EXT RARE SDA-34MB
Posted: Fri Apr 03, 2026 7:33 pm
42 years ago March 1984, a Noted Ruger D/A Collector and RCA member Mr. Sonny Johnson wrote an article for the March 1984 RCA Journal Issue Vol. 8 No.1
He reports on his new discovery of a Ruger Police Service-Six, SDA-34MB a 4”.357 Mag. previously unknown variation His SDA-34MB has four distinct features that regular Police Service-Six revolvers do not have. MB = Machined Barrel.
No. 1 – A full 11/16” Bull Barrel from breech to muzzle.
No. 2 - The ERH is ½” wide, 1/8”wider than standard SDA revolvers.
No. 3 – Barrel Crown has a “LIP” which protrudes about 1/8” from the front of the sight rib.
No. 4 – The sight rib is a massive 17/32” wide with 12 fine grooves, vs the standard 3/8” rib with 7 coarse grooves. 5/32” wider! It was milled with the same tooling as the No.1 Rifle rib.
At the 1983 NRA Show in Phoenix AZ. he was able to confirm that his revolver was indeed factory through 3 individual factory employee’s in attendance at the show.
He learned later that the “LIP” was the result of a 1/16” machine set-up error. It was stated that his barrel should have been scrapped.
I wonder how many barrels were run before the error was caught and the fate of those barrels. Were they scrapped or assembled and shipped as part of a contract or special order.? But no way to letter for right now?
42 years later March 2026, I was fortunate enough to locate & buy my own SDA-34MB, identical to Sonny’s discovery. (wink) Mine is a Ruger Police Service-Six .357 Mag. Serial #152-79211. Made 1977.
I contacted Chad and ask him how many were made & that I had located one. He replied back IIRCC 8 or 9, due to rarity there was not a lot of info. How ever RENE lists the serial # range as #152-68188 – 152-79622, and also so a GF-34MB Ser.#152-87886 (Sonny’s?) Chad also told me that Sonny’s factory contact was none other than Steve Vogel, WBR’s son-in law who was in charge of LEO. Military And Foreign Government contracts.
Now the bad news...the gun was not stored properly and showed rust in several spots, the hammer & trigger sides were sad. I figured it at 70 – 75% ?. But I new it was very rare. I was hoping that the
condition would turn most away. As it ended up I got it with out any trouble.
There is a saying among collectors that I took Heed to….”When Rarity Trumps Condition” This gun clearly fits that adage, IMHO.
GB pictures,
SDA-34MB muzzle.
Standard SDA Muzzle
Upon receiving the gun I noticed that other than poor storage & neglect, it appeared unfired after proofing, note cylinder turn line. When I took her apart she was clean as a whistle on the inside no carbon nothing. I cleaned up the sides of hammer & trigger. I had a spare blue trigger assembly w/smooth trigger so I switched out the trigger from my gun replacing the smooth one after cleaning. After a couple of days of soaking in kerosene I started working on the Cylinder Frame & cylinder it's self with #0000 steel wool & oil, over the next few days this is how she turned out. I am going to replace the hammer though.
Terry
Note this picture shows 3 of the 4 different features of the gun. 1- 11/16" Bull barrel. 2- the ERH is 1/2" wide which is 1/8" larger than standard SDA revolvers.
3- The crown with 1/8" "LIP"
Muzzle Crown
Massive 17/32" Sight Rib which is 5/32" larger than standard SDA revolvers with 12 very fine grooves, vs standard 3/8" sight rib with 7 coarse grooves.
Last but not least Sonny's Article...
]
He reports on his new discovery of a Ruger Police Service-Six, SDA-34MB a 4”.357 Mag. previously unknown variation His SDA-34MB has four distinct features that regular Police Service-Six revolvers do not have. MB = Machined Barrel.
No. 1 – A full 11/16” Bull Barrel from breech to muzzle.
No. 2 - The ERH is ½” wide, 1/8”wider than standard SDA revolvers.
No. 3 – Barrel Crown has a “LIP” which protrudes about 1/8” from the front of the sight rib.
No. 4 – The sight rib is a massive 17/32” wide with 12 fine grooves, vs the standard 3/8” rib with 7 coarse grooves. 5/32” wider! It was milled with the same tooling as the No.1 Rifle rib.
At the 1983 NRA Show in Phoenix AZ. he was able to confirm that his revolver was indeed factory through 3 individual factory employee’s in attendance at the show.
He learned later that the “LIP” was the result of a 1/16” machine set-up error. It was stated that his barrel should have been scrapped.
I wonder how many barrels were run before the error was caught and the fate of those barrels. Were they scrapped or assembled and shipped as part of a contract or special order.? But no way to letter for right now?
42 years later March 2026, I was fortunate enough to locate & buy my own SDA-34MB, identical to Sonny’s discovery. (wink) Mine is a Ruger Police Service-Six .357 Mag. Serial #152-79211. Made 1977.
I contacted Chad and ask him how many were made & that I had located one. He replied back IIRCC 8 or 9, due to rarity there was not a lot of info. How ever RENE lists the serial # range as #152-68188 – 152-79622, and also so a GF-34MB Ser.#152-87886 (Sonny’s?) Chad also told me that Sonny’s factory contact was none other than Steve Vogel, WBR’s son-in law who was in charge of LEO. Military And Foreign Government contracts.
Now the bad news...the gun was not stored properly and showed rust in several spots, the hammer & trigger sides were sad. I figured it at 70 – 75% ?. But I new it was very rare. I was hoping that the
condition would turn most away. As it ended up I got it with out any trouble.
There is a saying among collectors that I took Heed to….”When Rarity Trumps Condition” This gun clearly fits that adage, IMHO.
GB pictures,
SDA-34MB muzzle.
Standard SDA Muzzle
Upon receiving the gun I noticed that other than poor storage & neglect, it appeared unfired after proofing, note cylinder turn line. When I took her apart she was clean as a whistle on the inside no carbon nothing. I cleaned up the sides of hammer & trigger. I had a spare blue trigger assembly w/smooth trigger so I switched out the trigger from my gun replacing the smooth one after cleaning. After a couple of days of soaking in kerosene I started working on the Cylinder Frame & cylinder it's self with #0000 steel wool & oil, over the next few days this is how she turned out. I am going to replace the hammer though.
Terry
Note this picture shows 3 of the 4 different features of the gun. 1- 11/16" Bull barrel. 2- the ERH is 1/2" wide which is 1/8" larger than standard SDA revolvers.
3- The crown with 1/8" "LIP"
Muzzle Crown
Massive 17/32" Sight Rib which is 5/32" larger than standard SDA revolvers with 12 very fine grooves, vs standard 3/8" sight rib with 7 coarse grooves.
Last but not least Sonny's Article...
]
