In 1911 John McColl became shop manager for Lawrie and excellent bagpipes were made until his retirement in 1935 or so.  The quality of sound, performance, and workmanship declined in the years following and was  never re-captured.  Lawrie stopped making bagpipes in the 1980 s.

I ve studied hundreds of Lawrie bagpipes.  Like most it s sometimes very challenging to establish a probable age.  In my experience, the very early Lawrie bagpipes had a very slender profile with somewhat chunky projecting mounts.  The mounts have a smallish bead close to the projecting plate.  The stocks were very "old profile" with rounded bottoms.  Below are a couple examples of authenticated pre-1900 Lawrie bagpipes.
In 1918 John McColl became shop manager for Lawrie and excellent bagpipes were made until his retirement in 1935 or so.  Lawrie bagpipes evolved during his tenure.  The depth of the bell became "shallower" if that's the right word.  The bead on the lower projecting mount became more pronounced as the years passed.
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This Lawrie bagpipe is hallmarked 1927 and changes in design are obvious.  Great playing bagpipe.
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You're very likely to find Lawrie pipes from this era with celluloid fixtures and elephant ivory bushings. (right)
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Makers of Old Bagpipe Place Home
R. G. Lawrie 1920 to 1940
The Bagpipe Place Museum