Rifle barrel smaller than bullet

Supp0rtLinux · October 7, 2009, 02:11 PM

Okay, perhaps this is stupid question, but I'm stuck on something...

I just bought a 30-06 Remington 700. The barrel is stamped "30-06 SPRG" (Springfield). And I bought a box of Remington labeled 30-06 Springfield ammo. I played around with it a bit... chambered a round or two and all is fine. I then proceeded to break it down and while disassembled I took one of the 30-06 rounds and put it tip-first into the end of the barrel. I guess I expected it to slide all the way in to the jacket/shell casing. But it didn't. It went most of the way in, but a good portion (1/8'' to 1/4'') of the bullet itself was still exposed. Is this normal? Does the bullet get pushed through a too-tight barrel when its fired? As a comparison, I also have a Ruger LCP (.380 auto). I just did the same thing to it and the bullet fit all the way into the barrel up the shell casing. I'm taking the 700 out shooting at a range this weekend, but before I fire it I want to make sure I'm not going to damage the gun nor myself.

gb_in_ga · October 7, 2009, 02:31 PM

Quote:

Is this normal? Does the bullet get pushed through a too-tight barrel when its fired?

This is normal. The bullet is swagged into the rifling and seals the bore. If the bullet didn't do this, the rifling couldn't spin the bullet and thus stabilize the bullet, and gasses would escape around the bullet.

hogdogs · October 7, 2009, 02:34 PM

gb is correct... Unless it is a slap wore out Lorcin .380 which I could drop a round in the barrel... casing and all

No wonder I had 2 foot groups at 20 feet

Traded it for a Maverick 88 and a nice Marlin 336 levergun

Brent

Supp0rtLinux · October 7, 2009, 02:39 PM

Thanks... I feel better now. But this does bring a follow-up question...

Since the bullet at its base is somewhat larger than the end of the barrel, does that mean that the bullet is slowed down when it exits the barrel? If so, how does this affect things like FPS, range, etc? Or do gun and bullet manufacturers account for this sort of thing (I'm assuming, but you never know til you ask). Related... assuming it does slow things down a bit, does this mean there are customizations that can be made to the barrel (replacement barrel, etc) that don't restrict it as much and allow for greater range, etc?

Doyle · October 7, 2009, 02:43 PM

In theory, a "tighter" than normal barrel would shoot the same bullet with a little less velocity than a loose barrel. However, it isn't something that you really need to think about. Any 30-06 you buy is going to have far greater "range" than you'll ever get to use effectively.

hogdogs · October 7, 2009, 02:47 PM

Also, the tightness is how you get the high FPS... Holds back the pressure in the barrel.
Brent

**Bud Helms** · October 7, 2009, 03:38 PM

Quote:

Also, the tightness is how you get the high FPS... Holds back the pressure in the barrel.

Well ... it lets the pressure build. A tight bore (within specs) is also conducive to good accuracy.

fisherman66 · October 7, 2009, 05:02 PM

Quote:

Since the bullet at its base is somewhat larger than the end of the barrel, does that mean that the bullet is slowed down when it exits the barrel?

It's not any larger diameter at the muzzle (unlike a shotgun which might have a choke). The barrel is uniform. It appears to be wider at the breach because there is a chamber that holds the entire shell and a little freebore or throat for the bullet to pull up just slightly shy of the rifling.

Here's a decent place to start since it shows actions clips.
http://www.howstuffworks.com/machine-gun.htm/printable

Waterengineer · October 7, 2009, 08:03 PM

Its good when it is tight.

fisherman66 · October 7, 2009, 08:14 PM

Quote:

Its good when it is tight.

Thought I'd lock you in before you changed it.

Thor, Zeus, Apollo; this is a family site!

peejman · October 8, 2009, 01:41 PM

That's why you get copper (or lead) fouling in the barrel. The bullet bites into the rifling and leaves a little of metal behind as it travels down the barrel.

The 60,000 psi chamber pressure also causes the barrel to expand ever so slightly when the round is fired. The pressure drops considerably as the round travels down the barrel.

October 7, 2009, 02:11 PM	#1
Supp0rtLinux Member Join Date: October 7, 2009 Location: Florida Posts: 31	Rifle barrel smaller than bullet Okay, perhaps this is stupid question, but I'm stuck on something... I just bought a 30-06 Remington 700. The barrel is stamped "30-06 SPRG" (Springfield). And I bought a box of Remington labeled 30-06 Springfield ammo. I played around with it a bit... chambered a round or two and all is fine. I then proceeded to break it down and while disassembled I took one of the 30-06 rounds and put it tip-first into the end of the barrel. I guess I expected it to slide all the way in to the jacket/shell casing. But it didn't. It went most of the way in, but a good portion (1/8'' to 1/4'') of the bullet itself was still exposed. Is this normal? Does the bullet get pushed through a too-tight barrel when its fired? As a comparison, I also have a Ruger LCP (.380 auto). I just did the same thing to it and the bullet fit all the way into the barrel up the shell casing. I'm taking the 700 out shooting at a range this weekend, but before I fire it I want to make sure I'm not going to damage the gun nor myself.

October 7, 2009, 02:34 PM	#3
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	gb is correct... Unless it is a slap wore out Lorcin .380 which I could drop a round in the barrel... casing and all No wonder I had 2 foot groups at 20 feet Traded it for a Maverick 88 and a nice Marlin 336 levergun Brent

October 7, 2009, 02:39 PM	#4
Supp0rtLinux Member Join Date: October 7, 2009 Location: Florida Posts: 31	Thanks... I feel better now. But this does bring a follow-up question... Since the bullet at its base is somewhat larger than the end of the barrel, does that mean that the bullet is slowed down when it exits the barrel? If so, how does this affect things like FPS, range, etc? Or do gun and bullet manufacturers account for this sort of thing (I'm assuming, but you never know til you ask). Related... assuming it does slow things down a bit, does this mean there are customizations that can be made to the barrel (replacement barrel, etc) that don't restrict it as much and allow for greater range, etc?

October 7, 2009, 02:43 PM	#5
Doyle Senior Member Join Date: June 20, 2007 Location: Rainbow City, Alabama Posts: 7,167	In theory, a "tighter" than normal barrel would shoot the same bullet with a little less velocity than a loose barrel. However, it isn't something that you really need to think about. Any 30-06 you buy is going to have far greater "range" than you'll ever get to use effectively.

October 7, 2009, 02:47 PM	#6
hogdogs Staff In Memoriam Join Date: October 31, 2007 Location: Western Florida panhandle Posts: 11,069	Also, the tightness is how you get the high FPS... Holds back the pressure in the barrel. Brent

October 7, 2009, 08:03 PM	#9
Waterengineer Senior Member Join Date: February 7, 2006 Location: Aurora, CO and Palm Beach, FL Posts: 863	Its good when it is tight.

October 8, 2009, 01:41 PM	#11
peejman Member Join Date: April 14, 2009 Location: East TN Posts: 79	That's why you get copper (or lead) fouling in the barrel. The bullet bites into the rifling and leaves a little of metal behind as it travels down the barrel. The 60,000 psi chamber pressure also causes the barrel to expand ever so slightly when the round is fired. The pressure drops considerably as the round travels down the barrel.