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View Full Version : Problem with Mega Billet Upper and TRX Extreme



Zzzake
02-24-11, 22:23
Thank you all for helping a Nub !

As I was tryin to install the trx rail, that thing in 046.jpg kinda gets in the way. I try to force it on there and turn the rail to the upright position where everything lines up, the screws now wont close. Am I suppose to really jam it close?

Is this suppose to be normal? Anyone had this problem before have any suggestion for me?

All feedback welcome !!!!

fuse
02-24-11, 22:25
Wow, looks like it won't fit on the receiver

fuse
02-24-11, 22:32
Wow, looks like it won't fit on the receiver

CoryCop25
02-24-11, 22:47
That little nub protruding from the rail is the index point that lines the rail of the upper with the rail of the handguard. I am guessing that the thickness of the billet upper is hindering the rail from twisting into place. There are several things you can do, it just depends on how you want to tackle the issue. You can file the nub off but you may have a rotation problem with your rail. You can shave the upper or the nub down so it will clear the upper as you rotate it or you can replace the upper or rail. Unfortunately, not everything fits with everything.

ssracer
02-24-11, 22:57
Yup. That's the indexing tab to easily get the top rails aligned. Looks like your only option if you want to keep the trx would be to eliminate the tab. I doubt it would cause a problem, you'd just have to be careful to make sure the upper rails are properly aligned.

jeminyned
02-24-11, 23:07
You may just need to loosen-up the two set screws on the bottom of the trx and pry it apart (ever so slightly) to allow it to slide onto the barrel nut and fit flush with the receiver while it is canted/tilted by that index nub before twisting it into alignment with the top rail of the upper receiver. Try that first - before you go ballistic on it - worked for me.:dirol:


That little nub protruding from the rail is the index point that lines the rail of the upper with the rail of the handguard. I am guessing that the thickness of the billet upper is hindering the rail from twisting into place. There are several things you can do, it just depends on how you want to tackle the issue. You can file the nub off but you may have a rotation problem with your rail. You can shave the upper or the nub down so it will clear the upper as you rotate it or you can replace the upper or rail. Unfortunately, not everything fits with everything.

Zzzake
02-24-11, 23:26
Wow, looks like it won't fit on the receiver

Nope, it doesnt, :(

Zzzake
02-24-11, 23:29
That little nub protruding from the rail is the index point that lines the rail of the upper with the rail of the handguard. I am guessing that the thickness of the billet upper is hindering the rail from twisting into place. There are several things you can do, it just depends on how you want to tackle the issue. You can file the nub off but you may have a rotation problem with your rail. You can shave the upper or the nub down so it will clear the upper as you rotate it or you can replace the upper or rail. Unfortunately, not everything fits with everything.

Thanks for the input! What I had in mind was to try to thinner the index point nub first before just filing it off but not sure if it will work like i wanted to.

Zzzake
02-24-11, 23:41
You may just need to loosen-up the two set screws on the bottom of the trx and pry it apart (ever so slightly) to allow it to slide onto the barrel nut and fit flush with the receiver while it is canted/tilted by that index nub before twisting it into alignment with the top rail of the upper receiver. Try that first - before you go ballistic on it - worked for me.:dirol:

I will definitely try that first but I think slightly might not be enough. In 48 and 50.jpg (i took the barrel nut off, the align point nub thing is already touching the upper receiver and there rail is way off to the left side.

in 51.jpg, the right bottom half of the nub is what im planning to thinner

ssracer
02-24-11, 23:43
Looks like at the very least it will need to be trimmed. Clearly the external dimensions of billet and forged receivers are not the same

Zzzake
02-24-11, 23:45
a better view

Zzzake
02-24-11, 23:46
Looks like at the very least it will need to be trimmed. Clearly the external dimensions of billet and forged receivers are not the same

yup, did not know that before :(

az doug
02-24-11, 23:52
I installed one on a billet upper and ran into the same problem. I removed the tab and it installed without any further issue. As others have noted the tab is only to assist with the rail's alignment.

jeminyned
02-24-11, 23:58
If it's way off to the left then pull it back off the barrel nut and clock it to the next notch upward toward upper rail on the receiver and repeat until it lines up and fits flush - it only needs to turn like one notch from vertical to line up, assuming you have the barrel nut properly aligned with the gas tube hole in the receiver. I put one on my carbine length upper and have one ordered to install on my new middy from BCM! I don't see why billet would have anything to do with it really but hey, I don't have one, yet! Good Luck with it!


I will definitely try that first but I think slightly might not be enough. In 48 and 50.jpg (i took the barrel nut off, the align point nub thing is already touching the upper receiver and there rail is way off to the left side.

in 51.jpg, the right bottom half of the nub is what im planning to thinner

ssracer
02-25-11, 00:04
I don't see why billet would have anything to do with it really but hey, I don't have one, yet! Good Luck with it!

because the external dimensions and shape of billet uppers and lowers differ greatly from standard forged lowers. The internal dimensions are the same, but the external dimensions are generally much beefier.

for example:

forged:
http://jsgunparts.com/wholesale/images/55d71c0ce7ef6e61431666b05f027505.jpg

Billet:
http://www.adxtactical.com/store/pc/catalog/jd.308set_1209_detail.jpg

jetspeed8
02-25-11, 06:25
I am having the same issue (same parts) and called Mega-Arms and talked with Jason. The best fix is to take a dremmel tool/or small grinder and very gently start to take material off the inside of the index point until it will slide over the Billet Upper portion. Touch up the portion you ground down, with some paint, and you should be good to go.

No one will be the wiser, except you.

jeminyned
02-26-11, 14:06
because the external dimensions and shape of billet uppers and lowers differ greatly from standard forged lowers. The internal dimensions are the same, but the external dimensions are generally much beefier.

for example:

forged:
http://jsgunparts.com/wholesale/images/55d71c0ce7ef6e61431666b05f027505.jpg

Billet:
http://www.adxtactical.com/store/pc/catalog/jd.308set_1209_detail.jpg

Pardon my Ignorance and Thanks for clearing that up for me! Those look awesome, especially that JD matched set. Now let's see if original poster (Zzzake) will the take jetspeed8's advice, since he has the same problem, and let us know how that worked-out for him. :)

Lawmaker
02-26-11, 20:53
Yes please post the finished job.

kwrangln
02-26-11, 21:29
Just take the nub off completely, it'll be fine. On mine the nub doesn't contact the upper at all, hasn't moved a bit since I installed it.

Zzzake
02-26-11, 22:13
sorry for late response, did make it work with just a simple filer. I did not want to just file off the nub completely so i just thinner it little by little so it can still be used as a alignment nub. It turned out very simple.

in 011, the alignment is still tiny bit off but i think i can use a light rail to lock it down then tighten the screws on the rail for a better alignment. The barrel and bcg still not delivered yet so i cant post a complete finished job, sry.

Thank you all for all the inputs :)

m249saw
03-01-11, 20:26
I had the same problem with my Mega billet upper with both Larue and Daniel Defense Lite rails. Sold it.

Vltors (newer ones) or good ole forged do the trick

Skyfire1201
03-02-11, 15:51
I had the same problem with my Mega billet upper with both Larue and Daniel Defense Lite rails. Sold it.

Vltors (newer ones) or good ole forged do the trick

Are you saying the Vltor MUR can work with the TRX extreme without any modifications?