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Posted: 10/14/2008 9:35:49 AM EDT
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What the heck is a "F marked" front sight? I'm going to build a 14.5 + FH mid length and someone told me I need a "F marked" front site. Is that true and what the heck is it? THANKS!!!! |
Thanks for the info. Please continue to make me smarter; why does 14.5 puzzle you, am I saying / planning something wrong? |
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Well I don't understand the 14.5"/pinned thing. Also I don't like the idea of a 14.5" midlength. 16" works great with a midlength, 14.5" works fine with a carbine length. A lot of people over on Lightfighter who had 14.5 midlengths have ditched them after 3-5-10k rounds.. Some people here who don't shoot as much may not have any issues. But issues go up when you shoot more... Personally I like 16" midlengths the most and the extra .75" or whatever a 16" + A2 FH is works fine for me. Also I get more velocity out of a 16". And I don't have to deal with the hassle of a pinned FH when I want to change rifle setups, which I do quite often. |
Thanks for the great thoughts. I'll chew on that and make a decision tomorrow. |
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Simple version: The carbine length gas system as we currently know it has been tuned best for use with a 14.5" barrel. That is what the carbine case system is optimized for, ever since the 652. I know, the first carbines had 10" barrels, ect. ect. but this is the simple explanation, the carbine gas system has been being continually tuned since then primarily for the 14.5" barrel. The midlength gas system addresses problems that arise from excessive dwell time, linked to length of barrel remaining ahead of the gas port, on 16" carbines. Because the 16" carbine with 7" gas system is an inch and a half longer than the optimal barrel length, it messes with the harmony between gas tube length and barrel length established by the 14.5" barrel, and is therefore somewhat harsh on the action of the weapon. The midlength addresses this problem by extending the gas system, almost as long as the barrel has been extended, two inches of gas tube to an inch and a half of barrel, which re-establishes the harmony between the barrel length and gas port, solving the dwell time problem. Therefore, a 14.5" midlength is in many ways, a solution looking for a problem, and is actually shorter than optimal for the gas system, which could potentially cause a host of problems, similar to ultra shorty carbines, many of which either need special work done, or are built from an altogether different spec to account for the issues. IMHO, if you want 14.5" with pinned suppressor (all my carbines are such), go with a carbine length gas system, or, if you're dead set on a midlength, get a 16" barrel. And yes, this was the simple version.  Notice I didn't go into gas ports, or too much into the mechanics of why one is superior to the other, this is the simple version. If you want to chime in with more details or add to it, go right ahead, they're intentional omissions to make it easier to understand. HTH, ~Augee PS: To answer the original question, on a midlength, the "F" marked FSB might not be necessary due to the longer sight radius, I would imagine it to be a "won't hurt, won't help' situation, however, I've never tried to zero a midlength with irons, so I could be completely off base here. I'm somewhat of a carbine fan myself. |
FWIW, I have 2 midlength 14.5" builds, both with the gov't profile CMMG barrel. My first build is approaching 2000 rounds of use. No failures. Gun runs smooth as butter, recoils softer than my carbines, and is my favorite gun in the collection. That is why I now have 2.  She's a keeper... 
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You could do like some of who want the mid length look did. Run a 14.5 inch barrel that's designed for carbine length, a low profile gas block and then mid length free float over that. Will give the looks of a mid length free float system but still use the optimal length gas system for the barrel length. |
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