if there was one)

 

[hmonnier]

From reading what y'all have said, it almost looks like one should avoid a fast burn powder, because the difference betwixt min and max is greater. Based on suggestion from a local who claims to do a lot of shooting/reloading, the powders i have are Win 231 and Accurate No2.

Or am i all wet as usual????

 

[Rimfire5]

hmonnier,
Part of the differences come from the configurations of the rifles used by the bullet manufacturers that actually test their bullets. Sierra and Hornady for example. (Deveral manuals don't test. Lyman uses other's data and some of it is very old. Berger uses QuickLOAD software to provide the data but even then, the barrel length, and temperature have to be supplied. QuickLOAD software is a bit conservative in their results.)
A further complication is created by each company's litigators. Hornady is incredibly conservative. Nosler is less so. Sierra is sort of in the middle.

The low end of the powder tables shouldn't be a problem. The PMax loads might be and should always be treated with some caution, even those from the conservative manuals.

hounddawg

I have had some experience with high pressure indications with a 6.5mm CM with loads that shouldn't have caused the gigh pressures that were resulting.

It wasn't the powder manual's fault, it was caused by a tight chamber.
Turns out that some manufacturers use tight chambers to get better accuracy.
I sent my rifle, with lots of data and pictures of the primers and cases, back to the factory and they reamed out the chamber by a couple of thousandths.

The problem disappeared and I can now shoot that rifle with loads close to PMax.
And the rifle is just as accurate as it was before it was bored out.

 

[hounddawg]

Rimfire this is the data straight from the Hogdon site

.260 Rem has a case capacity of apx 53.5 grains of water

Hogdon says for H4350 using a 140 gn bullet (Nosler Partition) the min 39.0 max 42.0 142 gn . For 142 gn ( SMK)it shows 41.5 min and 44.5 max

Now the 6.5 CM has a case capacity of 52.5 gns or 1 gn less. For the 140 gn bullet 36.0 to 40.0C (Amax bullet) and the 142 gn (SMK) is 38.8 min and 41.5 gn max.

Now that tells me that is bad data. Now if anyone wants to argue angels on a head of a pin then feel free but common sense says that the .260 Rem data for the 142 is out in left field. Just speaking for myself but I will never trust single source data again

After thinking a bit I emailed Hogdon to tell them they need to check it

 

[USSR]

hmonnier,

Okay, based on the powders you have (W231 and AA #2), we know you are talking about a handgun cartridge. So, what cartridge is it, and what type and weight of bullet are we talking about?

Don

 

[RC20]

I haven't experienced it either RC20, but know someone with a .50 that was working up a load and that happened. Not a good gun to experience a squib in.... (as if there was one)

For sure not, ouch. It was a listed load?

I have squibed more than once but because I didn't put powder in a case.

(and yes I should)

No powder is not an issue in my 30 cal stuff. Pistols yes.

 

[RC20]

From reading what y'all have said, it almost looks like one should avoid a fast burn powder, because the difference betwixt min and max is greater. Based on suggestion from a local who claims to do a lot of shooting/reloading, the powders i have are Win 231 and Accurate No2.

Or am i all wet as usual????

You just need to be careful with powders that are fast, small amounts go from 0 to over quickly.

Any powder listed is going to be fine.

I don't use Unique in 30-06 jacketed of course!

 

[Unclenick]

Hounddawg,

I suspect, as I have when I've brought up conflicting looking Hodgdon data to them before, you may get a reply back stating they have a ballistic technician's signature on a test document showing those numbers are what he got.

It is odd data, though. According to Bryan Litz, the 140-grain Amax and the 142-grain SMK are both 1.375" long, yet that data has the A-max seated longer and lists a 40-grain charge as compressed, while the SMK is seated shorter and lists 41.5 grains as not compressed. So either two substantially different lots of H4350 were used or the case lots were different and had substantially different capacities. Both are possible, but whatever caused it, clearly an apples-to-apples comparison was not being made.

The load developers go to some trouble to try not to publish bad data, but it happens. Typically, the bullet makers seem to develop most of their loads in production guns, looking for pressure signs, and then have only the top load tested for pressure (to save money) and the rest are estimates. If one of their measured maximum loads has even a single round that goes over the SAAMI MAP value, they lower it. This seems to be a fairly universal practice and is described in detail in the last of the printed ring binder version of the Hodgdon manual. It is not how ammunition makers use the SAAMI limit, though, which is as a limit for the average of ten rounds, where the handloading manuals written today treat it as an upper limit for any member in the sample.


Hmonnier,

Using powders that are too slow can ring or bulge a barrel. They also ignite poorly, leave a lot of fouling, and require heavier charge weights to achieve a given velocity. The powder should be matched to the gun and the bullet.

The way I pick powders is to look at Hodgdon's data and at the peak pressures listed for each. As they explain in their print manual, because they size the loads so the worst case high-pressure cartridge in a sample does not go over the SAAMI MAP number, the powders listed with the highest peak pressure numbers are the powders that had the lowest pressure variation in their tests. That's a good sign ignition was consistent, and those are the powders I would look at first in the range of fast to slow.

 

[hounddawg]

I have seen minor .1 differences using different bullets with different bearing surfaces or a 1 or 2 grain difference in weight but 3.0 grains is pretty much out in left field.I don't need Quickload to see that someone has screwed up.

Back to the OP get at least 2 sources then start at the lowest, you may not be as lucky as I was

 

[reddog81]

What are the loads you're looking at? Sometimes lead bullet data stops very short of max pressure. Most reputable load data shows the pressure the load is generating. If the listed pressure is quite aways off from max you can probably assume they stoped at that load based on something other than pressure. Some lead bullets will start leading in the barrel so they stop going any higher. How much higher can you go as a reloader? That's impossible to know without trying to find different load data that goes higher.

With rifle loads the brass, exact bullet being used, how far out it's seated, primer, gun being shot can all make a big difference when reaching the pressure limits for a cartridge.

 

[USSR]

What are the loads you're looking at? Sometimes lead bullet data stops very short of max pressure. Most reputable load data shows the pressure the load is generating. If the listed pressure is quite aways off from max you can probably assume they stoped at that load based on something other than pressure. Some lead bullets will start leading in the barrel so they stop going any higher.

Exactly. Big difference between swaged lead store bought bullets which may be too small for your needs, and cast bullets properly sized and using a good alloy.

Don

 

[Archie]

When looking at different loading books, note the firearm used, the barrel length, the particular make of bullets and the age of the book.

One can use - for instance - more powerful loads in Ruger No 1 than in a Trapdoor Springfield even if they are both .45-70.

Keep in mind not all reloading books are made from information obtained on the same day. A load shoots different on a hot day as opposed to a cold day.

Bullets are different. Especially those made to be 'deep penetrators'. Heavy duty bullets can have a different internal design and will not crush fit in rifling like others.

The good news is a somewhat overload will generally not blow up like a hand grenade. I have ruined a couple primer pockets without damaging my rifle. However, an over load can damage a chamber or locking lugs without "explosion".

So. I will generally start with an 'average' starting load. Pay attention to the force needed to open the bolt and extract the empty case. Check with a chronograph if possible and see if velocity is what the loading manual predicted (close). Check the primer to see if all is well, then look at the rest of the case is as should be.

Work up slowly and as needed.

Load for sufficient velocity, not all possible. Squirrels, deer and elephant usually can't tell the difference in one or two hundred feet per second. And accuracy. Gotta make sure it hits.

 

[Unclenick]

...but 3.0 grains is pretty much out in left field.

It's unusual, but not impossible if the powder lots changed. Bulk density can vary ±3% in stick powders pretty commonly and the burn rate tolerance for canister grade IMR powders is ±5% according to the older print Hodgdon manual I have (vs. ±3% for their ADI powders). Hodgdon keeps reference powder for testing that has their target properties, but sometime in the few years I gather than the GD Valley Field plant in Canada that makes IMR extruded rifle powders changed the process because the original was too expensive, and I wouldn't be surprised if changes due to that switch caused a new batch of reference powder to be formulated. So, while it's an unusual variation it's just not an impossible one.

I want to restate the lesson Houndawg is bringing to this discussion to emphasize it: The load differences in the IMR4350 data for the 140 and 142 grain bullets in the 260 Rem represented about 7% of charge weight. Starting loads are typically 10% below maximum, so, if you started to work up to that 44.5-grain load with the middle value, just 5% low, as Houndawg said he did, that was already 2% past the 41.5-grain maximum that turned out to be the one that actually applied, even though it was given for a different bullet. I've commented on this in the past, having twice found starting loads in manuals that were about at maximum for the gun I was using: Don't ever follow the common advice to start in the middle of a published load range. Always start at the bottom and work up. Just divide the range into 2% steps and fire one of each. If they get too hot on the way up, you'll see the signs before you get all the way to the top value, and you want to give yourself a chance to catch those.