NM Blackhawk 45 Colt Tight Cylinder chambers

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philthephlier

Bearcat
Joined
Sep 8, 2009
Messages
17
I have seen a number of references to tight cylinder chambers on 45 Colt Blackhawks. What do I look for and under what conditions do I or should I ream them. I have seen a chucking reamer in .452 on Amazon.com for a bit over $20. Is that a good price?. It's new, not used.
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
20,993
Welcome to the Forum!
Well, sometimes a cylinder is made a bit "tight" and doesn't shoot as well as it should.
A Dial Caliper measurer can measure the ID of the cylinder and see if it needs reaming. I would do it ONLY after I'd done a bit of testing to see if it actually shot "bad."
Then,, reaming a cylinder can be one of the ways to fix it. In a 45,, it should be close to .4525 to be good for most bullets.
 

DGW1949

Hunter
Joined
Apr 10, 2005
Messages
3,638
Contender has you on the right track.

Unless you're a machinist and have the right set-up stuff, that $20 chucking reamer aint the right tool for the job.

DGW
 

c.r.

Single-Sixer
Joined
Apr 23, 2008
Messages
436
I'm sure y'all are aware of this, but just thought I'd clarify something.........It's not the CHAMBERS that are tight, but the THROATS that tend to be undersized on the 45 Colt Blackhawks. Isn't there technically a difference?

~c.r.
 

Driftwood Johnson

Blackhawk
Joined
Sep 25, 2007
Messages
699
Isn't there technically a difference?

Yes, you are correct. It is the chamber throats that are sometimes a little bit tight. The chamber is the larger diameter portion of the hole where the cartridge sits. The chamber throat is in front of the chamber, and is the portion of the cylinder the bullet passes through on its way to the barrel. It is also possible to have tight chambers, but that is a separate issue.

Using the inside measuring points of a caliper is not the best way to measure the diameter of a relatively small hole. There is a built in error because the tiny flats on the knife edges of the points cannot be brought completely tangent to the diameter of the hole. A better way to measure the hole is with calibrated pin gauges, or a micrometer designed specifically for measuring the inside of holes.

Frankly, unless you are getting terrible accuracy, I would not worry about it. You can also determine the best size bullet for your chamber throats by simply seeing how much effort it takes to shove a bullet through them.
 

eric conrad

Buckeye
Joined
Sep 8, 2003
Messages
1,468
philthephlier, check this site out. CAS is a long time forum member who does beautiful work. Cas has reamed five or six cylinders for me and I am very
happy with his work. www.cylindersmith.com

Eric
 

Ruber

Single-Sixer
Joined
Sep 24, 2008
Messages
432
I agree with Driftwood and Contender on waiting to see what the accuracy is like, especially with the bullets you want to shoot. I recently picked up a .45 BH through Davidson's where the throats came out to .4523" and after some work on the action and trigger, it shoots phenomenally well with the bullets I want to be using in the field. There's no way I'm sending it off to ream out .0002". But it seems like measurements are all over the board and I'm not sure how many people write about it when things are working well. And like Driftwood mentioned, using an inside mic or other designed for small internal radiuses work best.
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
20,993
c.r. is correct. I should have made that clearer.
Driftwood Johnson has also made some excellent points to consider. And as mentioned,,, CAS does excellent work if it's needed.
 

pvtschultz

Blackhawk
Joined
Oct 11, 2005
Messages
553
My thoats were ~0.450" to 0.451" when I bought it and resulted in skid marks when shooting lead 0.452" bullets. I used the Beartooth Bullets method of opening mine by wrapping some emory cloth around an aluminum rod and working them with a drill. I did this until a measured 0.4520" bullet would pass through the throats with a bit of a push.
 

foxtrapper

Single-Sixer
Joined
Apr 30, 2008
Messages
495
Send it to Cas. He will fix it if it needs cutting, and send your moola back if it doesn't. I think the money taken in by him throating cylinders gets donated to a Fireman fund. Real good people :D
 

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