Monthly Club Special 20,250: Beam Me Up

Definitions underlined, (ABC)* indicating anagram of ABC, {} deletions and [] other indicators.

Across
1 Pistol to flourish, pursuing something sparking in tree (10)
WITGATBOOM – GAT [pistol] to BOOM [flourish], pursuing WIT [something sparking]. Isn’t wit more “sparkling”? Well it doesn’t matter really
6 School do printed material, omitting biblical books (4)
CHIZ – CHI{nt}Z. Do as in “cheat”, chiz as in Molesworth
9 Antelopes recorded originally in Pliny’s case with jokes (7)
PYGARGS – R{ecorded}, in P{lin}Y GAGS
10 Eastern ceremony with complicated mass Irish-American brought west (7)
MATSURI – MAT + reversed IR-US
12 Bitter blow for Italy: cheers welcoming Spaniard getting bronze (10)
TRAMONTANA – TA, “welcoming” RAMON getting TAN
13 Once again alien force invades (3)
EFT – E.T. invaded by F. Old word for “again”
15 On reflection, quietly approve sort of leather wader (6)
DIKKOP – P OK KID, reversed
16 College cleaner embarked on a trip (8)
BEDMAKER – (EMBARKED*). FOI, though we called them bedders I think
18 Asphalt that’s unlimited suited for covering nearly half of internal area (8)
UINTAITE – {s}UITE{d}, “covering” INT{ernal} A
20 English misses lacking in variety fell for Wexford wastrel (6)
STALKO – STAL{e} [lacking in variety, “missed” by E] + K.O. [fell]
23 Eastenders in dramatic row slam Corrie (3)
CWM – the last letters, or eastern ends, of {dramati}C {ro}W {sla}M
24 Awful pun: pilgrim is colouring deeply? (10)
IMPURPLING – (PUN PILGRIM*)
26 Float old things the competent should know about primarily (7)
OROPESA – O + ROPES [things the competent should know] + A{bout}. A “fish-shaped float used in marine minesweeping”, obviously
27 Recalled Egypt once, note, appearing in fifteen stained glass pieces? (7)
VITRAUX – reverse all of U.A.R. TI, “appearing in” XV
28 Cold, salty water for winding back ligature (4)
AESC – reversed C SEA
29 Exchanging tips on craft, starship’s engineer to accept bread snack? (6,4)
STOTTY CAKE – SCOTTY TAKE [starship’s engineer | to accept], with C{raf}T exchanged
Down
1 Raised hatch, mainly to view storms across loch? (4)
WAPS – reversed SPAW{n}. Scottish storms
2 Mongolian ready to pull personnel on Karakoram peak up (7)
TUGHRIK – TUG H.R. on reversed K1
3 Expensive medicine, a superior leftover, turned to a bitter fluid (5,8)
AURUM POTABILE – A U RUMP + reverse TO + A BILE
4 Italian composer’s lack of reserve upset yours truly (6)
BUSONI – reversed NO SUB [lack of reserve] + I [yours truly]
5 Played with brass ring on mop head in need of replacement (8)
OOMPAHED – O on (MOP HEAD*)
7 Idiot replacing line from Yank’s long mail (7)
HAUBERK – HAU{l->BERK}
8 Unknown to babble at length about one tiny item charged (10)
ZWITTERION – Z [unknown] + WITTER ON “about” I
11 Admiration for wonder article in truth a lot may put differently (13)
THAUMATOLATRY – A in (TRUTH A LOT MAY*)
14 Triple crown for Scotland finally and rugby clubs clan briefly over the moon (10)
SDRUCCIOLA – S{cotland} {an}D R.U. C + CLA{n} “over” IO
17 You and one drunk to set about irrational perfectionist (8)
UTOPIAST – U and TOAST [something drunk], “set about” PI
19 Grey matter involving the writer’s one vexatious to Scottish lawyer (7)
NIMIOUS – NOUS “involving” I’M I
21 Snake’s tongue half concealed: I see it now! (7)
LANGAHA – LANG{uage} + AHA!
22 Hold centrists in Congress to ban, advancing nothing (6)
GROVET – {con}GR{ess} + VET{O}, advancing the O to first position
25 Bar turned around by cracking beer (4)
AXLE – X “cracking” ALE