rear BUIS question, yes i searched...

[kymudder08]

so i am in the process of building an AR. spikes lower with BCM upper group with Magpul accessories and MI handguard/rail. my only problem is the sights. at first the local AR guy i was consulting suggested a 9" rail, remove the stock front sight and use front and rear matching BUIS. well, i got to looking and finally decided that i dont need 9" of rail space (all i want is a flashlight), and i like the look of the stock front sight. this will also cut costs a bit. so the million dollar question is what is a good quality sight that will match up with the stock front sight? what is the term "cowitness" and "1/3 cowitness" ive been reading mean? im planning on using an aimpoint red dot in the near future so i would like to be able to flip up the rear sight in case the optic fails and just look thru the optic using iron sights. which rear sight and quick disconnect mount would be good for this? sorry, uber noob here. lol

[Nobody_Special]

Use the orange search button on top of the page. You will find your answers. I got flamed here not too long ago because I didn't realize there are two search keys. The orange search key works great.

[fivefivesix]

searching on a seperate google page works good for me, however cowitness means your fron and rear sites are inline with the red dot sight. look thru your rear sight, thru the red dot and then the front site and all three line up. lower 1/3 cowitness means your front and rear site linesx up at te lower part of your red dot. so if your rds failed move to the lower portion of your rds and your buis will be tere.
like i said open a new browser and type in cowitness ar15 sites or somthing along thoses lines and you should find what your looking for. and yes the search between calender and faq works great
and as far as a rear site the daniel defenses rear a1.5 works great or a carry handle.
ill let someone else tell you about f marked front sights

[DaBears_85]

A good thread on co-witnessing:

https://www.m4carbine.net/showthread.php?t=17049


As far as searches, I just go to Google and type:

site:m4carbine.net (your subject here)

I find this works best for me.


J

[kymudder08]

thanks guys, really appreciate it. F marked FSB??

[fivefivesix]

http://i834.photobucket.com/albums/zz266/mkIII1022/SU1HMDAzMTMtMjAxMTAyMTUtMjAyNi5qcGc.jpg
see the f stamped on the fsb, they are a little taller shelf where the sight pin screws in, not being a dick but a search on this will yeild some great pics to show the difference. f marked fsb are used on models with carry handles

[The Cat]

Hey Mudder!

Personally I like the Troy BUIS. Like you, I kept my regular FSB - I wanted my carbine to be as rugged and simple as possible. In my opinion, the Troy is about the toughest folding BUIS I've seen. It's well-made and easy to adjust - but not so easy that it'll be readily knocked out of adjustment.

[DaBears_85]

http://i925.photobucket.com/albums/ad97/DaBears8586/1b73f7d1.jpg

[kymudder08]

thanks. if i read on BCM website, the upper group i ordered was has the f marked FSB. this is the upper i ordered http://www.bravocompanyusa.com/ProductDetails.asp?ProductCode=BCM-URG-M4-16 please tell me its money well spent lol. also ordered the magpul ASAP ambi sling mount, BCM stock hardware kit with standard buffer, and a stag LPK to go in the spikes lower i have. hopefully i made good choices with what i was told by the AR guy and local shops. would like to have gotten a BCM lower but had to get what was available here since you have to have it called in like a gun. it was the spikes or a double star

[DaBears_85]

thanks. if i read on BCM website, the upper group i ordered was has the f marked FSB. this is the upper i ordered http://www.bravocompanyusa.com/ProductDetails.asp?ProductCode=BCM-URG-M4-16 please tell me its money well spent lol. also ordered the magpul ASAP ambi sling mount, BCM stock hardware kit with standard buffer, and a stag LPK to go in the spikes lower i have. hopefully i made good choices with what i was told by the AR guy and local shops. would like to have gotten a BCM lower but had to get what was available here since you have to have it called in like a gun. it was the spikes or a double star

It was definitely money well spent. One would be hard-pressed to do better than BCM.


J

[kymudder08]

awesome, very pleased to hear i did good for my first time haha. also have the magpul CTR stock and MIAD grip to order. and the MI t series carbine length rail (or actually, whats the longest rail i can get for that upper and still keep the FSP? stuck on troy and DD rear sight, didnt wanna spend that much but its still less than spending the money on front and rear BUIS magpuls and longer rail

[kymudder08]

also forgot, how would the rear flip up MI sight be?

[DaBears_85]

awesome, very pleased to hear i did good for my first time haha. also have the magpul CTR stock and MIAD grip to order. and the MI t series carbine length rail (or actually, whats the longest rail i can get for that upper and still keep the FSP? stuck on troy and DD rear sight, didnt wanna spend that much but its still less than spending the money on front and rear BUIS magpuls and longer rail

Well, it depends. If we're just talking about a standard carbine-length rail system, then 7 inches is the most you're going to get. However there are other rails on the market that go past the FSB on the sides. I prefer the KAC M4 RAS, as it's a two-piece design (which makes for easy maintenance) and is rock solid. Plus, it's what I'm familiar with from being in the Army.

You can get KAC factory seconds for $150 which is a hell of a deal:

http://www.knightarmco.com/shop/index.php?main_page=product_info&products_id=32

Most people say they can't even find the blemishes.


J

[Stickman]

(all i want is a flashlight)


The use of a longer rail aids in reducing barrel shadowing. Take your flashlight, and put it next to your forearm. Turn the light on with it positioned halfway between your elbow and wrist, point it at the celing. Note the shadow your barrel/ arm casts. Now move the light down to your wrist. Notice how much less shadow there is now.

The longer rail serves a few different purposes.

[Eric D.]

You do mean removable carry handles, right? F marked fsb's are used in conjunction with flat top uppers.


f marked fsb are used on models with carry handles

[Eric D.]

I had a MI buis and I didn't care for it personally. I didn't like the detent mechanism and the sight itself is pretty conspicuous when flipped down behind optics (They do have a lo-pro model, however). I have the troy buis now (bcm branded) and I won't ever look further. Its a fantastic buis.


also forgot, how would the rear flip up MI sight be?

[DaBears_85]

also forgot, how would the rear flip up MI sight be?


I had a MI buis and I didn't care for it personally. I didn't like the detent mechanism and the sight itself is pretty conspicuous when flipped down behind optics (They do have a lo-pro model, however). I have the troy buis now (bcm branded) and I won't ever look further. Its a fantastic buis.

A BUIS, like with everything regarding AR's, is highly subjective to the end users preferences. That said, it's difficult to tell someone that either brand x or brand z would suit them best. I usually just tell people to go with the Troy Battlesights. Mostly because while everyone may have a different preference as far as sights are concerned, everyone will agree that Troy makes a top-notch BUIS. I personally prefer the A.R.M.S. #40L. Hope that made sense.


J

[DaBears_85]

I'm not sure how much you know about lights but this thread I started awhile back has some great info in it:

https://www.m4carbine.net/showthread.php?t=53169


I ended up going with this:

http://www.vltor.com/scount-mount-ocg.htm

http://www.surefire.com/G2-Led

http://www.surefire.com/Click-On-Lock-out-Tailcap-Z59

I really like it. It's a nice, simple little setup. One could definitely do worse.


J

[Chaotica]

Correct me if i am totally wrong here, my understanding is between Mid length and carbine length, Mid is the way to go, for accuracy, and for smoother function?, now it is my understanding that going with a "Barrel" mounted front sight is more accurate than a "Free Float Rail" mounted front sight? and is more noticeable when the barrel is hotter,

IE: a 9" non floating fore grip with an "A sight" (or any barrel with a A-Sight" pinned), will me more accurate at longer distances than "Free Float", 10" or 12" rail with a flip up installed on the rail once things heat up?

[DaBears_85]

Correct me if i am totally wrong here, my understanding is between Mid length and carbine length, Mid is the way to go, for accuracy, and for smoother function?, now it is my understanding that going with a "Barrel" mounted front sight is more accurate than a "Free Float Rail" mounted front sight? and is more noticeable when the barrel is hotter,

IE: a 9" non floating fore grip with an "A sight" (or any barrel with a A-Sight" pinned), will me more accurate at longer distances than "Free Float", 10" or 12" rail with a flip up installed on the rail once things heat up?

You're right about the first part but have the second part mixed up. A free-floated barrel is going to be more accurate than a non free-floated barrel. The difference in accuracy is negligable though and would probably only be noticed by precision shooters using match-grade ammo.


J

[fivefivesix]

You do mean removable carry handles, right? F marked fsb's are used in conjunction with flat top uppers.

yes thats what i meant to say. thanks

[kymudder08]

Wasn't necessarily asking what the best sight was for diff apps. More like which is better quality and won't crap out on me. Also if it would have an absolute cowitness with the fsb

[QuadBomb]

Aside from looking cool, the A-Frame standard front sight base is just fine. Leave it on there and you'll have half of your BUIS set already. It won't be too obnoxious in taking up part of your sight picture, and if you use a magnified opic it will be practically invisible.

[kymudder08]

the upper group, stag LPK, stock buffer kit, and ASAP sling mount from BCM came in today. this stuff is awesome, shipped fast and gave me 2 AR15 magazines (the reading kind lol) and a BCM hat along with their catalog. havin what i have assembled today. all i have left is the magpul CTR stock, MIAD grip, MOE trigger guard, rear buis, and front handrail all in FDE. havent decided yet but i might just say screw the FDE and just get black because one of the local gun shops has ALLLLLL of the parts i need (want), just in black. what would you guys do? spendin this kinda money id hate to just settle with black and regret not goin with the FDE.

[The Cat]

spendin this kinda money id hate to just settle with black and regret not goin with the FDE.


Speaking as a reformed gear-queer fashionista, black's *always* in style. FDE may or may not be in the coming years. You don't want to take the chance of showing your firestick off to somebody a few years from now and they roll their eyes and say, "That's sooooo 2010!" (Same thing happened with green AR furniture in the summer of 1993)
But if you MUST go FDE, do so with easily-replaced accessories, like stocks, rail covers, mags, etc.
Black is slenderizing, too. You don't want your cute little carbine slinking up to you and asking, "Does FDE make my buttstock look BIG?!?" :D

[kymudder08]

lol this is very true. i just wanted it to help camoflauge the gun since black stands out in the woods or whatever. im wanting to get the 7" MI tseries rail so i can keep the stock FSB, well i read on a sight that it requires the removal of the FSB and some nut. does this mean just to install it then put the parts back on or what? it could mean both bc it was a general description for all diff lengths from carbine to full barrel length. thanks

[DaBears_85]

Wasn't necessarily asking what the best sight was for diff apps. More like which is better quality and won't crap out on me. Also if it would have an absolute cowitness with the fsb


A BUIS, like with everything regarding AR's, is highly subjective to the end users preferences. That said, it's difficult to tell someone that either brand x or brand z would suit them best. I usually just tell people to go with the Troy Battle Sights. Mostly because while everyone may have a different preference as far as sights are concerned, everyone will agree that Troy makes a top-notch BUIS. I personally prefer the A.R.M.S. #40L. Hope that made sense.


J

SKD Tactical has a flat $5 shipping fee and outstanding shipping times.

http://www.skdtac.com/Troy_Folding_Battle_Sight_Rear_p/tro.101.htm?1=1&CartID=0


J

[kymudder08]

this should work with the FSB correct? BCM rear sight (http://www.bravocompanyusa.com/BCM-Folding-Battle-Sight-REAR-p/bcm%20rear%20sight%20troy.htm)

[DaBears_85]

this should work with the FSB correct? BCM rear sight (http://www.bravocompanyusa.com/BCM-Folding-Battle-Sight-REAR-p/bcm%20rear%20sight%20troy.htm)

Yes, it will work just fine. It's a Troy Battle Sight branded with the BCM logo, but you probably already know that. :)


J

[kymudder08]

aight man thanks!!!

[DaBears_85]

aight man thanks!!!

No worries, as a fellow compatriot on this site is fond of saying. Glad I could help. You might also consider taking a class or two if you ever get the chance, they're a blast. :)

Good luck.


J

[sacmaster]

If all you want is a flashlight on the rail, I suggest just getting a MOE handguard (assuming you went with carbine gas) and get the IWC 1" light mount for it with a Surefire G2LED. It mounts up great and puts the light pretty far forward. I just put one on my M&P, and I love it.

For a rear BUIS, I went with the Larue fixed sight, and it is awesome.

My other AR is a BCM middy/frankengun with an Eotech EXPS and Magpul BUIS. I much prefer the Larue BUIS on my M&P to the Magpul BUIS on my BCM. Now I'm just waiting for IWC to release the light mount for the middy handguards because I'm so impressed with the carbine version.

No reason for a rail, unless it's a free float, IMHO.

[kymudder08]

id like to find a class, sounds fun. now hopefully the 7" MI tseries freefloat will fit and still use the FSB haha

[DaBears_85]

Hopefully you got the two-piece rail system.

Either of these two:

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=244

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=247

If not then you're going to have to remove the FSB and the handguard cap. But even with the two above you still have to cut off the delta-ring, which is why I suggested something like the KAC M4 RAS above. There's no need for a free-floated rail system unless you're a precision shooter. You're not going to notice the difference in accuracy.


J

[kymudder08]

The ar guy at the local gun shop is completely assembling the rifle for 30 bucks. Its his hobby so no biggy to him for money. He's got the tools to remove the parts on the barrel necessary and reinstall everything. It's the t series 7" freefloat handguard by MI

[DaBears_85]

The ar guy at the local gun shop is completely assembling the rifle for 30 bucks. Its his hobby so no biggy to him for money. He's got the tools to remove the parts on the barrel necessary and reinstall everything. It's the t series 7" freefloat handguard by MI

Ah, gotcha. I didn't know you were having it done by a smith. Speaking of which, it's nice to hear one actually recommending BCM for a change. You don't come across that very often, usually they're just peddling whatever crap they have on hand (Bushmaster, Olympic Arms, DPMS and so on).


J

[kymudder08]

Well, he's not an actual smith. He's ex military and has built around 10 for himself and other people. Seen a couple and they're nice. He works at one of the gun shops here. I chose bcm bc of the forums. He said double star upper group lol. That was bc of my price range tho