Just a thought. Thinking about various methods of bedding an AR barrel it occurred to me that a few warm up shots create enough heat expansion to secure the same effect as bedding or an interference fit. What do you guys think?
AR barrel bedding
- Thread starter daddyscleo
- Start date
LVLAaron
Gold $$ Contributor
All of mine are bedded.
Historic floods and Nessie kept me out of the home range this weekend, so I thought I'd work on something a little different.
Thought I'd take this beater AR I built a barrel for and would try and improve it. Bushed the takedown pin holes and adjusted location to take up the slop between the upper and lower. Now she's tight as a glove.
Next challenge is getting a Rifle-1" straight gas tube to fit the adjustable gas block I have for this. :|
Thought I'd take this beater AR I built a barrel for and would try and improve it. Bushed the takedown pin holes and adjusted location to take up the slop between the upper and lower. Now she's tight as a glove.
Next challenge is getting a Rifle-1" straight gas tube to fit the adjustable gas block I have for this. :|
-1 or +1?All of mine are bedded.
Historic floods and Nessie kept me out of the home range this weekend, so I thought I'd work on something a little different.
Thought I'd take this beater AR I built a barrel for and would try and improve it. Bushed the takedown pin holes and adjusted location to take up the slop between the upper and lower. Now she's tight as a glove.
Next challenge is getting a Rifle-1" straight gas tube to fit the adjustable gas block I have for this. :|
If never heard of -1 rifle has system.
Rifle speed has straight gas tubes
LVLAaron
Gold $$ Contributor
-1
www.whiteoakarmament.com
18-Inch Varmint Uppers, 1-8 Twist (.223/5.56)
18 inch Varmint Upper 223 556 1-8 twist
www.whiteoakarmament.com
Me comprende now.-1
18-Inch Varmint Uppers, 1-8 Twist (.223/5.56)
18 inch Varmint Upper 223 556 1-8 twist
I can see a short rifle gas being nice on an 18”.
rickiesrevenge
Silver $$ Contributor
What recievers require heat to install a barrel?
Depends on your barrel extension
You would need to shoot a lot to get the chamber end hot enough to expand very much. Would you want the rifle to be inaccurate or have a drifting zero until it warms up? Blue Locktite always worked well for me. Lots of over thinking about this imo.
LVLAaron
Gold $$ Contributor
BCM are heat to fit uppers.
White Oak sells oversized barrel extensions, they are heat to fit by proxy.
Don't mix the two.
This has all been tried before. Some say do it and some say it doesn't matter. I have never seen a difference on target, except for when bedding the back of the upper receiver to the lower. That did make a bit of difference in reducing elevation dispersion. For the average shooter, it will not make any noticeable difference.
Not being a builder of rifles, I can only speak from experience from shooting. My Colt A2 in 5.56 shoots 1" average at 100 yards with hand loads. My Aero Precision M4E in 6 ARC shoots an average of 1/2" at 100 yards with 105 Hornady match. I've seen AR 15's in 6 ARC that cost more than twice as much as my Aero and shoot .4", .5" groups with 105 match ammunition.
For me an additional $1,500 will not serve me at all. If I can establish, even a lean to rest I can hit a deer in the head at 300 yards in just a few seconds. For a rifle and scope that was just under $2,000 do I need more?
With that said the rifle gets carried more than shot.
^^^^^^
As well as centurion receivers.
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There are many long threads about this. The options are a tighter barrel extension, a tighter thermal fit upper, or some type of bedding compound.
I have used the BCM thermo-fit uppers. It is a TIGHT fit, think you better put the barrel in the freezer, and use a powerful heat gun on the upper, and some grease.
If you don't want to go through the trouble, use some Loctite 660 gap filling bedding compound.
Then there is the school of thought that with an appropriately torqued tight barrel nut, it doesn't matter. Truthfully I haven't objectively tested it either way.
I have used the BCM thermo-fit uppers. It is a TIGHT fit, think you better put the barrel in the freezer, and use a powerful heat gun on the upper, and some grease.
If you don't want to go through the trouble, use some Loctite 660 gap filling bedding compound.
Then there is the school of thought that with an appropriately torqued tight barrel nut, it doesn't matter. Truthfully I haven't objectively tested it either way.
jelenko
Gold $$ Contributor
Yeah!
JaoeyP
Silver $$ Contributor
I think you'll have the best results on an AR15 platform using the highest quality barrel you can afford paired with an upper receiver that separates the attachment of the barrel from the mounting of the handguard. I have a 6 Arc I built that had a noticble shift going from bipod/rear bag to shooting off just a bag on a barricade.
Some of the uppers that do this are the Aero enhanced upper and Seekins Precision. There are more options I can't recall at the moment.
If you're not worried about positionally induced impact shifts, just focus on the best barrel you can afford. Getting a quality bolt that is headspaced to your barrel is even better. I spent the money to get a Bartlein with fitted JPE bolt when Compass Lake was still making barrels for the consumer market and have zero regrets. I believe you can get Craddock to spin a Bartlein still. Thing is wonderfully precise. XCaliber and Criterion seem to also be good options for the AR.
No! First it is not a consistent and controled process. There is no way to make it a consistent process.
This is not a complicated or expensive thing to do. Shimming the barrel is cheap and easy.
The process of using Loctite 609 is also well established and it is also used on damaged crank pulley knose or harmonic balancer knose in a pinch to repair a damaged surface for sealing with out machining to press on a crank saver or similar. I use shims but I have known people that have used the Locite method that is building on the part to change diemensions not at all like using Loctite Thread Lockers.
You used to be able to purchase sleeves as well but I do not think Borden makes them any more. I think it was Borden.
Before the Youtube National Socialist changed their rules which is seems to be hourly now there where even video's showing you how to do it. I sure they are still on the internet just not on youtube.
If you have the tools and have ever rebarreled an AR this is not something that should scar you. Just take your time and go slow.
The thermal conductivity of aluminum is about 10x that of stainless steel, and the thermal expansion coefficient of aluminum is about 4x that of stainless steel. The heat transfer coefficient of steel to aluminum is very high, only slightly lower than that of steel to water. So if the barrel extension were heated to the point of expanding in size, the contacting receiver mortise would expand MORE and actually become looser than the cool state. This is why creating the tight, consistent bedding fit between barrel extension and receiver is important.
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