Harrison Beene (harrisonbeen) said:

Sorry I have not been here in years, I may have missed the discussion somewhere. If I did could you point me in the right direction? After all of the HK versions and designers moving to SIG, is the SIG MCX Spear LT the best design currently available to civilians

Welcome back.

The Spear LT is a nice looking rifle. 

The problem for me is that it's at least the 3rd, possibly 4th iteration of the MCX design, which has swung wildly from 6lbs to 7.9lbs in weight for a 16" rifle; now it's 7.5lbs. I'm also not sure how backwards parts compatible each rifle change has been - SIG is notorious for dumping support for past products, such as their previous 5xxx series of rifles. 

Also for all the hype theres very little info on basic aspects of the rifle, like if the barrel is Cold Hammer Forged. And general track record of the latest iteration leaves few clues as to long term durability. 

....

In terms of top grade, legit military capable but civilian available rifles on the US market:

-FN SCAR 16s

-KAC SR15 Mod2 

-Noveske Gen 4 (currently in limited use with DEVGRU)

-LMT MRP Monolithic rifles (as used by NZ and others)

-LWRC IC in either DI / Piston 

-Colt 6940 Monolithic 

-CZ Bren 2 

-Springfield Hellion (aka VHS-2) 

-Steyr AUG A3M1 

-Tavor X95 

....

Limited to AR15's, I'd say the LMT is the top of the market due to its fully monolithic upper, ambi lower, modular barrel system, and that LMT has won multiple international military contracts:

https://shopblackrifle.com/lmt-mars-l-16-5-56-mrp-mlok/

Thanks, great info.

I had a SCAR when they first came out and tried it for 18 months shooting 3 gun but I was faster through the course with a plain old DI AR15. I was faster getting on target with the AR probably  from shooting them since the late 80s. I'm sure enough training could have cured that.

I have 2 LWRCs but changed the barrel out on both of them to get better accuracy, still 4150 CMV and Melonite treated.

I still have a X95 mainly because it's 26.5" long with a 16" barrel but like the SCAR I am quicker with an AR type rifle. 

This leads me to the next question, Is a piston system really cleaner enough, reliable and durable enough to make it worthwhile on a military rifle?   They say the BCM filthy 14 (DI rifle)went 28,900 rounds before they cleaned it but that is just one case and I'm sure they lubed it 10 times more than normal just to keep it going.

It seems the MCX Spear is the last of the line that started with the 416, 516, 816, Virtus and now Spear Lt.  I like the design (folding stock and AR180 guide rods)IF it is reliable and durable enough.

Excuse me for unloading but there are very few forums that discuss all military firearms to the depth that the members here do.

According to the Garand Thumb review video the SIG does have a CHF barrel with Nitride treatment.

Harrison Beene (harrisonbeen) said:

Excuse me for unloading but there are very few forums that discuss all military firearms to the depth that the members here do

Not at all, I'm sure we're all happy for the discussion, especially as right now we're in a bit of a 'slow news day' period for general weapons news.

...

The piston is definitely cleaner; my AUG for example you can barely tell has been fired if you pop it open after a few hundred rounds. 

The question is whether greater cleanliness matters, and is it worth the increased weight / cost / reciprocating mass compared to DI?

Using LWRC, as they are one of the few companies to offer identical rifles in DI and Piston:

LWRC IC DI: 6.6lbs / $1300-$1600

LWRC IC-A5 Piston: 7.3lbs / $2400-$2600

That's + 11.2oz (~an ACOG) + $1000 (cost of an ACOG) for piston ability. Vs just cleaning the rifle a bit, which with a Nickel Boron coated BCG is a pretty easy wipedown. 

...

I'd say the biggest advantage of the SIG LT is the sweet folding stock, rather then it being piston.

Overall I think the LT could be a great rifle, but as with all SIG products, I'd want to wait 1-2 years of market Beta testing before snagging one to make sure all the flaws are discovered. 

If you wanted to experiment with a budget option of SIG LT type AR18/AR15 hybrid, the Brownells BRN-180 and PSA Jakl look like a lot of fun for ~$1000.

https://www.brownells.com/the-trigger-times/guns--gear/brownells-brn-180-line/

https://palmettostatearmory.com/jakl.html

https://www.thefirearmblog.com/blog/2021/05/20/tfb-review-brownells-brn-180-gen-2-upper/

BRN180:

PSA JAKL:

There's also the Taiwanese T91 piston AR uppers that I hear good things about, also quite budget bang and very close to military spec.

https://atlanticfirearms.com/wolf-a1-upper

Budget ar15 components from Asia tend to be very close if not full military spec. Only the fancier guns actually deviate from that.

A friend a of mine (serves as a sniper) uses Norinco AR15 for IPSC comps also internationally says its the cheapest and most reliable ar15 he ever owned. ( i imagine that is not down to exceptional Norinco quality,but simply Norinco using mil-spec parts that are the cheapest and most plentiful, while higher-end guns start gaming the bolt carrier mass , buffers , springs and gas system lenghts ,  making guns smother and faster to run but also reduce the reliability.

Mr. T (MrT4) said:

Budget ar15 components from Asia tend to be very close if not full military spec. Only the fancier guns actually deviate from that.

In this case the concern is mostly the barrel, due to a peculiarity with US import law. Lots of times we end up with EU/Asia/etc made parts but US made barrels. 

However in the case of the T91 I was wrong, its not a US barrel but rather a Taiwanese blank finished in the US:

So all in all an excellent way to get a real military grade piston upper for a reasonable price for testing.

I found a MCX lt 16" 5.56 at Sportsman's Warehouse, I've been looking for months.

Harrison Beene.  That's a name I haven't seen for quite a while.  How have you beene, Harrison?  

Too busy machining parts to get on the forums but I shut the CNCs down in 2017, built a house near Key West and retired.  The problem now is I am bored and reading about guns makes me spend too much money.

How are things with you?