I have three M69s.
#1 Rnd Count: 2,700.
Everything from 320gr WLNGC at 1,180 fps (Max load of H110 from Hodgdon’s online manual) to 240gr SWCBB at 800. Ninety percent of those were 240gr JHP Fed Fact chronoed at 1,215 fps (1,375 from 7 ½” Ruger Bisley hunter) and 265gr SWCGC at 1,140 fps
Point of reference – 250gr Keith (Lyman 429421), 21.1gr A2400 chroned 1,250 fps at 5 long paces from muzzle and 83 deg F. The 240gr Fed Factory load chromed 1,215 fps at 5 long paces and 45 deg f.
About 2,500 rounds, the gun started binding in both single and double action. Sent it back to S&W on their dime. They “fixed the crane/yoke”. Turnaround time from doorstep to doorstep was 3 weeks exactly.
No problems since.
#2 Rnd Count 4,500 +.
Mostly 240gr SWCBB at a chromed 880 fps (maybe 15% 240gr Fed Fact and 265gr SWCGC mentioned aboe.
No problems to date
#3..Rnd Count less than 100 (fuction tested, sighted in and put back in safe as a backup).
Here’s a picture of sight in target for gun #3 (two circle – final sight setting w/265gr SWCGC at 1,140 fps).
Here’ a target I shot (benched at 25 yards) with gun #1 to check POI with same POA. Rear sight was bottomed out and POA was center of center diamond for all loads. Only shot two rounds of each load to minimized recoil induced fatigue and minimize target clutter.
NOTE: GUNS BEING DELIVERED NOW HAVE SIGHTS THAT ALLOW FOR ZEROING WITH .44 MAG AMMO (based on rear sight blade and POI of my GUN #3).
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Brian Pearce covered the M69 and appropriate load data in Dec 2014 (#293) issue of Handloader Magazine. If you have a M69, you should consider ordering a copy from Wolf Publications
http://www.riflemagazine.com/magazine/index.cfm?magid=689 .
With the Hornady 240 XTP Brian listed 24.5gr H110 as Max. A max load of 21.5gr of A2400 was listed as max for both the 240gr Nos JHP and 250gr Keith.
Here’s a brief recap of the article excluding load tables.
Article addressed strength & durability w/long term use of .44 Mag level ammo – shot over 2,700 round while testing and discussed engineering features.
S&W Reengineered yoke to place enough supporting steel surrounding bbl threads to handle Magnum pressures and allow increased barrel shank diameter.
Due to location of bolt notches (chamber wall thickness at weakest point is .040” in 629 vs. .052 in M69) cylinder strength is more than adequate to handle .44 Mag pressures. Ball detent lockup is a plus and “aids chamber alignment and durability”.
All endurance package features previously/currently incorporated in 29/629s have been included in M69.
Brian quotes S&W “the L=frame has a strong durable frame and barrel built for continuous Magnum useage”. Further, S&W engineers subjected the M69 to endurance testing with full power .44 Mag ammo and passed with ease.
Per Brian “IT SHOULD BE EMPHASIZED, HOWEVER, THAT THESE GUNS ARE NOT DESIGNED FOR LOADS THAT EXCEED MAXIMUM SAAMI PRESSURE GUIDELINES FOR THE .44 MAGNUM, OR 36,000 PSI”.
Regarding recoil he said the smaller L-frame’s lower bore axis “translates into decreased muzzle lift, less felt recoil and quicker follow up shots”.
Balance of article is basically discussion of load data specific to the M69 with some other observations.
Showed a table comparing velocities M69 vs M629 with various factory loads (210gr thru 300gr). Also included a couple of load data tables covering bullets from 180 – 300gr.
Hope some of this helps.
Paul