Colt "New Service"

[c east]

I was told not to shoot "Factory" UMC ammo in this pistol...It is 45 Colt and I thought all 45 colt was loaded to safe pressures...It is in excellent condition...Thank You Honest Charlie....

[St. George]

About the only reason to not shoot "factory" ammunition by a particular brand name is if that ammuntion has been found to be inherently dangerous.
Remington has a lot of ammunition loaded in Mexico.
Maybe there's some variety of prejudice at work, here - much like the old bias against optics made in Japan.

I'd shoot it with "factory anything", myself - the things were built like bank vaults and are as strong as can be.

But if you don't want to shoot it, well - you and I ought to talk...

Good Luck.

Scouts Out!

(if you don't already know its manufacture date - PM me with the serial number and I'll let you know)

[SIR WILLIAM]

The reason I have heard repeated is sensible but, wrong.  UMC uses a red lube.  It does build up in the chambers IF you never clean up. It looks like rust.  It isn't.  If you use UMC,  clean as normal.  It really shows up in stainless steel revolver chambers.  It has scared a few people.  It looks like the Masque of the Red Death.  Good Vincent Price movie!