Steel Shot questions

[Qtiphky]

I'm just getting in to loading for steel shot. I have been loading shotgun shells for nearly 40 years but am now just looking in to this. A few questions for those who have experience in steel.

In the manual, it says that I need to use a different charge bar for steel shot. I don't understand why. If I used to load 1.5 oz of lead, and use the same charge bar, I understand that steel is much lighter, but wouldn't the volume in the shell be the same? So instead of it still being a 1.5 oz load, it may only be 1.25 or whatever the ratio would be. I understand different wads are needed, and it says to only load the steel shot to the top of the wad, but isn't that more based on volume as opposed to weight?

Also, shooting factory steel I shoot 3" 12 ga. I don't see any recipes that would duplicate the velocity of factory loads. Typically they run in the 1500fps range and all the recipes are closer to 1300fps. Should I load 3" or can I get the same ballistics with 2 3/4" shells?

[Unclenick]

Velocity depends in part on the amount of powder you use. A bigger shell has room for more powder, so you should not expect a shorter shell will match it's ballistics.

Pressure is also affected by the mass of the projectile. It determines the inertial resistance the burning powder builds pressure against. If you use the lighter charge of steel shot, the powder charge would have to be increased or a faster powder used to be able to build pressure against the lower inertial resistance with good ballistic efficiency. So you need the different shot bar if you plan to use the same load, and will want a wad that accommodates the added shot volume. If you are in a competition that requires a certain shot weight, that will also require the different wad and shot metering bar.

As to matching commercial load velocities, manufacturers often have access to powders that are not available to handloaders, so that is one possible factor.

Another factor is that reloading data is developed a bit more conservatively than commercial loads are because they have the limitation that they are made using data book recipes with powders that vary a bit from lot-to-lot in burn rate and exact energy content, while commercial loads are developed using pressure test guns that let the manufacturer adjust the charge to match the characteristics of each specific lot of powder employed in a run of loads. This makes it safer to load near the top of the pressure range.

[totaldla]

Get ahold of Ballistic Products Inc (bpi) "Advantages" manual. This is a pretty good source if high-performance steel shot reloading information.
Yes, you can meet and easily exceed factory velocities.
But please understand that you must follow the recipes exactly - no substitutions.
Start looking for Alliant Steel powder as well.