Double Reamed Chambers

[M. De Land]

Chambers are gang reamed in turret mills at the factory and each reamer has a plus or minus diameter tolerance at sharpening before they are replaced. This is why there are different diameters of chambers one receives in their finished guns. I always check all chambers with a plug gauge as well as the barrel bore and ream and lap to consistency in both.
I have also found chamber mouths out of round as well as over size. These irregularities show up when reamed as the bluing reveals them against the fresh reamer cuts.
Another interesting thing I have noted over the years is that a revolver can be quite a bit out of alignment and still shoot quite accurately if all chambers have the same amount of misalignment.
Still for the best accuracy of course good alignment is necessary.

 

[rodwha]

Chambers are gang reamed in turret mills at the factory and each reamer has a plus or minus diameter tolerance at sharpening before they are replaced. This is why there are different diameters of chambers one receives in their finished guns. I always check all chambers with a plug gauge as well as the barrel bore and ream and lap to consistency in both.
I have also found chamber mouths out of round as well as over size. These irregularities show up when reamed as the bluing reveals them against the fresh reamer cuts.
Another interesting thing I have noted over the years is that a revolver can be quite a bit out of alignment and still shoot quite accurately if all chambers have the same amount of misalignment.
Still for the best accuracy of course good alignment is necessary.

I’m curious what you think of the hand reamers such as Brownell’s, what was suggested to me long ago. I’ve been skeptical about the self aligning. I’d be really upset having spent a couple hounded on a reamer only to find I’ll be needing a new cylinder and sharing all over.

My Pietta NMA cylinder has been reamed to 0.449” and chamfered but I’d like to take it out to 0.453-4” down to the bolt stops as my grooves measure 0.4535”, but I’ve been reluctant to try this myself. Is it as easy as they say in your opinion?

 

[M. De Land]

I’m curious what you think of the hand reamers such as Brownell’s, what was suggested to me long ago. I’ve been skeptical about the self aligning. I’d be really upset having spent a couple hounded on a reamer only to find I’ll be needing a new cylinder and sharing all over.

My Pietta NMA cylinder has been reamed to 0.449” and chamfered but I’d like to take it out to 0.453-4” down to the bolt stops as my grooves measure 0.4535”, but I’ve been reluctant to try this myself. Is it as easy as they say in your opinion?

I've done by hand, with a frame mounted reamer spud and in my mill table on the drill press aligned with plug gauges. The frame spud is the most accurate and the drill press is by far the more accurate set up than by hand as it is really easy to get a chatter going by hand reaming while trying to feel in the centering of the reamer and keep it their while enlarging the ID. It can be achieved by hand and feel if cuts are light and patients is exercised but is tricky and not for the faint of heart.
I use standard chucking reamers with a 45 degree taper on the end to transition into smaller ID's.
I use straight fluted reamers although spiral reamers are less likely to get a chatter going.