Front sight post heights

[easy]

.... say that 5 times fast.

Does anyone know about different front sight post heights and their relation with barrel lengths, or sight radius?

Are there height standards followed by manufacturers depending on the length of barrel assembled on, or do they just slap the same post on all the different lengths of barrels?

 

[Leg]

This gets tricky real fast, but I'll try and do a brief explanation.

When Colt initially introduced short barrels it was determined that a taller post was required due to the shorter sight radius. Tall posts that are .040 taller are available just for this reason.

Than they had to go and f**k it all up by coming out with flattops that weren't cut low enough. Because of that they came out with the "F" height front sight base where the shelf for the post sits .040" higher, thus essentially replacing the older tall post method.

What has never been fully explained to me is why, if a 20" flattop needs an F height FSB, and carbines need a taller front post (or F height FSB), why do flattop carbines not require both the taller front sight post and the F height base to compensate for both the reduced sight radius and lower plane of the rear sight.

Most manufacturers seem to send out regular height front sight bases, putting in taller posts where needed. A few companies install F height FSB's. Apparently the odd company marks their sight as F height even though they aren't. It really doesn't matter that much. If you find you don't have enough adjustment, order a tall post.

 

[easy]

Hey thanks for that Leg.

After measuring some of the spare sight posts and some installed on guns, then measuring the bases on ARs I own, the differences are confusing.

There's plenty of adjustment range, just wondered if there are standard heights used in the industry. Then again its nice to have the post base flush with the tower base intead of the post sticking up.

I'm an iron sights kinda guy, eh.

 

[Leg]

The front sight base should have an F stamped on the left side if it has the shelf cut higher, but like I said, a company or two have stamped theirs regardless of height, probably because they were losing sales to the 'net commandos who think it a vital neccessity. Like Hungry says, "Yer #### 'ill fall off...."