45 Colt diameter?

[Jayhawkhuntclub]

So what diameter is the 45 Colt? I know the stories about the historic variability of both the chambers and the barrels. But I think 100+ years is long enough to settle on a diameter. The reason I ask is most lead bullets I see are sold at 0.452" which should be in theory 0.001" over the bore diameter. So why does Hornady & Winchester sell their XTPs at a diameter of 0.452" (Sierra at 0.4515")?

 

[J Miller]

So what diameter is the 45 Colt? I know the stories about the historic variability of both the chambers and the barrels. But I think 100+ years is long enough to settle on a diameter. The reason I ask is most lead bullets I see are sold at 0.452" which should be in theory 0.001" over the bore diameter. So why does Hornady & Winchester sell their XTPs at a diameter of 0.452" (Sierra at 0.4515")?

They vary just like everything else. Most are generally in the .451" to .452" grove diameter range. My OM BH .45 is .452". My S&W 25-5 is .4515", and my Uberti Cattleman is ...... I don't know, never slugged it.
Both of my lever guns run in the .451" range.

The thing is, it's not the barrel that's the critical dimension with revolvers. It's the chamber throats.
If they are right with the bore say .451" to .452" grove diameter, with a .4525" throats your pretty much good to go with any .451" to .452" lead or jacketed bullet.
If they are over sized, then things can get a bit more complicated.

Since the end of WW II, almost all jacketed bullet makers have settled on the .4515" to .452" bullet diameter for the .45 Colt and ACP bullets.

But, Winchester and Remington still make their .45 Colt ammo to SAAMI specs with .456" and .455" lead and jacketed bullets. Yes, the Winchester STHP is .455".

Other makers such as CorBon, Speer, PMC are using the newer .451" to .452" size for the jacketed bullets.
Hornady is using .454" lead bullets though.

There is no iron clad size rule for the .45 Colt.

And for 90% of my ammo I've found all of my .45 Colts shoot a bit better with ammo using .454" lead bullets. Only when I've loaded some of the heavy loads does the .452" bullets shoot well.

Joe

 

[Bucks Owin]

I agree with Joe. My .45 BH has a .452" barrel, .456" throats and likes .454" lead bullets. (And Win's 225 gr STHP factory load) And even lead bullets seem to like to be pushed kinda hard for best accuracy. My Hornady lead 255 gr loads seem to like around 1150 fps when using HS-6 which is "warmish" for that powder but gives them a good "bump" I expect. I'm a little leery of going much faster with them, I think they are probably designed for CAS velocities/pressures, not a case full of H-110. Haven't shot an awful lot of jacketed .451-2", have been using dies too loose for them, but again, faster seems better.....FWIW, Dennis (Who will have two sizing dies for all ".45 Colts"... :roll: )

 

[mindustrial]

XTP & Sierra's run on the high side. My 44 mag XTP's are .430, & Sierra's are .4295. Nominal should be .429, so in line with the .45 caliber bullets.

The last bag I bought of Remington Molly coated hollow base bullets were .455 - .455. Just perfect for oversized throats in old guns.

 

[Bucks Owin]

.

The last bag I bought of Remington Molly coated hollow base bullets were .455 - .455. Just perfect for oversized throats in old guns.

Glad to hear that, I've been thinking of ordering a bag or two, although they're listed by Natchez as "Remington Bulk Pistol bullets, .454 45Colt LD". I guess it's the same bullet....Dennis (Who thinks this topic should get moved to the reloading section!) :wink:

 

[Driftwood Johnson]

Howdy

Originally the groove diameter of 45 Colt was .454. I'm looking at a copy of a US Ordinance data table from 1882 right now, and it calls out the groove diameter as .454 min, .455 max. Colt stopped making the Single Action Army in 1940 in order to free up production capacity to make more 1911 Government models.

At the end of the War, I don't think Colt had any intention of starting production of the SAA again, sales numbers had been very low for the years leading up to 1940. But Colt did not count on two things. First of all, they did not know that televisions in almost every home suddenly started bringing the likes of Roy Rogers, and Hoppy, and all the rest into everybody's living rooms. And secondly, a young man named Bill Ruger came along and tapped into the growing demand generated by all those living room cowboys, first with a 22 caliber single action revolver, and shortly after that with a 357 Magnum single action revolver. So Colt finally started producing the old SAA again in 1956.

At this time, groove diameter for 45 Colt was changed from .454 to .451, in order to match the groove diameter of the 45 ACP guns.

Here is the latest version of the SAAMI spec for cartridges, chambers, and barrels for 45 Colt that I have. Using the tolerance indicated, what the drawing is saying about bullet diameter is there is a range from .450 to .456.

Now look at the barrel dimension. The tolerance is calling out groove diameter as .450-.454.

.454 bullets are primarily meant for the old guns, with the .454 groove diameters, .452 bullets are primarily meant for the postwar guns with the .451 groove diameters. However it is true that it can be tricky choosing a bullet diameter when chamber throats and rifling grooves are not well matched.

 

[Enigma]

Very good info, Driftwood! Personally, I like to err on the side of caution. Since I shoot cast/swaged lead bullets almost exclusively in my .45 Colts, and I have one of the notorious M25-5 S&W revolvers (with .456-.457" throats), I load either .454" cast bullets or the Remington bulk .455" diameter swaged bullets.

Even in my .4525" throat, .452" groove Ruger, these bullets shoot the best.

 

[tomiswho]

I have a SRH .454, a NMBH .45 Colt, and a S&W 25-7 (Model of 1989) and they all seem to shoot the 250g .452 RNFP bullets I get from Georgia Arms just fine. The .452 XTP's work fine in the Ruger's but I haven't fired them in the Smith. I shoot the Smith very little, I'm trying to keep it looking new.

 

[maxpress]

i know cas shooters who like to size soft cast bullets at the upper limits because they say the seal and rifle in the bore better.

forrest gump says: "know i dont know about thaAt"

but hey whatever tickles your fanny.