SIG MCX review

[Trigger]

On the firing pin safety issue, it was in part a fix for a non-problem. The bolt carrier is light enough that if you drop the bolt on a manually chambered round (one not stripped out of the magazine, but dropped manually into the chamber) there is a chance it could slam fire. So Sig redesigned the carrier, added a firing pin retaining spring, lightened the firing pin, and added a hammer-activated firing pin stop. The firing pin stop is not compatible with lightened or match hammers. The stock MCX has a lousy trigger, and desperately needs an aftermarket trigger.

Since all this was done to fix a non-problem, the first solution is to not drop the bolt on a manually chambered round. The next would be to install the upgraded bolt carrier, but remove the firing pin stop while retaining the firing pin spring. This will allow the MCX to use better triggers+hammers than stock. The new firing pin stop is also a device that might make the rifle less reliable or prone to malfunction. I'm not convinced that it is reliable.

YMMV.

[Wyoming Shooter]

My rifle shipped with the "new" bolt carrier, firing pin stop, and charging handle. The factory trigger is dreadful. I spoke with Michael Chandler at SIG about replacing it with a Geissele SSA. Mr. Chandler informed me that SIG is now selling its own replacement trigger - the "Sig Sauer Match Grade AR Trigger Kit" for $114. He claims it's very similar to the Geissele. I asked him if it was manufactured by Geissele and didn't get a definitive response. It wouldn't surprise me. The Sig trigger is about half the cost of the Geissele. I ordered the Sig trigger. I was told it will arrive in about 3 weeks. I'll keep y'all posted.

[Wyoming Shooter]

I ordered a Sig factory replacement trigger on 05/26/17. Total cost was $114. The trigger arrived 06/10/17. The packaging indicates "Made in United States" but does not designate the manufacturer. Replacing the MCX trigger is much like replacing a standard AR trigger. If you've not replaced an AR trigger before, I encourage you to watch some instructional videos or have a smith do the work. The new trigger is much smoother and lighter. My trigger scale indicates an average break of 4 lbs 15 oz. Range testing to follow. From the Big Empty, ELN.

[Sensei]

Of note, today I tried the purple hammer spring that came with my ALG ACT trigger. This lighter spring would was producing light primer strikes every third round or so with Barnes TAC-TX. The mil-spec hammer spring works flawlessly.

[MSparks909]

I ordered a Sig factory replacement trigger on 05/26/17. Total cost was $114. The trigger arrived 06/10/17. The packaging indicates "Made in United States" but does not designate the manufacturer. Replacing the MCX trigger is much like replacing a standard AR trigger. If you've not replaced an AR trigger before, I encourage you to watch some instructional videos or have a smith do the work. The new trigger is much smoother and lighter. My trigger scale indicates an average break of 4 lbs 15 oz. Range testing to follow. From the Big Empty, ELN.

2 stage or single stage?

[Wyoming Shooter]

2 stage or single stage?

It's a two stage.

[Sensei]

Another 20 rounds of Barnes TAC-TX and 60 rounds of Remington 120 grain were fired today with the ALG ACT installed. Half of those rounds were with a SiCo Omega. No issues with the light primer strikes that were occurring with the purple hammer spring, and the rifle ran 100% both suppressed and unsuppressed.

Trigger weight with the gray, mil spec hammer spring is right at 6 lbs - not too shabby. The standard factory trigger was 9 lbs in my rifle.
@Wyoming Shooter, are you able to measure the weight of the new Sig replacement trigger?

[Wyoming Shooter]

My trigger scale indicates an average break of 4 lbs 15 oz. Range testing to follow. Best, ELN.

[Default.mp3]

Wonder what they actually changed internally. The price has certainly gone up.

[Beat Trash]

I'd also be interested in seeing what has been changed. From what I can tell so far:

Heavier weight barrel.

The Sig two stage trigger that actually gives you a decent trigger pull comes installed.

Nicer M-Lok handguard.

"Cool Kids" colors, Grey or FDE

The stock is now 5 position vs. 3.

The overall weight went up about 1.5 lbs.

And of course, the price has been adjusted to match.

This would explain why Budsgunshop.com was able to buy up a bunch of MCX's and blow them out at $1,349.

I will be interested in seeing how the newer barrel shoots with a variety of bullet weights in 5.56mm

I have been kicking around buying an MCX Patrol from Buds all week. Yes it's cheaper than what I project the actual selling price of the Virtus will be. But I don't like the original MCX key mod hand guard and trigger. So I'd buy one of the new Midwest Industries M-Lok hand guards and one of the Sig triggers. All of the sudden the price difference is shrinking.

Side note, I just looked on the Sig Sauer web site. The picture of the original MCX patrol is still on the site, but when you try and click on the product to get information on the original MCX, it says, "page not found".