Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Site Notices
11/22/2017 10:05:29 PM
Posted: 9/18/2004 4:37:22 PM EST
I just got my DPMS high rise upper switched with a CMT A3 upper. When I pull the bolt back it is really stiff and hard; when I release it is fine; just really hard to pull back.

Any reason why this is happening? I am using a DPMS carrier/bolt.

When I dry fire it, it function properly.

This did not happen before the switch.

Any suggestions?

Thanks,

Mac
Link Posted: 9/18/2004 4:45:37 PM EST
Can you feel anything rubbing. It is possible that the upper and lower are slightly out of alignment and the resulting drag is the cause of the increased resistance. Look inside your buffer tube for new scratches/gouges.
Link Posted: 9/18/2004 4:47:47 PM EST
Things not lining up? Is the carrier draggiing the buffer tube?

I have CMT uppers on Bushmaster lowers with no issues. Although I believe CMT makes BM uppers and lowers.
Link Posted: 9/18/2004 4:48:51 PM EST
[Last Edit: 9/18/2004 4:51:27 PM EST by M11293]
When I seperate the upper/lower and take the bolt out with the charging handle it sticks. When I take the bolt/carrier out without the help of the charging handle it slides like glass.

Does this help?

ETA: The front take down pin is a little stiff coming out.
Link Posted: 9/18/2004 5:02:48 PM EST

Originally Posted By innocent_bystander:
Things not lining up? Is the carrier draggiing the buffer tube?

I have CMT uppers on Bushmaster lowers with no issues. Although I believe CMT makes BM uppers and lowers.



How do I check if it is dragging the buffer tube?
Link Posted: 9/18/2004 5:31:43 PM EST
How do I check for upper/lower alignment?
Link Posted: 9/18/2004 5:40:13 PM EST
I checked the buffer tube and nothing was wrong, smooth as can be.

SOMEONE HELP ME!!!!
Link Posted: 9/18/2004 5:44:07 PM EST
Remove the upper. Remove the charging handle. Now replace the bolt and cariier. Slide it in and out with your finger and feel the bolt cam to lock. How does that feel?
Link Posted: 9/18/2004 5:48:23 PM EST

Originally Posted By innocent_bystander:
Remove the upper. Remove the charging handle. Now replace the bolt and cariier. Slide it in and out with your finger and feel the bolt cam to lock. How does that feel?



It locks quite easily. Anything else I should look at?
Link Posted: 9/18/2004 5:52:50 PM EST
Try running the charging handle back and forth in the receiver. Look inside and see if there is any bare aluminum where it looks as though something is rubbing...specifically the charging handle.
Link Posted: 9/18/2004 6:02:01 PM EST

Originally Posted By Bradd_D:
Try running the charging handle back and forth in the receiver. Look inside and see if there is any bare aluminum where it looks as though something is rubbing...specifically the charging handle.



All is fine. The charging handle runs smoothly and the carrier runs smoothly if they are by themselves. If they are together then they get sticky. I have used these same charging handles and bolt carrier/bolt together in the previous upper.
Link Posted: 9/18/2004 6:05:38 PM EST

Originally Posted By M11293:

Originally Posted By Bradd_D:
Try running the charging handle back and forth in the receiver. Look inside and see if there is any bare aluminum where it looks as though something is rubbing...specifically the charging handle.



All is fine. The charging handle runs smoothly and the carrier runs smoothly if they are by themselves. If they are together then they get sticky. I have used these same charging handles and bolt carrier/bolt together in the previous upper.



Look at the top of the channel where the charging handle rides. Any bare aluminum? I was thinking maybe there is something in the receiver causing the charging handle and carrier to ride out of sync with each other.
Link Posted: 9/18/2004 6:07:36 PM EST

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By Bradd_D:
Try running the charging handle back and forth in the receiver. Look inside and see if there is any bare aluminum where it looks as though something is rubbing...specifically the charging handle.



All is fine. The charging handle runs smoothly and the carrier runs smoothly if they are by themselves. If they are together then they get sticky. I have used these same charging handles and bolt carrier/bolt together in the previous upper.



Look at the top of the channel where the charging handle rides. Any bare aluminum? I was thinking maybe there is something in the receiver causing the charging handle and carrier to ride out of sync with each other.



On the charging handle there is some bare aluminum. Not in the upper.
Link Posted: 9/18/2004 6:09:21 PM EST
[Last Edit: 9/18/2004 6:11:26 PM EST by lu380]
Maybe the upper is machined a little loose, causing the bolt carrier to tip up slightly up when you pull on the charging handle. This would explain why the bolt slides like glass all by itself, and the charging handle pulls smoothly by itself.

In other words, the charging handle contacts the carrier near the front. When you pull the charging handle, the front of the carrier tips up while the back of the carrier tips down, causing drag.
Link Posted: 9/18/2004 6:13:56 PM EST

Originally Posted By M11293:

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By Bradd_D:
Try running the charging handle back and forth in the receiver. Look inside and see if there is any bare aluminum where it looks as though something is rubbing...specifically the charging handle.



All is fine. The charging handle runs smoothly and the carrier runs smoothly if they are by themselves. If they are together then they get sticky. I have used these same charging handles and bolt carrier/bolt together in the previous upper.



Look at the top of the channel where the charging handle rides. Any bare aluminum? I was thinking maybe there is something in the receiver causing the charging handle and carrier to ride out of sync with each other.



On the charging handle there is some bare aluminum. Not in the upper.



Look carefully at the thin channels where the notches on the charging handle ride. You may need to use a flashlight.
Link Posted: 9/18/2004 6:19:01 PM EST
Check the gas tube.
Link Posted: 9/18/2004 6:26:49 PM EST

Originally Posted By innocent_bystander:
Check the gas tube.



Gas tube looks ok. Anything I should look for on the gas tube?
Link Posted: 9/18/2004 6:32:05 PM EST
More than likely the tolerances of the little channels where the charging handle rides are tight and when you charge the weapon if you don't pull perfectly straight on the charging handle it is dragging. I've run into this before myself. Bare aluminum on the charging handle indicates something somewhere is wearing. It's not necessarily anything to be concerned about, but we need to figure out where it's coming from.
Link Posted: 9/18/2004 6:33:25 PM EST
Is the gas tube off to one side where it could bind the carrier or charging handle? Is there any crud in the locking lugs?
Link Posted: 9/18/2004 6:38:53 PM EST
No. I am sorry for my stupidity. I have always wondered what are the locking lugs?
Link Posted: 9/18/2004 6:45:20 PM EST
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.
Link Posted: 9/18/2004 6:52:31 PM EST

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?
Link Posted: 9/18/2004 7:01:15 PM EST

Originally Posted By M11293:

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?



Have you actually bent it or are you just pulling a little bit to one side when you charge the weapon? Do you charge with a finger on each side of the handle or do you charge on the left side only?
Link Posted: 9/18/2004 7:03:37 PM EST

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?



Have you actually bent it or are you just pulling a little bit to one side when you charge the weapon? Do you charge with a finger on each side of the handle or do you charge on the left side only?



Left side only because of scope.

Anything I should do?
Link Posted: 9/18/2004 7:08:34 PM EST
[Last Edit: 9/18/2004 7:09:45 PM EST by Bradd_D]

Originally Posted By M11293:

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?



Have you actually bent it or are you just pulling a little bit to one side when you charge the weapon? Do you charge with a finger on each side of the handle or do you charge on the left side only?



Left side only because of scope.

Anything I should do?



Bingo. The same thing happened to me when I started charging left side only. You are pulling and torquing the handle to one side when you charge the weapon. There isn't a whole lot you can do about it, but it is self-limiting so the wear will stop eventually. The only other option is to try and force yourself to pull straight back on the handle.
Link Posted: 9/18/2004 7:10:23 PM EST

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?



Have you actually bent it or are you just pulling a little bit to one side when you charge the weapon? Do you charge with a finger on each side of the handle or do you charge on the left side only?



Left side only because of scope.

Anything I should do?



Bingo. The same thing happened to me when I started charging left side only. You are pulling and torquing the handle to the left when you charge the weapon. There isn't a whole lot you can do about it, but it is self-limiting so the wear will stop eventually. The only other option is to try and force yourself to pull straight back on the handle.



I don't like bad habits.

I sure hope I can get it to function. I still don't understand why my DPMS high riser didn't have issues and still doesn't. CMT tighter or not broken in?
Link Posted: 9/18/2004 7:17:02 PM EST

Originally Posted By M11293:

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By Bradd_D:

Originally Posted By M11293:

Originally Posted By M11293:
I think I have found my verdict. One side of the charging handle has more wear than the other side. If a push to the opposite side of the charging handle latch it runs like glass. I guess I have beny it just slightly.


Maybe not

Would buying a new charging handle fix this problem?



Have you actually bent it or are you just pulling a little bit to one side when you charge the weapon? Do you charge with a finger on each side of the handle or do you charge on the left side only?



Left side only because of scope.

Anything I should do?



Bingo. The same thing happened to me when I started charging left side only. You are pulling and torquing the handle to the left when you charge the weapon. There isn't a whole lot you can do about it, but it is self-limiting so the wear will stop eventually. The only other option is to try and force yourself to pull straight back on the handle.



I don't like bad habits.

I sure hope I can get it to function. I still don't understand why my DPMS high riser didn't have issues and still doesn't. CMT tighter or not broken in?



More than likely the CMT has much tighter tolerances. They are very nice uppers.
Link Posted: 9/18/2004 7:34:34 PM EST
Anything you would recommend? Will it smooth out after a while, Bradd_D?

Thank you very much for all your help guys...

Mac
Link Posted: 9/18/2004 7:40:44 PM EST

Originally Posted By M11293:
Anything you would recommend? Will it smooth out after a while, Bradd_D?

Thank you very much for all your help guys...

Mac



Yeah it should wear to a certain point and stop then it should be smooth.
Link Posted: 9/20/2004 12:53:49 PM EST
Just an update...

I shot my AR yesterday and all went well except the stiff charging handle. I asked the range owner if he had a charging handle I could try on my rifle and he let me test their rental Armalite charging handle. The used Armalite charging handle worked smooth as glass.

Should I just buy a new charging handle?

Thanks
Link Posted: 9/20/2004 1:14:48 PM EST
CDNN had new Colt takeoff charging handles for $12.99.
Link Posted: 9/20/2004 1:15:23 PM EST

Originally Posted By innocent_bystander:
CDNN had new Colt takeoff charging handles for $12.99.



Link to CDNN?

Thanks
Link Posted: 9/20/2004 1:20:52 PM EST
http://www.cdnninvestments.com/www.cdnninvestments.com/

Sounds like a bent charging handle.
Link Posted: 9/20/2004 1:24:04 PM EST
Link Posted: 9/28/2004 12:45:36 PM EST
Well, I stuck my old single upper receiver on my lower with the CH, Bolt/Carrier and pulled it back a few times. It ran like glass. I messed with it some more. Stuck the CH/Bolt/carrier in the new CMT and it runs smoother than any AR I have held or owned. I guess the CH just now feels like it wants to work for the new upper.

Weird...
Top Top