I’ve collected 51 serial numbers so far and I need your help to expand it! Here’s my observations and opinions, all these are based on my personal experiences and not conclusive.
Gongxian rifle’s designs evolved over the course of production from 1928 to 1935. Those changes were correlated with the changings of marks. I categorized Gongxian 98 rifles into three production phases based on its design features and receiver ring markings.
About Gongxian 98 crests, find more here:
Phase 1 production from 1928 to 1933.6. Early rifles (Highest observed is 25111) do not have receiver crest like the later products, the top of the ring is blank. The Arsenal commenced to stamp production date and arsenal symbol no latter than 1931. At this period, all rifles are serialized with a pattern of K or KA prefix and numbers.
No official documents to explain what does the K and KA mean, Generally we believe K is the first letter of Kunghsien (Gongxian). I have two assumptions on the prefix KA. It could be abbreviation of Kunghsien Arsenal or A could be the letter to indicate the sequentially numbered rifles from 0001-9999 after the first 9999 rifles.
Unfortunately, we have not seen an example of KA0001-KA9999 yet. And no other letters were used. The lowest number observed is KA16xxx, they either added the serial number to five digits (KA10000) following the serial number of KA9999 or they might add both prefix A and five digits number following the serial number K9999.
Phase 2 production from 1933.7 to 1934.1. Gongxian 98 rifles produced since 1933.7 were slightly modified and a simplified crest marking appears on the receiver ring. The serial number pattern did not change except on limited numbers of specimens from September 1933 production rifle.
I’ve observed two rifles (81389&81538) made in 1933.9 have a unique serial number pattern. No KA letter prefix was found and the 81389 one has a letter M suffix while the 81538 doesn’t have.
Standard KA pattern 1933.7
Special one from 1933.9. (Below) This type of SN I guess only a limited numbers of rifles at some time in September have it, earlier 1933.9 rifle has standard KA pattern serial numbers as well as the later production rifles until 1934.1.
Phase 3 production from 1934.2 to 1935.8. Gongxian rifle had its major modification in Feb 1934 by replacing outdated Gew 88 pattern barrel with Mauser 1898 pattern stepped barrel that copied from Mukden T13. Crest marking was further simplified while the serial number changed to Mukden Type 13 pattern. Letter prefix was gone and the number digits continued growing from previous numbers. A symbol borrowed from Type 13 stamped in front of the serial number. This symbol is the “acceptance marking” used by Beijing Government (1912-1928). No idea why they copied it (It’s reasonable that Type 13 has it as the rifle was produced at Mukden arsenal which under the control of General Zhang Zuolin, the warlord who became the last president in 1927) and even stamped it on later Type 24 short rifles! This type of serial number was used until the cease of production of Gongxian 98 rifle.
As a comparison: Mukden T13 (below)