Understanding Reloading Data

[haymaker]

I am reloading .357 mag 158gr. JHP. The bullets I'm using are Speer 158gr. JHP #4211 and Hornady HP XTP #35750.
I'm using H110 powder with CCI 550 mag primers.

Load data for H110 in the Hornady 9th edition lists a min. load of 12.7gr and a max of 15.6gr.

Speer manual #14 lists a min. of 13.9gr and a max. of 15.5gr.

The Lyman 49th edition lists a min. of 16.3gr and a max. of 17.0gr.

The min. in the Lyman manual is higher than the max. in both the Hornady and Speer manuals.

Using a RCBS chrono factory American Eagle 158gr ammo gives me an average 1160 fps with my 4" Ruger Security Six. 16.5gr of H110 gives me 1115 fps. I'm a little under the max. listed in the Lyman manual but way over the max. listed in both the Speer and Hornady manuals. Should I ignore the Lyman manual or should I split the difference? I'm trying to achieve factory velocities for 158gr. JHP.

 

[WIL TERRY]

NEVER ignore anything in loading data. NEVER ! ALL of it is valid. And what is factory FPS from your pistol for 158gr projectiles ?
And so it goes...

 

[contender]

Look a bit closer at ALL the info in each manual. Look to see what bullet & primer each one used. Look at what firearm they used to get their numbers. A Universal Receiver is a lot different than a production DA revolver etc.

Next,,, I have a method of how I approach each new loading.
I look at several manuals,, and see what the lowest starting charge is with the components I'm using. I also see if there is a lower listed starting load.
I start with the lowest one of those two.
I also look at the highest load for my selected components, and then I stay a bit below that. UNLESS,,,,, that load is the highest of all my manuals. Then I stay below the max charges of the one that is lowest of all of them.

I load my ammo in test batches,,, and chrono them myself all while checking for accuracy. Safety first,,, with accuracy being my goal. Most of the time,,, I've found my most accurate loads are not the max charges, or even ones close to them. But I let my chrono tell me when I'm getting close to velocities that are published as the top end.

 

[Twoboxer]

IME getting handloads with cannister grade powder to match many factory loads gets tricky as they are likely to use powders (or blends) not available to us.

Just to add to the confusion, Sierra V lists min/max for 158gr with H110 as 13.3/16.3. Quickload says 16.5gr just nudges past max rated pressure. Hodgdon reload data on line says min/max is 15.0/16.7gr. All this makes 16.3gr look good to me with a small safety margin.

Were I doing those hand loads, I'd go with the Hodgdon data. Hodgdon's data is in most cases more conservative . . . though obviously not in this case. Dunno if I'd stop at 16.3 and be happy with 1115fps (which seems lower than any source claims 16.3gr should deliver), or push to 16.5 or even 16.7 if there are no signs of high pressure, or try another powder.

BTW, different batches of powder can be +/-5% of standard. That gives a possible range of 10% max variation between your powder batch and the Tester's. Also, your scale and/or powder measure may be part of the problem here.

If the recoil with your hand loads seems less than or equal to factory ammo, you have another indicator you are OK.

 

[jsh]

As mentioned above speed isn't everything accuracy should be your goal.
As mentioned each and every different manual will have some what different results. You wonder why?
First is the barrel or gun it was tested in. What was the barrel length? How many rounds has it fired? If it was a closed breach pressure rig very seldom will you get the same speed out of a wheel gun,as some gasses purge and are lost between barrel and cylinder.
Bullet design is another variable. Hornady,Nosler,Sierra etc are all different.
Powder lots can vary also.
I have no less than25-30 manuals. I use them all. Some of the older ones have powders listed that have not been made for years,they are still good reference material.
As to reading pressures with sticky brass expanded web areas etc, this has all pretty much been proven to be false info. A lot of times by the time cases stick, primer pockets expand or webs stretch you are way past any safe load. In a nut shell if you don't have a pressure measuring setup it is just a guess.
Always,always err on the side of safety. If you have questions on data, call the bullet or powder manufacturers they are always glad to help.
The Internet is a wonderful thing but very few things are 100%.
Jeff

 

[Mobuck]

There's lots of variability in data(just as there is in actual firearms). I like to use at least two sources and 3 is better. In addition, I load using a chronograph stopping at the listed max velocity even if I'm below the listed MAX powder charge.
The Lyman #49 is getting a little old(compared to data books from the major bullet makers) so if the Speer and Hornady are fairly recent, the canister powder may have changed slightly.
FYI I use 16.5 of H110(2005-2006 production) with Speer 158JHP in Federal cases and CCI SPM primers-it's a hot load but hasn't caused any problems for me. NOT A LOADING RECOMMENDATION

 

[Jimbo357mag]

The latest Hodgdon data from their website http://www.hodgdonreloading.com/data/pistol for H-110 and 158gr XTP's says;

Hodgdon - H110 - .357- 1.580 - start 15.0grain - 1,418fps - 28,600 CUP ------ Max - 16.7grain - 1,591fps - 40,700 CUP

I would use that. Expect some difference between bullets. A sturdy gun will give you lots of margin for error as the 357mag data has been downgraded over the years.

I have shot 158gr XTP's with 15.0gr and 16.0gr of H-110, both excellent.
btw I use standard primers because it doesn't get really cold here.

 

[mikld]

Contender's post is right on. I use these methods too, and rarely am dissatisfied.

Reloading manuals differ? Think about this. Say you invited 25 ballistic technicians from different powder manufacturers, bullet manufacturers, and those that have testing labs to your shop. Tell them to go to their respective labs and develop loads for "___", using common components. They all go back to their labs and use slightly different components (different lots of powder, different lots of primers, bullets, and even brass). They use their own equipment, that may differ in type (universal receiver, real gun) differ in condition (new or really used). Different labs may have different ambient conditions (Texas springtime humid/hot or Oregon cool). The techs. may be well experienced or maybe new at testing. Will they all come back with identical results?

 

[DGW1949]

Lay your Hornady bullet next to your Speer bullet in a manner which allows you to visualize which of the two sits deeper into the case when both are inserted down to their crimp groove.
The deeper the bullet sits, the more case capacity it takes up.
When all else is equal, a decrease in case capacity results in a higher operating pressure. Perhaps that explains some of the discrepancy which you are seeing in suggested loads.

DGW

 

[Jimbo357mag]

Lay your Hornady bullet next to your Speer bullet in a manner which allows you to visualize which of the two sits deeper into the case when both are inserted down to their crimp groove.
The deeper the bullet sits, the more case capacity it takes up.
When all else is equal, a decrease in case capacity results in a higher operating pressure. Perhaps that explains some of the discrepancy which you are seeing in suggested loads.

DGW

I have noticed that XTP bullet load data is always different than other bullets of the same weight. It usually requires a little more powder for Max. That would mean it has a little less friction for some reason, possibly. I often use data for Sierra/Speer bullets for XTP bullets without problems but not the other way around.

 

[Mobuck]

Lots of factors affect pressure.
Bullet jacket material- hardness, thickness, shape of base.
Bullet shape-length of bearing surface, shape of nose, location of cannelure.
Bullet makers have their individual designs and material choices and all are different.

 

[Chuck 100 yd]

Lots of factors affect pressure.
Bullet jacket material- hardness, thickness, shape of base.
Bullet shape-length of bearing surface, shape of nose, location of cannelure.
Bullet makers have their individual designs and material choices and all are different.

Exactly my thoughts! All of the replies above are valid also.

 

[Rook]

In my opinion you go with the specs put out by the powder manufacture. Just about every caliber I reload is with Hodgdon powder so I go to their website and use their loading info.

 

[sliclee]

When only the first shot counts use NOSLER PARTITION Lee

 

[Rodfac]

In lieu of anything else, I'd check the Hodgen Loading Site on line. It has their most current data, vs other loading manuals that may be outdated or have made a mistake in transposing Hodgen's data. The Lyman data is transposed as I understand it...i.e. they don't do their own testing with jacketed bullets, IIRC. Not saying manuals are incorrect, but you need to verify.

The bullets used in the actual loads listed in various manuals make a difference...it's the seating depth. Combined overall length may not give you the same data from one brand of say, 158's to another. It depends on the canelure location, and also the ogive radius. Either can change the COL to some extent. It's a relatively easy mathematical process to figure the seating depth then convert it to a COL that you can use.

HTH's Rod

 

[gunzo]

Lots of factors affect pressure.
Bullet jacket material- hardness, thickness, shape of base.
Bullet shape-length of bearing surface, shape of nose, location of cannelure.
Bullet makers have their individual designs and material choices and all are different.

Exactly my thoughts! All of the replies above are valid also.

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