View Full Version : SI Defense...yay or nay?

06-20-2011, 1:20 PM
I'm beginning a new build and am wanting to do something different from my norm. I have nothing concretely done yet, but I wanted to ask yall before I bought anything. Does anyone have any experience with SI Defense products? I'm looking at ordering their matched bullet upper/lower set.

06-20-2011, 4:05 PM
I have one of their matched billet upper and lowers I am currently assembling into my first 6.8 SPC II build. I have found everything to be a nice tight fit, no assembly issues thus far. I actually have had the lower for about a year. I was waiting for them to release their gen 3 billet upper with FailZero coating to complete my desired build. ( This upper will be almost all FailZero coated components, ELPK with FZ hammer,disconnector, trigger, FZ BCG, and FZ BAD selector with KNS pins.)
They have been good about communications when I had questions, although they are a smaller shop, so sometimes you have to leave a message and wait for them to respond. All in all very happy with the upper and lower thus far. I also think it looks pretty nice for a colored billet lower (which I didn't see too many to any of other than black when I was looking.)
I went with the dessert sand and FailZero two tone look and I am VERY happy with the appearance. I am just waiting on the barrel to arrive from AR15Performance.com and I can complete assembly. I will post up opinions and pics after I shoot it :) - F

06-20-2011, 4:40 PM
I have a SI matched upper and lower in 7.62 I'm getting ready to build.
Seems to be quality stuff.

09-07-2011, 10:05 PM
Bumping this thread to see if anyone has any more opinions/experiences.

I'm thinking about one of their barrels for an upcoming build and have not been able to find much on them from searching.

09-07-2011, 10:21 PM
I went with an SI Defense upper for my DPMS based 308 build as it was one of the only receivers available in the old DPMS rail height that matched up with the available aftermarket rails at the time. The machining on their products is top notch. All parts fit up without issue and the barrel extension fit to the receiver was about as close to perfect as I could ask for. My only complaint is that I ordered it anodized in FDE, and the version they sent me was instead painted in FDE. It looks like it was a quick fix to cover up a bad anodizing job perhaps, as the finish under the paint appears to be anodized in a tan or FDE color. The paintjob also has quite a bit of dust and debris imbedded in some areas, making me think it may have been done in a rush. The paintjob does match pretty well with Magpul and Ergo FDE though, so I decided just to run it rather than play the disgruntled consumer role.


09-07-2011, 10:32 PM
No experience with their matched billet upper/lower set, but I did do two builds on their stripped AR-15 5.56/.223 lowers.

I got both lowers from a group buy during the Obama craze. Some buyers, including me, had problems fitting PMAGs. SI Defense promptly took back those lowers, fixed the issue, refinished the lower, and footed the shipping both ways.

I had no problems installing a DPMS and a Daniel Defense LPK. Fitting was perfect.

Would buy again, just based on their awesome customer service. Not to mention their awesome roll mark:
https://s-hphotos-sjc1.fbcdn.net/249842_508809361805_200400799_30320282_5293310_n.j pg

09-07-2011, 11:01 PM
I forgot the reason, but I don't think they use the skull and bone rollmark anymore. The new rollmark looks like this:


09-08-2011, 3:56 PM
the only one i handled was way out of spec, the lpk was loose and upper had lots of play. it was from a batch of bad lowers that went out but i read that they were good about replacing the bad lowers.

09-08-2011, 9:19 PM
In researching for my AR 308 build I've heard nothing but good things about them. I'm currently in a holding pattern on the build since I have some other things going on which is fine by me as I'm really liking the buzz surrounding their 308 bolt, even though it's been on pre-order for about 10 months or so.