Glue together light weight rimfire AR barrel

[55fairlane]

Before we get into the barrel, I want a national rimfire sporter championship so bad I can taste it. The CMP has really put the "screws" to us in making sure no high dollar target rifles show up, the CMP wants this to be a shooters match not an equipment race. In particular rifles are limited on weight, this does cause problems, we will work around this.
This year there were 712 people in the nation match with 131 in my division (tactical unlimited) I shot my way to a 9th in my division and a 17th overall, Here are so e pictures.

 

[55fairlane]

Ok , to light up my new build I started by making an aluminum barrel nut. This nut holds the barrel into the upper and gives the Han gaurd someplace to bolt to.
The grey color is after I had it hardcoated. This knocked off almost 1¾ pounds. Darn things are heavy, but I'm trying to hold a full pressure 5.56 round...

 

[55fairlane]

Ok, next step, light weight barrel. I thought about turning down my current barrel, but ruled against that, my current set WILL SHOOT, and I did not want to jeopardize set up. The down side to my current set is, I am right on the max weight allowed, so the rifle is a little front heavy & the rifle on shoots high velocity ammo.
I know the CMMG style bolt carrier group will run on standard velocity, after looking on the CMMG website, they freely publish the barrel detail for there barrel to bolt dimensions, I printed out that print and ordered a bolt

 

[55fairlane]

Now is where the fun begins, I weighed my old barrel and started doing to calculations, and I determined that a 9/16 outside diameter barrel 18 inches long will come in at the weight I want, but the barrel to upper trunion needs to be aluminum, but how to hold it to the barrel? If 648 Loc-tite will hold a rimfire barrel liner in place it will hold this together, and a call to Loc-tite verified that

 

[55fairlane]

I choose a "bentz " reamer, please note the floating chamber reamer holder, A) I made B) was on the cover of machinist workshop magazine
I trued up the barrel, turned the bolt register area, and a 9/16 diameter (to hold on in a collet), chambered, & finally profiled the barrel

 

[55fairlane]

Seeing how the barrel will be a "straight taper" I will crown the barrel in a collet

 

[55fairlane]

Next, turning the aluminum trunion, Loc-tite to the barrel, and make the extractor cuts

 

[55fairlane]

The rifle runs fine on CCI standard velocity, but I have not shot for groups...yet. just function fired the gun. I did have to break the edge where the chamber meets the break face

 

[Packard V8]

I know less than nothing about the class you're shooting, but what about it makes an autoloader the choice?

shooters with manually operated actions are given extra time in rapid-fire to compensate for the difference.

jack vines

 

[55fairlane]

I know less than nothing about the class you're shooting, but what about it makes an autoloader the choice?


jack vines

Thee auto loader is the choice because you never "brake position " to operate the bolt and cycle the rifle. This is especially helpful during your "rapids" we shoot 2 5 shot strings rapid, including offhand. The auto loader allows for quicker follow-up shots. Even in the slow fire section