Thanks JohnKSa for that moment of clarity. I appreciate it....
You can find pressure curves that show definitively that the pressure drops as the bullet moves down the barrel.
There are several at this website.
https://www.frfrogspad.com/intballi.htm
There's an initial peak that happens very early in bullet travel, then from there on, the pressure drops continually until the bullet exits.
However, even though it is lower by the time the bullet exits from the barrel, it is still significant enough that the push it creates on the back of the bullet is also significant. Even though it's dropping as the bullet moves down the barrel, it's still exerting enough force to keep accelerating the bullet.
From one of the pressure plots on the linked website, it can be seen that the chamber pressure in that particular case is still over 10,000psi at bullet exit. That's still going to be pushing on the bullet with a lot of force, even if it's not as much force as it was earlier.
Think of as pushing a heavy cart. At the beginning, you have to push very hard, then as it gets rolling, you can stop pushing quite as hard, but even so, you can keep it speeding up even by pushing with less force than you used at the beginning to get it started. The longer you push, the faster it goes, even if you're not pushing as hard at the end as you were at the beginning.
That's about 5 posts worth of good information in one.Excellent FIRST POST AWARD goes to ...
Boomholzer ^^
WELCOME to THR
Noise is probably a little louder in a pistol, but not enough percievable difference if niether are surpressed.
Download a decibel measuring app to your phone and take the two guns to the range.
Place the phone in your shirt pocket and record five shots with each gun, then record five shots with the phone on a table to the side.
Report the results.
/thread.
Port pop is absolutely something to keep in mind.The other interesting fact is that the longer barreled Beretta's breech is much closer to my ears when in a firing position than a pistol's breech is when held at arms length. That might not mean much in a manually operated gun, but in autoloaders . . .
Thanks for all the replies.
I was just wondering if, with 9mm, it's the same as it is with 22lr. I have a 22lr pistol that is definitely louder than my 22lr rifles. And I have fired 38 Special out of a top load 1851 revolver and it was FAR louder to me than the same load out of my 1873 Taylors with 20" barrel.
So, I would hoping that a PC Carbine, with the 16" barrel, would be enough of a difference to where I could still keep the 9mm I have when I get rid of my pistols.
Yep that's some sensitive hearing alright, have you thought about a suppressor a dead air wolfman would work on 9mm and a 5.56 rifle.Because I have sensitive hearing, and 9mm blast is [IMO] about at the limit I like to be exposed to [even with ear plugs and ear muffs], I may have to give up on 9mm completely [and my AR-15 for that matter] and just stick with 22lr......and the 38 Special out of my 1873 lever rifle. Shooting guns isn't my life, and if I can only do those types of firearms, I would be fine.
...Another factor in pistol carbines and perceived noise is action timing. Direct blowback auto loaders will open the action earlier then a cam'ed or locked breech auto pistol...
Couple of possible steps to take, while we are at this,would be a huge benefit to people
Understandable, another suggestion would be a linear compensator or shrouded brake they help some to direct noise away.mavracer, I don't really want to jump through the government background check and $200 tax stamp hoop.....wait the how ever long period of time, spend the several hundred on a suppressor, just so I can shoot 9mm. It's unfortunate that suppressors require so much when it would be a huge benefit to people. I do appreciate the advice!