Shaffer Machining Front and Rear Sights - BCM Front Sight Base - AmbGun Minuteman 180 Review

KAK Handguard Deflection Study
https://blog.kakindustry.com/handguard-deflection-comparison

My recent comparison of carry handle irons vs ACOG I found that I could score almost as well on an AQT with irons.

The excellent PSA Carry handle sight is needlessly heavy though…just don't need the carry part.

So I started looking for a high quality, fixed irons package.

Shaffer Machining’s 6061 aluminum front and rear fixed irons are 11 ounces lighter than the ACOG and even less top heavy…tippy. And 9 ounces lighter than the carry handle/a2 front sight setup

With these sights, my UTG Pro ambi AR drops below 6 pounds. Less mass for ambi transitions and snap shooting. It is very noticeable.

The $190 Shaffer sights als save about $1300 compared to the ACOG.

So weight savings and cost savings are significant

Consider the opportunity cost for each…more money for ammo and training. Weight savings means another mag of ammo in your loadout.

The Shaffer sights are beautifully manufactured but there are alternatives…Troy, Larue, and Scalarworks

Scalarworks went with 7075-T6 on their Peak/01 sights. 1.4 ounces lighter, but they do lighten your wallet $68 more than the Shaffer sights.

88% of the weight savings for 73% the cost is a good place to be in the quality irons market.

We do give up the click adjustable elevation wheel of the carry handle sight. I kind of miss it, but without it there is a simple battle sight zero guideline.

Room clearing dead on using just the front sight shroud.
100 yards aim for belt buckle/belly button for center of mass hit
200-300 yards, point of aim and impact pretty close
400 yards aim at head for center of mass hit.

My friends at Leapers sent me one of their UTG Super Slim fixed rear sights that have the click adjustable elevation wheel, but like the Taiwanese made carry handle sights the detents are too indistinct.

An American made or a UTG Pro version, will be a winner for those who want to retain the click adjustable elevation wheel.

The Shaffer irons sights mounted beautifully on our UTG Pro based Ambi AR project rifle. The rear atop the receiver, the front out at the end of the Breek Arms handguard. I started off zeroing right handed and found that I had to max out the windage all the way left. Merited investigation. The sights were obviously properly mounted. Then I noticed that the barrel was not precisely centered in the handguard.

A bit of research and I found the KAK handguard deflection test (link in description). It seems they tested four handguards and it was quite normal to see a 5+ MOA deflection. This works out to about 2/100th’s of an inch at the end of the handguard or about 5” at 100 yards or 10” at 200.

I suspect the majority of the flex is in the link up between the handguard and barrel nut.

Since I routinely sink into a loop sling both left and right handed with the forward sling QD mounted out at the end of the handguard…well, This looks about as smart as doing lead sled load testing atop a portable plastic table.

A scan of iron sight service rifle competitors, I do not see anyone using irons mounted on the handguard…seems all are using an A2 barrel mounted front sight gas block.

So…I picked up an F height A2 FSB from BCM. Drilled and tapped for 10-32 threads for set screw mounting. Added a second dimple in the gas block journal, mounted the FSB to the barrel, and removed the Shaffer handguard mounted sight. Contrary to reports that FSB’s are soft and easy to drill…That BCM FSB was a challenge to drill, but presumably the threads will endure. I ended up cutting off the bayonet lug when the smallest of my starter bits broke off. I should have cut off the sling yoke while I was at it.

Word on the internet is that using set screws is not as strong as the tapered pins. I’d sure like to see a scientific test of that claim.

I can detect the added weight of the FSB, but it’s well worth it for the additional 3 ½” of sight radius over the handguard mounted front sight. Overall 20” sight radius.

If you’re looking for irons as your primary AR sighting system, I’d go with the Shaffer rear sight paired with a BCM A2 FSB. I really do not understand why anyone would spend top dollar for a beautiful Shaffer or ScalarWorks front sight only to mount it on the AR handguard…other rifles with a monolithic rail, sure, but not on a 5 MOA flexy handguard.

I am VERY happy with my Shaffer rear sight and BCM front sight. Lots of sight radius in a featherweight system. And it handles blowing snow better than optics…no frost on the lens, snow in the peep, just blow it clear.