Backyard chrono testing

[Double B]

Chrono results x3 different setups this afternoon and figured I'd report back.   Winchester 120 ranger pump with 2 different length barrels (same .660 choke) and a late 90s Mossberg 835 w turkey choke.  3 shot strings of 3" Winchester Longbeard xr #5 factory listed @1200 fps. 1 shot each w 2 3/4" Rem Nitro turkey #5's factory listed @ 1260 fps for comparison.   Conditions were overcast 40 degrees and 10' from chrono. 

Note the subsonic shots.  Pretty sure these were shells that had loose pellets rattling.......any input?

Winchester model 120 w 21" comp n choke.   3" LB 5's 1193/1081/1202.   Rem nitro turkey 2 3/4" 5's. 1218


Winchester model 120 28" comp n choke 3" LB 5's  1226/1065/1181.  Rem nitro turkey 2 3/4" 5's. 1224


Mossberg 835 24" .676 stardot 3" LB 5's  1216/1241/1237.   Rem nitro turkey 2 3/4" 5's 1226. 


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[owlhoot]

Low velocity shot kinda strange .
Thanks for the information.
The comparison between barrel lengths is interesting, not much of a loss at all for a 7" shorter barrel. Believe there was some pattern problems with those rattling shells too?

[Double B]

Quite possible owlhoot.  If I find a rattling loose shell from now on i save it out for crow or vermin.  Not sure why it lost so.much velocity, maybe the capsule that contains the shot was busted and that effected speed.  No problem exceeding advertised fps with fresh Longbeards in the shorter barrels I checked.