Colt New Service,45 colt problem

bushrod2 · May 10, 2010, 10:46 PM

I have a Colt new service with a four digit serial number. Colt says it was mfg. in 1903. Chambering is 45 colt. My problem is that the cylinder throats slug out at .451 and the barrel slugs out at .454. I thought the gun was all original.
What diameter bullets should I size my cast lead to? They drop from my mold at.454 I don't want to damage the gun but I do want to load and shoot it

Powderman · May 11, 2010, 12:30 AM

You will never get that revolver to shoot straight in that configuration.

You will have to do one of two things...

1. Have the cylinder throats reamed to .454; or,
2. Rebarrel with a .451 bore.

Scorch · May 11, 2010, 04:26 PM

Agreed, you will need to have the gun worked on to correct one or both of those issues.

Pre-WW2 45 Colts used a .455" bore diameter, post-WW2 45 Colts use a .451" bore diameter, so factory-loaded 45 Colt ammo often used/uses hollow-based bullets to expand and fill pre-WW2 barrels. FWIW, a new .451" bore barrel or a take-off barrel from a Colt 1917 revolver would screw on perfectly, allowing use of modern 45 Colt ammo with a reasonable expectation of accuracy.

James K · May 11, 2010, 08:37 PM

It depends a lot on condition, but installing a new barrel on a 1903 Colt NS might be nose-cutting. Those guns are bringing good prices in good original condition, and a barrel change will cut it in half. Reaming the chamber throats won't alter the value.

Jim

May 10, 2010, 10:46 PM	#1
bushrod2 Member Join Date: February 12, 2008 Location: ohio Posts: 30	Colt New Service,45 colt problem I have a Colt new service with a four digit serial number. Colt says it was mfg. in 1903. Chambering is 45 colt. My problem is that the cylinder throats slug out at .451 and the barrel slugs out at .454. I thought the gun was all original. What diameter bullets should I size my cast lead to? They drop from my mold at.454 I don't want to damage the gun but I do want to load and shoot it

May 11, 2010, 12:30 AM	#2
Powderman Senior Member Join Date: September 7, 2001 Location: Washington State Posts: 2,166	You will never get that revolver to shoot straight in that configuration. You will have to do one of two things... 1. Have the cylinder throats reamed to .454; or, 2. Rebarrel with a .451 bore. __________________ Hiding in plain sight...

May 11, 2010, 04:26 PM	#3
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	Agreed, you will need to have the gun worked on to correct one or both of those issues. Pre-WW2 45 Colts used a .455" bore diameter, post-WW2 45 Colts use a .451" bore diameter, so factory-loaded 45 Colt ammo often used/uses hollow-based bullets to expand and fill pre-WW2 barrels. FWIW, a new .451" bore barrel or a take-off barrel from a Colt 1917 revolver would screw on perfectly, allowing use of modern 45 Colt ammo with a reasonable expectation of accuracy. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

May 11, 2010, 08:37 PM	#4
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	It depends a lot on condition, but installing a new barrel on a 1903 Colt NS might be nose-cutting. Those guns are bringing good prices in good original condition, and a barrel change will cut it in half. Reaming the chamber throats won't alter the value. Jim