# 10mm mag



## HogHunter (Mar 13, 2018)

I recently purchased a Super Redhawk in 10mm. The brass extends about half way down the chamber. That leaves a lot of room to extent the over all length of the cartridge, which creates more room in the brass for powder and in affect, would create a 10mm mag without having to rebore the cylinder. Can more powder be added to increase bullet speed without causing an increase in pressure. The maximum pressure for 10 mm is 37,500 psi, which is higher than 44 mag (36,000 psi), 41 mag (36,000 psi), or 357 mag (35,000 psi) and I do not want to increase pressure.


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## Steve M1911A1 (Feb 6, 2008)

HogHunter said:


> ...Can more powder be added to increase bullet speed without causing an increase in pressure...


The implications of your question leads me to believe that you do not yet know much about interior ballistics.
Generally speaking, you can't increase bullet velocity by merely adding more propellant, because the result will always be higher (and maybe more dangerous) chamber pressure.

In the simplest terms, bullet velocity is a balance between bullet weight (mass) and propellant-generated pressure.
If you increase the propellant's pressure, you will also need to reduce the bullet's mass. Thus, a lighter bullet may be driven to greater velocity without unduly increasing the resulting chamber pressure because it will leave the chamber sooner...before the peak of the pressure curve. Or something like that.

In order to safely and meaningfully experiment with pressure and velocity, you need some sophisticated (and expensive) equipment.

A better method would be to buy a whole library of reloading manuals from propellant, bullet, and tool manufacturers, and then to search through them for an already-developed load which does what you want.
Follow that specific "recipe" scrupulously, and don't experiment by changing any of it.


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## HogHunter (Mar 13, 2018)

> Originally Posted by Steve M1911A1
> 
> The implications of your question leads me to believe that you do not yet know much about interior ballistics.
> Generally speaking, you can't increase bullet velocity by merely adding more propellant, because the result will always be higher (and maybe more dangerous) chamber pressure.]
> ...


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## HogHunter (Mar 13, 2018)

Let me start from the beginning. I was researching the 10mm cartridge and found a person that was boring the cylinder so longer brass would fit into the chamber, same diameter, just longer. His intention was to create a 10mm mag. His theory was pressure could be kept at 37,500 psi, but more powder would produce more speed. That made me wonder, why bore the cylinder. The bullet is deeply seated in the brass, just do not seat the bullet as deep and get the same results, more case capacity and more powder. I am not trying to argue, I just want to know if it can be done.


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## win231 (Aug 5, 2015)

HogHunter said:


> Let me start from the beginning. I was researching the 10mm cartridge and found a person that was boring the cylinder so longer brass would fit into the chamber, same diameter, just longer. His intention was to create a 10mm mag. His theory was pressure could be kept at 37,500 psi, but more powder would produce more speed. That made me wonder, why bore the cylinder. The bullet is deeply seated in the brass, just do not seat the bullet as deep and get the same results, more case capacity and more powder. I am not trying to argue, I just want to know if it can be done.


The short answer is it can't be done _safely_. As SteveM1911 said, you would need the sophisticated & expensive type of equipment used by ammo manufacturers. And when ammo & firearms manufacturers do such experimenting, they test fire guns by remote control in a bomb-proof cubicle. There are other factors (unknown to you) that can increase pressure to dangerous levels. Experimenting on your own can cost you your eyes & fingers & it's not worth it.


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## tjkarch60 (Jul 14, 2017)

Think of it this way, a cartridge contains powder that burns and produces pressure. The bullet is a plug that holds that pressure in, until it reaches a point that forces the bullet out and on its way down the barrel.
A heavy bullet will resist the pressure build up longer than a lighter weight one and you must use less powder, otherwise the pressure will build too high and cause a failure. 
Lighter weight bullets get moving sooner and the powder will continue to burn as the bullet is leaving the case and this keeps the pressure to a safe level.

So while your assumption of just seating the bullet not as far into the case may seem reasonable at first glance, it certainly isn't worth the risk of losing hands, fingers, eyes over. I load my Glock 20 (10mm) to the higher safe loads from reloading books and it has worked well for me to get the full potential from the 10mm. If I wanted any more, I'd just get a bigger caliber/gun. 

It sounds like they guy was going to use longer cases to get a 10mm Mag, like the 357 Mag is just a longer 38 Special. Sounds interesting, but I'll wait until the ammo factories use their experience to make it and test it.


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## hollywood63 (Jan 9, 2017)

His intention was to create a 10mm mag

He won't be creating the 10MM Mag

http://www.sixguns.com/tests/tt10mag.htm

I know its a old posting but its a good read


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## pic (Nov 14, 2009)

The ideal powder ignition would be a simultaneous full ignition of all acceleratants at once. Hard to achieve. 
Hard to achieve, thus creating many additional variables causing inconsistencies to an exact performance of the projectile


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