.454 lead bullets in .45 Colt New Vaquero - pressure concerns?

[Tallinar]

Hello,

First off, I apologize if I’m not posting this in the most appropriate forum.

I recently acquired a brand new .45 Colt Ruger New Vaquero with 4 5/8” barrel. I haven’t shot .45 Colt for a good while, but I have a few hundred light cowboy loads that my dad and I had loaded up several years ago for a Rossi M92 that I no longer have. These loads are all pretty light (225 gr LSWC with around 5.0-5.5 gr of 700X or Red Dot...can’t remember exact at the moment). However, bullets are sized in .454.

As I understand it, modern .45 Colt guns are usually grooved at .451, with chamber throats in the neighborhood of .452 (.4525 being desirable). By contrast, it sounds like older Colts and even some reproductions are closer to .454.

I’ve read and understand that using bullets that are sized larger than the chamber throats can cause higher pressures.

My question is: Should I be concerned about shooting .454 lead bullets in this gun? Or am I risking damage to the gun (or myself?) I’ve shot a number of them already, and haven’t noticed any concerning behavior. Accuracy at 7 yds has been acceptable, and I haven’t experienced any leading to speak of. I am inclined to maybe just finish shooting these up, and then try to load .452 in the future.

Seems like this may be one of those cases where I’m overthinking it. These loads are probably light enough, and the bullets soft enough, that whatever minimal pressure increase may be happening in the chamber is inconsequential. Seemed good to ask though. Thanks!

 

[Slamfire]

I have fired tens of thousands of 0.452" and 0.454" 250 to 255 cast lead bullets in my various 45 LC revolvers. Heat makes more of a difference, at least in velocity, than does the difference between a 0.452" or 0.454" bullet. I believe that if higher pressures were happening, I would see something over the chronograph. In time, I started buying 0.454" cast bullets and using them in everything, my New Service revolvers won't shoot accurately with 0.452" bullets, and since the bullet diameter does not make an accuracy difference or velocity difference, I might as well buy the bigger bullet.


S&W M25-7 45 LC 0.452” chamber mouths

255 LSWC (.452") 8.5 grain Unique lot UN331 WLP (nickle) primers
2-Sep-90 T ≈ 92 ° F

Ave Vel = 859
Std Dev = 56
ES = 172
Low = 780
High = 952
N = 6


255 LSWC (.454") 8.5 grain Unique lot UN331 WLP (nickle) primers
2-Sep-90 T ≈ 92 ° F

Ave Vel = 867
Std Dev = 61
ES = 161
Low = 791
High = 952
N = 6

 

[reddog81]

The lead sizes down pretty easily. .454 will work just fine. If your throats are .452 then.453 or .454 is probably ideal.

 

[ArchAngelCD]

I have also shot many .454" bullets in newer .45 Colt revolvers. As a matter of fact in my Vaquero they are more accurate.