# New BlackHawk 357/9mm convertable



## Sheleti (Jan 21, 2011)

Hi all.
I just purchased a New Model Blackhawk 357/9mm revolver.
I would like to know, what is an acceptable distance for the gap between the cylinder and the barrel forming cone.

I am new to revolvers and recently dveloped an interest in them. 
I currently own purchased but have not shot (verymuch) the following.
a 357 Rossi double action 6 shot 4 inch barrel. Purchased new
a 454 casull Tarus 6 shot 8 inch barrel. Won at a gun drawing.
I recently purchased a used Rugger stainless steel .44 black powder 8 inch ? barrel and the Blackhawk .357 mentioned above.
I can see daylight through the gap in the rossi and Tarus but I was told that they are not made to as tight a toleence as the Smiths and Ruges.
However I also see daylight through thr gap in question on the Ruger .357.
As I said I am new to this any help comments are appreciated.
Thanks in advance


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## DJ Niner (Oct 3, 2006)

Hello,

You should be able to see SOME light between the barrel and cylinder on ALL revolvers (this is called the Barrel/Cylinder gap, or B/C gap). If the front face of the cylinder is actually touching the rear of the barrel (no light through gap at all), then the two surfaces will rub when the cylinder rotates, which can get worse when the weapon is hot and/or dirty. This rubbing/drag will make it difficult to thumb-cock the revolver, and even more difficult to shoot it in the Double-Action (DA) mode (just pulling the trigger), as the trigger has less leverage to rotate the cylinder than the hammer does when thumb-cocking.

When the weapon is clean and cold, most revolver B/C gaps will probably fall between .004 inches and .012 inches. Smaller than .004", and the cylinder may drag when hot or dirty; much larger than .012" and you'll be losing more gas pressure than normal through the gap when firing, and getting more flash and "spitting" of hot gunpowder particles, too. Sometimes accuracy will be poor on revolvers with larger B/C gaps (usually with softer lead bullets), but not always. You can measure the B/C gap with a set of precision feeler gauges.


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## Baldy (Jun 21, 2006)

Here's a good read on how to check out a revolver...:smt033

Revolver Checkout Procedure


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## Sheleti (Jan 21, 2011)

DJ Niner said:


> Hello,
> 
> You should be able to see SOME light between the barrel and cylinder on ALL revolvers (this is called the Barrel/Cylinder gap, or B/C gap). If the front face of the cylinder is actually touching the rear of the barrel (no light through gap at all), then the two surfaces will rub when the cylinder rotates, which can get worse when the weapon is hot and/or dirty. This rubbing/drag will make it difficult to thumb-cock the revolver, and even more difficult to shoot it in the Double-Action (DA) mode (just pulling the trigger), as the trigger has less leverage to rotate the cylinder than the hammer does when thumb-cocking.
> 
> When the weapon is clean and cold, most revolver B/C gaps will probably fall between .004 inches and .012 inches. Smaller than .004", and the cylinder may drag when hot or dirty; much larger than .012" and you'll be losing more gas pressure than normal through the gap when firing, and getting more flash and "spitting" of hot gunpowder particles, too. Sometimes accuracy will be poor on revolvers with larger B/C gaps (usually with softer lead bullets), but not always. You can measure the B/C gap with a set of precision feeler gauges.


 Thanks DJ 
Sheltie


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## Sheleti (Jan 21, 2011)

Baldy said:


> Here's a good read on how to check out a revolver...:smt033
> 
> Revolver Checkout Procedure


Thanks Baldy
Very good article. I sent it to my brotheras he is in the market for a used revolver.
I now am relived and sure I made a good purchase.

Shelti


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## bykerhd (Jul 25, 2012)

I have a Ruger convertible that came with the 9mm cylinder and no .357 cylinder.
A .357 cylinder was found and purchased on E-Bay.
It fit and functions perfectly.

A range rod showed timing at least as good as the 9mm cylinder.
Cylinder gap on the 9mm is a tight .0025.
The E-Bay .357 cylinder deal came in at .004.
I'm a happy camper and will shoot both with confidence.

A box stock Ruger .357 Bisley I have goes about .008 cylinder gap and is still very accurate.
A couple S & Ws in the safe go about .005 gap.


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## BowerR64 (Oct 2, 2012)

I picked up some wood grips for mine from a different version or something that fit perfect. Now it looks just like the .44 i traded away 










38, 38+P, 357 9 and 9+P


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## ThisIsMySig (Jul 7, 2012)

Hey Bower, That is a beauty. The hard rubber grips that come stock on these revolvers don't do them justice.


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## TOF (Sep 7, 2006)

A friend talked me into trying Titegroup powder in my new GP100 loads. The as delivered .004 gap was too tight and powder residue would jam rotation. I opened it up to .007 and the problem went away but I will not use Titegroup anymore. Several other powders I had used prior to opening the gap were much cleaner and did not cause rotation problems.


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## jdeere9750 (Nov 28, 2008)

TOF said:


> A friend talked me into trying Titegroup powder in my new GP100 loads. The as delivered .004 gap was too tight and powder residue would jam rotation. I opened it up to .007 and the problem went away but I will not use Titegroup anymore. Several other powders I had used prior to opening the gap were much cleaner and did not cause rotation problems.


What were the cleaner powders that you found? Or, if the list would be shorter, what were the dirty powders?


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