Last month, I was fortunate to find one of my "Grail guns": a near new condition 629-4 in 4 inch.

I'm trying to decide whether or not it is worth having the cylinder throats reamed on this revolver. I have slugged both the barrel and the chambers several times, and I come up with the same measurement each time:

Groove diameter is .4295
Chamber diameters are .0011 smaller, and are .4284.

So, do you think this .0011 difference is enough to warrant reaming the cylinder throats? My feeling is that reaming it out will head off any leading issues.

So far, the gun shoots well with jacketed bullets. I know I can cast up various hardness’s of bullets and then try different loads, but in the end that may be a waste of time so I appeal to the more experienced cast bullet shooters here…

Thank you for your help.

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Benefactor Member, NRA

I have a 629-4 "Hunter" with measurements that would be similar to yours- tight throats. I was concerned until I shot it. I will be leaving it as is, it is a tack driver. ;D

For the record, the throats were about .4285, and I have been using Leadheads 250gr Keith, sized to .431. From everything I've read, it shouldn't shoot like it does, but it does! No leading problems, either.

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Rangerone:
I have several 629's that have throats that are .4285. I have not slugged the bbl because of the difficulty in measuring 5 groove bbls. I will say this...I shoot nothing but my own cast boolits out of all my .44 mags, and even the .4285 throated guns don't lead with boolits sized .431 and Bhn 11 to 14, as long as I use the slower powders such as 2400, H-110 and WC820. I will get minor leading on some of the guns if I switch to faster powders such as Green Dot or Unique. I deal with this issue by running 5 or so gas checked .431 boolits down the bbl at the end of a shooting session. I think too much emphasis is often paid to "the boolit must match the throats theory". Shoot the gun and see how it does, and then let us know the results.