Congrats on you new M69.
I've had both barrel lengths since they first came out. My favorite is the 2.75". Load it the desired level of power for your needs and enjoy. Here are some chrono results taken over time:
Chronoed these from the 2.75” M69. Three rounds at 5 Long paces from muzzle and 68 deg F. Larger sample could change the results a bit. Largest ES was 42 fps. All in new Starline cases and CCI 350 primers.
225gr Barnes XFB with 18.1 gr A#9 avg (1,214 fps (muzzle vel from Labradar)
240gr Cutting Edge Flat Point Mono – 22.6 H110 1,218 fps (1,247 fr 2.5” 329 Alaska Backpacker) Muzzle vel from Labradar
240gr Zero JSP with 24.0gr H110 avg 1,126 fps
240gr JHP Fed Factory avg 1,125 fps (bought at an estate sale “44a 1981 production” – 1,375 fps from 7 ½” RSBH)
260gr WFNGC w/23.0gr H110 avg 1,125 fps
265gr CSWCGC (Lyman Thompson) with 17.5gr A2400 (Deep Seat – crimped over front drive band) 1,119 fps avg
265gr SWCGC (429244) 23.5gr H110, seated and crimped in crimp grove in Mag cases ---------- 1,162 fps
310gr FNGCDC (Lee) with 20.0gr H110 avg 1,100 fps
325gr WLNGC (BTB) with 22.0gr H110 avg 1,104 fps
The 4 ¼” gun gives 40 to 100 fps additional velocity.
I Was curious, so I bought some 305gr Buffalo Bore and Underwood ammo – here are chrono results.
Buffalo Bore, 305 LBT LFN HC rated 1,325 fps
Underwood, 305 LFNGC Plated (HiTech?) rated 1,325 fps
LabRadar muzzle velocity at 33 deg F
S&W M69 2.75" ===> BB 1,195 fps ===> Under 1,147fps
S&W M69 4.25" ===> BB 1,276 fps ===> Under 1,248 fps
Ruger SRH 7.5" ===> BB 1,395 fps ===> Under 1,315 fps
My 2.75" with modified Hogue Tamers
The M69 is my favorite .44 mag revolver platform.
FWIW,
Paul
