A few basic(?) questions...

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11 years 6 months ago - 11 years 6 months ago #24815 by pookybear308
A few basic(?) questions... was created by pookybear308
More Noob stuff...please bear with me here:

1) Does a barrel need to be of the same manufacturer as the bolt or are they pretty much the same item from the same drawings?

2) Exactly where on the barrel does one measure to get the correct diameter for the correct gas block?

3) Is the front iron sight best located on the barrel/gas block or on the rail on the free float guard?

4) In casual shooting, need the handguard really have venting?

Assume that the gun is set up for field activities, non-competition, no full auto, no optics or dots, minute of carcass accuracy acceptable.

Bring it on, Oh Learn'd Ones...I'm listening. :bow:

ps- AR15 and AR10 handguards don't interchange, do they?
Last edit: 11 years 6 months ago by pookybear308. Reason: forgot a question

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11 years 6 months ago #24816 by jtallen83
Replied by jtallen83 on topic A few basic(?) questions...
You can find the gas block info here; www.ar10t.com/forums/armalite-inc/13131-...echnical-specs#17766

I'll let the guys that know answer the rest, saw a "308" barrel for sale, looks like an AR-10 barrel so I'll be waiting for that answer myself.

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11 years 6 months ago #24822 by SOC
Replied by SOC on topic A few basic(?) questions...

pookybear308 wrote: More Noob stuff...please bear with me here:

1) Does a barrel need to be of the same manufacturer as the bolt or are they pretty much the same item from the same drawings? (I highly recommend they are)

2) Exactly where on the barrel does one measure to get the correct diameter for the correct gas block? (The location where the gas port is drilled roughly 2/3 down the barrel from the chamber end)

3) Is the front iron sight best located on the barrel/gas block or on the rail on the free float guard? (The further apart your front and rear sights are from each other the more "sight radius" you'll have and you'll get better accuracy.)

4) In casual shooting, need the handguard really have venting? (no)

Assume that the gun is set up for field activities, non-competition, no full auto, no optics or dots, minute of carcass accuracy acceptable.

Bring it on, Oh Learn'd Ones...I'm listening. :bow:

ps- AR15 and AR10 handguards don't interchange, do they?

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11 years 6 months ago #24824 by 13fcolt
Replied by 13fcolt on topic A few basic(?) questions...

pookybear308 wrote: More Noob stuff...please bear with me here:

1) Does a barrel need to be of the same manufacturer as the bolt or are they pretty much the same item from the same drawings?

2) Exactly where on the barrel does one measure to get the correct diameter for the correct gas block?

3) Is the front iron sight best located on the barrel/gas block or on the rail on the free float guard?

4) In casual shooting, need the handguard really have venting?

Assume that the gun is set up for field activities, non-competition, no full auto, no optics or dots, minute of carcass accuracy acceptable.

Bring it on, Oh Learn'd Ones...I'm listening. :bow:

ps- AR15 and AR10 handguards don't interchange, do they?


1.
.308 ARs don't have the same standards as AR15s. Every brand does it's own thing, so a DPMS barrel will not work in an Armalite and so on. Even if a bolt from one brand did happen to fit in the barrel extension, there is little chance it will be compatible with the carrier. The best policy it stick with one pattern. This does get confusing when every other yahoo calls everything an AR10. Only Armalite makes the AR10.

2.
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This spot in the red square, Typically gas blocks will be .625 for lightweight profile, .750 is the most common size around, and heavy barrel gas blocks typically run .936. Keep in mind that while these are most common, some oddball sizes are out there.

3.
They are not stable enough for mounting optics or front sights. It takes almost no pressure at all to flex a FF tube and see why.

4.
No, not really but I think it is a good idea. Things do heat up.


And no. Different size barrel nut means different handguards. Unless you mean the stock plastic usgi looking things. Those might swap, but I have never tried it.
The following user(s) said Thank You: Siscowet, pookybear308

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11 years 6 months ago #24872 by OleCowboy
Replied by OleCowboy on topic A few basic(?) questions...
Some really good questions and like 13 Fox said, everybody calls them an AR and they are NOT! If you want to re barrel or install a new major end item, barrel, hand guards, gas blocks, bolt carrier group etc etc. SPECIFY ArmaLite you have an Armalite.

Yes, I know there is no shortage of experts out there that think ALL AR components regardless of manuf are interchangeable. Certainly many parts are but buyer beware.

On that note a word about 'Mil-Spec': I have written plenty of Mil-Spec requirements for various contracts for the Army and we have them for EVERYTHING from how you write software to weapons. They go from simple to quite complex. In the case of weapons one of the prime driving forces is to insure that the logistics of the battlefield are not so complex as the unit armorer has to carry a box full of different firing pins, or hand guards etc. Granted this does bring about some compromise. But the Army has indeed adapted. At one time almost all soldiers carried the same gun, today even at the Squad level there are several different weapons each with it own unique functionality to allow us to fight and win on the killing fields.

The other prime factor is to establish a standard of performance and quality of components.

Lastly is the need to have a balance in specs in order that in the event of a World War with a large standing army such as China or Russia we have the ability to turn on the machines of capitalism and meet global requirements. This is especially true in Ammo where sudden requirements can put a lot of pressure on the manuf system.

Think of some of the manuf of weapons in war time: Quaker Oats, GM, Singer Sewing Machine etc. For this reason every guy with a JC Whitney Universal Reloader who dreams up the 'magic' cartridge then heads up tot he Army Weapons boards along with a letter from his Congressman and (today) a half dozen flavors of SOCOM soldiers to vouch for it being the best thing since lasers. NOTE the 6.8, which is now its its 3 iteration trying to convince the Army its the end all be all the Army is fools for not adopting it...maybe something about not being able to meet a sustained requirement of 12.5 million rds per month production of ball ammo.

Point being look deeply at those claim Mil-Spec. Which is not to say you cannot have Mil Spec components in your build, but a complete MS weapon (AR) outside the military is rare...

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11 years 6 months ago - 11 years 6 months ago #24882 by pookybear308
Replied by pookybear308 on topic A few basic(?) questions...
I've never had the technology, the tools, or the detailed specs to be able to prove or disprove a claim of "Mil-Spec" so I usually just ignore it as advertbabble...though I know such a thing exists.
At this point, I'm trying to build my first attempt using a CMMP lower, a "DPMS pattern" upper, and a "slightly used Armalite AR10" barrel. Before I shop for my BCS, are there likely to be any useful identifying markings on this barrel when it arrives? I'm a bit disapointed to find out how...uhh...independent the AR10 clone manufacturers might be and the BCS will be my next most expensive purchase. I'd be most pleased if it actually locked up to the barrel. :unsure:


(terrible later thought) So, am I to understand that it's not just the barrel & BCS that need to be the same brand, the upper must also be to guarantee fit & lockup? OMG!
Last edit: 11 years 6 months ago by pookybear308. Reason: forgot a question

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11 years 6 months ago #24891 by faawrenchbndr
Replied by faawrenchbndr on topic A few basic(?) questions...
Barrel and bolt carrier group do NOT need to be the same brand.

You need to buy new, quality pieces though.

Armalite and DPMS pattern barrels are interchangeable, need to use the barrel's gas tube.

Sending a pm
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11 years 6 months ago #24938 by SOC
Replied by SOC on topic A few basic(?) questions...
Make sure your barrel nut is a pattern match to your upper receiver, DPMS and Armalite have different thread pitch.

I also recommend getting the headspace checked regardless of weather the barrel and bolt match.

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11 years 6 months ago #24940 by faawrenchbndr
Replied by faawrenchbndr on topic A few basic(?) questions...
Never head spaced an AR in the last 29 years.......never had an issue.
Don't buy junk and you will not have a problem. Only buy from established companies, the new start ups like PSA, are nothing but a hassle.

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11 years 6 months ago #24943 by 13fcolt
Replied by 13fcolt on topic A few basic(?) questions...

faawrenchbndr wrote: Barrel and bolt carrier group do NOT need to be the same brand.

You need to buy new, quality pieces though.

Armalite and DPMS pattern barrels are interchangeable, need to use the barrel's gas tube.

Sending a pm


Do you have a reference for this? I'm not saying you are wrong, but I could have sworn armalite put out a no-go on doing this. Of course now I can't find that reference.

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