My "I Want An AR Thread"

[strickj]

I gots a question.

Does it matter what type of upper is used,on any given lower? Meaning would an M4car,and an A2 both fit the same lower?

[TripleDigitRide]

I'm no expert, but from what I can tell, yes, they will all work together.

[Guest Mugster]

I gots a question.

Does it matter what type of upper is used,on any given lower? Meaning would an M4car,and an A2 both fit the same lower?

Well, generally yes. But in black rifles there are 2 platforms, the ar-15 and the ar-10. The ar10's mag well is quite a bit bigger to handle .308 sized stuff.

In ar10's, dpms and armalite stuff is not interchangeable without some mods from what i know of it. The mags are also somewhat different I think.

In ar15's, its uncommon, but there's a couple of different pin sizes. Some upper's and lower's use a large pin. The small pin is pretty standard...but if your looking at cheap/older parts its worth checking. There is an adapter kit, and I haven't seen many ar-15 upper/lowers with the oversize pin holes in awhile.

[TripleDigitRide]

Does anyone know if LMT offers a barrel twist other than 1/7 on their 16" flattops? And, what about that from sight that's already on the barrel? I've decided to go with Troy folding sights (unless I change my mind again), so can the stock sight be easily removed, or is there more to it?

[Guest 45AUTO]

buy you an ar and you will love it more then anything.a fun gun to shoot.

[TripleDigitRide]

buy you an ar and you will love it more then anything.a fun gun to shoot.

That's what I'm trying to do. I already have the lower half complete. Now I'm trying to figure out the upper half. I wanted to go with the LMT upper, but 1/7 twist is all I'm seeing. Everyone suggested I go with the 1/9 twist, so I've got a decision to make.

[Guest Verbal Kint]

What length barrel are you going with again?

[TripleDigitRide]

What length barrel are you going with again?

16"

[Rightwinger]

Does anyone know if LMT offers a barrel twist other than 1/7 on their 16" flattops? And, what about that from sight that's already on the barrel? I've decided to go with Troy folding sights (unless I change my mind again), so can the stock sight be easily removed, or is there more to it?

Well, it will be easy to remove but its part of the gas system ! If you remove a standard front sight you will have to replace it with a flat or pic railed gas block. You have to ensure you get one that matches your barrels diameter and that will cover up the area that the old one covered or you'll have barrel showing that was probably not smoothed as much and is of a different color (maybe unblued even).

I would suggest that you buy one already set up for BUIS with the gas block with rails on top so you don't have to punch any pins and scrape up your barrel. You would also have to remove any flash hider to get the old one off and the new one on so you would probably want another crush washer for that....save your self the trouble if your set on the back ups and get it totally flat the first time.

Get the RRA !

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=266

A4 Flat top on a mid length complete upper, hit the drop down and add the weaver gas block +35 or the detachable sight gas block +75. Your out the door for 505.00 or 545.00. I would spend the extra scratch to get their new half smooth half 4 rail handguard system as well ! That thing is the cats ass!

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=380

[TripleDigitRide]

Well, it will be easy to remove but its part of the gas system ! If you remove a standard front sight you will have to replace it with a flat or pic railed gas block. You have to ensure you get one that matches your barrels diameter and that will cover up the area that the old one covered or you'll have barrel showing that was probably not smoothed as much and is of a different color (maybe unblued even).

I would suggest that you buy one already set up for BUIS with the gas block with rails on top so you don't have to punch any pins and scrape up your barrel. You would also have to remove any flash hider to get the old one off and the new one on so you would probably want another crush washer for that....save your self the trouble if your set on the back ups and get it totally flat the first time.

Get the RRA !

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=266

A4 Flat top on a mid length complete upper, hit the drop down and add the weaver gas block +35 or the detachable sight gas block +75. Your out the door for 505.00 or 545.00. I would spend the extra scratch to get their new half smooth half 4 rail handguard system as well ! That thing is the cats ass!

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=380

I was looking at the RRA Half Quad earlier today. It's damn near a perfect fit for what I think my needs will be.

I now have the money to finish this rifle, but I'm trying to get my ducks in a row. I want to make sure I buy the right stuff the first time.

Edited July 27, 2008 by TripleDigitRide

[Guest Verbal Kint]

Several companies make such barrels... Stag Arms and DPMS, to name two, both make 16" 1:9 barrels, if you're going to piece together an upper... or replace the barrel on whichever complete upper you choose.

Here are some links:

DPMS 16" AR-15 Lite Barrel 1/9 Twist Ratio

Stag Arms 16" M-4 Barrel Chrome Lined 1/9 Twist Ratio

You could always have Joe, or anyone else that's knowledgable, piece an upper together for you. Pick the upper you want, barrel, components, etc.

[TripleDigitRide]

Still going with the front and read flip sight issue; I have seen some pictures where the handguard covers the gas block. This seems to allow for the front flip sight to be mounted right on the end of the hand guard. What type of gas block are they using? And, does this mean I'd have to use a longer handguard to cover the gas block?

[Guest Verbal Kint]

Still going with the front and read flip sight issue; I have seen some pictures where the handguard covers the gas block. This seems to allow for the front flip sight to be mounted right on the end of the hand guard. What type of gas block are they using? And, does this mean I'd have to use a longer handguard to cover the gas block?

They're using low-profile gas blocks, like the LaRue Tactical or Noveske. Several brands out there, actually, but those are two of the better ones. This allows the rails to cover them and reach further out on the barrel.

How long you want the rail, compared to the barrel, is your own preference. I went with a 10.5" barrel, and am ordering a 9" rail. It will cover my gas block, since it uses the carbine length gas tubes, and leave 1.5" of barrel. Pretty close to the end, yet does leave some exposure. Just my preference of what I wanted to run with.

In regards to a full-length (16") barrel, I'm not sure how far out the gas tube is... or what length would be needed to cover the block on it. I'm sure someone makes one, but I just haven't researched that area of a build.

I know Larue makes rails up to 13.2", and I know there are several companies that make free floating tubes for this application (if you're not wanting to run a rail). Daniel Defense also makes 12" rails that allow for normal front sight posts and gas blocks. It really all just depends on what exactly you're wanting to run.

[TripleDigitRide]

I'm wondering if the gas block on the carbine is closer to the receiver than the gas block on the mid-length. If so, maybe I could go with the carbine upper, and use a mid-length handguard. Not sure if it will work, but I'll look into that option.

[Guest Verbal Kint]

I'm wondering if the gas block on the carbine is closer to the receiver than the gas block on the mid-length. If so, maybe I could go with the carbine upper, and use a mid-length handguard. Not sure if it will work, but I'll look into that option.

Barrel length dictates where the gas port is drilled at, and which gas tube is required. You can use the same gas block on any of the lengths... just a matter of where the hole is, on the barrel, that it will cover. The upper receiver themselves, are all the same.

I'm just not that knowledgable on the longer barrels.

There are carbine, mid-length, and rifle length gas tubes... which match up to their respective length barrels. You can see a comparison here:

Basically I can run any length barrel I want on my AR build... but if I go longer (to a mid-length or rifle setup) than the 10.5" it will normally have on it, I'll have to swap the barrel out and also the gas tube out. Everything else, including the gas block itself, can be re-used.

[TripleDigitRide]

Barrel length dictates where the gas port is drilled at, and which gas tube is required. You can use the same gas block on any of the lengths... just a matter of where the hole is, on the barrel, that it will cover. The upper receiver themselves, are all the same.

I'm just not that knowledgable on the longer barrels.

There are carbine, mid-length, and rifle length gas tubes... which match up to their respective length barrels. You can see a comparison here:

Basically I can run any length barrel I want on my AR build... but if I go longer (to a mid-length or rifle setup) than the 10.5" it will normally have on it, I'll have to swap the barrel out and also the gas tube out. Everything else, including the gas block itself, can be re-used.

That's what I was thinking. That being the case, I think I should be able to go with the carbine upper, but use the mid-length handguard. This would allow me to use the low-profile gas block. I'm just trying to avoid having the weaver type gas block at the end of the handguard.

Edited July 27, 2008 by TripleDigitRide

[Rightwinger]

Yes! That would be the ticket

[TripleDigitRide]

OK, back to the twist question again.

I know many have suggested the 1:9 twist, but will the 1:7 do the very same thing, plus allow me to shoot heavier rounds if I want? Or is there a real advantage going with the 1:9?

[Guest Verbal Kint]

The 1:9 is pretty much a civilian / competiton twist rate, where as the 1:7 is the military rate. Unless you're planning on doing a lot of precision competition, where you absolutely need the most accuracy you can get over long distances, the standard 1:7 twist will be more than adequate.

IMO, I'd just go with a good 1:7 barrel.

[TripleDigitRide]

I can't think of many places I'll be able to shoot over 100 yards, so as long as the barrel is pretty accurate out that far, I should be fine.

I also need to make sure the Troy folding front and rear sights would mount directly to the upper and RRA Half Quad handguard. I want to keep them as low as possible.

[Guest Verbal Kint]

Yep, they'll mount directly to the standard rails.

However, (not having seen the Half Quad in person) is the railed portion towards the rear of the guard? Or is it out in front? All the photos I've seen of the Half Quad seem to show it in a position where the rails are at the back of the guard, with the smooth portion out front. Is that accurate?

If so... you'll be shortening your sight base, compared to if you had it at the farthest reach of a full rail. Not a concern, if you will be true BUIS, but something to consider if you're looking at the utmost accuracy (like you were in barrel twist).

Edited July 27, 2008 by Verbal Kint

[TripleDigitRide]

Yep, they'll mount directly to the standard rails.

OK. I'm getting closer to a decision. I think.

If I decided to go with the LMT, how difficult is it to remove the fixed front sight and replace it with a low-profile gas block? I don't think LMT offers an upper with anything other than the fixed front sight.

Edited July 27, 2008 by TripleDigitRide

[Guest Verbal Kint]

Disregard my last post... actually found a photo of the RRA Half Quad handguard installed.

You'll be good to go... and will mount directly to it. Sorry for the confusion.

Edited July 27, 2008 by Verbal Kint

[Guest Verbal Kint]

OK. I'm getting closer to a decision. I think.

If I decided to go with the LMT, how difficult is it to remove the already attached front sight and replace it with a low-profile gas block? I don't think LMT offers an upper with anything other than the fixed front sight.

Just a matter of unscrewing the front flash hider and removing it, driving the pin out of the front sight, and sliding it off. Then putting the new gas block in it's place, and either pinning or scewing it on (depending on which method it uses). Re-attach the flash hider.

That's another thing to consider... how the gas block attaches. My LaRue Tactical GB uses two set scews in the bottom. My barrel of choice was already dimpled for this, but some aren't and require the dimpling (easily done my a smith, or by yourself with the jig you can buy). Other blocks are pinned on. Yet others are clamped/screwed on.

Just be aware of which style you get, and how your barrel is currently. Might require the additional dimpling, but that is a quick/easy modification.

[TripleDigitRide]

:rofl: How many times have you actually done this?

Depending on how the A2 post/GB was installed, this could prove to be a total PITA.

You make it sound like a 5 minute job, which 95% of the time, its not.

So it's not a good idea?

I'm not sure how much of this thread you've been reading, but I know I don't want a fixed front sight. I want the Troy front/rear folding sights. I also like the RRA Half Quad (only comes in mid-length). I really like the LMT upper. I guess all the 16" LMT's are carbine. What would you suggest?