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View Full Version : AR add-on (BUIS, sling, and handguard) questions


Fear58
04-13-2011, 10:33 AM
Hey all,

So I've been holding back this question for sometime with the hope of simply running into the stuff I would need at local gun shops... I've had the AR for 9 months now and so far no dice...

I have a DPMS oracle upper with a bushnell (AA) holosight and a top and bottom picatinny rail on the standard oracle glacier guards. The rifle can be seen here...

http://www.nelsontactical.com/products/images/dpms/dpmsoracle.jpg

My main troubles right now are the MBUS iron sights I have. My front MBUS sits on the picatinny I threw on the glaciar guard... the main problem with this is the glaciar guard itself has a tendency to "slip" and rotate about maybe 1/8th inch when the grip is held firmly (thus losing zero). It's a bummer it does this, and I inspected the glaciar guard to see why it does this. It appears as if the manufacturing of the plastic is just 1/8th inch short in plastic when it snugs back into the handguard rings...

And as for just throwing the MBUS on the gas block picatinny, I've ran into many a forums saying not to do this, as it will melt the polymer magbus. I'm a bit skeptical (especially when I live in a state where I'm only allowed to throw 10 rounds down the tube at a time)... but I'll take their word for it time being.

Anyone have any solutions to the handguard slight rotation thing/ ever seen it happen? I'm not too fond of throwing a quad rail system on this gun. Perhaps buy a front sight that can sit on the gas black and have a raised front sight post?

2nd question: Sling options. I'm looking for the best 1-point system out there... any recommendations? I need one of those sling attachments that sit between the buffer tube screw thingy, right?

Also, could anyone recommend a good-cheap AR tool? I'm constantly screwing in that buffer tube threaded thing (someone fill me in here?) by hand after a range visit...

Thanks!

AeroEngi
04-13-2011, 10:38 AM
Get a pair of Troy front and rear BUIS. You can put the front sight on the railed gas block and not have to worry about them melting/deforming and losing zero.

Fear58
04-13-2011, 10:43 AM
Get a pair of Troy front and rear BUIS. You can put the front sight on the railed gas block and not have to worry about them melting/deforming and losing zero.

Will the Troy front compensate for the lowered picatinny on the gas block? As it sits lower then the upper's rail...

tomd1584
04-13-2011, 10:54 AM
you need either a Front sight designed for a gas block, or switch the gas block to one that is same-plane as the upper receiver. Or you need to add a freefloat handrail that will keep the sight zeroed.

AeroEngi
04-13-2011, 10:55 AM
Will the Troy front compensate for the lowered picatinny on the gas block? As it sits lower then the upper's rail...

I'm not sure if it will compensate for the lower rail but the front sight can be adjusted for elevation. You might have to adjust the front sight more than normal for it to be zeroed at whatever distance you want. It should have enough adjustment for you to do that. Hopefully someone else will chime in soon and clarifiy this.

motorwerks
04-13-2011, 11:10 AM
Troy also makes a Gasblock height front sight

dieselpower
04-13-2011, 11:43 AM
Yeah you need to ditch that MBUS system with your set up. Its not going to work. The M4 fatty handguards are awesome for keeping the heat off your hand, they suck at mounting stuff. They are not the proper height, they have internal ribbing that interferes with mounting and they expand and contract with heat. No you can not see them expand and contract...trust me its happens enough to move your MBUS even if you tighten it down with a 200 lb crowbar. You need to mount on that gas block. For now mount the MBUS on it, just keep in mind two things
1) the gas block gets hot and can melt the MBUS
2) the gas block is the wrong height and you will need to test the zero and figure out where it is.

You really need to buy a set of BUIS from Troy which are made for your rifle set up. You can sell the MBUS for like $50 to offset the cost of the Troy set.

I would keep the Fatty M4 handguards..they are worth every penny to someone who cooks off a 30rd magazine. You can really tell they work.

motorwerks
04-13-2011, 11:47 AM
http://troyind.com/battlesights/front-folding-battlesights

or just buy a rail and be money ahead since you may end up with one anyway. The gasblock sights are $$BREAD$$ and $130 will get you pretty far into a rail.

Fear58
04-13-2011, 11:49 AM
Phew! Those things are money...

Is there any cheaper alternative to troy gas block mount front sights?

motorwerks
04-13-2011, 11:57 AM
Phew! Those things are money...

Is there any cheaper alternative to troy gas block mount front sights?

Yankee hill rail, not much more but you will get WAY more out of it.

http://www.yhm.net/store/forearms.html

I run 2 of the Spector diamonds and love them. Both have plastic (polymer) BUIS on them and havent ever had a problem with ether set.

jdmacl
04-13-2011, 12:13 PM
As for your buffer tube issue and sling attachment, you need to change out your receiver end plate with one that is set-up with a sling attachment point. There are a number of them out there, depending on the configuration you want.

When re-assembling, the buffer tube and extension/castle nut should be assembled with Locktite or the castle nut and end plate should be staked together.

There are a number of relatively inexpensive (>$10) wrenches out there at online, or I got mine on EBay.

motorwerks
04-13-2011, 12:21 PM
Dont loc-tite the castle nut. :D

Stake it maybe but getting it nice and tight is all that should be required. I have 5 have built way more then that and I've never had one come loose with thousands of rounds down range. I'm not saying it cant happen, but it hasn't to me.

high_lander
04-13-2011, 12:27 PM
I went the YHMs, gas bock front site. Good quality. The Troys are good as well.

motorwerks
04-13-2011, 1:59 PM
I went the YHMs, gas bock front site. Good quality. The Troys are good as well.

yup... I have 2 of each. I need to send one of my troys back though. Its heli-coils pulled out.

AeroEngi
04-13-2011, 2:16 PM
How much do you want to spend? Another alternative is you can buy a nice free-floated quad rail and put your front MBUS on there.

I also didn't use any loctite on my castle nut. All I did was tighten it really well with a castle nut wrench and it has stayed put after going through approximately 600 rounds.

C_1
04-13-2011, 2:28 PM
Mounting anything on plastic hanguards, most of the time, its not going to be sturdy. Standard handguards, and most 2pc rail handguards are going to wiggle. If you dont want to go with a free float, you can wrap a bit of electical tape, around the ends of the handguards, where the delta ring is at, to help eliminate some wobble.

The basic stock tool is about $10. Or you can get a $35 multi-tool or Spike's cool stock tool.

Sights on plastic handguards is not really a good idea. And do not mount the plastic front MBUS on the gas block, it'll eventually melt. You need to get a metal front sight that mounts on the gas block. TROY, Midwest Industries, and YHM, make pretty good metal front sights (remember to get the gas block height one).

As for a sling, its really preference. I use a IKH SLAP, with the a Tac Strap rear sling tail (snap shackle & D-ring) on a BFG VCAS, and a ITW MASH hook up front. I can switch from 1 to 2pt. BFG VCAS is good stuff, but check out Magpul's MS2/3 and the Emdom Gunslinger.

pdugan6
04-13-2011, 2:29 PM
ditch that forend and get a free floating forend. get a magpul ASAP (ambidextrous sling attachment point) and a magpul MS2 multi mission sling system. and if you want to switch to a 2 point get the magpul RSA. that is a great setup for sling and a free float forend is always an improvement.

dieselpower
04-13-2011, 2:36 PM
ditch that forend and get a free floating forend. get a magpul ASAP (ambidextrous sling attachment point) and a magpul MS2 multi mission sling system. and if you want to switch to a 2 point get the magpul RSA. that is a great setup for sling and a free float forend is always an improvement.

LOL..he's trying to stay within a budget and you are offering a $300+ option...:eek:

keep the HGs
Sell the MBUS
Find a good BUIS that will work with the gas block you have
Get a single point attachment and sling

all this is under $100 if you search around.

Fear58
04-13-2011, 3:46 PM
LOL..he's trying to stay within a budget and you are offering a $300+ option...:eek:

keep the HGs
Sell the MBUS
Find a good BUIS that will work with the gas block you have
Get a single point attachment and sling

all this is under $100 if you search around.

Diesel I like your style... I've been kickin this exact idea around for awhile hahah. Thanks all though!