I just got my SSA trigger in the mail.

After I installed the trigger and hammer the hammer feels like its binding in the receiver and it wont drop.

Like the spring is too wide or something.

The Armalite trigger i had in there worked fine, Did I put something together wrong? How can I trouble shoot this, I dont want to keep popping the trigger and hammer pins in and out.

Sometimes the back, side of the trigger will drag on the side of the safety. Is yours doing this? If so you need to dremel the side of the safety or replace it.

If that's not it I don't know what to tell you exept that others will be along with other ideas. Maybe Bill will see this too and know what else to check for.

Ok, I just put the hammer in without the spring or trigger and found I couldn't rotate it without severe binding in the receiver. I measured the width of the bosses for the hammer pin and found this
.686 Geissele
.680 Armalite

something is out of spec on this one.

Now I am kinda worried about the pin holes becuase it must have taken a lot of force to rotate the hammer when the spring was in before.

Before I get flamed for bad mouthing a vendor before contacting them, I am not saying the trigger is out of spec, It very well could be the receiver. I will let you guys know the outcome of this one, I will have to contact Geissele next week.

Hmmm....interesting.

What brand of reciever are you using?

Aero Precision

The Armalite LPK fit fine in it, I have around 500 rounds through it.

Does anyone know if there is a spec for the width of the hammer pin boss on the hammer?

I have an engineering drawing that gives the interior width of the triggerwell as .690".

I've seen this drawing several places - I'll see if I can find it online.

ETA - Here you go.

I have a used SSA sitting upstairs and I just mic'd it - I got .672" on the hammer and .679" on the trigger.

You have probably not damaged the pin holes.

If I have damaged the pin holes, correct me if I am wrong but the pins are held in with springs so they would have to be totally out of wack to cause a problem right?

There is quite the difference between .686 and .672. I understand you need some type of a running fit between the trigger and inside of the lower but tight enough not to be sloppy, it almost seems like the SSA trigger is binding with the radius at the front of the trigger well

Update:

I spoke with Geissele this morning and the dimension for the hammer width is .690 +/- 3 so my receiver is tight. The tech I spoke with said this comes up fairly frequently so if anyone else runs into it, he said it is totally ok to file the hammer to make it fit. Its either that or hog out the lower with a dremel!

Do not hog out your lower receiver.  It will be forever ruined. Always modify the less expensive, easily replaceable part.   Do as the tech guy suggested, just lightly file or grind the sides of the bosses on the trigger or hammer until it fits down into your receiver and moves freely on the respective pin.

Geissele is making them too big. The .690 dimension on this print. M16 Print has a tolerance of +.005 or -.005 which would make the min dimension of an M16 receiver .685. This would make ALL Geissele triggers too big. No wonder it comes up quite often.

Just checked a new in the bag never installed Geissele SSA hammer at .680" and also an Armalite 2 stage hammer at .676".

Napots,

Don't do anything to the trigger or receiver.  Contact Barb at sales at geissele dot com or call the shop and we will send you a new trigger.  It looks like your hammer is just slightly above the upper width limit.  With a receiver well width at the low end or the radii that can intrude into the hammer pin holes there can be interference.

And interference does not come up often.  Whoever you talked to should have sent you a trigger no questions asked.  I'll find out tomorrow.

Hey,

I just want to let you guys know I spoke to Geissele again and they are taking care of me. They are sending me a new hammer that is at the bottom of the tolerance for width so it should fit in my lower.

I am impressed to get this kind of response out of these guys this day in age and they are a top notch company that stands behind their product and takes care of their customers, and thats a rarity.

Amazing.  I just installed a new Geissele 3-gun trigger into an Aero Precision lower.  Same issue with the hammer dragging.  Did exactly the same things: re-installed without springs to see if the problem persisted. (Yep.)  Measured Geissle hammer and got .686.  Measured the perfectly functional  hammer that had come out of the same lower and got .676.  Then I came online to see if anyone else was having the same problem, did a quick Google search, and found this thread.

This is my first Geissele trigger, and based on their rep you gotta assume they're doing a lot right, but maybe they oughta shave a few thousandths off these hammers.

(You really gotta love it: with AR's we're stymied by tolerances that are off by a few thousandths; if we were dealing with AK's the hammer would be rattling around in there like a BB in a bowling alley.)

That's always good advice, but in the case of a Geissele trigger's price v. today's lower receiver prices, the lower could be the less expensive part.

ETA - A moot point, of course, considering Geissele's CS.

We have had some hammers that run big on the dimension across the trunnions.  They fit and work fine in any mil spec lower.  However, the Aero lowers must have the radii in the corners coming back too far in the straight wall section of the receiver.  This was a problem in early AR10 lowers too.  Armalites fix was to knife edge the hammer trunnions.  To prevent this form happening in the future we are 100% checking all hammers with a .682" max size.

Contact us directly Gryo and we will send you a new hammer that we will custom grind smaller.  Napots made out on his issue.  He got a free complete trigger assy with a custom ground hammer along with a stone to fix his existing trigger.