Weld up PCC hammer height?

Ryan Groves · Apr 8, 2017

I have a Gesseile SD-3G in my new PCC, I have one in my regular 3gun AR and love it, plus wanted the continuity between guns. Anyways, out of the first ~450 rounds I've put through it I have had 4 failure to resets in some shape or fashion. Either a two round burst, or simply wouldn't reset until charging the bolt again.

I am using a QC-10 lower, Nordic upper, and QC-10 BCG (worth noting I was able to test a JP bolt with same trigger and would not reset even once, calipers showed QC-10 having .4 mm lower rail on the BCG).

My question: is there is any reason I'm not considering as to why welding a bead to raise the height of the SD-3G trigger closer to milspec wouldn't work? As you see in the picture there's a pretty good difference in height between the two hammers. The fact that .4 mm bolt difference made a world of difference in reseting, has me thinking a little higher trigger might be all I need to get 100% reset. I've also read where people were able to use the .308 hammer in the regular pin hole AR Gold trigger group to get reliable resets with it in PCC's.

Obviously I could just sell the SD-3G and go another route, but not quite ready to give up on this yet unless there is a reason welding it up would be a problem. Thank you for your input.

Glock_21 · Apr 8, 2017

Have you tried a Kaw Valley bolt?

I have the KVP bolt and a Timney trigger and it runs like a champ.

Matt1911 · Apr 8, 2017

I think the Timney hammer is taller.
I don't see a reason why it wouldn't work. Just make sure it's nice and rounded.

Glock_21 · Apr 8, 2017

Jesse posted a while back about wanting to weld up a hammer or the ramp on a bolt. He was trying to get an AR Gold trigger to run in a PCC rifle. I don't know if he ever tried it or not.

Ryan Groves · Apr 9, 2017

Travis Lowry said:
Have you tried a Kaw Valley bolt?

I have the KVP bolt and a Timney trigger and it runs like a champ.

Kaw Valley = Faxon right? Put calipers on it at Tony's and it didn't seem to have any lower rail then the JP bolt. QC-10 had the lowest so went with it. Heard the Timney triggers do run pretty well, might go that route if I sell this.

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Ryan Groves · Apr 9, 2017

Matt Rigsby said:
I think the Timney hammer is taller.
I don't see a reason why it wouldn't work. Just make sure it's nice and rounded.

Wondering if the issue has anything to do with sear engagement amount instead of just hammer height. Know the light single stages, like the SD-3G, don't have much sear purchase. Could maybe be the violence of the blowback system doesn't reset consistently. I don't know, just speculating since I'm not the gunsmith, hence posting here.

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Wall · Apr 9, 2017

Ryan Groves said:
Wondering if the issue has anything to do with sear engagement amount instead of just hammer height. Know the light single stages, like the SD-3G, don't have much sear purchase. Could maybe be the violence of the blowback system doesn't reset consistently. I don't know, just speculating since I'm not the gunsmith, hence posting here.

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I told you this the other day in the shop.
That's why the hiperfire works so well for PCC, because of the long reset on those triggers.