We are all here because we enjoy the 10mm. It pushes the ballistic boundaries of standard size auto-loading handgun.
In pursuit of these boundaries many forum members hand load their own ammunition. Others reload for economy, providing generally more shots per dollar than factory ammunition.
Now for the warning.
You will often find loads in this forum which exceed published load data. I, like others have been known to exceed published data on occasion. In such situations I personally have carefully and meticulously measured to the best of my ability how my gun is behaving with a given load and observer closely for any signs on each and every cartridge that I have entered a dangerous realm.
There can be many reasons why published data stops at a given point, and those reasons are usually not disclosed in published data. Also, each gun is an entity unto itself and may react differently. Industry accepted margins of error are built into published data as well to account for possible extremes in environmental conditions.
The stance of the forum is to follow published load data. Exceeding such data may result in serious injury. Maximum loads should be in new brass of quality manufacture, using load data of the same vintage as the powder. In the absence of published starting loads, maximum loads should be reduced by 10%. The loader should work up, usually in 5 steps, checking for signs of danger or excess pressure until the maximum is reached. If pressure signs become evident before the maximum is reached, you have reached the maximum for your gun. Fall back to the last safe load and record it as a maximum in your data.
Since most of use do not possess equipment to carefully measure pressure other means must be used. One of the best methods is to measure case head expansion. Visually inspecting primers is NOT a reliable indicator of excess pressure. Case head expansion is unique to each gun and should be tracked when working up max loads. Any sudden change in case head measurement should be treated as an indicator of excessive pressure, and the next lower charge should be considered maximum for your gun.
Unless otherwise indicated as safe, maximum loads should not be reduced by more than 20%. Under certain conditions, especially in large magnum rifle calibers, such excessively reduced loads can produce dangerous pressure spikes. In handguns, the largest danger of very light loads is a bullet stuck in the barrel undetected.
You may choose to exceed published load data, stopping only when indicated by your good sense or in some cases loss of digits, eyesight and/or massive blood loss (I saw a similar statement in the most recent Handloader and couldn't help but plagiarize it). We hope no forum members are ever injured while shooting, whether from factory ammo or hand loads.
We suggest every forum member acquire and maintain for reference a library of load data from a variety of sources and reference that data carefully anytime working up a load. We further suggest any load you see in this forum, or any other internet forum, be carefully cross referenced against published load data before being attempted in your gun. Even if the load falls within the range of published data, follow that standard guidelines to work up to the charge.
We would ask that members as often as possible indicate loads that are over published maximums, and also indicate the source of load data they are using or used as a starting point.
Further, we ask that not only the charge, but the other components, especially primer brand and type be carefully documented. Changing from one primer brand to another of the same type can create pressure variations of as much as 10,000 psi or more according to recent data developed by Handloader.
As always, we appreciate your contributions to our community and look forward to many your many tales regaling the great 10mm Auto cartridge!