I noticed that for the .308 (165gr bullet) and the 30-30 (150gr bullet) and IMR 3031 powder his charges are two to three grains higher than my manuals and the Hodgdon data. Why is this? Don't know about his other data.

Thanks for the heads up...

Don

I have several examples of max loads in well known publications that vary as much as six grains....

This is not at all unusual.....get used to it....it's why we work up!

Published reloading data is only correct in the rifles they were tested in.

Each rifle is unique to a certain extent.

Some will accept higher charges than others - even from the same make and model.

That is why one should atart low, and work up gradually.

The same goes with velocity.

Each rifle might have a different velocity than an identical one with the same charge.

We once had 5 Mannlicher rifles, all identical, all in 270 Winchester chambering.

We shot Norma 150 grain ammo in them, and the velocity differences between the slowest to the highest was about 150 fps!!

Velocity differences can be experienced between different lots of the same powder as well.

Smith's data is a few years old -- like a decade.

It's higher because of attorneys. Smith is not liable, mfg's are.

quote:

Each rifle might have a different velocity than an identical one with the same charge.

You got that right. My ex-son-in-law and I have matching Winchester M70 Featherweight rifles chambered to the .257 Roberts. Even the scopes are the same. Using the max load in the barnes manual with the 100 gr. TSX bullet, his rifle delivers 3024 FPS and my rifle only 2851 FPS, both loads shot over the same chronograph on the same day. I do believe I could have gone another grain higher in the powder charge, but then there might have been a problem should we have to borrow ammo from each other during our recent deer hunt.
Paul B.

Most of the manual data is worked up in SAAMI minimum chambered test barrels or higher quality than what is on your rifle. Factory chambers are often huge compared to the minimum SAAMI chamber.

quote:

Originally posted by Red C.:
I noticed that for the .308 (165gr bullet) and the 30-30 (150gr bullet) and IMR 3031 powder his charges are two to three grains higher than my manuals and the Hodgdon data. Why is this? Don't know about his other data.

As mentioned, different rifles can produce very different results.

Also, max loads in published data depend heavily on the individual powder lot used. Differences in density between lots can cause different lots of the same powder to behave as if they aren't the same powder at all. I load for double rifles, and their regulation is usually dependent on correct velocity. With the same bullet, case, and primer, I once had to use 5 more grains - an increase of 10% - of a new lot of IMR 4350 to get the same velocity and regulation I had gotten from the previous lot. With the same charge of both lots, the velocity difference was a bit over 200 fps. That's firing ammo loaded with the same charge of both lots back to back from the same rifle over the same chrono on the same day. The 4" difference in regulation confirmed the disparity in velocity.

The above are the reasons that lab tested reloading data can only be used as a general guide, and why manuals instruct the reloader to work up. It's just as important to work up when changing lots of the same powder as it is when changing powders entirely.

Further, Smith's data is attributed in footnotes to manufacturers and, as mentioned earlier, is old. Many reloaders don't realize how rapidly and radically professional pressure testing methods and equipment have changed in recent years, and today's technology is much more accurate than the old. Quite a few max loads in that old data have since been found to have been more than just a little over SAAMI/CIP max. Most of the difference you notice between the old and new manuals isn't "lawyer padding" - myths die hard - it's the difference between old technology and the much advanced new technology in wide use now.

If I take:
a different brand of bullet but same weight
a different brand of primer but same type
a different lot of powder but same weight
a different brand of powder measure but same weight
a different brand of brass but same weight
a different brand of rifle but same cartridge
a different brand of dies but same OAL
a different brand of press but same OAL
a different handloader but same project
a different bench but same project
a different range but same project
a different brand of calipers but same project
a different day to the range but same project

Both guys work up a load to the threshold of short brass life and quantify the long and short of brass life.

Both guys back off a safety margin and compare loads.

I think what you will find is that everything is very close until they apply safety margins. One guy may reduce powder by 0.2% while the other may reduce by 20.0%.

But if Denton were here, he would measure the pressure, compare it to a SAAMI registered pressure, and declare HE has found the right load.