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urikagold
27 April 2008, 09:00
I have been doing a lot of research on the subject and I have to say that this is the best site I have found. Great pics, great content, and a great forum. I have been around shotguns my whole life, so I am not totally new to guns. I am however totally new to rifles and to AR's. I have got the "disease" now and want to build one. Will it be better for me to build or to buy a complete gun? My budget will not be too much of an issue as I will probably spend about the next year building the gun.

I have many questions though. Is 5.56 and .223 the same? What are M4 feed ramps? What is the function of a gas block and is there a difference between an add on gas block and a front sight? Is headspacing when building an upper hard to do for an inexperienced person?

I know I will need some special tools to do the build. My wish list to this point is as follows: Mega or Sundevil lower, Magpul UBR stock for sure that thing is awesome. Noveske barrels seem pretty awesome and don't know what upper I will choose. I do want railed handguards so probably DD Omega or something from Vltor.

Please help me with input and insight.

TigerStripe
27 April 2008, 12:51
Hi!

.223 and 5.56 aren't the same, just very close. .223 is not loaded as hot as a 5.56 round. The brass of a .223 cartridge isn't as thick as a 5.56. The chamber is tighter on a .223 barrel compared to a 5.56 chambered barrel. The simple rule is you can fire .223 in a 5.56 barrel gun, but you can't (safely) fire 5.56 in a .223 chamber gun.

M4 feed ramps are easier to explain with pictures better than trying to describe them. M4 feed ramps help to feed ammo from the mag and help in stopping failure to feed problems compared to rifle feed ramps. You have to make sure the upper receiver and the barrel extension are M4 cut to avoid serious feed problems.

I hope this helps somewhat.


TS

urikagold
27 April 2008, 18:19
So what do most guys chamber their guns in? I have seen pictures of M4 feed ramps, but what does M4 signify. If I understand you correctly they are there only to help with feed problems. Is there a feed problem when matching different barrels to different uppers?

I will be using this gun for home defense, fun shooting, some 3 gun matches, and maybe some dog hunting (coyotes and stray dogs that mess with my horses). I do want to build a very good rifle though. I probably won't be able to build or buy more that one for now and I like the fact that the AR platform seems pretty modular.

I am also thinking 16 inch barrel, but wouldn't be opposed to going to an 18 if it would suit my purposes better. Or maybe just get one of each.

Back to my question on headspacing. If I am going to build my own upper I am going to have to head space the bolt and the chamber. Is this a tricky thing to do? It seems pretty important.

TigerStripe
27 April 2008, 20:59
So what do most guys chamber their guns in?
Most people have 5.56 guns.

I have seen pictures of M4 feed ramps, but what does M4 signify.
It just signifies that they were introduced on the M4 carbine, which most soldiers have now.

If I understand you correctly they are there only to help with feed problems.
Yes.

Is there a feed problem when matching different barrels to different uppers?

Yes and no. You have to have the same type barrel extension and upper. M4 barrel extension needs an M4 cut upper. Most companies identify which type of upper or barrel extension in the description. If there's any doubt, ask.


I will be using this gun for home defense, fun shooting, some 3 gun matches, and maybe some dog hunting (coyotes and stray dogs that mess with my horses). I do want to build a very good rifle though. I probably won't be able to build or buy more that one for now and I like the fact that the AR platform seems pretty modular.

I am also thinking 16 inch barrel, but wouldn't be opposed to going to an 18 if it would suit my purposes better. Or maybe just get one of each.

A 16 inch barrel should work unless you plan on shooting coyotes at long distances.


Back to my question on headspacing. If I am going to build my own upper I am going to have to head space the bolt and the chamber. Is this a tricky thing to do? It seems pretty important.

Generally if you buy a new barrel from Company A and a bolt from Company B you won't need to (check the) head space on them. The matched pairs you mentioned in your other thread are a little better. If you're going to do extreme accuracy work that might come in handy.


TS

Stickman
28 April 2008, 11:16
I have many questions though. Is 5.56 and .223 the same? What are M4 feed ramps? What is the function of a gas block and is there a difference between an add on gas block and a front sight? Is headspacing when building an upper hard to do for an inexperienced person?

I know I will need some special tools to do the build. My wish list to this point is as follows: Mega or Sundevil lower, Magpul UBR stock for sure that thing is awesome. Noveske barrels seem pretty awesome and don't know what upper I will choose. I do want railed handguards so probably DD Omega or something from Vltor.




As TS already commented, the differences between 5.56 and .223 are subtle, but real. The 5.56 is a better way to go in a combat weapon as I have seen .223 chambered weapons choke and fail to extract 5.56 ammo.


The gas block is what bleeds gas into the gas tube (from the barrel) and cycles the weapon. The Front Sight Base (FSB) acts as the gas block on traditional AR15/ M16s. Many people who are adding on a gas block are keeping it under the rail for additional protection, its one of the things I do on my builds. The Noveske barrels are available with a low profile gas block pinned in place, instead of using set screws.


Headspace isn't going to be a concern if you are going with quality components.

John Hwang
29 April 2008, 11:34
I've also have seen many M4 feedramps & uppers not lining up correctly which can cause feeding issues. Misaligned M4 feedramps can cause feeding issues as well. The key is not whether it has M4 feedramps or not but whether the parts fit well together and were they installed properly. I have plenty of rifle style feedramps and they have all worked extremely well (even in full auto)

urikagold
29 April 2008, 18:00
So the feed ramps are cut into the upper right? Will the company i am buying the upper from tell me what compatible barrels will fit their upper? If not how do I check and or change alignment?

TigerStripe
29 April 2008, 19:06
A company can tell you if they have the M4 cuts or not, but if you're doing the building it's partly going to be partly you to make them line up.

John is 100% right about rifle cut feed ramps working. The M4 cuts were introduced to increase feeding reliability, but don't guarantee it. There are AR's that have been around since the sixties that will feed fine with rifle feed ramps.

I would buy the parts from someone like John who will sell you good parts. I've had to tell people to send their rifles back due to unmatching feed ramps or having them file some of the excess material where the upper and barrel extension didn't match up. These were pre-built uppers...


TS

Stickman
29 April 2008, 19:21
So the feed ramps are cut into the upper right? Will the company i am buying the upper from tell me what compatible barrels will fit their upper? If not how do I check and or change alignment?



Deal with a reputable company, and explain your concerns. No one should have have a hard time double checking your build or upper receiver group to ensure everything is up to spec for you.