Trigger question. Surface or Through hardened

[atblis]

I have a DPMS lower parts kit, and I was wondering if the trigger parts are now through hardened rather than simply surface hardened.

I heard a rumour that they are all now through hardened. True or not?

Getting ready to embark on some trigger tweaking. Should be fun.

[atblis]

Anybody? Guess I'll have to find out.

[albatrossarmament]

Im afraid surface......Ive heard of alot of guys polishing the surfaces to make them smooth, only to reach the soft inside and have a pouty face. I'd call DPMS to verify though.

[atblis]

I am absolutely expecting surface hardened. It would be really sweet to pick up some through hardened parts as that would save me some trouble. I emailed DPMS, it's probably not a question they're keen to answer. Probably feel I shouldn't be modifying their parts anyways.

Anybody know of any of the standard trigger groups (DPMS, Bushmaster, High Standard, etc. etc.), are through hardened?

[Warg]

Let me first preface my response by saying that I'm fairly new to ARs and there are many others with vast more knowledge and experience than I.

I have modified triggers and hammers for my plinkers using parts from RRA, DPMS and Bushmaster. Beware, this is only a sample size of four. These were purchased around April, but I have no idea when they were actually manufactured, what lot, etc. All were surface hardened only. This was readily apparent when I removed the hooks from the hammer in an effort to reduce mass as I was using lighter weight JP springs.

After breaking through the surface hardening with a cutoff wheel- I'd estimate approx 1/16" or so, the metal would cut like butter. My experience indicates that the surface hardening is probably sufficiently deep to lightly polish the sear surface and hammer face (where it will contact the bolt). However, factory tooling marks were sufficiently deep among all of these that I was not able to remove all of the marks for fear of breaking through the surface hardening. Some recommend the use of polishing stones with the proper jig to maintain correct alignment of sear surfaces. I did not feel comfortable using these given the depth of the tool marks.

I did notice an appreciable reduction in creep from the polishing, but I would NOT recommend doing this yourself for a fighting weapon. I read many accounts of custom trigger jobs gone bad after many rounds were put through the FCG (of course have no way of knowing how aggressive the polishing jobs were on these).

Not sure about through hardening by other manufacturers. Perhaps Grant can help?


Regards,

Gene

[atblis]

Awesome. Thanks for the info.

Yeah, got a response from DPMS. They stated that their parts are hardened per Mil spec. Not what I asked and probably intentionally vague. This leads me to believe they are only surface hardened/

I have Power Custom Series II Jig. So I was planning on tweaking some angles, but nothing dramatic.

I did take a Arkansas stone to my current trigger/hammer. I didn't even take out all the machine marks. Initially it was much smoother. Unfortunately it now has grittiness to it which leads me to believe that I broke through the surface hardening. :(

Makes me wonder what Bill Springfield does? If he cuts any new angles, he pretty much has to reharden.