AR Accurizing

[LVLAaron]

Historic floods and Nessie kept me out of the home range this weekend, so I thought I'd work on something a little different.




Thought I'd take this beater AR I built a barrel for and would try and improve it. Bushed the takedown pin holes and adjusted location to take up the slop between the upper and lower. Now she's tight as a glove.








Next challenge is getting a Rifle-1" straight gas tube to fit the adjustable gas block I have for this. :|

 

[Bamban]

Unsolicited input.

Worth the short read. Check out the bcg tilt section. Would like to hear your opinion. I have a different solution from his.

Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half. - Free Online Library

Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half. - Free Online Library

Free Online Library: Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half.(TECH TOPICS) by "American Gunsmith"; Sports, sporting goods and toys industry Sport, sporting goods and toys industry

www.thefreelibrary.com

 

[Fast14riot]

One functionality tip on gas tube fitment, I always put a drop or two of blue locktite where the tube enters the gas block. Seals it nicely to prevent blow by and short cycling.

 

[LVLAaron]

Unsolicited input.

Worth the short read. Check out the bcg tilt section. Would like to hear your opinion. I have a different solution from his.

Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half. - Free Online Library

Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half. - Free Online Library

Free Online Library: Maximizing The AR-15: A former military armorer reveals his secrets for cutting AR-15 group sizes in half.(TECH TOPICS) by "American Gunsmith"; Sports, sporting goods and toys industry Sport, sporting goods and toys industry

www.thefreelibrary.com

Interesting read. I haven't had any thoughts about the carrier fit other than I know it's gonna be sloppy. I plan on checking the lug contact and hand filing/lapping if it's bad.

 

[Bamban]

I sleeve the tail and cut the slot for the tube pin. Bore the buffer tube for proper clearance. Final home the tube with brake cylinder hone.

 

[jds holler]

Couldn't ya just put some kinda Creedmoor barrel on it and call it good? jd

 

[LVLAaron]

I sleeve the tail and cut the slot for the tube pin. Bore the buffer tube for proper clearance. Final home the tube with brake cylinder hone.

View attachment 1649766View attachment 1649767

What material are you using for the sleeve? I love this

 

[Bamban]

SS. Bore and turn as needed for clearance. They are JB welded to the tail. Here are a couple close ups.

 

[RPSGuns]

SS. Bore and turn as needed for clearance. They are JB welded to the tail. Here are a couple close ups.

View attachment 1649776View attachment 1649777

I did this to one of mine and it made a huge difference.

 

[LVLAaron]

What OD do you aim for on your sleeve?

 

[Bamban]

What OD do you aim for on your sleeve?

They vary depending on the upper for slip fit

 

[whatsupdoc]

I did this to one of mine and it made a huge difference.

Can you elaborate on huge difference? Group size?

 

[LVLAaron]

This is an interesting no name upper for the project. The bore is 1.012+- (Spec is 1.000 +.006)

 

[whatsupdoc]

In my experience building an accurate AR the barrel is the most important part
followed by a stiff heavy walled upper to reduce flexing. A good trigger and
of course good ammo. There are other "things" you can do to improve accuracy but most shooters will not see the improvement.

Next is the nut behind the wheel, if you cannot control the trigger everything else
is a moot point.

 

[LVLAaron]

I'm definitely a nut.

 

[DR_2297]

I sleeve the tail and cut the slot for the tube pin. Bore the buffer tube for proper clearance. Final home the tube with brake cylinder hone.

View attachment 1649766View attachment 1649767

What clearance are you targeting Nez?

 

[RPSGuns]

Can you elaborate on huge difference? Group size?

Went from roughly 2" groups to just under 1". After tightening the upper and lower fit and tuning the gas tube, I've got it down to .5 moa.

 

[jelenko]

Went from roughly 2" groups to just under 1". After tightening the upper and lower fit and tuning the gas tube, I've got it down to .5 moa.

How was the rifle held while firing?

What did you do to tune the gas tube?

 

[RPSGuns]

How was the rifle held while firing?

What did you do to tune the gas tube?

It was shot with front bipod and rear bag. I guess I should also note the groups were only at 100yds. I have not shot it further than that.
I tune the gas tube by making small bends so that the tube can enter the gas key without it making contact as it enters the key, lots of bend, test, bend involved. It probably took me an hour and a half to get it adjusted to where I like It. The upper and lower were tightened by using the Accu-shim. I also bedded the rear lug on the upper to help with any side to side movement.

 

[DR_2297]

I always think all of the voodoo with service rifles is of diminishing returns. Do nothing but use good parts and a good quality well machined barrel with decent ammo and 3/4 moa 20 shot groups from a rest is pretty achievable. That’s kind of the gold standard for high power competition. I’ve had some better but could never quantify why.