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AR Technical Discussion Dive into the details and specifications

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  #1  
Unread 01-12-09, 01:25
Aggunner Offline
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First post and first time installing a VTAC tube

After reading all I could about the VTAC / JP forearms, especially on here, I finally pulled the trigger and ordered two of them. The instructions sucked but the install was pretty straight forward.

Here are the two uppers that I built up.





Started with a brand spaking new LMT 10.5 and a new BCM then I proceeded to bastardize them a bit.










I know there are a lot of people out there that say the loc tite is not necessary but I've had my share of crap come loose on me and I just didn't want to chance it. If I ever have to pull the thing apart I'll just heat up the nut or bake the entire upper to get the loctite to weaken.

Last edited by Aggunner; 01-12-09 at 08:59
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  #2  
Unread 01-12-09, 01:53
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where'd you order from? i cant find any
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  #3  
Unread 01-12-09, 08:33
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They both look very cool...my preference for handguards.
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  #4  
Unread 01-12-09, 09:00
Aggunner Offline
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Quote:
Originally Posted by bkb0000 View Post
where'd you order from? i cant find any
I got them from Brownells, granted they had been on back order since the beginning of November.
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  #5  
Unread 01-14-09, 19:17
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Nice install! I ordered two of these as well and couldn't quite get my head wrapped around the instructions. It became easier to see how it all fit together once all components were in hand.

Once you got the "outer nut" put on did you have a small gap between it and the receiver?

I did on one of mine and couldn't live with it, so after 3 hours with a file and sand paper, it gave a nice, tight lock-up with the receiver.

Once the red loc-tite set did you run into any problems with it wanting to turn once you torqued the "inner nut" onto the barrel and into the "outer nut"?

Good pics. Wish I would of had them a month ago.

Very helpful post. Thanks.
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  #6  
Unread 01-14-09, 20:45
An Undocumented Worker Offline
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My M&P15 vtac has a gap between the outer nut and the reciever, there is really no way around it without modifying the part, plus having it contact the face of the reciever could cause the tube to be offcenter if the face of the nut and reciever were not parralell. Oh yeah it was also loctited on there from the factory too.
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  #7  
Unread 01-14-09, 22:00
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Very nice builds!
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  #8  
Unread 02-02-09, 16:49
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Quote:
Originally Posted by shawn c View Post
I did on one of mine and couldn't live with it, so after 3 hours with a file and sand paper, it gave a nice, tight lock-up with the receiver.
One wonders if that would cause any problems once the parts started heating up? It might actually be better to have a slight gap???
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  #9  
Unread 02-21-09, 00:35
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I really dig the SBR. I was planning on putting one together that would have been almost exactly the same but now that I have orders for Ft. Drum, it might have to wait awhile.

What lengths are the tubes? I am putting together a NYS compliant gun and was looking at running a mid-length tube on a carbine length system or a full size tube on a mid-length system. Add a CAR entry stock and a PWS Tim's Tiny One and I think I'll be set.
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  #10  
Unread 02-21-09, 01:45
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Nice pictures for a step by step tutorial. I know the instructions don't paint a clear picture for some folks--you've taken care of that.

The VTAC is a neat HG. I installed one several months ago. The process was straight forward, the components were well made, and the thing hasn't moved. I like it.

--usp_fan
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  #11  
Unread 02-21-09, 12:48
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I'm up in the air about between VTAC and PRI GEN III.

Can anyone tell me how the VTAC gets hot? This is the only thing holding me back.

I know the PRI stays cool with large volumes of fire, but obviously the VTAC costs less.

Can anyone shed any light?

Chris
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  #12  
Unread 02-24-09, 23:38
bigdumbparatrooper Offline
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What model of gas block did you use for your uppers?
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  #13  
Unread 02-25-09, 22:38
lumpia Offline
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Very nice builds. I love the way the VTAC looks. Do you think it will fit over a shaved fsb?
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  #14  
Unread 02-25-09, 23:33
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Yes it does.
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  #15  
Unread 02-28-09, 19:44
RAM Engineer Offline
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Quote:
Originally Posted by lumpia View Post
Very nice builds. I love the way the VTAC looks. Do you think it will fit over a shaved fsb?
Quote:
Originally Posted by usp_fan View Post
Yes it does.
Ok, a couple of questions for you guys with VTAC tube experience:

How much of a space is there between the top of the gas block/shaved FSB and the inside of the tube? It looks like a TIGHT fit on all the pictures I've seen. Any problem with sling pressure putting the tube into contact with the barrel and/or the barrel contacting the tube during firing?

Also, I've heard that their bolt-on accessory rails are not Picatinny spec. Is this still true? Have you had any problems attaching anything to the rails?

I REALLY like the idea of these tubes, but I've never seen one in person or fired one. I'm considering on for a custom build.

Thanks,
Jason
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  #16  
Unread 02-28-09, 19:57
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I have the carbine length rail on my duty gun at work, and ran it in the Vitac carbine 1.5 class...We shot the hell out those guns, and I never really felt the forearm get too hot. I was wearing thin gloves though, but the handguard is pretty well ventilated. For something that doesnt have the "cheesegrader"look, the Vitac handguard is the way to go.

Last edited by diving dave; 02-28-09 at 20:00 Reason: forgot pic
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  #17  
Unread 03-01-09, 21:40
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another odd vtac ? that the folks in this thread seem qualified to answer.

If i want a vtac on my 16" carbine but want to have the barrel cut at 14.5 and have a vortex FH pinned, could I get by with the followinf steps?

1. buy vtac
2. remove barrel and mail barrel, fsb, and vtac barrel nut to shop.
3. shop cuts and re-assembles barrel with vtac nut, pins fh
4. I drive out pins of fsb, slide forward to fh, slide handguard FROM THE REAR over the vtac nut, tighten nut, attach handguard, re-insert pins on fsb.


I know it seems like a huge PITA just to lose an inch, but I'm weird like that.

BTW , nice carbines

Last edited by bankfraudguy; 03-01-09 at 21:41 Reason: ...
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  #18  
Unread 03-02-09, 15:41
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Quote:
Originally Posted by bankfraudguy View Post
another odd vtac ? that the folks in this thread seem qualified to answer.

If i want a vtac on my 16" carbine but want to have the barrel cut at 14.5 and have a vortex FH pinned, could I get by with the followinf steps?

1. buy vtac
2. remove barrel and mail barrel, fsb, and vtac barrel nut to shop.
3. shop cuts and re-assembles barrel with vtac nut, pins fh
4. I drive out pins of fsb, slide forward to fh, slide handguard FROM THE REAR over the vtac nut, tighten nut, attach handguard, re-insert pins on fsb.


I know it seems like a huge PITA just to lose an inch, but I'm weird like that.

BTW , nice carbines

Yes, you could do that...
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  #19  
Unread 03-02-09, 22:20
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Can anyone with VTAC experience comment on how well the system disippates heat? At what point, if ever, would I need a glove on my support hand to keep things comfortable?

Also how easy is it to add a bit of rail to allow an XT-07 to be mounted at 1:00?
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Last edited by John Hearne; 03-03-09 at 10:24
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  #20  
Unread 03-03-09, 20:46
Aggunner Offline
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sorry for not keeping up with this thread.

The tubes are 9 and 11" and I was using the factory FSB that I cut down.

Oh and for those concerned with removing the nuts after being loc tited down, it's no biggy. Just use a heat gun and get the collar nice and hot then use a wooden dowel to turn the collar off.

I'm headed to a EAG class this weekend so I'll give a range report on the tubes.
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