M4/AR15 Barrel drawing?

[LVLAaron]

Would like to try and build an AR15 barrel from scratch. I have some barrel extensions from White Oak already...

Looking for dimensional drawings of some barrels.

I suppose the only critical dimensions are the barrel extension and gas port location, yes?

 

[shortgrass]

Also, the length and size of the thread for the extension. That bolt has to go in and have room to rotate, but not too much......

 

[jepp2]

Looking for dimensional drawings of some barrels.

Gas port diameter, varies depending. Lilja has some available.

 

[whatsupdoc]

 

[LVLAaron]

While we're here - Any books or literature on the subject?

 

[GenePoole]

I got an M4 barrel from Anderson once that had the boss behind the gas block area too large for a GI KAC handguard to fit. Had to turn it down on the lathe. I complained to Anderson that this barrel was not, in fact, mil-spec if a mil-spec hand guard would not fit. They did not respond. Just another factor to consider.

 

[Bamban]

While we're here - Any books or literature on the subject?

Send me an email with your number on Saturday I will call you back. I'll be glad to share what little I know about doing AR15 barrels from blanks. I've done a couple or so.

Regards,
Nez Rongero
81STFACP@GMAIL.COM

 

[spitfire_er]

I have a print I made several years ago for the barrel extension. Shows pretty much all the measurements. I did it based off some Mil spec parts I had sitting around at the time. Most measurements should be really close. You still need to headspace the bolt to the barrel and extension though and double check everything. Let me know if you want it and I can send it your way. critical measurements of course of threads and headspace. The cone I think you can fudge a little as far as diameter. I made mine a little wider than noted above but not by much.

With the gas port they are pretty easy to figure out. I believe there is shoulder measurements out there listed, and the gas port if need be you can measure your gas block and get it where it needs to be. You have to do the extension first, then drill the gas port last. Indexing fixture helps if you need to dimple for set screws.

 

[LVLAaron]

I have a print I made several years ago for the barrel extension. Shows pretty much all the measurements. I did it based off some Mil spec parts I had sitting around at the time. Most measurements should be really close. You still need to headspace the bolt to the barrel and extension though and double check everything. Let me know if you want it and I can send it your way. critical measurements of course of threads and headspace. The cone I think you can fudge a little as far as diameter. I made mine a little wider than noted above but not by much.

With the gas port they are pretty easy to figure out. I believe there is shoulder measurements out there listed, and the gas port if need be you can measure your gas block and get it where it needs to be. You have to do the extension first, then drill the gas port last. Indexing fixture helps if you need to dimple for set screws.

If you have it I'll take a look at it. I'm getting my head wrapped around how to deal with the headspace/extension fitment.

This guy seems to have the math and dimensions figured out.

I have a mile of old 223 barrels and will start playing with it this weekend.

 

[spitfire_er]

I sent you some stuff.

 

[jelenko]

Send me an email with your number on Saturday I will call you back. I'll be glad to share what little I know about doing AR15 barrels from blanks. I've done a couple or so.

Regards,
Nez Rongero
81STFACP@GMAIL.COM

He has.

 

[DaveTooley]

If you have it I'll take a look at it. I'm getting my head wrapped around how to deal with the headspace/extension fitment.

This guy seems to have the math and dimensions figured out.

I have a mile of old 223 barrels and will start playing with it this weekend.

The extension is nothing more than a removable receiver ring. Same dimensions as a bolt gun. Now figure out how to time the gas port to fall in the groove.

 

[LVLAaron]

Hadn't thought about that. How important do you think that is? I'll have to go check my other custom barrels that hammer and see where the ports are.

 

[VA_XTC_Shooter]

It’s not. Some barrels it’s impossible given groove/land width less than gas port diameter.

 

[DaveTooley]

I get paid well to time the gas port. It matters in the long haul.

 

[VA_XTC_Shooter]

I get paid well to time the gas port. It matters in the long haul.

From a smith perspective, sure if you have a demand and willingness to pay extra for it. I am saying it doesnt matter for accuracy, barrel life, etc. There have been multiple smiths that focus on accurate ARs come out and say it doesn't matter and one only does it because customers believe it is important, so easier to do it than field phone calls.

If you have real data that shows it matters, i am all ears.

 

[DaveTooley]

From a smith perspective, sure if you have a demand and willingness to pay extra for it. I am saying it doesnt matter for accuracy, barrel life, etc. There have been multiple smiths that focus on accurate ARs come out and say it doesn't matter and one only does it because customers believe it is important, so easier to do it than field phone calls.

If you have real data that shows it matters, i am all ears.

I guess it depends on your perspective. Accuracy is a bunch of little things that add to something greater than its parts. My data; firearms manufacturing engineers, ammo manufacturer ballisticians etc. Contracts are awarded based on the tangible and the intangible. So you take care of the tangible parts. In the groove is better over the life of the barrel. Period.
I believe that those who go in harm's way should have the very best. Don't you?

 

[VA_XTC_Shooter]

I guess it depends on your perspective. Accuracy is a bunch of little things that add to something greater than its parts. My data; firearms manufacturing engineers, ammo manufacturer ballisticians etc. Contracts are awarded based on the tangible and the intangible. So you take care of the tangible parts. In the groove is better over the life of the barrel. Period.
I believe that those who go in harm's way should have the very best. Don't you?

Not all govt contracts are in the best interest of the end user. I'd take that with a grain of salt for justifying a method/use. Accuracy of military rifles is not always #1 requirement, and when mentioned it is not to the level of accuracy competitive shooters require.

I am not aware of data from the sources your referenced as your data. Have you seen the data? Can you please share it?

 

[butchlambert]

From a smith perspective, sure if you have a demand and willingness to pay extra for it. I am saying it doesnt matter for accuracy, barrel life, etc. There have been multiple smiths that focus on accurate ARs come out and say it doesn't matter and one only does it because customers believe it is important, so easier to do it than field phone calls.

If you have real data that shows it matters, i am all ears.

Dave has probably chambered more barrels in a week than most on this forum has done in a lifetime.
Think about this-Does our government use him because he knows what he is doing?

 

[VA_XTC_Shooter]

Dave has probably chambered more barrels in a week than most on this forum has done in a lifetime.
Think about this-Does our government use him because he knows what he is doing?

Not arguing his experience, just asking to see the data.