So I have a SD-C installed in my BCM lower… The possible problem I have is with the hammer pin. No matter how I center it up in the receiver, it moves out a bit to the right side as pictured below when the hammer cycles. I have not live fired it yet. This is all based on dry firing. It has not moved out past the pictured point yet. I really hope it doesn’t start to walk out on me during sustained live fire. I know the pin has plenty of receiver to rest on but this just doesn’t look right.
Is this a problem or a common occurrence? I have not encountered this potential issue with a few other receivers and SSA’s or SD-C’s that’s why it’s bugging me. Please advise…
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I have this same issue occurring in my CMMG lower. Parts kit is a CMMG as well. My hammer pin sticks out on the right side just a bit. IDENTICAL to how yours appears. Its as if I’m looking at a pic of my receiver! At first I was very concerned about it. I have fired just shy of one thousand rounds and it has not walked outward any further. I have dry fired a ton also. I assume the pin is being held captive by the hammers J-hook. The gun functions %100. Now whether this is proper or if its a problem with parts dimension, I can not say. In my worthless opinion I don’t forsee problems, but I will admit it is a bit nagging if you’re the OCD type.
I just installed my SD-C also. For my guns which had hammer pin walk, I have been able to replicate extreme pin walk by dry firing the gun about 30 times.
With my SD-C, after installation, I did a function check then dry fired it about 50 times…I do see the pin rotating, but I’m not seeing the pin slide out like my problem trigger. I think the hammer J-spring is functioning as it’s intended–as a detent to keep the pin from sliding.
I don’t think it’s a problem, but I won’t be able to test-fire this gun until May 15th. Please keep us updated with your findings!
When installing the pin you should feel it “snap” in place. This occurs when the recess machined in the pin is engaged by the piece of spring steel wire inserted in the “center” of the hammer. When the spring steel wire engages the recess in the pin the pin is installed correctly whether the pin sticks farther out one side or not.
Thanks for the reply guys. I pushed the pin in pretty fast and didn’t feel for the engagement. I’ll push it out and back in slowly when I’m home in the AM.
I’ll update.
Mine looks exactly the same. Over 2k on the SD-C now. So long as both hammer and trigger pins are correctly seated with the spring grooves its not like its going to walk any further. Just the natural resting point as you suggest. Don’t worry about it, it is completely normal; go and shoot.
The only way you are going to “fix” it IMO is to go and buy 20 different lower receivers and try each one…if you were lucky, you’d get one with a 100% flush fit. ETA - sorry, just noticed you already stated do not have the trouble with other receivers…however, still not a problem.
I have a SD-C on a DD lower and it’s pretty even. Had one on a RRA lower and it was even as well. So I got off from shift this morning and went straight to work. I pushed the pin out and slowly pushed it back in until I could feel the engagement. I did feel one but it was light. Yep, as before, it’s settling a bit on the right. Once my upper gets back in I’m going to have to fire the shit out of it. From what you guys are saying I should be good to go.
With that said, is it the pin that is out of spec? For example the center groove is more to the left of center?
Knowing how precise and attention to detail oriented Geissele are, I doubt it is the pin that is out of spec; I’m more inclined to think the variation is in the receivers.
Thanks Dan for the pictures. I’m not doubting Geissele at all. Sometimes things slip through the cracks when it’s massed produced that’s all. I’m more of a function > form kinda guy but this just stuck out as odd that’s all.
Also, unless they changed it recently, my newest SD-C doesn’t have “Geissele” on the hammer. Just my observation.
Can’t answer that. I would have to measure the exterior walls of the lower and the pin. Best guess, it is the pin that is a little off, but again, best guess.
Also a slight possibility that the hole in the hammer that the retaining wire spring fits in to is a little off center.
The bottom line is that none of this should effect the way your firearm functions.
One option is to re-install pin with ends reversed, to see if the pin ends up in proper position.
If the pin takes a good push to get moving, its only a cosmetic issue in my opinion.
I had a lower parts kit from a well known manufacturer that didn’t have the j wire installed in the hammer. I didn’t notice until taking the rifle out and after a number of rounds it began to double.
The lack of the j wire allowed the hammer pin to walk out to the point it was not engaging one side of the receiver.
As long as your hammer pin snaps into place, you are GTG. The pin is not going to walk out. If both hammer and trigger pin are protruding out the same amount, it is most likely the receiver.
If you want to check your hammer and hammer pin center alignment, pull the hammer from the rifle and insert the pin into the hammer until it snaps into place. You should see an equal amount of the pin protruding from each side.
If you have any questions or see something that is not to your satisfaction, you can call the shop at 610-272-2060. FYI in the event that you would send the trigger back to us, I do a 24 hr turn around on all returned triggers. (and yes, I do feel like the Maytag repairman at times)
