AR Build question: Std trigger or RRA NM 2 stage trigger


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offthepaper
November 21, 2006, 02:16 PM
I'm considering my first AR build. My question concerns the lower. Should I go with a std trigger mechanism (comes with some of the kits) or go for RRA NM 2 stage trigger (comes assembled in the lower for about $155). What exactly is a "2 stage trigger" as compared to the std trigger. Pro's or Con's? My present thoughts are to build a 20" flattop model. I plan to shoot this at 100-200 yds. If in the future, I decide to do a second build of an AR Carbine 16", would the same advice apply. Any info greatly appreciated. Thanks in advance.

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ocabj
November 21, 2006, 02:24 PM
If you buy the RRA NM 2-stage, you should expect it to fail. The RRA NM trigger is known to lose the 2nd stage over time such that it becomes one long single stage pull with no discerned 2nd stage.

White Oak sells a tuned RRA NM 2-stage trigger that will avoid this problem.

I don't know what kind of adjustments you can get out of the RRA NM trigger, but you'll want one that lets you adjust both the first stage and second stage weights. Depending on what kind of shooting you'll be doing (not distance, but actual use), you may want a heavy 1st stage and light 2nd, or vice versa.

On my high power service rifle, I have a Geiselle trigger set to 4lb 1st stage and .6lb 2nd stage. If I were building a field use rifle, then I'd probably go with a 3lb 1st stage and a 2lb 2nd stage (basically lighter in the 1st and heavier in the 2nd than a competition gun).

Bartholomew Roberts
November 21, 2006, 02:26 PM
A two-stage trigger is a trigger where you take up some of the weight as you pull the trigger until you reach a point where the trigger stops. At this point, you are right on the edge of firing and additional pressure will cause the rifle to fire. Two-stage triggers are very popular for accuracy work.

A single stage trigger should theoretically not move at all when you apply pressure until it goes bang. In actual practice, there is a usually bit of creep or slack in the trigger. Single stage triggers are generally popular for rapid follow up shots.

The RRA 2-stage trigger is nicer; but less reliable. The stock trigger is a single-stage. In the RRA 2-stage, the pin holding the disconnector to the trigger can fall out and disable the weapon. You can upgrade the reliability of the RRA 2-stage by replacing the pin holding the trigger and disconnector together with a solid pin that goes all the way through and cannot fall out. Adco Firearms offers a modified RRA trigger like this.

Generally though, I still recommend the stock trigger if reliability is important. At distances of 200yds, you should have no trouble hitting targets with the stock trigger and I shoot out to 600yds with a stock trigger myself.

jagdpanzer347
November 21, 2006, 02:30 PM
Offthepaper, I just picked up a Stag lower yesterday and also am pondering what to build. I was checking out Delton's site and they offer the RRA trigger as an upgrade for eighty bucks in their kits.

-jagd

Caimlas
November 21, 2006, 02:58 PM
I have a 16" RRA AR15 with the two-stage trigger. I've had it for a bit over a year now, I think (I'm so bad at keeping track of years, months, etc. - it was this time of the year when I got it, at any rate). The trigger didn't so much go to a long "single stage" trigger as it went to a single stage trigger with a (just guessing here) 3 ounce trigger. It gradually required less tension as time and rounds went by, to the point where it would double-fire with a single trigger press. I should note that I did notice the trigger getting lighter, but just figured (falsely) that it was wearing in.

I sent it back to Rock River Arms early this spring, IIRC, and they replaced, tuned or did something else to it. I imagine I put somewhere close to 1,000 rounds through the rifle between the time I got it and I sent it back under warranty for repairs. Since getting it back I've shot probably another 500 rounds through it, and haven't noticed any problems - I imagine it's a somewhat 'hit and miss' in terms of failure, so Rock River only tunes/fixes the bad ones. Or maybe it's endemic to the design - I don't know. I do know that I recognized the problem before sending it in after only the first shooting session, maybe 100 rounds max.

Were I to do it again, I might forgo the Rock River 2-stage trigger, as I've also heard they tend to have this problem. However, I most certainly would get a 2-stage that's known to be reliable.

(Due to the low tolerance of part measurements in 2-stage triggers, it's natural to assume that they'll be less reliable, overall, than standard triggers. I think it's reasonable to assume the standards will last a substantial amount of time longer before needing replacement or tune-up. However, I believe that many of the 2-stage triggers out there now offer user-adjustable set screws, making the fix fairly trivial. Don't quote me on that, iv'e got no 1st person experience in that dept!)

For a description of the trigger differences:

Single-stage triggers, at least on ARs (and in my experience) are what you'd expect on a combat weapon: not tuned in the least bit, and fairly long squeeze, with a trigger weight/tension substantially more than you'd expect to find on a good hunting rifle (or, at least, as my hunting rifle, a Tikka T3, has). There is no "glass rod break", as they say - though I have heard that it is fairly easy for a competent gunsmith to lighten and keep reliable (ie don't try it at home/unless you know what you're doing).

Double stage, on the AR, is essentially the same, except instead of the consistent, long trigger pull, the first bit of let up is really, really soft - maybe 1/5th of an inch, if that. It's just enough to let you know you've started to engage the trigger - which is good, because the 2nd stage does 'break like a glass rod'. That is, it's crisp, relatively easy to break, and feels finely tuned.

I believe I've read that the Jewel 2-stage triggers are essentially the best you can get for your money - but also some of the most expensive. I dont' recall if they're drop-in or not.

Hope this helps.

El Tejon
November 21, 2006, 03:34 PM
I would avoid two stage triggers. I have seen too many fail at gun camp.

dmftoy1
November 21, 2006, 04:09 PM
Wow. . .I guess my experience is quite a bit different. I love the RRA two-stage triggers and have them on both of my AR's. I've only put maybe 2k through each but never missed a beat nor changed other than get a little cleaner breaking on the second stage.

My triggers both came with replacement pins and the highest I've seen a replacement 2 stage RRA trigger kit around here is $120 so $155 seems a bit high to me.

Have a good one,
Dave

Bartholomew Roberts
November 21, 2006, 04:32 PM
My triggers both came with replacement pins

The replacement pins for the RRA trigger are the hammer and trigger pins that go through the receiver. They are about .001" bigger than the holes on the lower receiver in order to give a nice tight fit and they are also nicely polished. If you use those same pins with a stock trigger, you'll also notice an immediate (but slight) improvement in the trigger.

This is not the same as the pin that holds the disconnector and trigger together though. That pin can come loose and if it does, the rifle stops working. The standard RRA 2-stage pin is short enough that if it works loose or breaks, it can vibrate out of place. The ADCO fix uses a hardened steel pin that is longer. It is unlikely to break and it is too long to vibrate out of the hole.

I have an RRA trigger in one of my rifles as well and haven't had any problems with it; but they are more fragile than a stock trigger (and adjustable triggers are more fragile than either the RRA or the stock trigger).

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