How to read the SRS list

Can someone tell me how to read the SRS sales list? Sometimes I'm not sure about what the stuff behind the S/N means. Just to give a few examples:

9404PED 030928SA (FROM FT BENJ HARRISON)
What does the PED behind the S/N mean? And what does 030928SA mean?

10224GP 111810ROCKY MOUNTAIN RC (RETURNED)
What does the GP mean? RC in this context doesn't mean Russian Captured, doesn't it?

15528BAN 010528RHODE ISLAND
BAN?

Well, it's basically the stuff behind the S/N and the numbers afterwards :) . Any help would be appreciated!

"030928SA"=March 9th,1928 at Springfield Armory
"PED"= Pederson Device,usually Testing.
"GP"= Gallery Practice, .22
"RC"= Rod Club/aka. Rod and Gun Club.
"BAN"= Bannerman,Commercial Enterprise,Military Surplus
"010528"=January 5th,1928

Also look at the bottom of each page and these are also listed there in fine print.

I only have the digital list, there are no foot notes. Can someone summarize the meanings? Found several other that I wasn't able to explain, for example 353003SGSM, 407279SG, 1020230IM, 1216874NMP, 1225056RCVR, 1228880IM, 1229715MANN, 1230023SPL, 1231733NMC, 1244359HB, .....

Hello Again

SGSM=Sight Glass Sight equipped with Maxim Device
SG= Star Gauged
IM= International Match
NMP= National Match/pistol grip, very early 1920's designation/very short lived/different because it had a Sporter Butt Plate
RCVR= Receiver/ generally considered NM receiver but actually somewhat interpretative
IM= International Match
MANN= MANN accuracy Device/ Testing of ammunition
SPL= Special Target/SA sales Designation
NMC=National Match "C" stock,Late Sales Usage,actually earlier NM's restocked for sale.middle to late 1930s in most cases.
HB= Heavy Barrel /Target

Respectfully submitted
Ed Byrns

Would the maxim device refer to a suppressor ?
Chris

Yes,with a suppressor.
Just a note,I was always under the belief that"SGS" could have meant STAR GAUGED/SIGHT.
But came to the conclusion it was what I wrote previously , and the optics were tubes not W&S
Ed Byrns