trigger housing group question

i assembled THG from old parts .it seems to work okay as near as i can tell except it won't cock unless i pull the trigger aft a bit (not in the rifle). it seems to function okay installed in a rifle.
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all my other THG''s seem to cock normally outside the rifle. looks like a sear clearanne thing. again, it works okay when installed.
any inputs appreciated.
thx,
goo
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swiss army bushy... ("i don't need no steenking flash suppressor !"):
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http://farm3.static.flickr.com/2634/...7f1fc5d990.jpg
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http://farm4.static.flickr.com/3426/...97d713d242.jpg
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