Truing a new AR receiver

[FMJBT]

I have heard of people going this route before. When you say, "interesting", how interesting are we talking?

To get the old barrel out, you'll need a propane torch or heat gun to get it up to around 350-400 degrees, then a wooden or nylon dowel to insert from the back of the receiver to tap out the barrel using a hammer or dead blow mallet. Have an assistant standing by with gloves to catch the barrel when it comes loose.

Most of the time this procedure works pretty well. Just make sure when you install the barrel that none of the Loctite gets on the barrel nut threads. If that happens it takes a lot of heat for a longer period to get everything taken apart, running a higher risk of changing the heat treatment of the receiver and/or barrel. Receivers typically are not very expensive though compared to barrels and the cost of enough ammo to burn up a barrel. I tend to think of the upper receiver as a consumable part, especially on bedded rifles.

[steelheadmike]

Along the lines of the other thread, your ability as well as ammo selection/quality will be the biggest variables with regard to accuracy. There's a long road with lots of hurdles before you worry about lapping the face of a receiver (especially an Aero).

Just about any old free floated upper should the get close to MOA with good rest, good ammo, a good shooter, and a decent trigger.

[milotrain]

I have heard of people going this route before. When you say, "interesting", how interesting are we talking?

When you rebarrel do you want to put a torch on the upper and barrel junction until it smokes? If no then don't do this.

[flyboy3394]

If you are a good shot, your components will give you the results you want, especially for the money you seem to want to spend.

What you won't get with your components are the absolute tightest groups possible with the AR platform. You will have to invest much more research, time and money into your rifle, ammunition, and shooting skills in order to reach the fabled point of diminishing returns. And at that point, you also won't be here asking us goons what works best.

I mean, I already bought everything I need. Just waiting for it all to arrive. All I need now are the barrel and a muzzle device. And yeah, not quite to that point yet. Don't have a ton of money and time to get to the point of diminishing returns. Just want something that goes pew and will give me at most 1moa.

[flyboy3394]

When you rebarrel do you want to put a torch on the upper and barrel junction until it smokes? If no then don't do this.

Sounds like something i should just send to Randall to do, along with the new barrel to be fitted.

[ar15barrels]

Is there a way to check the true-ness of the receiver when I get my barrel?Some formula or tool?

[Rusty_Shackleferd]

Neat. I wish I had my own lathe.

[milotrain]

Sounds like something i should just send to Randall to do, along with the new barrel to be fitted.

If you are buying it all as parts then you should do this. First because you will want the barrel and bolt checked for headspace anyway, so you might as well get the face cut while it's there. It's easier to just skim cut the face than to measure it and see if you need to skim cut the face. Second because it's cheaper unless you already have all the proper tools. The tools are not expensive but combined with headspace gauges, etc it will end up costing more than sending it to a gunsmith to take care of.

[flyboy3394]

If you are buying it all as parts then you should do this. First because you will want the barrel and bolt checked for headspace anyway, so you might as well get the face cut while it's there. It's easier to just skim cut the face than to measure it and see if you need to skim cut the face. Second because it's cheaper unless you already have all the proper tools. The tools are not expensive but combined with headspace gauges, etc it will end up costing more than sending it to a gunsmith to take care of.

I mean I have the tools to take down and put together any part of an AR, but I guess my concern is whether i could do it well enough myself. My guess is no, so I will probably be sending it off to Randall, since I have heard such great things about his work.

[Glockrocks]

Here's the upper I went with, supposedly it's trued so all I need to do is finish building it and try it out. I posted a link to the one I bought, but I did not buy it from this vendor.

http://bpoutfitters.net/RainierArmsUltraMatchBilletUpper

[ar15barrels]

It's unlikely that the Aero is far out if out at all, if it is out of true then you should have it turned true on a mandrel fit to the bore of the receiver.

I have yet to find a forged AR receiver with a perfectly flat front face while checking face runout.
Most have about 0.001" to 0.002" of runout and I check/correct them all the time.

The only receivers I have ever found to consistently have a flat front face are Vltor MUR's which are billet receivers.

[milotrain]

I have yet to find a forged AR receiver with a perfectly flat front face while checking face runout.
Most have about 0.001" to 0.002" of runout and I check/correct them all the time.

The only receivers I have ever found to consistently have a flat front face are Vltor MUR's which are billet receivers.

Maybe the more correct statement is I've never felt that I needed to true any of my receivers, they've all shot well enough for me (between 1/2 and 3/4MOA) and they have all been quality. Indeed I would be surprised if they had less runout than one or two thou. So to me that functions as "true" for this application. I would fix it if visually you could see that it was not true, otherwise I'd leave it alone unless you were building a special snowflake upper.

I'd also true it if I didn't have a pile of projects that I'd rather do instead of making a mandrel to true AR15 upper receivers.

[ar15barrels]

Maybe the more correct statement is I've never felt that I needed to true any of my receivers, they've all shot well enough for me (between 1/2 and 3/4MOA) and they have all been quality. Indeed I would be surprised if they had less runout than one or two thou. So to me that functions as "true" for this application.

Vltor MUR's usually show about 0.0003" of face runout.

[milotrain]

Vltor MUR's usually show about 0.0003" of face runout.

I'll happily admit that I don't have the hardware or the patience to actually measure that.

Turn a mandrel on centers, stick it on matched v blocks and spin it? Somehow index the tail end so it doesn't move in thrust? Hell my lathe's bearings have at least .0005" of runout.

I'm good, the last time I didn't clean an MR31 or an MR was not the rifle's fault. Good to know about Vltor MURs for building a match gun though.