This is from the 1978 Simmons Hdw. catalog when guns were listed by price ie. "Dollar Grade". The price specified the wood grade, checking, engraving patterns, and damascus quality.
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/US-Makers/Parker/i-zrC3fDd/0/Kw4m6xVc7SwgdwQRgc9xLgPt2GQbwBTmVqVtBZ4Xv/XL/1878%20Simmons%20Hdw.%20Price%20List%20-%20Cropped-XL.jpg)
After the introduction of the top lever guns about 1880, the guns were assigned a letter grade.
But it's complicated

In the 1882 Parker Bros. catalog the Qualities R, S, T & U were listed with TWIST barrels, and the Qualities N, O, P & Q were listed with FINE ENGLISH TWIST barrels. Ribs were marked TWIST, PLAIN TWIST, or STUB TWIST. Quality P guns have been found with Damascus Twist barrels, but marked Twist and Stub Twist.
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/US-Makers/Parker/i-VbPS7Gz/0/NKK6b2c2wV4qqL2ZD82SwRW4rpGpGrCsWWnh4LfSg/M/Parker%20Price%20List%2C%20July%201%2C%201882%20-%20Cropped-M.jpg)
Stub Twist
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Damascus/Parker/i-NWPbLG2/0/MVBj7CTjKf9pGjPNcFGmBGrfcJHwXdc9V7wFpbnNw/S/Parker%20Stub%20Twist-S.jpg)
Refinished barrels marked Stub Twist but are Plain Twist
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Damascus/Parker/i-cG8wKWt/0/McFvrqBBSpjjFJ56jmhkLnfqTh3TggqTWQ29tBcRv/M/Bernard%20Ribbon%20%20Refinished%20Parker%20Stub%20Twist-M.jpg)
Damacus Twist marked Twist
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Damascus/Parker/i-PMRwbwD/0/MbJsq86FQcdRwRbt8WFbGPMDRFX9LPd4WZf8cjb4k/M/Parker%20Damascus%20Twist%20marked%20Twist-M.jpg)
Your barrels originally looked something like this
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Damascus/Parker/i-VSnFJWL/0/M3RLTBh2L9kMrdfMCfbSMqxkPmsXjcJDQGM7T6HnQ/M/Twist%20under%20FE-M.png)
BTW I've never seen the 'M' that is on your barrels
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Damascus/Parker/i-bqGvmbb/0/LPD5DMWn8NbFWJGrdPhCSF84vhf8GLrgGTqvsNFBb/M/Plain%20Twist%20M-M.jpg)
In the Hammerless guns the Qualities PH & NH are usually listed with FINE ENGLISH TWIST barrels.