HELP - Why the difference?!?

[thawein1856]

Ok so I've got my press set, scale up, and started doing some tests (still waiting on bullets). I took people's advise and got 2 different reloading manuals, Speer 14 and Lyman (current edition). I'm set up for 45 ACP using IMR 700X with 230 Gr TMJ. The Speer says that my starting is 4.6 with a max of 5.1. The Lyman says that my starting is 3.6 with a max of 4.8.

That's a HUGE difference! Anyone know which is less wrong?

Also, I have a Lee Pro1000 with the Auto disk powder measure and I can't get it to be consistent at all. If you have one and have any tips or tricks it is much appreciated.

Thanks!

[Sideline Shooter]

You can have different load recipes from what type of gun or barrel length they were tested on. Some are done on a universal receiver and some from a specific gun. Also manufacturer's are covering themselves when it comes to maximum loads, liabilities.
That's why it is recommended to have 2 or more books. Start at the lowest charge and work your way up to what is maximum in YOUR gun, not the maximum listed.

sideline shooter

[Low-Pressure]

You will always see different recommendations from different books. Like said above... start low and work you way up. Good luck and be safe.

[Revoman]

Did you check the Hodgdon website? They are the current producer of that powder and should have data for your load.

Once you get that, you can cross check with the data that you already have in book-form and start from the low end between the two that agree.

[Cyclepath]

I was also concerned about the discrepanices. For .45ACP Jacketed Lee suggests starting at 4.5gr and 5.0gr max. Hodgdon\IMR\Winchester reloading manual suggests 4.9gr max. You have Lyman's data. I would start low as suggested and work up watching for pressure signs. Use the lowest max and start at least 10% below until you find something that works. Be sure to cross reference as stated in the previous posts.


I have a Lee Pro AutoDisk I noticed that what Lee states in the AutoDisk instructions are lower that what I was getting in powder charges. Here was Lee's customer service response -

"With 24 holes in 4 disks, you will not get the exact charge weight you require. You will get close, and never get more than specified. Different powders meter differently, some with more uniformity than others. Another variable is powder density. The manufacturers tell us powder can vary 15% from lot to lot. If you want to get closer to the prescribed charge, get the Adjustable charge Bar, p/n90792 - $9.98. Our goal is to provide a consistent powder charge. We feel this is more important than the exact weight in the charge table. Varying a velocity by 50 FPS, from a book specification, is less important than each round producing the same velocity. CONSISTANCY!"

Hope this helps.

[mousegun]

The thing to remember when looking up loading manual recipes is that ALL the components affect the final pressure and velocity data. Specific brands of powder, lot number, brand of primer, brand of brass, brand, style and weight of the bullet, barrel length, chamber tolerances, air temperature, altitude, and on and on, make up the load profile. It ain't just powder and ball. This is why there are starting loads. Start there and stop once an accurate, moderate pressure load is found. Maximum should NOT be a goal, only a limit past one should not venture with the components called for in the manual data. Different components and testing methods are why the manuals all differ.

If any of the components called for are changed BE CAREFUL and watch for pressure signs. If a component isn't specified, it usually means the maximum will take that into account.

The best tool for safe reloading is an inexpensive chronograph and the knowledge how to use it. Every firearm has a characteristic bullet weight/velocity range and the chronograph will tell you when you're reached that level more surely than any pressure signs. It's the best indicator of safe load levels without having to "feel" for them blindly.