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Need advice with barrel replacement |
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Posted: Oct 30 2019 at 10:11am |
Something I've never done before, I am
installing a barrel (UEF) into a receiver (Rock-Ola SN 1719792). See photo of it
handtight.
Per instructions in Rob Clark's video, I cleaned the shoulders and threads REAL GOOD, wire brushed and inspected. I did an initial hand tightening and the barrel rotated to the location shown in my photo. I compared this position to the one shown in the video and it was short. So I filed just a little off the skirt as the video explained. I did another hand tight and the barrel did not rotate any further, so the skirt is not the limiting factor. The base of the barrel appears engaged with the seating area of the receiver. Question: Has it rotated enough in this position to continue rotating it to line up the index marks? I have the proper tools: barrel vice, and wrench. Would appreciate your opinion please, and thanks much. |
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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Charles
Grunt Joined: Mar 21 2016 Location: Maryland Status: Offline Points: 587 |
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I once had a problem like this. Unscrew the barrel slowly and listen for the click of the last thread of the barrel clearing the breach. Stop. Pushing the barrel in and SLOWLY continue turning the barrel, listen for another click. Then screw the barrel in again and see if that makes any difference to the aliment marks. If there is a difference but still not right on, repeat the above until the marks are about 1/8" shy of the marks and finish with the barrel wrench. Good luck.
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Charles
Co B 1st Batl.115 Inf. Reg. 29th. Divi. 4.2 Heavy Mortar Co Retired Life member NRA |
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J D Shelby
Recruit Joined: Oct 24 2019 Location: 23702 Status: Offline Points: 11 |
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The new barrels I have installed have stopped at about the same location I lubed them up and cranked until they indexed. Rest assured both were difficult and indexed when I stood on the wrench handle.
My receiver wrench is a 2 piece and goes around the entire receiver i had the barrel vise clamped in a heavy duty vice. I have also replace barrels that indexed turning by hand because someone either machined or filed on the barrel shoulder, I had to have shims made for it.
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Molon Labe
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Charles,
Attempted the procedure 3 or 4 times. Heard no clicks. Indexing did not improve. Many thanks for the input though.
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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GotSnlB28
Hard Corps Joined: Jan 01 2016 Location: WI Status: Offline Points: 892 |
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I've only barreled a few up but hand tight was about where yours is. One was a little stubborn and I needed a 12in cheater pipe over the wrench handle to get the job done. My wrench is a 1 piece and I shim the sides with strips cut from a pop can so there is no play. It's a bit of a nerve-wracking job.
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floydthecat
Hard Corps Joined: Oct 13 2016 Location: Mississippi Status: Offline Points: 1996 |
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Where are you Ted Syme?
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kro1970
On Point Joined: Jan 01 2016 Location: Central Florida Status: Offline Points: 301 |
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That looks correct to me and should index without a problem. I would not file anything and would be more concerned if it hand tighten closer to the index marks.
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manteo97
On Point Joined: Jan 15 2016 Location: Victoria, B.C. Status: Offline Points: 61 |
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Agree with both kro 1970 and JD Shelby. "Hand tightening" is very subjective, ie my little gurlie like hands vs. my pipeline welder buddy....I use an adjustable wrench to hand tighten. I use a custom made receiver wrench with a 3' extension, clamped in a heavy duty vise with a few special clamps to squeeze the jaws tight. Have done about 50 barrel replacements. |
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Thanks for the encouragement. I'll give it a shot with what I have.
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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J D Shelby
Recruit Joined: Oct 24 2019 Location: 23702 Status: Offline Points: 11 |
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use caution and make sure you have the wrench aligned proper a fellow on the CMP forum crushed the spring tube on a receiver not sure what he did but I can see it happening with some of the wrenches out there.
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Molon Labe
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Thanks for the advice, Malon
I bought the tools from Brownells and they are suppose to be some of the best. I'll be sure to take caution of where I place them on the BR.
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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jackp1028
Hard Corps Joined: Jan 01 2016 Location: Cloudcroft, NM Status: Online Points: 1273 |
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@Colreed, could you check the headspace at finger tight and then again at the index mark to see if there is much difference? Just curious.
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JackP
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Sure, Jack
Be glad to. Might be a while. Not quite ready to do the job. But I'll get back to you. Reed
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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blackfish
On Point Joined: Mar 30 2016 Location: 999-0 Status: Offline Points: 289 |
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Jackp1028, you could easily figure out on paper how much headspace varies per degree or ten of rotational offset given that the barrel/receiver threads are 20 per inch. It's not very much.
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jackp1028
Hard Corps Joined: Jan 01 2016 Location: Cloudcroft, NM Status: Online Points: 1273 |
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@ blackfish, so if 1 divided by 20 equals .050" per turn and, per the OP's image which looks like more than 1/8th of a turn, the change is greater than .00625". The difference between "Go" and "No Go" per TM-9-1276 is only .005". I am curious if this is what he actually sees. It might make the difference between having to finish ream the chamber or possibly having excessive headspace. Like I say, I'm just curious.
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JackP
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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JACKP
Success. I got the barrel on and lined up good. Before I did, I made some headspace tests with three different bolts using Clymer gauges. Then I made the same test after aligning the index marks. Surprising to me was that the little bit of barrel rotation I made affected the headspace more than I thought. In fact, it made the difference between pass or fail with the no-go guage. See the following chart for the results. Thanks everyone for your interest and advice. |
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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floydthecat
Hard Corps Joined: Oct 13 2016 Location: Mississippi Status: Offline Points: 1996 |
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Interesting. The unmarked bolt seems to be the tightest, if I interpret the data correctly. Could you determine if it was for-sure USGI or commercial? Reason for asking is that I have discovered Iver Johnson bolts in particular seem to run .003 to .004 longer from face-to-face.
I have an IJ 9mm and hardened it with a GI bolt and discovered the two modified GI bolts were shorter than all three IJ bolts I have. I certainly don’t recommend one should put commercial bolts in GI guns, but if one had a carbine with long head-space, it would be worth a try. Just an observation.
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jackp1028
Hard Corps Joined: Jan 01 2016 Location: Cloudcroft, NM Status: Online Points: 1273 |
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@colreed, thank you for sharing this data. I was concerned that there might be even more of a difference than one might expect because of the of the possible plastic deformation of the threads and shoulder under the crushing force of the torque required to reach the index mark. 1/8 to 1/4 of a turn is quite a bit. Do you have any idea how much torque it actually took to to reach the index mark? Also, did you use any lubricant or anti-seize?
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JackP
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colreed
Grunt Joined: Feb 15 2016 Location: Hockley, TX Status: Offline Points: 450 |
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Jack, I applied
some anti-seize to the threads and it torqued to the index mark easier than I
imagined it would. I don't think it was abused during the process. I didn't
measure the torque and didn't use a cheater bar. I did lean pretty hard on the
short wrench handle, but had the idea that the anti-seize helped quite a bit.
No way to know for sure now. Floydthecat
asked about my un-coded round bolt. I can't tell for sure it is commercial or
not. There are NO MARKINGS of any kind. Below are some comparison photos of it
with the Win bolt. There are some obvious differences in the manufacturing, but
weight and over external measurements were identical.
Length circumference
lug-to-lug (outside) weight Win
bolt 3.133
0.556
1.070
80 grams Un-coded
3.133
0.556
1.070
80 grams There
was, however, an obvious difference in the firing pin cut as shown by the
photo. Win
bolt 0.530 Un-coded
0.566 Why this
is.....I don't know. I referred to the CCNLs for a possible explanation and
only found NL 370 which spoke of some round bolts that were mfg without the
incorporation of all the design changes approved for the round bolt. I believe
these were sometime marked with an X but the mfg code was still on the bolt.
Obviously this in not the case here. Maybe another member has some info on
this. photo two photo three photo four photo five |
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"Rescuing one animal may not change the world, but for THAT animal, THEIR world is changed forever"
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ncin1911
On Point Joined: Dec 13 2018 Location: Hoosier State Status: Offline Points: 435 |
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Looks like might be cast bolt. Iver Johnson? I am sure someone on here will chime in with the answer.
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