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Posted: 4/18/2024 10:42:32 PM EDT
Tonight I was attempting to fit a barrel into an upper with a really tight fit. The manufacturer even sent a note with the upper, advising to apply heat to help the barrel fit. It helped a bit, but I could get the barrel in all but a 1/8" by using a wood block to tap the barrel in. I cannot get the barrel on any further, so I'm planning on removing the barrel then trying again after removing some material from inside the receiver. I greased up the barrel before inserting it so it's not bare metal on metal.
What is a good way to remove a barrel that's really stuck? I'm going to buy a 1" dowel tomorrow and try to tap it out. Any other advice would be appreciated. |
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I have a plastic round I use now. In the past I have used an inverted socket sized to fit in the upper on a long extension or two.
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Originally Posted By j3_: I have a plastic round I use now. In the past I have used an inverted socket sized to fit in the upper on a long extension or two. View Quote Success! I found a deep well socket that mic'd close to 1" diameter, and an extension long enough to stick out of the receiver. I placed the receiver block in the vise with the barrel pointing down, then tapped on the extension until the barrel was free. |
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Wouldn’t it be better to remove material from the outside of the barrel extension as that’s the replacement part as opposed to the receiver which is the permanent part?
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Originally Posted By Princeton: Wouldn’t it be better to remove material from the outside of the barrel extension as that’s the replacement part as opposed to the receiver which is the permanent part? View Quote I subscribe to the idea of altering the cheaper part over a more expensive part. I got the BCM upper for $50 and the BA barrel for $130. |
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Do not remove material!
1. Put the barrel in the freezer for an hour. 2. Heat up the bare receiver with a heat gun until you need gloves to hold it. 3. Fast as you can, grab them both and slip the barrel in with one quick motion Piece of cake. To keep from marring your barrel extension with a hardened socket use a short stick of 1/2” sch40 PVC and a mallet to remove tight barrels. I do this all the time (insertions and removals of very tight barrels). Tight is good. |
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Did you apply Shell Aero 33 to the outside of the extension to help it slide in? Or did you try to go in dry?
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A section of Delrin round is good kit to have on hand for next time.
Heat the "nose" of the receiver prior to assembly, the barrel extension will slide in. A handheld torch or heat gun is all it takes. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
Did you apply Shell Aero 33 to the outside of the extension to help it slide in? Or did you try to go in dry? View Quote Yes. I used anti-seize compound. The fit is so tight going bare metal on metal would be impossible. Heat the "nose" of the receiver prior to assembly, the barrel extension will slide in. A handheld torch or heat gun is all it takes. View Quote I heated the "nose" of the receiver per the note that came with the receiver. As mentioned, I got the barrel inserted to the point before the index pin would mate, then it wouldn't go any further. I have not tried freezing the barrel before inserting it yet. I understand with this upper a tight fit is expected and heat is recommended. The issue is it's tight AF and with no amount of heat would've made it slip in. My goal is to remove just enough material it will slip on while heated. |
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Originally Posted By Moondog: Yes. I used anti-seize compound. The fit is so tight going bare metal on metal would be impossible. I heated the "nose" of the receiver per the note that came with the receiver. As mentioned, I got the barrel inserted to the point before the index pin would mate, then it wouldn't go any further. I have not tried freezing the barrel before inserting it yet. I understand with this upper a tight fit is expected and heat is recommended. The issue is it's tight AF and with no amount of heat would've made it slip in. My goal is to remove just enough material it will slip on while heated. View Quote Sounds like the receiver wasn't hot enough. EDIT: I misread, you mentioned material removal at receiver not extension. My bad. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
Originally Posted By TGWLDR: Sounds like the receiver wasn't hot enough. I wouldn't remove material at the extension personally. View Quote View All Quotes View All Quotes Originally Posted By TGWLDR: Originally Posted By Moondog: Yes. I used anti-seize compound. The fit is so tight going bare metal on metal would be impossible. I heated the "nose" of the receiver per the note that came with the receiver. As mentioned, I got the barrel inserted to the point before the index pin would mate, then it wouldn't go any further. I have not tried freezing the barrel before inserting it yet. I understand with this upper a tight fit is expected and heat is recommended. The issue is it's tight AF and with no amount of heat would've made it slip in. My goal is to remove just enough material it will slip on while heated. Sounds like the receiver wasn't hot enough. I wouldn't remove material at the extension personally. This. I’ve shimmed quite a few extensions with SS shim stock and gotten things very tight. My method is usually to install one of those rubber muzzle/thread protectors on the muzzle end of the barrel and place it muzzle down on a block of wood. Then I’ll use another block of wood on the rear of the receiver and lightly tap the rear of the receiver until they’re mated. Make sure the index pin and index pin slot are aligned before doing this or you’re going to have to hammer everything back apart. Conversely, I’ve also used the barrel nut to draw both together if they’re fairly close. Once again, ensure the pin/notch are lined up or you’re going to damage something. |
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Small toaster oven for the receiver and throw the barrel in the freezer for a couple hours. It will slide together perfectly.
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Originally Posted By TGWLDR: Sounds like the receiver wasn't hot enough. I wouldn't remove material at the extension personally. View Quote Ding ding ding! We have a winner! The idea of removing material when you have a thermofit upper is a bad idea. If you don’t have a heat gun, you likely don’t have the tools to remove any material evenly. |
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More success! After a little bit of polishing with emery paper, I heated up the upper and the barrel slid in! The was a little resistance, but a tap with the rubber mallet resolved that.
I didn't have to remove much - a couple passes until the anodizing was smooth where the barrel contacted the receiver. An interesting note is I discovered my Magpul BEV block is very heat resistant. I heated the nose of the receiver until it was too hot to touch, and the BEV block held up. I figured the retaining pin would've melted. |
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next time put the barrel in the freezer for 2 days AND heat the receiver. done.
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The receiver is aluminum.
It will expand faster than steel. Just heat it more. Some of the responses in this thread are literally making my head spin. Removing material is NOT needed. A little more heat is. Last build I did was a reduced I.D. upper (solgw) and an oversized barrel extension. Heat was all that took, and that one wouldn’t go in at all without it. The reason it gets stuck the further you go in is because there’s more material there (top rail, bottom lug). Just need to add a touch more heat. Great shooting upper. No need to freeze anything, just hit the upper with a torch and call it a day. |
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@Moondog. Was your upper a $50 blem? Mine was also tight and I ended up running a hone inside.
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When I use to work in a machine shop. When we did tolerance we would do the cold part in dry ice. Hot part in oven. This would get 2 pieces that weren’t even close to fitting. To slide in easy. Just be quick.
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Originally Posted By OTDR: I wish people would stop posting this nonsense, its been debunked many times. My testing confirms, freezing the barrel extension does nothing . Just heat the upper. https://i.imgur.com/jw9tCw9.jpeg https://i.imgur.com/gTZgxu9.jpeg https://i.imgur.com/MymSERJ.jpeg https://i.imgur.com/BTwm7Vb.jpeg View Quote Originally Posted By ajclune: When I use to work in a machine shop. When we did tolerance we would do the cold part in dry ice. Hot part in oven. This would get 2 pieces that weren’t even close to fitting. To slide in easy. Just be quick. View Quote Home freezers at 0- minus 10ish degrees never did shit for contracting steel dimensions IME. Dry ice on the other hand has been useful in several instances. Edited. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
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Originally Posted By OTDR: Exactly, it does nothing yet people keep posting it does. View Quote View All Quotes View All Quotes Originally Posted By OTDR: Originally Posted By TGWLDR: Home freezers at 0-10ish degrees never did shit for contracting steel dimensions IME. Dry ice on the other hand has been useful in several instances. Exactly, it does nothing yet people keep posting it does. Edited my post for clarity. But yeah, heating the receiver to proper temp is all that is needed. |
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Can't never could 'til try came along.
"All welchers should be removed from the EE".-Aimless R.I.P. to the EE |
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Originally Posted By TGWLDR: Home freezers at 0- minus 10ish degrees never did shit for contracting steel dimensions IME. Dry ice on the other hand has been useful in several instances. Edited. View Quote 10-4. I have used liquid nitrogen multiple times to contract bushings for heavy equipment. Let them boil in a styrofoam cooler for 5 minutes and they slide right in by hand. But yes, as mentioned above, a home freezer does nothing. |
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Originally Posted By OTDR: I wish people would stop posting this nonsense, its been debunked many times. My testing confirms, freezing the barrel extension does nothing . Just heat the upper. https://i.imgur.com/jw9tCw9.jpeg https://i.imgur.com/gTZgxu9.jpeg https://i.imgur.com/MymSERJ.jpeg https://i.imgur.com/BTwm7Vb.jpeg View Quote damn. learned something new. ive always just done this and had no issues so I always thought it worked. thanks! |
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