A little background --

I have a Bushmaster XM15, E2S, 20-inch HBAR.  I've been shooting South African 5.56 with the stock trigger group with no problems, other than a large group size :-)

I recently installed a Jewell trigger, everything else remains the same.  Now, I'm having frequent (20-30%) failures to fire.  I think that either the hammer spring on the Jewell is lighter than the stock hammer spring or that the overtravel adjustment may need tweaking.

Anyone else run into a similar problem?  If so, what do you recommend as a correction.  Thanks.

Since you know that the FCG is causing the problem, then I would say that you need to re-adjust the FCG.

If when done with the FCG and still having problems, then check out the firing pin and FP channel.  Your looking for protrusion, and and a bur at the cam location on the FP that may be binding the FP.

But chances are that you have the FCG set wrong.

Hope this helps.

SA ammo has somewhat hard primers.  They light fine with standard mil spec type triggers, but may fail to ignite with lighter aftermarket triggers.  I'll bet that if you change ammo to something with commercial primers, that will take care of it.

Good call eric I thought the same thing...
You may try using the GI hammer spring if you can? I think the Jewell trigger is made different though?Try lots of different ammo thats the only way to know for sure..
Beretta92
Heres me at Knob Creek Machine Gun Shoot and Worlds Largest Military Gun Show Friday-Sunday

Well guys, thanks for the ideas but after a trip to the range this weekend, I continue to have failures to fire with both Winchester .223 and SA 5.56 ammo.  I tried diffrent mag and ammo combinations and none corrected the problem.  Sometimes, the hammer wouldn't reset after detonation.  Other times, everything seemed good to go but a trigger pull produced a "click."  I've asked Jewell to send me a new hammer spring.  My hunch is that it's either the hammer spring or the infinitely adjustable Jewell really isn't, you ned to have sear disconnect and/or overtravel adjustments within a specific range or operation.  If the new spring doesn't do it, the whole trigger assembly goes back to Jewell.

Quoted: SA ammo has somewhat hard primers.  They light fine with standard mil spec type triggers, but may fail to ignite with lighter aftermarket triggers.  I'll bet that if you change ammo to something with commercial primers, that will take care of it.

I don't buy into this statement.  If the FCG, including the firing pin extrusion is set up correctly, your going to get a clean strike.

I have a match rifle that the hammer is milled down to next to nothing to decrease lock time.  The hammer spring has been tweaked to 2 1/2lbs trigger pull and all I needed to do is adjust the firing pin extrusion for clean strikes. This rifle will strike/fire even the hardest primers; causing ignition.

What it may boil down to there is no such thing as a drop in match trigger.  They need to be set, checked and the rest of the rifle brought up to speed to function.

Just my take on the idea.

Dano, I'd have to agree with you.  There may be some gunsmiths tha install dozens of these things and know exactly how to set them up.  For a guy like planning to install one and only one, it sure isn't going as planned.  To their credit, Jewell said they'd replace it with one they preadjust and test for me.  I'll tell you one thing though, for the price of the trigger you'd think you'd get decent installationa nd setup instructions.  They really suck!

FYI:   There is not such time as a pre-adjusted trigger for an AR-15.  Each FCG will need to be set per Receiver.  Due to the different manufactures of receivers, there is no way to fine-tune the trigger unless the trigger is in the receiver.  What they can do is set the trigger up for a wide range of receivers, but will leave a lot to be desired in your rifle.

And, when it comes time to re-adjust the trigger, will you need to send the trigger back once again??????

While it is true that there is no way to fine-tune a trigger off of the receiver, if Jewell can get the trigger so that it functions, at least AR15newbie would have a starting point for future and more precise adjustments, wouldn't he?  Just a thought, I have never tried adjusting an AR trigger in any way, just my bolt gun, 10-22, and handgun triggers, so I don't really know about them.  I was planning on getting a either a 2-stage, or single stage adjustable trigger as soon as I get my ejection problems corrected.  ( I know....sounds like a personal problem, take it easy on me.)

Bob

Bob,

Unlike Newby, if you have a problem, I live in Denver and can show you how to set the trigger up or take a look at your rifle to fix it.

As for being close, This is a $175 trigger and close only counts in horse shoes and hand grenades.  If your going to move up to a match trigger, then you should learn how to set it up correctly.

Quoted: I was planning on getting a either a 2-stage, or single stage adjustable trigger as soon as I get my ejection problems corrected. Bob

Hard to go wrong with the RRA 2-stage trigger, no adjustments to tinker with, and both of mine dropped right in and worked perfectly. :)

Quoted: Quoted: I was planning on getting a either a 2-stage, or single stage adjustable trigger as soon as I get my ejection problems corrected. Bob Hard to go wrong with the RRA 2-stage trigger, no adjustments to tinker with, and both of mine dropped right in and worked perfectly. :)

Oh contraire, A polished and fitted RRA trigger is leaps and bonds better than the stock RRA trigger.  
Again, there is nothing like a trigger that is fitted to a receiver. No creep, and it breaks is if breaking a small glass rod.

It maybe me, but all the years shooting bench rifles and slaving away behind Anschutz rifles has spoiled my tastes for fine triggers.

Quoted: Oh contraire, A polished and fitted RRA trigger is leaps and bonds better than the stock RRA trigger.

While I'm sure that you can improve almost any trigger with enough work, I really doubt the improvement to be gained will be noticed by a vast majority of the shooting public.  A few hundred rounds through the gun will also do good things for the trigger.  I think "leaps and bounds" is overstating the case by "leaps and bounds".  YMMV

Johnwill, I guess that it just comes down to a matter of taste and needs.

For some people, the RRA trigger over the stock trigger is a vast improvement. But even on the stock trigger/hammer, there are ways to improve it without having to mill it.

The quickest way to improve a stock trigger is to install a setscrew under the trigger in the pistol grip threads. Using the setscrew, you limit the trigger take-up by tighten the screw until the trigger is tight against the bottom of the selector when the rifle is on safe. On some rifles, this will take up at least half or more of the take-up travel before the hammer breaks.  Then install shims to the sides of the trigger (at the pins) to remove the sideways movement of the trigger. This prevents the trigger from canting when pulled, and again produces a crisper trigger feel.
The hammer/trigger sear surface can be polished and the pins can be polished to take out the gritty feel of the stock trigger. To lighten up the stock trigger, the hammer spring can be tweaked.
If you compare this trigger to a RRA, the only difference will be the two stage pull verses the single stage of the tightened stock trigger, And the stock trigger add-on have cost you less that $1, over the $100 for the RRA trigger.

Note: If you have a mill, then you can set the disconnector to release the hammer at the end of it's stroke, and set the hammer sear for a creep less trigger break.  But this part of working a trigger over,  should be left to a smith, including installing a trigger over-travel set screw.

Don't get me wrong, I like the RRA trigger, it reminds me of my days using a M-1 match rifle. It's just that the stock RRA trigger is a few steps back over a worked factory trigger, and lacks the precision and versatility of a tuned Jewel trigger.

If given the chance, try a worked-over RRA trigger to see for yourself how much of an improvement the smithing of the trigger can achieve.  As for the Jewel, It can be swapped from rifle to rifle, and still only need to be tuned using a few wrenches.

To summarize, John you are correct, most people will never need, nor require a true type match trigger. Most of the time, a standard AR-15 will out shoot them.  It's the few that will step up to the plate and discipline themselves to become match shooters.  It's here where the trigger/rifle must be at it's best, and not a limitation to the shooter.

Just food for thought.
         Or
Trouble shooting is not only limited to the rifle, but the shooter as well.