AR-15 Backup Sights: evolutionary process

With the proliferation of flattop rifles it is inevitable that backup iron sight (BUIS) systems will become more important to shooters and manufacturers. On my first AR-15 I had a front sight base (FSB) that was the traditional A-post design. This design integrates the gas block and the FSB as a fixed unit. I took off the removable carry handle and purchased a simple rear sight so that I could co-witness the iron sights through the optics. I found out quickly that this really wasn’t the best solution. With a cheap Eotech clone on the rifle, the FSB was so high that I had to raise my cheek weld much too far just to see over it. Eventually I took the plunge and replaced the FSB with a low profile gas block from Doublestar. This was really nice because it allowed me to put my optics as low as possible. This makes the zero much more consistent across the first 200 meters. So, what to do for iron sights?

I tried some different BUIS systems and I frankly didn’t like how bulky and heavy they were, not to mention how expensive. Having been a fan of Magpul products I was delighted when they introduced their Magpul Backup Sights (MBUS). I bought a front and rear set from eBay for about $110 and was immediately convinced these were the best option for my rifle. The sights are polymer so clearly they would not withstand the same level of abuse as their metal cousins but for my purposes they were good for 99% of any situations I could envision. Besides, anyone who has seen the PMag torture test videos can understand that with Magpul the bar is set very high for product performance.

I found the sighting adjustment to be an easy task and deploying the sights could be accomplished with only one finger. Likewise, folding them back down was also a one-finger operation. I was sold: these were the right sights for me. Eventually those sights went with the gun when it was time for a replacement. I have since used these sights several more times.

I recently purchased a Ruger SR-556 (more on that later) and before it arrived I ordered another set of MBUS sights for it. My plan was to remove the Troy Industries sights and install the Magpul units instead. The only gotcha for this scenario is that the gas block on this gun is just too hot to use for mounting the MBUS front sight. Yes, plastic does melt when it reaches barrel temperatures. When I received my rifle the Troy sight on the front wasn’t even mounted on the gas block anyway so the sight radius would be unchanged. Just for fun I shot the rifle with the Troy sights and was amazed at how much I liked them. The sight picture is like an H&K with those round front “ears” fitting perfectly into the circle of the rear aperture. Hmm. I had a feeling that I was about to trade down in terms of the sight picture. Nevertheless, I had already purchased the MBUS sights and figured that I was already comfortable with that sight picture. Besides, who needs all that weight?

I removed the front Troy sight and made a startling discovery: the sight is extremely light. Oh boy, now it was really interesting. All my reasons for using the MBUS were gone! One last hurdle remained: the “Ruger” moniker shone bright white on the front beveled edge of the Troy sights. I honestly loathe having bright, distinct logos on any “tactical” gear. If the idea is to be unobtrusive then why on Earth would I want to announce my position with bright white letters? I struggled for several minutes before deciding to return the Troy sight to the gun and give those a try. If I get really OCD I can just use a Sharpie on the lettering.

I have put quite a few more rounds through this setup and while most were using optics I have used the Troy sights enough to feel that this is the right setup. I will keep the MBUS sights for another rifle but for The Beast (my pet name for the SR-556) the Troys are wonderful. They also take up surprisingly little space when folded down.

So, for me I think both are great products. If I had to start from scratch I can almost certainly say that I would opt for the less expensive Magpul sights but damn, those Troys are nice!

Smoke ’em if you got ’em!


About William Daugherty

William Daugherty is a firearms enthusiast, competitive shooter and Second Amendment advocate living in the Upper Connecticut River Valley region of Northern New England.
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