Negative. Asked and answered. Pressure is not measured in the barrel, it is measured in the chamber. Why ask for advice and ignore it? It is obvious you DON'T understand.I do understand the pressure is measured in the barrel but a shorter Barrel does not allow the pressure to build as it would in a longer Barrel before being released. I am not expecting the pressures or muzzle velocity to be by the book in the smaller Barrel that is a known
More engraving force does not necessarily mean more velocity. Past a peak point, it means less velocity. Less engraving force is a more practical way to get more velocity. When I first started messing with moly coated barrels shooting lubralox coated bullets, I found this out. My 6x284 lost almost 200 fps using the max load I had reached for uncoated barrel and uncoated bullet. I was then able to go up on powder to the point I was getting 200+ fps over the old established maximum load. I finally quit messing with Moly because the end result is not worth the effort.It has been answered that shorter barrels cannot take more charge weight safely. It has been answered that this is because the peak pressure occurs very early in the barrel travel distance.
What is velocity the result of? That has been answered, but less clearly. At the back of the bullet the pressure due to the powder burning is exerting a force on the bullet. On the bullet, the barrel exerts an engraving force. The pressure building and maintaining high pressure for a longer period is what makes velocity. Essentially the integral of the pressure curve over the barrel time(distance)
So, your short barrel has low velocity due to less barrel time. The fix is a longer barrel or more engraving force. More engraving force will drive up the start pressures though, so I would not recommend experimenting there. It also seems to not improve velocity much.
Going to a powder like Longshot which have a longer burn curve is your answer, but is not where you want to go.
Something like 700x is a nice “puff” powder, but often has low velocities. That is what it is.
BTW, 700X is also known for extreme charge variation in volume measured loads. Be cautious.
Quickload can be a good teacher, for the person whom wants to really dive into the why of reloading.
You know what "assume" does.One of the best ways to blow up a gun is to start making assumptions when hand loading.
Glad we could help you get it figured out. Happy loading.Okay so I think I've got a good handle on it $30,000 PSI for example is in the chamber as the bullet travels down the barrel the pressure must drop because there's more area to fill and continues to drop as more area is made available until exiting the barrel so the pressure in the chamber and Barrel is always much greater than the 14.7 PSI on the outside of the barrel thus it's continuously being pushed until exiting I would like to thank those who answered seriously and to the few that were mainly just mean you guys need to take a break from The Forum
Marco Califo said:Pressure does not increase as the bullet travel down the barrel. Barrel length and pressure are not related at all.
Yes, but from your post it sounds like this phenomena is occurring an entire 26". It is in actuality done In less than 6 inches unless you are using a powder so slow that it is out of burn rate range of cartridge. Kind of like one day many years ago when I used to drink I loaded some 357 mag with RL25. 90 % of the powder got "puked". It probably did reach peak pressure close to end of barrel.Now, to really boggle your mind, many modern smokeless powders are "progressive burning". Meaning the burning rate of the powder changes as the pressure changes.
As the bullet moves down the barrel, there is more space for the powder gas to fill. The rate this happens is the expansion ratio. Modern progressive powders are formulated to burn in such a way that this expanding area is filled by powder gas at (as close as can be attained) full pressure. Matters more with rifles than handguns, but the principle applies to both.
Even the "weakest" rounds push their bullets with several TONS of pressure per square inch. High pressure rounds can push with a couple dozen tons of pressure on the base of the bullet. So, yes, it scoots right along, overcoming the resistance of the rifling and reaching speeds of hundreds or thousands of feet per second.