My parts all arrived early and I couldn't resist putting a few mags through my SBR. Here are some initial thoughts.

Lower:
Spikes Tactical on a Form 1
Spikes complete LPK
Magpul MOE SL Grip & SL-K Stock
Macon Armory Buffer (full at 7.5oz using spikes carbine spring)
Stern Defense Adapter Block
Bobbed Hammer w/ JP light spring kit

Upper:
Stern Defense
Raptor LT charging Handle
Primary arms Black Friday MD-ADS
Vortex Spitfire 1x
Strike Industries Ultimate Dust Cover
BCM MLOK VFG

Ammo: Federal AE 115gr

Mags: 3x Glock OEM & 1x ETS each loaded once

Install: Only took a few minutes and went as expected.
Shooting: 100% function for the 130 rounds of ammo tested today

The Awesome:
-100% function
-Fit and Finish was top notch and I really like the Rail
-Puts a damn big smile on my face

The Minor (Upper):
-Dust cover lost the detent somewhere between mags 3 & 4. I messaged Stern about getting a replacement kit sent. More of a PITA than anything.
-They sent 2x of the same size allen wrench. I had the proper size but again just pointing out.
-For me I felt like they put STERN Defense in too many places on the upper. I already swapped out the CH which had their logo (just prefer raptors) and will swap out the dust cover. I feel the rest of the logos are just fine. Just really the CH and dust cover put me over the top.

The Minor (Buffer):
-Buffer had some rust on the face and a pit on the side from what appears to be carbon contamination. Scrubbed it using a brush and oil but still has a pit on the side of the buffer from the rust. Does not impact function in the least bit but for the price I wish they could take a littler better care to avoid this or check before shipping.

Mags: 2 of the 3 glock mags drop free when empty. 1 for whatever reason does not. Also towards capacity its almost like they hang up and have to really force the round using a LULA. Happened on first loading of each mag for around 2 rounds each. May be normal but I have no experience with them and just wanted to point out. My 1x ETS mag I own dropped free and functions for the 1 cycle it had.

Overall Impression: Very happy with my purchase and can't wait to put more rounds down range. Only had a few minor little "Bad points" to try to balance it out. The more important thing to me is fit & finish & function and all three of these are excellent.

Any questions ask away.



ETA 1: Measured mags and found the one that would not drop free needed some sanding around Mag catch area. Drops free now.
ETA 2: Stern messaged me Saturday night and will have a new cover assembly and wrench in the mail on Monday.
ETA 3: Macon just shipped me a new buffer free of charge.

Thank you for the prompt and generous offer! Emailed you my order number (1277). Thanks again!

@jdodd

I realize this is not directly related to the Stern device.   Looking for opinions.

Currently I have a Colt design magazine adapter.   It works.   What I don’t like is what happens when I drop a loaded magazine.

This would be a pistol that I have in my get home bag, so I don’t baby it.  Also I don’t maintain it as I should.

I have other (much nicer, and SBR) Colt and Glock style lowers so I have many magazines for both.

I carry a G19, so magazine compatibility would be great.

I just hate changing something when the system functions.

I don't think going "glock" anything is ever the wrong answer haha. Is it worth your time to part out / sell your colt specific parts? Do you have the extra disposable income to cover the cost delta between what you sell the others for vs what a new setup will cost? If so and you want to I say go for it. Doesnt sound like you have to convert by any means but life is too short to be unhappy with your guns.

I have enough guns & ammo my "need" box is very full. Anything from here on out is very much a "want" and as such if I am unhappy or just not thrilled with something I sell it and move on. To fund this build I sold my 10.5" 5.56 upper. Not a damn thing wrong with it, very accurate little monster. However it just didn't put a smile on my face...so its gone.

I agree.   It’s not the cost that bothers me, it’s that I have a system that’s 100% in my get home bag.   It’s a 100% when I’m using it.   I have dropped a mag or two and it’s a mess.

I think I’ll get it and keep what I have.   Sell one that doesn’t make the cut.

1/28 Update:

I swapped some parts (Vortex Spitfire 1x and BCM VFG) and put another 3x Glock OEM Mags through the gun today. 100% function with new total round count of 229 rounds. I decided this was a good time to take out the adapter for an inspection and clean the upper. Powder residue was manageable and nothing major to report.

Only visible wear was a little bit on the ejector which I would expect. Nothing major at all and ill keep an eye on it as round count goes up.

Side Note: When I had the adapter out I played with the mag release. It protrudes into the adapter so i wondered if I could spin it in enough to touch the glock mag which I could. So if you thread it all the way in to the very last full revolution that seats and your mags stick just a little check that. In my normal position it works fine this was just me playing around.

Per manufacturers website it works for both 9mm and .40s&w magazines.

Link

2/5 Update:

I put another 62 rounds through the gun using 2x new ETS magazines. They loaded harder than normal and would not feed. I had numerous failure to feeds on both
magazines. The following/spring would actually get hung up and get stuck in the mag body at various points north of half way. This would put zero pressure on the rounds above the stuck follower leader to the failure to feed.

I will will keep the 1x ETS mag that appears to work and will be sending back the two new/bad ones for a refund. I will not be buying ETS in the future and only going with OEM.

Yes.

Son in law is using this adapter with .40 S&W

Just put in my order to replace the colt style mag well in my SBR.  Current adapter is a Rock River or Spike, do not remember which.  Will just sell it and mags after checking out the Stern.  Reason is I am a glock fan boy, have several, and will be getting the new Ruger Takedown eventually, so, lots of options with my Glock mags.

Update 2/6:

The ETS magazine thing was bugging me. I took my one original mag and put 31 flawless rounds through the gun. Something was just plain wrong with the other two. The spring looks way different, almost like they are now coated with a semi translucent plastic. Either way Gunmagwarehouse gave me a no questions asked RMA and refund on the two bad mags so they are going back.

Ill keep my one good ETS in the back of the safe because it looks cool. Besides thats its all OEM from here on out. I dont want to be the QC for ETS mags going forward.

My Glock Carbine shoots ETS mags just fine- I toss them up on the berm, shoot them about 30ish times from a G18 mag, and then stop buying crap mags.

Same for SGM, Korean, Food-Town-Brand...

Already shipped back the two I just bought. My original one ill keep for fun and at least it looks cool loaded haha.

I just bought 6x on brownells for 169 shipped between a sale a coupon code for $10 off / free shipping.

Lesson learned

Update

Received the Stern Mag Block.   Sent my bolt to them for the "Glock Cut".  Sent on Monday, got it back on Saturday.  Had previously installed the mag block and checked my Glock mags, pre and post 2004.  Only my 33 Glock Factory stuck just a bit on release, all others worked great.  By stuck, just felt some friction, did not drop free.

Put the SBR back together.  Ran 5 dummy rounds for ejection, etc., then fired 5 rounds, all worked great.  Very happy camper!

After the “Glock Cut” will the bolt still work with Colt style mags?

I have no idea, best contact Stern.  I sold my original mag block and colt style mags.

Yes. The cut just narrows the base of the 9MM bolt so it will fit through the feed lips on the Glock magazines. If the bolt worked with Colt mags before, it should still work after being cut for the Glock mags.