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Posted: 1/6/2023 10:33:05 AM EDT
I picked it up yesterday.
It is my first experience with the MCX platform, and is my first complete Sig rifle.
(I have a 516 upper, and like it, but, even with the Lancer carbon fiber handguard, it is almost a pound heavier than the Spear LT upper... so I'm guessing it will not get shot much moving forward and will probably be for sale soon)

Anyhow, I've got a couple questions/observations on the Spear LT after taking it apart last night.

1) Is there a torque spec people like to use for the handguard screws?  I don't see one in the manual.

2) Does anyone happen to know if the selector is reversible?  I guess I'll find out soon enough but just wondering.  I'm a lefty and like the profile of the safety overall, but want to have the longer lever on the right side.

3) After getting it back together, I notice a slight deflection of the top rail on the handguard, straight up, compared to the upper receiver rail.  It really isn't bad and doubt it will cause any kind of issue bottoming out a front sight or anything like that.  Most people would likely not even notice.  I'm just wondering if I'm the only one here.  I didn't notice it before I took it apart, but didn't look very hard either.  Now the slight deflection appears, it seems, no matter how I seat the handguard onto the upper, and whether it is installed on the lower or not, handguard screws in or out, etc.  I've seen the same sort of thing plenty of times with various AR uppers, and the fix is usually to either not worry about it, or lap the front of the upper... obviously that isn't an option here.  It's really not enough to make me very worried about it either way; I'm just wondering if I'm the only one.

Thanks and happy Friday.
VP
Link Posted: 1/6/2023 11:19:41 AM EDT
[Last Edit: DVCNick] [#1]
One correction... above, I weighed the Spear upper without the BCG in it... oops.  It is actually very close between the two; within a couple ounces with the Lancer handguard installed.  The 516 is a 14.5".
Link Posted: 1/6/2023 12:53:37 PM EDT
[#2]
I popped the stock safety out; unfortunately it is not reversible.

Dropped in a Seekins for now.
Link Posted: 1/6/2023 2:31:21 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
I popped the stock safety out; unfortunately it is not reversible.

Dropped in a Seekins for now.
View Quote


I have a radian Selector in my VIRTUS and that works fine, i'm not Left Handed but the radian has changeable switches
Link Posted: 1/6/2023 3:27:40 PM EDT
[#4]
The G super-configurable is currently holding the title as my favorite, though I bought a bunch of Seekins before I got into the G's.

I guess I'm a little old school and still much prefer the 90 degree throws (though the Seekins can be set up for 90 or 45).  There isn't an off-side lever small enough to keep from seriously digging into my hand with the 45 throw.  For that matter the 45 even messes with my strong side thumb holding the pistol grip like normal.
Been meaning to try a Radian but haven't got one yet.
Link Posted: 1/6/2023 10:49:19 PM EDT
[#5]
No tq on the screws. Harder you tighten harder it will get to take the lower receiver take down pins by the way. I keep those two screws tight but not too much.

Not reversible. I like them and decided to leave em alone
Link Posted: 1/7/2023 10:02:36 AM EDT
[#6]
I wouldn't go above 25 inch pounds on the HG screws, 15-20 should be sufficient, believe they have blue thread locker on them?
Link Posted: 1/7/2023 10:10:35 AM EDT
[Last Edit: Kgknight1037] [#7]
They do have thread locker on them.  OP, i just took my handguard off the other day for a muzzle device change out.  When I screwed the HG screws back in I did it until i was met with mild resistance.  Theres no need to overtighten and potentially mess something up.  You can always recheck it if it bothers you.  The posts above recommendation is also a safe bet.
Link Posted: 1/7/2023 11:22:34 AM EDT
[Last Edit: DVCNick] [#8]
Thanks guys.  I'm pretty sure I blew right past 25 in lb, so I'll back them off a bit.

Mine do have something red on the threads from the factory, though it is definitely not standard red loctite.
I think adding a little blue as necessary should work fine.
Edit:  I was pretty close to 25inlb already.  Heading to the range now.
Link Posted: 1/7/2023 12:58:03 PM EDT
[#9]
Put a witness mark on them so you can visually inspect on your maintenance schedule. Speaking with a Sig Armorer, it's not required to get into and clean the gas piston every time. I know you did on the initial as did I, just information.
Link Posted: 1/7/2023 6:01:31 PM EDT
[#10]
Makes sense.  I was googling around to see how often folks clean the gas block/piston but didn't really find a consistent number.

I shot 260 rounds through it today.  Initial impressions:

Accuracy:  Brand new barrel obviously; it might settle in a bit, but with the same ammo/conditions/shooter as my Geissele ARs, it is running about .5" bigger groups at 100yd with good ammo.  With 55gr fmj bulk loaded stuff it was actually just about the same.  I know some say piston guns may not be as accurate as a good direct gas AR, so maybe it is what it is.  Really not to bad though.  Also I think neither the stock or trigger are really conducive to super tight groups, so trying different stuff there might help as well.

At speed:  My perception is that it is recoiling a bit more than a well gassed AR with a similar muzzle device.  I felt like it is less forgiving and I had to keep locked in to really keep it on target.  Hits indicate that it is recoiling straight up a bit more, but not a massive difference.  Again, I feel like a better trigger and beefier stock would probably help make it easier to shoot at speed.

I'm trying to decide whether to shoot it in a local outlaw carbine match tomorrow.  I probably will.

So far so good; I would call today a definite success; I plan to keep shooting it and will probably put a better trigger in it soon.  I have a couple Larues sitting around.  The stocker isn't bad, just a touch of non-gritty creep; it's just a bit heavy overall.
Link Posted: 1/8/2023 3:46:13 PM EDT
[#11]
I use a magpul ctr on mine and it feels a lot better than the skeleton stocks.
Link Posted: 1/9/2023 1:51:07 PM EDT
[#12]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By xxflyingturtlexx:
I use a magpul ctr on mine and it feels a lot better than the skeleton stocks.
View Quote


Is there a pic rail folding tube adapter that is considered better than the others?

Also, did you guys get one of those taper barrel shoulder adapters in the box, in case you want to run a non-tapered muzzle device?  I thought I read somewhere they were supposed to be included, but don't believe I got one.
Link Posted: 1/9/2023 2:06:03 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:


Is there a pic rail folding tube adapter that is considered better than the others?

Also, did you guys get one of those taper barrel shoulder adapters in the box, in case you want to run a non-tapered muzzle device?  I thought I read somewhere they were supposed to be included, but don't believe I got one.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
Originally Posted By xxflyingturtlexx:
I use a magpul ctr on mine and it feels a lot better than the skeleton stocks.


Is there a pic rail folding tube adapter that is considered better than the others?

Also, did you guys get one of those taper barrel shoulder adapters in the box, in case you want to run a non-tapered muzzle device?  I thought I read somewhere they were supposed to be included, but don't believe I got one.


I got one with mine.
Link Posted: 1/9/2023 10:08:21 PM EDT
[#14]
Surprised nobody has realized that the safety selectors are in fact reversible, but not in the traditional sense of flipping the whole thing over. You just drive the roll pins out from each selector arm, pull them off, and re-install on the other side. The Cross uses the same selectors and is reconfigurable as well
Link Posted: 1/9/2023 11:32:37 PM EDT
[#15]
On the current ones, or at least the one received on mine, the left side (larger) lever is not removable; it is one solid piece with the center shaft part.
Link Posted: 1/10/2023 1:39:55 AM EDT
[#16]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
On the current ones, or at least the one received on mine, the left side (larger) lever is not removable; it is one solid piece with the center shaft part.
View Quote

Well damn, I stand corrected. Thanks for the new info.
Link Posted: 1/10/2023 9:30:31 AM EDT
[#17]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Will816:

Well damn, I stand corrected. Thanks for the new info.
View Quote


I wish I'd got the one you describe... I really like the profile!

I emailed Sig about the missing shoulder adapter, and since I was at it anyway, included my concerns about the rail dimensions.  We'll see what they say.
Link Posted: 1/10/2023 2:01:52 PM EDT
[Last Edit: xxflyingturtlexx] [#18]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:


Is there a pic rail folding tube adapter that is considered better than the others?

Also, did you guys get one of those taper barrel shoulder adapters in the box, in case you want to run a non-tapered muzzle device?  I thought I read somewhere they were supposed to be included, but don't believe I got one.
View Quote


This: 1913-interface-folding-knuckle

or this: Stock Adapter Low Profile Tube - 1913 Folding

Mine came with a shoulder adapter
Link Posted: 1/11/2023 12:36:01 AM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Zerlak:


I got one with mine.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Zerlak:
Originally Posted By DVCNick:
Originally Posted By xxflyingturtlexx:
I use a magpul ctr on mine and it feels a lot better than the skeleton stocks.


Is there a pic rail folding tube adapter that is considered better than the others?

Also, did you guys get one of those taper barrel shoulder adapters in the box, in case you want to run a non-tapered muzzle device?  I thought I read somewhere they were supposed to be included, but don't believe I got one.


I got one with mine.


My 300BO Spear LT was missing the taper adapter; I emailed SIG customer service and they are sending me one at no charge.
Link Posted: 1/12/2023 9:39:30 AM EDT
[#20]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By triode:


My 300BO Spear LT was missing the taper adapter; I emailed SIG customer service and they are sending me one at no charge.
View Quote


Good to know, thanks.  I have not heard back yet.

I've been looking at this rail some more, and right now I'm seeing something that seems really odd.  Keep in mind this is my first MCX experience, all I know about them prior is the pre-Spear rails are known for "not holding zero" and the Spear is supposed to be better with new handguard screws.
I've got everything on mine tightened down good: both the new handguard screws, and double checked the two screws that hold on the bottom tab that links through the front takedown pin.

If I give the front left or right side of the rail a light "tap" with the heel of my hand, it moves visibly relative to the barrel, and stays there.  Tap it to the left, it stays.  Tap to the center, same.  Tap to the right, same.  Like I said, the offsets that result are more than enough to see visually, but it can be easily confirmed with a micrometer as well.
Either I'm doing something wrong here (I can't imagine what) or this rail is so loose that putting a front sight or anything else on it that would need to hold zero would be completely useless.
Is anyone else observing anything like this?
Link Posted: 1/14/2023 11:32:15 AM EDT
[#21]
I got a response saying basically that they no longer ship with the taper adapter.

Going to be supplying more info on the rail issue.
Link Posted: 1/29/2023 9:52:50 AM EDT
[#22]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
I got a response saying basically that they no longer ship with the taper adapter.

Going to be supplying more info on the rail issue.
View Quote
lol typical Sig

"Sorry we can't include this 2$ part with your 2500$ gun."
Link Posted: 1/29/2023 1:24:00 PM EDT
[#23]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ngc1300:
lol typical Sig

"Sorry we can't include this 2$ part with your 2500$ gun."
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ngc1300:
Originally Posted By DVCNick:
I got a response saying basically that they no longer ship with the taper adapter.

Going to be supplying more info on the rail issue.
lol typical Sig

"Sorry we can't include this 2$ part with your 2500$ gun."


That’s a slippery slope. How many optional $2 parts should they include for you? Rail mount Qd point? Qd swivels? Rail covers? Finger stops? Spare screws? Spare roll pins? Gas block taper pins?

It’s not something you need to use the rifle, and technically its an “armorer” level part replacement because it requires the removal of the muzzle device. The only function it serves is to use non-SIG accessories. Why don’t muzzle device manufacturers include a taper adapter for SIG barrels with every muzzle device they sell? Where does this line of logic end?

I’m just playing the devils advocate. My rifle cans are all old SIG SRD series cans so I never use them anyway, but it bothers me when people say “f%%% SIG for (insert whatever business decision”) because it slightly inconveniences them and saves a for-profit company, we all benefit from being in business, hundreds of thousands of dollars.($2 x however many rifles sig sells)
Link Posted: 1/29/2023 5:22:29 PM EDT
[#24]
I'm guessing it's really more about production/availability since they were out of stock on the website last I looked.
I do want to get one, as I will likely want the ability to put my Mini2 on it once it gets out of jail.
Link Posted: 1/30/2023 11:02:55 AM EDT
[#25]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
I'm guessing it's really more about production/availability since they were out of stock on the website last I looked.
I do want to get one, as I will likely want the ability to put my Mini2 on it once it gets out of jail.
View Quote


if you talked to CS, they can back order basically anything for you. I've always been pleased when I call to order vs order online.
Link Posted: 1/30/2023 2:53:37 PM EDT
[#26]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GraniteStateMike:


if you talked to CS, they can back order basically anything for you. I've always been pleased when I call to order vs order online.
View Quote


Thanks... I should still have plenty of time (although my last form 4, in 2022 came back in 4 months when most were reporting at least double that) but will keep that in mind if I don't see them in stock in the next few months.
Link Posted: 1/30/2023 3:07:59 PM EDT
[#27]
BTW... On the part of my inquiry with Sig about the general incredible ease with which the rail can be deflected, they sent it to some techs and are awaiting response, but the CS guy's initial feedback is that it is likely normal.
Not having ever handled any other MCX of any flavor, I have nothing to compare it to, but, I can say it is much easier to deflect than even the worst freefloat AR handguards I've ever seen.  I guess this makes some sense looking at how it mounts up.  At least the receiver rail is longer, and I assume anything zeroed would have to be mounted on it.  For me, this will just preclude the use of a front BUIS mounted all the way out, which, I guess isn't a huge loss.  Everything else I put out there doesn't need to be zeroed.  I assume the, ah, professional end users are putting the IR lasers, etc, on the forward part of the upper receiver rail.

Just looking at the design, the two new screws are clamping in a place that seems like it would be of minimal assistance compared to, say, the Arisaka device.  That makes me wonder if the Arisaka device is compatible with the Spear LT handguard.
Would anyone happen to have both a Spear LT and the current generation of the Arisaka device, and could comment?
Link Posted: 1/30/2023 3:41:50 PM EDT
[#28]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ngc1300:
lol typical Sig

"Sorry we can't include this 2$ part with your 2500$ gun."
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ngc1300:
Originally Posted By DVCNick:
I got a response saying basically that they no longer ship with the taper adapter.

Going to be supplying more info on the rail issue.
lol typical Sig

"Sorry we can't include this 2$ part with your 2500$ gun."


I emailed their CS and they shipped one out to me free of charge (and quickly.)
Link Posted: 12/17/2023 2:06:16 PM EDT
[Last Edit: azoutdoorsman] [#29]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DVCNick:
BTW... On the part of my inquiry with Sig about the general incredible ease with which the rail can be deflected, they sent it to some techs and are awaiting response, but the CS guy's initial feedback is that it is likely normal.
Not having ever handled any other MCX of any flavor, I have nothing to compare it to, but, I can say it is much easier to deflect than even the worst freefloat AR handguards I've ever seen.  I guess this makes some sense looking at how it mounts up.  At least the receiver rail is longer, and I assume anything zeroed would have to be mounted on it.  For me, this will just preclude the use of a front BUIS mounted all the way out, which, I guess isn't a huge loss.  Everything else I put out there doesn't need to be zeroed.  I assume the, ah, professional end users are putting the IR lasers, etc, on the forward part of the upper receiver rail.

Just looking at the design, the two new screws are clamping in a place that seems like it would be of minimal assistance compared to, say, the Arisaka device.  That makes me wonder if the Arisaka device is compatible with the Spear LT handguard.
Would anyone happen to have both a Spear LT and the current generation of the Arisaka device, and could comment?
View Quote
I torqued the handguard screw down to about 45inch lbs (page 65 in manual) and it all but eliminated any rail deflection. I tested the sights that are cowitnessed with my Eotech and there was no visible effect on alignment.

Arisaka also makes a zero retention device that adds another point of security to the rail.
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