Here's the story out of Wm. Albaugh's book, "Confederate Arms". It seems as though the Robinson, or Richmond Sharps got a bad foot forward because of troops who never had a breach loader, no less a new one. "Give a dog a bad name, and it sticks."...Here's the short version of the story.
40 new Robinson Sharps and 1,000 rds. of ammunition were received by the 4th Va. Cav. for field testing on March 1863. The cases opened and the men instructed to fire them, (I can just imagine the "Ooohs and Ahaas" as the men looked over these brand new breach loaders). Boys being boys, they loaded their new weapons, capped them, and...nothing. They hadn't cleared the packing grease from the nipples and flash channels, the guns didn't fire. They opned the breaches, cleared the flash channels of grease, all the while being careful to have the muzzles pointed to the earth, re-capped them, mounted them to their shoulders, and...According to Lt. N.D. Morris, "nine were fired, and seven of the nine burst."
Lt. Morris, took pen in hand and wrote to the Richmond Whig newspaper who ran the story under the headline, "An Outrage!" The story inplied the arms were totally worthless and dangerous to the user, 7 of 9 burst. What burst exactly?..And why?
The story reached Gen. Lee who had his ordinance cheif, Col. Gorgas look into the matter at once. Col. Gorgas did a good and thorough job of investigating what happened. He found that no barrels burst and no breach blocks failed. What happened was, "They load their arm and snap a cap without effect. A portion of the powder falls into the gas chamber in the slide. They hold their gun muzzle down to prevent powder from spilling at the breach and draw th slide down, by that means empty the powder remaining in the gas chamber into the mortice for the crank spring in the forestock under the barrel. They get the vent clear and fire the gunafter closing the breach, and the flash from the cap communicating with the powder in the mortice explodes and bursts a part of the forestock.
Col. Gorgas continues, "This is an unavoidable fault connected with the new gas check, the same accident happens to the origional Sharps in the hands of green men. This can be remedied by going back to the old fashioned smooth slide without the gas chamber and making the vent hole fuller. We would not get so perfect a gas tight joint, but the difficulty of having a portion of the powder falling into the slide would be remdied."
Col Gorgas goes on to say that no fault can be atributed to the manufacturer, and suggests that officers take the time to properly train their men in the use of the arm.
The article can be read in it's entirety in Wm. Albaugh's book, "Confederate Arms", pages 65-73. I hope this answers the question, as I stated in my previous post, Sharps had the same problem and the "bursting" was not unique to Robinson/Richmond Sharps carbines.