View Full Version : Century Fire Control Smoothing
January 01, 2009, 03:15
Looking for a little direction here. My STG has Century fire control parts. I just got around to firing it last weekend, and the trigger feels like someone dumped gravel in the action. I cleaned and oiled, cleaned and oiled with no appreciable change in the "grittiness." In looking over posts of how to do trigger jobs, I see that most of the improvement in the fire control group is usually obtained by higher quality parts like FSE. So my question is twofold. First is there any known fix for Century parts like buffing or polishing? Second, I would like opinions on which fire control parts give the smoothest pull/crispest break. I'm mainly interested in knowing about the following, without any consideration of 922r--I'm sick of reading about compliance parts--I'm just looking for unencumbered opinion:
Original South African/Rhodie etc.
I only want to know about metrics right now. Sorry if I butchered anything on the list; I need to learn more about the origin of parts...like does Rhodie signify anything different in terms of origin, for example.
Thanks in advance!
January 01, 2009, 11:20
Are your parts parked? Do the machined sear-trigger-hammer interfaces have anything other than a shiny, polished look to them? Does your lower contain gravel? While not to be treated lightly, this ain't nuclear physics here. Give it a critical look over on all the rolling (cross pins) and sliding (sear~trigger) interfaces. If it don't reflect a lot of light, it's a high friction surface. You can polish to remove problems, just don't take it to the level of changing angles or engagement depths. Having said that, I'll say this. Most disasters I've seen done on small arms have involved a neophyte who did a "trigger job" on his own with no guidance, and no real understanding of what the parts do. If you don't know how the lock work in any firearm does it's job, get some on scene help. Or farm it out. Just my $.02.
January 01, 2009, 11:24
The lightest/slickest of the bunch is or was FSE. No longer made or available from any sources I know of.
The original FCG's varied considerably, depending on use and wear. A like new stg had a smooth but heavy pull, somewhere around 7 lbs. A well used Imbel has a very smooth pull of 6.0 lbs. Good trigger for this type of rifle.
Had bad results with a Falcon set. Lot of casting marks and rough surfaces. Even the engagement surfaces were roughly cut. Several hours of grinding and stoning yielded a nice 5.0 lb trigger. Sort of a do-it-yourself kit, I guess. Have heard some members being happy with them lately so maybe they've improved the product.
A rifle with a Century FCG has a pull good enough to leave as is. About the same as the original Imbel.
I'd get in touch with Files member Moses for Fal trigger work.
Not sure what you're looking for here, and don't know much about them. Rhodie is the short name for Rhodesia, now Zimbabwe. These are a whole story by themselves. I believe they were mostly supplied by South Africa, mixed with FN. All metric and common features, lots of para's. They were painted funny however.
January 01, 2009, 11:36
you can take the parts out .make extended pins to go thru the receiver hole locations and place the fcg on the "OUTSIDE " of the rifle ..that way you can SEE the enguagement ..and it will be fittet to the rifle you have ....not from a jig /other ...hole locations can varry ....an option .....dont forget you "gillie bump test" tm. on saftey ....hammers have dropped before ...
January 01, 2009, 12:19
My Century HTS is decent at about 6 Lbs second pressure. There is some "bumpiness" inherant to the FAL trigger by it's design, not the materials used in the construction. Bearing that in mind you will never get a match trigger pull in that design of mechanism.
OK, Having got that out of the way.
First do the simple stuff, just to eliminate that as a problem, before anything else. Strip the entire HTS & make sure it is spotlessly clean. Once the lower is empty do the same inside there as well. Then look for wear marks. These are where contact is being made & grittyness & friction increased.
Lubricating reduces friction & so drops wear as well. This slows down the natural polishing. This will make the rough feel last longer.
If you're working on any HTS care has to be the watchword, based on that here's what I'd do.
Friction from the sides of the parts can cause grittyness, not just the engagment points themselves. I'd concentrate on carefull polishing of the friction areas shown up by the wear marks from earlier, on the points where the sides of the sear contact the sides of the trigger. Same with the hammer. This will leave the contact surfaces unchanged & so still safe. If that doesn't improve things then try working the engagment points bone dry (no lube at all) several hundred cycles. (Protect the hammer from striking the front of the cutout while doing this or it'll get damaged) then strip, clean & re-lube & see what it feels like.
January 01, 2009, 13:28
Thanks for the tips, I'll let you guys know what I find and post pictures if I get stumped or find something "interesting."
January 01, 2009, 14:02
Someone suggested toothpaste on the engagement points, instead of running dry, for the couple-hundred-resets type of break in for a FCG. Might just be an AR thing, but it changed my STG's grittyness to a smoother, bumpy pull that had more consistant feel before the break.
January 01, 2009, 19:24
JB bore paste maybe, as an alternate?
Whatever "polishing compound" you use make 100% sure it's utterly removed after the polishing, or it'll just keep right on polishing.
Also avoid agressive compounds like valve grinding paste, it's just TOO aggressive.
January 01, 2009, 20:02
as for the valve grinding paste, most will be too aggressive. but if you do this often or just have use for it there are some very fine valve grinding pastes available. I no longer rebuild engines so I don't have a current source, but this is the brand we used http://www.msdiscount.com/columnar.aspx?cat_id=5832&session_id=652232369&category_site=STARTOOL
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