45 Colt Cylinder Sizes

[bigtee]

Just picked up my Ruger Bisley Blackhawk in 45 Colt/45 ACP today. I pulled the Colt cylinder out and miced it. Sizes are from .4512 to .4518.I was worried about this wanting to shoot cast and having a NOE 454424 on the way. I know I need to slug the barrel to find the size on it. Just looking for some advice on the next steps. From what I have read the cylinder should be .4525.

The ACP cylinder mics .4512 to .4515, so I will shoot it for now till I get the Colt cylinder figured out.

What are my next steps?

[williamwaco]

Just picked up my Ruger Bisley Blackhawk in 45 Colt/45 ACP today. I pulled the Colt cylinder out and miced it. Sizes are from .4512 to .4518.I was worried about this wanting to shoot cast and having a NOE 454424 on the way. I know I need to slug the barrel to find the size on it. Just looking for some advice on the next steps. From what I have read the cylinder should be .4525.

The ACP cylinder mics .4512 to .4515, so I will shoot it for now till I get the Colt cylinder figured out.

What are my next steps?

You didn't mention how you "miked" it. This requires a special mike that very few reloaders have.

You are over thinking this issue.
I have been reloading revolvers since 1956 and I have never found it necessary to slug a barrel.
I have done it a couple of times out of curiosity but never to determine what size bullets to use.

Size them .454 and load 'em up and shoot 'em.

If they don't work, then lets worry about measurements.

[bigtee]

I miced with a telescoping gage and 0 to 1" mics, machinist by trade. I'm going to try some .452's loaded in 45 ACP and see what they do.

[dubber123]

You are fortunate.. The ones I just checked on my brothers BH ran .455" average. At least you have metal to work with. I don't have many molds that cast fat enough to fit the throats on his.

[runfiverun]

I just shoot 452 in mine, I didn't even bother to measure.
it shoots just as well as the 44 special I did measure.

[Piedmont]

Next step should be shooting the heck out of it. Looks like you got a good one.

[jaydub in wi]

Next step should be shooting the heck out of it. Looks like you got a good one.
My 45 colt Blackhawk measured .449. Glad you got a good one.

[Guesser]

I was given a NMBH Ruger 45/45 convertible in 2005, new production. It didn't shoot well at all. I slugged the bore, .451 and very smooth. Good. I had been sizing .452. I read an article in Hand Loader Magazine about the variations in cylinder chamber throats in Ruger 45 caliber revolvers. Using pin gauges I determined that the throats of both cylinders, 45/45 convertible, remember; varied so widely as to be essentially unbelievable. I took the pins and the cylinders to a machinist/gunsmith and had him do it. His conclusion verified mine. The throats varied from a tight .442 to a not so tight .4505, 12 throats and not one was in spec. I bought the tooling from Brownells and uniformly standardized all 12 throats to .4525. I'm still sizing my castings to .452 and they are superb performers from a gun that had been an abysmal failure at accurate bullet placement.

[williamwaco]

I miced with a telescoping gage and 0 to 1" mics, machinist by trade. I'm going to try some .452's loaded in 45 ACP and see what they do.

OK, you got me there. I envy your skills andn equipment.

BUT

My advice stands.

You are over thinking this issue.
I have been reloading revolvers since 1956 and I have never found it necessary to slug a barrel.
I have done it a couple of times out of curiosity but never to determine what size bullets to use.

Size them .454 and load 'em up and shoot 'em.

If they don't work, then lets worry about measurements.

[DougGuy]

There is a simpler way.. Use the boolit for a pin gage. Take the boolit you want to shoot and see if it will go in the front of the cylinder. If it won't then ream the cylinder throats. Most shooters opt for .452" boolits, so if you go to the .4525" reamer and some Tap Magic, it will clean up nicely and your boolits should slide into the front of the cylinder throats semi snugly.

There really isn't a need to slug the Ruger barrel to check what it's diameter is. They are pretty consistent on land/groove diameters, right at .451" the thing you do want to check in the barrel, is the threaded portion that screws into the frame. The easy way to do this other than slugging it, is to take a cleaning jag and patch it very tight in the bore. When you get it to the part that goes into the frame, if it stops and gets really hard to push, you have a thread constriction. If it pushes through with not a super great change in the effort required to shove it that far, it's not enough of a constriction to cause accuracy or leading problems.

This is actually a more practical way to check than slugging, because what it does to your arm to shove the cleaning patch through there, is exactly what it will do to the boolit coming through it from the other direction. If your constriction is fairly noticeable, call Ruger and let them send you a prepaid label and get them to fix it. That's a better fix than fire lapping or taylor throating and it's well... Free!

Edit: Also.. The softer the alloy you will shoot, the less any of this matters because if there is enough gas pressure behind the softer boolit, it will happily swage down to go through the tight spots, and then back up again when it gets into the barrel. It is only when you are using ACWW or harder alloys that the boolit will not "obturate" or swage up to fill the bore when it passes through the tight spots..

[bigtee]

I checked the barrel with a jag and patch and can't tell any difference. I'm waiting on my mold and sizer to come in, NOE 454424 255gr and a .452 sizer. I did try a jacketed bullet that mics .4515 and it won't go in all holes in the front of the cylinder. Maybe I am over thinking it, when I get everything in I will go from there.

Thanks to everyone for the advice.

[DougGuy]

Nahh not overthinking, this is typical for Ruger. I 'd rather they be tight than so loose they shoot like a scattergun! They take a little tweaking here and there, no biggie.

[Guesser]

The problem with my throats at .442 and up to .4505 was that the cast bullets were being swaged so small that the were loose in the bore. That's why I followed the recommended reaming procedure. An unqualified success. Look up Handloader in late 05 or early 06 and you'll get the full picture.

[propwashp47]

I have a pair like yours they shoot fine with cast or fmj. not one ragged hole but better than me offhand.so I never checked them for size. I will tell you the way they handle recoil with a 255 hc over 18.5 gr of 2400 will put a big smile on your face. enjoy what you have and go have some fun.