Any explanation as to why barrels shorter than 16" comes in 14.5", 12.5", 11.5", 10.5", 7.5" lengths?
What is the extra half an inch for???
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Any explanation as to why barrels shorter than 16" comes in 14.5", 12.5", 11.5", 10.5", 7.5" lengths?
What is the extra half an inch for???
extra velocity :D
because threads are .5"
to be comp they have to be 16" and when you pin and weld all flash hiders or musl br are 5.5 2.5 and so on
How come with barrel lengths starting from 16" and above the extra .5" is no longer there?
With respect...thread length has little/nothing to do with it...or wouldn't the the "rifle" barrel be 20.5"? Just askin'...
11.5" was the barrel length that finally worked reliably on the late 60's XM177-series carbines after trials with 10" barrels showed the mechanics of that length weren't working quite right. (The current "carbine length" gas system was set in iron on the 10" barrels for the most part). 10.5" and 11" were tried, but 11.5" worked out to be the sweet spot for a short barrel given the tech of the time.
Once it got running reliably, the XM177 effectively became THE symbol for SpecOps during the Vietnam era. Some the first popular 'pinned' muzzle attachments were 4.5"ish long fake "moderators" that were silver soldered onto 11,5" barrels to make the M4gery of it's day, a civ-legal XM177 look-alike.
If I recall correctly, the 14.5" barrel length was selected simply because it facilitated proper mounting of a standard M7 bayonet on a weapon using the previously standardized carbine-length gas system and standard flash suppressor, and...pun intended...it just stuck.
As for the others...I have not a clue other than pure mystique.
MikeN
Not sure of the why an extra .5, but i do question barrels that are advertised as 16' and are really 15.5 plus a flash hider. I have recently been reviewing a number of uppers and came across this. got an explaination that did not make any sense. end up with a 16' + flash hider by LMT. I had been using a 11.5' with a 4.5' flash hider which was fine at 100 yards or less, but was not cutting it at longer ranges. The rifles with a 15.5 length barrel + .5 perm flash hider was LWRC.
where the crap are you seeing 15.5s?
Barrel length is measured from the tip of the muzzle (not flash suppressor) to the breech/bolt face. To measure a barrel's length you can use a cleaning rod and run it down the bore until it touches the bolt face. At this point mark the cleaning rod at the muzzle. Remove the cleaning rod, measure the distance from the tip of the rod to your mark and subtract the distance from the tip of the flash suppressor to the end of the muzzle.
If you have been doing this or a comparable method and coming up with 15.5 then something is wrong, unless the flash suppressor is "permanently" mounted. I suspect you have not been using this or a similar method.
if the barrel is off the receiver, just subtract .5" from the total length from muzz to barrel extension. a 16.1" barrel will be 16.6" from feedramps to crown.
First of all, this isn't even in English. Second, it has nothing to do with NFA laws. Military rifle design is not in any way hampered by the NFA. I have read some really off the wall shit on the internet, but this post has really caused me to question humanity.
^ This.
Also, 14.5" barrels are really 14.6" or so. 10.3" and 10.5" barrels are that long because it allows you to have a FSB with a bayonet lug and I'm pretty sure 12.5" barrels are that long because it is the shortest you can go and still mount an M203. 7.5" I have no clue.
Dustin
i have a 10.625" barrel. :eek: