9mm fps speeds

All available weights of FMJ bullets, are they all the same speed coming out of a carbine barrel ?

no they are not.

What weight is faster ? Lighter or heavy ? Are they all subsonic ?

lighter is faster, less mass to move

james r chapman wrote:lighter is faster, less mass to move

But will a 115grain fmj still be subsonic ?

Not out of a carbine, no.

My fragile memory tells me about 300 fps difference between my glock 17 & pcc 9mm, but it's been a long time.

DEPENDS ON THE AMMO. SOME 9MM HAS BEEN MADE JUST FOR CARBINE USE. TZZ MADE SOME GREAT CARBINE AMMO. IF YOUR LOADING FOR 9MM CARBINE WSF IS A GREAT POWDER FOR THAT. DESIGNED FOR SHOTGUN LONG BARRELS. GREAT VELOCITY OUT OF 9MM AR'S AND MARLIN CAMP9. JP

Ill give  a example  using two of my guns pistol ammo   147gr 3.3 sport pistol   Glock 34      930 fps
16 in barreled pcc  same load  1226fps

Multiracer wrote:All available weights of FMJ bullets, are they all the same speed coming out of a carbine barrel ?

You'll find much factory produced sub-sonic 9mm ammo with a bullet weight around 147 grains. I have loaded some 147 gr. JHP Zero bullets that stay below the sound barrier in my carbine, yet remain accurate. If your goal is to shoot suppressed, the heavier bullets might be the ticket. With a suppressor equipped carbine, there is a distinct difference in the sound level of a sub-sonic bullet and one which breaks the sound barrier.

As always ...be careful.
I have a couple of manuals that warn against using 147 grain bullets in reloads for carbines.
Not sure why  but I tend to trust the "experts".

STEVE SAMELAK wrote:As always ...be careful.
I have a couple of manuals that warn against using 147 grain bullets in reloads for carbines.
Not sure why  but I tend to trust the "experts".

All firearm manufacturers advise not to use reloads in their guns. I suppose if we always listened to the "experts" there would be no reloading equipment or components sold. Certainly there are few, if any published loads for .45 ACP that are useful in precision pistol shooting. Does that mean that bullseye pistol shooters shouldn't use the bullet and powder combinations that have been used successfully for decades? One should always be careful and prudent when reloading and shooting, but I personally think that the "experts" are sometimes overly cautious. Maybe because of lawyers advising about possible litigation?

The warning was in a  reloading manual (speer#14), not firearm instructions.

If you think about it, it really is rocket science and small cases go from propellant to explosive.

Anything traveling at less 1126 fps is considered to be subsonic and everything greater than that is traveling at supersonic speed.

Allen Barnett wrote:Anything traveling at less 1126 fps is considered to be subsonic and everything greater than that is traveling at supersonic speed.

Pretty simplistic statement - and not always true.  Mach 1 varies greatly with temperature.  Mach 1 at 120 *F is 1180 FPS.  At -40 *F, Mach 1 drops to 1004 FPS.
Source for the above velocity numbers:  https://www.weather.gov/epz/wxcalc_speedofsound

STEVE SAMELAK wrote:I have a couple of manuals that warn against using 147 grain bullets in reloads for carbines.

Must be an issue with firearms timing - 147s could have a different impulse on recoil then standard 115 or 125 grain loads.  That, and the longer pressure curve from using slower powder could result in unlocking the bolt while the chamber is still under pressure.

There once was a US military prohibition against using 147 grain ammo (Special Forces antiterrorism load for MP-5 roller locked carbines) in Beretta M9s and civilian Model 92s.   Failed slides were contaminated with traces of Tellurium.  Shoot enough 147s, and slides broke during recoil.  A change in slide manufacturing, (removal of Tellurium from the process) stopped slide failures.
Source for M9 slide failure information:  https://www.defensereview.com/the-true-story-of-the-beretta-m9-pistol/

BE Mike wrote:

Multiracer wrote:All available weights of FMJ bullets, are they all the same speed coming out of a carbine barrel ?

You'll find much factory produced sub-sonic 9mm ammo with a bullet weight around 147 grains. I have loaded some 147 gr. JHP Zero bullets that stay below the sound barrier in my carbine, yet remain accurate. If your goal is to shoot suppressed, the heavier bullets might be the ticket. With a suppressor equipped carbine, there is a distinct difference in the sound level of a sub-sonic bullet and one which breaks the sound barrier.

This is the exact problem I am having.

Multiracer wrote:

BE Mike wrote:

Multiracer wrote:All available weights of FMJ bullets, are they all the same speed coming out of a carbine barrel ?

You'll find much factory produced sub-sonic 9mm ammo with a bullet weight around 147 grains. I have loaded some 147 gr. JHP Zero bullets that stay below the sound barrier in my carbine, yet remain accurate. If your goal is to shoot suppressed, the heavier bullets might be the ticket. With a suppressor equipped carbine, there is a distinct difference in the sound level of a sub-sonic bullet and one which breaks the sound barrier.

This is the exact problem I am having.

As one who shoots with a can on a 9mm carbine, I'd suggest going with the 147 gr. JHP bullet. Coated and cast bullets will heavily foul a can and mine doesn't disassemble for cleaning. I'd shoot for a powder charge that will stay around 1,000 fps out of your carbine. I would start with a recommended load that is barely supersonic and work my way down (usually we do the opposite). I'll send you a PM.