Lengthen chambers to 2 3/4" ??

[todd allen]

Originally Posted by George Neal

I'm interested in advice on the advisability of lengthening the chambers on a Parker 12 and a Parker 20 from 2 1/2" to 2 3/4". The 12 is a well worn DHE #1 frame and the 20 is a VH #0 frame. Both were manufactured in the 1920's and are in sound condition. Neither are high condition, and other than being sound Parkers have no special collectors value. It would be NICE the use low velocity 2 3/4" ammo that is readily available rather than being limited to the 2 1/2".
If this is feasible I'd appreciate suggestions on a competent source of having the work performed.
I welcome your suggestions.

I had this conversation with Chuck Webb from Briley's some years back, regarding a circa 1900 H&H Royal SLE that I bought from him.
I measured the chambers, and they were 2 1/2". He advised to not lengthen the chambers, as that would take it out of proof. Rather, to taper the chambers, which would relieve the pressure at the step-down to the bores.
This is what we did.
You have already gotten some good advice here, from people who know way more than I do.
That said, I would talk to a good barrel smith from a legit company, and see what they say.

[Drew Hause]

Todd: I don't understand "taper the chambers".
Do you mean lengthen the forcing cones? Which at one point did not take a gun out of proof, but a friend specifically discussed this with the Birmingham Proof House and lengthening the forcing cones now does takes a gun out of proof.