Recently I took the trigger-hammer mechanism out for cleaning and to try and smooth up a little "gritty" feeling in the trigger pull.  Now, after several rounds (particularly of rapid fire) the trigger pin works out stopping everything.  Obviously I will pick up a new pin but I'm wondering if I did something wrong.  I didn't do anything to the pin except wipe it off.  Rifle is a Bushmaster Shorty.  Thanks, Dale

Trigger and hammer are just fine, is the retaining springs that need to be checked.

Start off with the hammer retaining pin.  Pull the hammer and check the bottom hole for the straight spring.  It fits straight up in the hammer bottom,  and keeps the hammer pin from walking.  Yours may have fallen out, or just have straighten it's self to the point that it will not retain the pin.  If the spring is still in the hammer, you may have to spin the hammer pin and deepen the center groove.

Once you straighten out the hammer retaining pin/spring, then move onto the trigger pin.  On this pin, the hammer spring legs go over the top trigger pin and retain the trigger pin. You may have missed the top of the C groove on the out sides of the trigger, bent the hammer spring legs to the point that they no long apply pressure to the pin, or just polished the side groves out of the pin.  Once you take a look at the problem, you will find the answer to keep this pin retained.


Note: If you need to deepen the grooves on the pins, use a drill and spin the pin while using a jeweler's file to deepen the grooves.  Don't go buck wild, or you will cut too deep and weaken the pin.  All that is needed is a slight groove to allow the springs the catch the groove.

Hope this helps.

Your lower holes may be worn too.
You might try a set of the DPMS anti-walk pins.

I had a very old Oly lower that did the same thing, the pins would walk out after a few rounds. I put a set of these in it and never had a problem again.



DPMS direct link:
A-15 Anti-Walk Pins

Thanks for the info...it sure helps to put things back together correctly.  I didn'ts have the hammer springs on top of the trigger pin...duh!  No wonder it went back together so easily.  The holes look ok so far but I'll keep that DPMS pin in mind.

dj

djames, I see that you spent some time reading the manual before you started tearing the rifle apart-NOT!!!!!!!!!

Before you go tearing into it again, read the repair manual, or at least look at the pictures!!!!!

old.ar15.com/books/TM9-1005-319-23.pdf

P.S. Next time you screw up, we will make you sit in the corner wearing the Dunce cap!!!!!!

Wow, now that is reallyl helpful.  As I recall, I did read the manual but clearly missed something.  Sure glad I got the first two helpful suggestions before your response.

Now I am confused.  I just noticed that it was you (Dano) who gave me the fix.  My apologies if I missed the humor.

dj

djames,
Stick around for a while and you will see that my sense of humor get even more twisted than this.

Hell, If you catch me and Royce having fun, you will see that we use Magic 8 balls, seeing eye dogs, and even blind man canes to make points.

Granted that some of you(newbies) see your rifles problem as the end of the world until fixed, we have seen it before, and have solved the problems many, many times.  If we didn't have fun and make jokes, we would die of boredom!!!!