Anyone have experiences with the Expo Arms uppers that Primary Arms puts out?

[Sig_Fiend]

First thing, the rail is suspect to me, it has a similar description and material list as the $65.00 ones I put on my .22 PCC and builds I don't intend to keep. Like this: https://www.joeboboutfitters.com/Mat...ot-mlok-15.htm (Although someone on the third shitter down told me that CMT was their source for these)

Busy now but I can post pics later. I have several I'm building, more for fun than any specific purpose. Currently have 9.5" and 15" Combat Series handguards as well as 10.3, 11.5, and 16 inch barrels. Note that Expo has two types of rails; the Patrol Series and Combat Series. Only the Combat Series is CMT sourced. The Patrol Series is from a different manufacturer.

I also have a CMT UHPR-13.7 Mod 1 HDX rail, so I've been able to compare the Expo Combat Series against it. Will post more tonight.

[Sig_Fiend]

The Expo Arms Combat Series handguards are closest in design to the CMT HDX MOD2 rails. The major difference is the removal of the QD inserts and holes as well as the elimination of the odd cosmetic slots at the back of the rails at 3 and 9 o'clock. In essence, it's like they took the front 80% of the HDX MOD2 rail with the back 20% of the HDM rail. Between this and the 10.3 and 11.5 barrel profiles from them, whoever is making these decisions at Expo Arms has piqued my interest. I appreciate well thought out specifications and configurations.

I actually really like that about these Expo Combat handguards. The staggered M-LOK slots theoretically improve rigidity and I don't need built in QD sockets. Best of the HDX and HDM rails combined. A 9.5" HDX rail is $189, an HDM 10.5" is $132, and the Expo Combat 9.5" is $99. I don't see how that's possible for the price, yet there it is. I'm guessing I'm gonna buy the hell out of these for quite awhile. ;-)

(ignore the fact nothing is torqued on these yet, like flash hiders, as I've been test fitting various components)






Barrel Nut & Mounting Hardware
The Expo Arms Combat Series handguards use the same exact 7075-T6 barrel nut and 17-4PH stainless mounting hardware as CMT rails. The rails themselves are 6061-T6. Also included is a single M-LOK QD slot.

The mounting hardware uses the same sort of methodology as SLR barrel nuts and mounting hardware. The barrel nut is grooved and does not need to be timed. The mounting hardware is notched to fit this groove while mating with the contour of the barrel nut. The important thing is, it is NOT a typical pinch lock type rail, so none of the typical worries like you'd have with those.


Fit & Finish
Both the rail and barrel nut are type 3 class 2 hard anodized. The rail finish looks excellent and on par with the more expensive HDX series rails. In comparison to my HDX MOD1 13.7", both the Expo Combat 9.5" and 15" look like the same exact quality of fit and finish. Also, the 1913 sections are scalloped on both the Expo Combat Series and CMT rails, as you'd see with other high quality rails.




Anti-rotation Tabs
The tabs have a tapered angle to them. Lately, I've mainly been using Aero upper receivers for builds, which I've found to be consistent. Using their standard M4 style upper receivers (not what they dub their "M4E1" style), I've found fitment of the Expo Combat rails to be snug, but not problematic. I've test fit 2 rails across 5 or 6 different Aero uppers to compare and all were consistent.

[DDTSGM]

Thanks for the effort you put in, I'm going to look into a combat rail for my next build.

[Sig_Fiend]

Couldn't find a more appropriate thread so, figured I'd use this one. Just saw Primary Arms is doing a ridiculous sale on the Expo 10.3 barrels. Just $77! I'd snatch them all up if I could. Of the two 10.3's and one 11.5 I have from Expo, all three gauged at exactly 0.070" ports.

[Wake27]

Couldn't find a more appropriate thread so, figured I'd use this one. Just saw Primary Arms is doing a ridiculous sale on the Expo 10.3 barrels. Just $77! I'd snatch them all up if I could. Of the two 10.3's and one 11.5 I have from Expo, all three gauged at exactly 0.070" ports.

That is a good deal but I'd be looking hard at the used market if I was buying right now. I've had a sub-500 round 10.5 upper built by JT at RAW with a Triarc barrel and Geissele MK16 that I haven't been able to sell for months. The barrel and rail alone cost more than what its currently listed for...