9mm max charge question.

[mikenbarb]

Im going to be loading Hornady 9mm 124gr. jacketed RN bullets with Unique powder and looking at data for them. I see that Hornady lists the max at 5.1gr Unique but the other data I have puts the max at the following, Hercules Unique is 4.8gr. and my Modern reloading manual puts it at 4.9 with 125gr. bullets and the Speer put the 125gr. at 4.5gr. Why do these people do this and almost all the load data differs from each other?? Is it safe to go with the bullet manufacturers data or should I stick with the powder manufacturers data and other current load data? And what kind of difference does the 125gr. versus the 124gr. bullet make in regards to the powder charge? All of these reloads are going to be shot out of a Walther P-38 WWII AC43 model and its a solid gun thats in great shape.
Thanks in advance.

 

[Loader9]

When it comes down to what data to use, always go with the bullet makers. The powder maker may not have used that brand or profile of bullet. Bearing surface makes a lot of difference in a small case like the 9mm. The powder maker may also have seated the bullet deeper and pressures were higher in their testing. Try to remember that the data published is an average of days of testing normally using one barrel. Barrels are not the same and you may be loading to a different altitude, humidity, temperature, lot number of powder, etc. So the data is a guide, not an absolute.

 

[Sevens]

To add to that great post, data also differs over time as powder is blended a bit differently and as the lawyers get involved and press them to lower their charges a bit.

The good news is that SAAMI and the powder/bullet/component makers always try to build safeguards in to this hobby of ours. You should always start low whenever any component changes, no matter which component it is. By starting low and building slowly (I like 0.3 grain increments) you can watch and examine brass closely for pressure signs.

Some published max loads will be under other published max loads. Sometimes, you get differing opinions from the SAME SOURCE! Your responsibility is to not simply take the data and let it be the final word, but rather to use your own skill to decide which load is your best load and work toward it-- build toward, don't simply draw it from a book and roll with it.

In a related note, have you ever heard some long time reloaders talk about not really caring for the .40 S&W so much? This is a good example why. Many calibers are quite forgiving with regards to pressure, COAL and returning a large spectrum of usable performance. .40 S&W, due to it's high pressure, relatively small internal capacity and stringent COAL requirements make it a less friendly cartridge for the reloader. Where you have LOT of room to play with COAL, bullet weight, chaege weight and pressure in a .38 Special, you have much less room to play with the .40 S&W before things can get ugly.

Also don't forget that Hercules Unique is a relic. It's no longer made. You may have some, you may even be able to buy some, I'm quite sure there's lots of it left to be found and used, and it's still good powder. But it's no longer made. Alliant owns the name and produces the powder and they HAVE changed it over time. The stuff you buy now in the black plastic can is similar to the cardboard can with the metal top & bottom, but it's NOT the same stuff.

 

[BigJimP]

Powders get reformulated, companies go out of business, companies start producing powders for other companies ( like Hodgdon is now producing Winchester and IMR powders )... etc and it means you need to keep updating any load data.

Look at the Min and the max for each recipe you have / look at the specific specs on the bullet used in the test - and in general - go with the newest data if you can figure out what it is. But until you find the consensus load on a minimum - and something pretty close on a max - I would keep looking ( and maybe change powders ). I tend to trust the powder company - not the bullet company. I also stay away from powders like Unique, unless its a newly published load, when I know the powder has been reformulated in the last year or two.

 

[mikenbarb]

Sevens, I know the Hodgdon is old and im using new Alliant Unique for the 9mm with new data from them and im starting at minimum as always but just concerned about the max charges that are varying from each book. Im going to start at min. and work my up in .02 grain increments to be on the safe side. Im going to find a happy place in the middle and stick with that. Im just plinking with it so im not worriesd about tack driving with it but I have always had good results with the new Unique powder and also Bullseye for other calibers. The best thing about the new Unique is that its alot cleaner burning than the old stuff.

 

[rg1]

It's always the safe way to work up loads and follow suggested load data from reliable sources. One key thing in reloading for 9mm is the overall length recommended. Shorter overall lengths in 9mm raise pressure dramatically. So I'd recommend to check recommended oal from your data source.
That said, I recently started loading 9mm with Unique and 124fmj's from Speer, Hornady, Remington, and Winchester, all 124 fmj bullets. Cases are mostly Win but also used RP, CCI, and others mixed in. I've only used CCI 500 SP primers. With Unique powder 4.8 grains is mild, safe, and not maximum with any of the above bullets and cases. I've loaded all the above bullets from 1.150-1.160" overall length. Do start with a little lower charge of powder and work up. The 5.1 grains of Unique is near maximum and be careful should you go above that.

 

[Loader9]

To give you an idea about OAL, pressure, and bullet design. I'm shooting a 124 gr Remington Golden Sabre out of my Baby Eagle 9mm. The GS bullet has a different profile than you'll find on any other bullet with a small bearing surface at the rear of the bullet only. I'm loading 5.5 grs Hercules Unique at max OAL and it shoots great. No signs of any kind of pressure and feels fairly mild in the hand. The brass isn't growing at the head, I don't have a primers flattening, and the pistol runs great with no FTF's. While I don't recommend anybody run out an duplicate this load, it shows what the OAL and bullet design variable can have on pressure. If you decide to try it, please start low and work up. Do not try it with a bullet of a different profile. YMMV

 

[WESHOOT2]

launch platforms differ

Assume nothing; work upward and determine your own maximum.

But suggest something other than Unique for doing so.

Safety first means exactly that LOL.

 

[mikenbarb]

WESHOOT, Why not Unique? I have had great results from it but I also have Bullseye.
Got another one for everyone. I just got some Black Talons in 147gr. and trying to find data for them with no results. I called Alliant and they said around 5.2 Unique but that seems real high to me. Im thinking of running them with 4.9gr Unique and it should produce around 1010fps. If anyone has any data on them, I would appreciate it.

 

[WESHOOT2]

reread your posts

Unique will be fine for your (overlooked first time I looked) goal.

Meter(?) cautiously.

FWIW, there are many choices beyond Bullseye and Unique; some are demonstrably better choices.
Mostly.

 

[mikenbarb]

Im using a Belding & Mull because I dont have many to do. If im going to do more, Im going to run them thru the Pr-Jector with an Ohaus powder measure thats dead nuts.

 

[PCJim]

To comment on the disparities in charges published by Speer compared to others, I believe that Speer's "copper clad" bullets are electroplated bullets. The copper is not as thick as that on a true jacketed bullet. When reloading with electroplated bullets, you should use recipes more in line with lead bullets rather than those for the true jacketed bullets. This would also explain the lower recommended powder charges published by Speer. Someone else can chime in and add some clarification / confirmation.