Hello everyone!! I really love this site and have learened a great deal here. I am a newbie here and am wondering the importance of the gas tub and block.  Are they needed? I Think I have all the piceses coming to build my first AR. I would like to list them and have you expierenced guros tell me what I need yet.
RRA EOP upper Complete
RRA stripped lower
RRA Complete charging Handel
RRA Complete bolt
GPSS AR lower kit
GPSS AR small pin Jewell Trigger
DPMS multi Tool
Hogue Overmolded grip and free float garud
Custom 20 inch ss 17 Rem barrel
Skelton stock, spring and tube.
I would like to thank all of you again!!!!

Yes, they are needed to cause your rifle to function semi-automatically.
The block holds the gas tube in position over the gas port drilled into the top of your barrel, and channels a bit of the explosive gas into the tube which ducts it into your bolt carrier to start the process of extracting and reloading.

Without them you'd have a modified bolt action rifle with a very loud, annoying jet of flame out of the port with every shot.

That said, you should already have a block and tube mounted on the RRA upper if its complete (meaning already assembled) as stated.


AH, rereading your post, I see I'm making an assumption about the "complete" upper-- Do you mean complete, as oppossed to "stripped"?
If its not coming "complete" with the barrel attached, you may need a gas tube and block.

Your barrel may come with a block and possibly a tube, but that's not guaranteed.
Tubes come in 2 lengths but it sounds like you'll need the longer one for the 20+ inch barrel.
Blocks have to match the diameter of the barrel, so check your order either to se if its included or find the barrel size. .75, .936, etc.

Everyone carries blocks and tubes, and other than the style of the block, as long as they attach properly, there isn't much difference in functionability between makers-- buy what you like.

By the way, welcome to the board and it sounds like a sweet set-up you'll have there.

Cheers, Otto

otto_esq
Thanks for the information and great insight to see thru my great spelling.

with my kit from DPMS, there is no block.

???

I know nothing about this gas block.  there is a gas tube that i installed, but i may have done it wrong.  It's an A2.  The barrel came with the front sight tower already installed on it and the handguard cap installed too.  

after i put the barrel in the upper receiver and tightened the nut, i slid the gas tube inside the hole in the upper receiver, then i slid it inside the hole in the front site tower.  I aligned the holes and now i am ready to drive the pin in to hold it in place.  If this is done correct, i'll pin it in place.  otherwise i guess i'll take it back apart.

The front sight base IS the gas block.

good, that means i won't have to pull it back apart.  

Thanks for letting me know.  Even if this is the only thing i learn today, at least i learned it HERE. :P