⚠ UPDATE: ⚠
There were some conclusions I reached in the above texts that were NOT CORRECT in light of recent research on my part. I originally came to the conclusion that straight-walled chambers were not used in the standard (non-fluted) round cylinder of Colt 1860 revolvers, and this is NOT the case.
According to author Charles M. Pate and his phenomenal work The Colt Model 1860 Army Revolver, the very first 1860 revolvers were made with ROUND cylinders and the standard straight chambers like we see today on the Italian guns. However, Colt quickly focused on making fluted cylinders in order to reduce the weight of the gun.
As the revolver was being proofed by the Army before adoption, they found some guns were bursting cylinders at the bolt notches. This was NOT a result of the fluted cylinder, but the straight chambers were the culprit. There just wasn’t enough metal between the chamber walls and the bolt stops.
Colt’s fix for this was the “cavalry cylinder”, that member sourdough mentioned in post #5. By adding a taper to the rear of the chambers, the wall thickness of the metal under the bolt notches was roughly doubled, and this cured the bursting issues.
Shortly before the cavalry cylinder was introduced and made the standard in June-July of 1861, Colt had started to produce the now-ubiquitous round cylinders again starting in April of 1861. Some speculate this was to reduce machining time and manufacturing costs and it appears Colt was phasing out the fluted cylinders during this period. Again, THE FLUTED CYLINDER WERE NOT THE CULPRIT of the burst guns, and in fact Colt continued to produce (or finish) some fluted cylinder guns featuring the strengthened “cavalry” chamber design for a while after.
SO, what this means is that some of the earliest 1860 Army revolvers had round cylinders and straight chambers, as well as those guns made in the first half of 1861. This amounts to quite a large number of guns.
All modern repros use the original straight chambers but today we don’t experience burst cylinders because the metallurgy far exceeds what they had during the time period. I won’t get in to the pedantry of all the minor details of correctness for today’s repros, but the chamber designs thankfully are NOT incorrect.
Sorry for the confusion!
-Smokey
