What you need if you like building ar15's

Jan 5, 2012
18,610
113
HK
Hey try taking a Dremel and polishing your chambers. It will help too

Cut the loop off a Glock bore brush rod. Chuck in a cordless drill, smear Fritz on the brush, and run it in and out the chamber like you were honing it. Also works good polishing reloading die bores. It'll get it mirror. If a person doesn't have Fritz. Aluminum mag wheel polish, Meguiar's polishing compound etc. Rinse the polish out the chamber/bore with some mineral spirits. Works like a charm.
 

Landrover

Member
Jun 23, 2017
168
28
New York
Ok. I build a lot of ar15's and I have come across a lot of problems everyone needs to know about.
1. Everybody coats differently
2. Everybody has there own idea on what the tolerances should be.
3. Everyone thinks SAAMI spec is SAAMI spec, its not.
Here we go.
1. Coatings:
Almost everyone in the industry sends their stuff out to get coated. Not to many coat their own stuff. While things get coated, the coatings might be applied thicker than need be. So for this I use 080-598-180WB 1 3/16"-16 tpi Tap from Brownells to run the threads on the castle nut and lower receiver to clean out the threads from over coating and burs. I use 100-016-681WB AR-15 Buffer Tube Die 1 3/16"-16 on all my buffer tubes. I use 100-016-682WB AR-15 Upper Receiver Die 1 1/4-18" on the barrel nut threads. I use 080-598-528WB 1/2"-28 AR-15/M16 Tap on the Flash Suppressor bird cage, and 080-598-529WB AR-15/M16 Flash Suppressor Die. using these will clean up all threads and everything will mate faster and better.
2. Tolerances:
Ok after the machining process is completed and the part is in its raw state, all tolerances might be into spec. Now they go get coated and depending on who is coating them depends on if they stay in spec. I buy .250 reamers from Pacific Tool and Gauge to run my front and back take down pin holes.
3. SAAMI spec.:
Now I know I'm going to run into resistance on this but this is how it was explained to me by a renown know barrel reamer manufacture. There are 3 types of chamber specs out there. 2 SAAMI and 1 that is what ever the manufacture thinks it need to be. Now with that said, SAAMI has a semi auto spec and a bolt gun spec. Semi auto has to feed and extract automatically. So the chamber is loose. With a bole gun the chamber is tight. That's why bolt gun guys use SB die sets to get down to a tight tolerance for their chambers. I buy reamers for all my barrels just because I found out not everyone corks their barrels before coating. I have found a lot of chambers and land and grooves have been coated in the barrel coating process and I have lost chamber tolerance. A light reaming and polishing is what I do to every barrel before installation.

That's just my 4 cents on the matter. I have fu%$ed up a lot of stuff and had to learn. Just passing it on so you don't waste any of your money on fu$# ups.
Just wanted to make sure everyone here knows this is my info. I am a professional when it comes to putting Ar's together. Everything in this article is from my knowledge.
 

easy rider

Fusion Educator
TGT Supporter
Jun 10, 2015
24,674
113
Odessa, Tx
There are a ton of videos on Youtube. Mostly if you are somewhat mechanically inclined and have a few tools you shouldn't have a problem. You can get specs from the manufacturer.
 

Landrover

Member
Jun 23, 2017
168
28
New York
There are a ton of videos on Youtube. Mostly if you are somewhat mechanically inclined and have a few tools you shouldn't have a problem. You can get specs from the manufacturer.
I was just told I had to tell everyone where I got my info because of plagiarizing issues. I'm trying to be on the up and up.
 

Recon2018

New Member
Jan 9, 2018
16
3
Austin, TX
Curious; does anyone here know how precision shooters "match" bolt to barrel for extreme accuracy/precision? Is it literally, grab a few bolts and hope one is the perfect spec?
 

easy rider

Fusion Educator
TGT Supporter
Jun 10, 2015
24,674
113
Odessa, Tx
Curious; does anyone here know how precision shooters "match" bolt to barrel for extreme accuracy/precision? Is it literally, grab a few bolts and hope one is the perfect spec?
Depends on what you want and how much you want to spend. I have used Ground Zero Precision's "Dead Bolt", one of the sponsors of TGT, and had very good results. My best advice is to research what you are looking for. If you search well enough you can often find good prices.
 

robertc1024

Moderator
Staff member
Moderator
TGT Supporter
Jan 22, 2013
18,251
113
San Marcos
On my only "precision AR" Precision Firearms reamed the barrel to headspace to the Grendel bolt I got as a package.
 

MarkB462

New Member
Oct 26, 2018
30
8
Austin
Ok. I build a lot of ar15's and I have come across a lot of problems everyone needs to know about.
1. Everybody coats differently
2. Everybody has there own idea on what the tolerances should be.
3. Everyone thinks SAAMI spec is SAAMI spec, its not.
Here we go.
1. Coatings:
Almost everyone in the industry sends their stuff out to get coated. Not to many coat their own stuff. While things get coated, the coatings might be applied thicker than need be. So for this I use 080-598-180WB 1 3/16"-16 tpi Tap from Brownells to run the threads on the castle nut and lower receiver to clean out the threads from over coating and burs. I use 100-016-681WB AR-15 Buffer Tube Die 1 3/16"-16 on all my buffer tubes. I use 100-016-682WB AR-15 Upper Receiver Die 1 1/4-18" on the barrel nut threads. I use 080-598-528WB 1/2"-28 AR-15/M16 Tap on the Flash Suppressor bird cage, and 080-598-529WB AR-15/M16 Flash Suppressor Die. using these will clean up all threads and everything will mate faster and better.
2. Tolerances:
Ok after the machining process is completed and the part is in its raw state, all tolerances might be into spec. Now they go get coated and depending on who is coating them depends on if they stay in spec. I buy .250 reamers from Pacific Tool and Gauge to run my front and back take down pin holes.
3. SAAMI spec.:
Now I know I'm going to run into resistance on this but this is how it was explained to me by a renown know barrel reamer manufacture. There are 3 types of chamber specs out there. 2 SAAMI and 1 that is what ever the manufacture thinks it need to be. Now with that said, SAAMI has a semi auto spec and a bolt gun spec. Semi auto has to feed and extract automatically. So the chamber is loose. With a bole gun the chamber is tight. That's why bolt gun guys use SB die sets to get down to a tight tolerance for their chambers. I buy reamers for all my barrels just because I found out not everyone corks their barrels before coating. I have found a lot of chambers and land and grooves have been coated in the barrel coating process and I have lost chamber tolerance. A light reaming and polishing is what I do to every barrel before installation.

That's just my 4 cents on the matter. I have fu%$ed up a lot of stuff and had to learn. Just passing it on so you don't waste any of your money on fu$# ups.
Good info. I've wanted to build one for quite a while now and I'm trying to gather as much information as possible. Trying to find reliable and correct info is the hard part.

Thank you
 

Charlie

TGT Addict
TGT Supporter
Mar 19, 2008
53,821
113
Kerr County
New question. Looking for advice regarding mid-length gas system on an AR. What length works best to be hidden under a 10.5 inch handguard? Mid-length, carbine length, etc.? It will be assembled with an adjustable gas block.
 

toddnjoyce

TGT Addict
Sep 27, 2017
8,984
113
Boerne
New question. Looking for advice regarding mid-length gas system on an AR. What length works best to be hidden under a 10.5 inch handguard? Mid-length, carbine length, etc.? It will be assembled with an adjustable gas block.
Carbine definitely, maybe mid. What’s the barrel length? Even with adj blocks, I’ll lean towards a longer gas system unless 300BLK, which always gets pistol.

https://www.at3tactical.com/blogs/n...-rifle-a-beginner-s-guide-to-ar15-gas-systems
 

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