45 long colt diameter?

I looked in speer reloading and it said .451 200 gr. so I ordered a bunch. well I get to talking to a friend and he said Oh, NO! so we looked at some other loading manuals and they had .452 diameter bullets.

this is just for a big revolver for plinking. Staying less than 13k psi.

Little confused on what i should be buying unless I just follow load data for the different diameters

I've only used .452 in my Ruger Blackhawk and Henry rifle. But they are hard cast lead. I believe the .451 is used mostly for copper jacketed bullets in 45 colt and 45 ACP in todays newer guns.

To be even more confusing old Colts were .454. Only problem you could encounter is they will be normally less accurate if your gun is .452. If they were lead instead of jacketed and undersize excess leading will result. Your gun may actually be .451. No one really knows without measuring. I have serious doubts it is an issue unless you have an old .454 Colt.

You do not want the cylinder throats to be "smaller" than bullet diameter. I got two Ruger .44 Specials last year, a Blackhawk and GP 100 and check them both for cylinder throat and bore diameter.

Brownells' Cylinder Throat Reamer for .45 Revolvers
https://gunblast.com/Brownells_Reamer.htm

You can also have a problem where the barrel bore diameter becomes smaller where it screws into the frame. This chokepoint in the barrel will squeeze the bullet diameter smaller and cause accuracy and leading problems.

A Contemporary Look At Barrel Leading and Related Sixgun Issues
https://gunblast.com/FerminGarza-Firelapping.htm

Accurizing the Ruger Single Action Revolver
http://www.castbullet.com/misc/accrsa.htm

Revolver Accuracy

In order to gain maximum accuracy from any revolver, the diameter of the bullets, the cylinder throats, forcing cone, and barrel all must be in harmony. Specifically, the bullet must be one to two thousandths larger than the bore, the bore must be uniform from forcing cone to muzzle, the muzzle must be properly crowned, and the cylinder throats must all be the same diameter as the bullet or .0005" larger. The cylinder throats should not swage the bullets, just guide them. You also need a good trigger pull. I measured these areas on my Blackhawk and this is what I found:

for plinking, you should be fine--usually the plated/jacketed bullets will be smaller diameter and lead will be larger--I always slug my pistol barrels so I know what size is the correct size for cast lead bullets but it wont hurt anything for plinking if they are undersized a bit, but it could cause more leading of the barrel

there are alot of things that can be done to a revolver to accurize it (fire-lapping, reaming chambers, throats, etc) but for just fun plinking your bullets will be fine

If you want a good do about anything within reason 45 Colt bullet get some Hornady 250 gr XTPs. They are designed to expand and perform at normal Colt 45 velocities starting out around 800 fps. Push them faster and they get real nasty on living things. I have shot deer with this bullet from a 45 Colt Ruger Black Hawk Pistol running it from 1000 up to 1300 fps and it REALLY opens up. I have used this bullet in a sabot out of muzzle loaders running them between 1600 and 1800 fps and they are REALLY REALLY nasty on impact.

Another good bullet is the 300 gr Speer JSP, It is a bit tougher bullet but very accurate in my 45 Colt Ruger. I am pushing it 1000 fps and I carry this load for bear protection while bow hunting and messing around in the summer on my hunting lease land that has a good number of black bear on it.

One thing I have learned over the past 40+ years of hand loading and shooting game is with calibers that start with 4 with 250+ gr bullets don't have to be going at warp speed to be real effective at breaking bone and putting man or beast down quickly.

You will not know if your .451 bullet will shoot until you try it. If it don't then that gives you an excuse to purchase something in 45 ACP. LOL

You will also see this with .44 Magnum Jacketed bullets from different mfgs. You will see .429, .4295, and .430.

The pistol is the modern "Judge" So I will check online as to what the barrel dia is.

The Taurus Judge is made by taking a . 45 LC pistol Which has an inside diameter of about . 451, and using a longer chamber so it can fire . 410 shotgun shells.

With the Judge don't expect very good accuracy with ANY bullet. That loooooooooog jump in the chambers that allow 410 Shot shells is really detrimental to accuracy. I faced this with an old T/C Contender with 45 Colt/410 barrel.