User Panel
User Panel
User Panel
|
Posted: 2/16/2013 9:22:31 PM EDT
[#1]
Quoted:
Hil, I bought an upper receiver with 10" 1/2 barrel which has been assembled by dealer, so unfortunatly I don't know the exact brand of each part he used. I tested it with 200 rounds of Sellier & Bellot commercial rounds. Do you think such wear over the stars of the bolt is normal, I mean for example the rounded edge corner marked with red circles ? Thank you. http://img89.imageshack.us/img89/96/p10200691.jpg Salu2 a to2 Bizio Can you post a few photos of the barrel extension? I've seen bolt wear like that when the barrel assembly was not indexed properly, causing the edges of the bolt lugs to hit the extension lugs while cycling. ETA: That BCG looks like it is in serious need of lube. Unless it is a NiB BCG, the discoloration is abnormal and could possibly be caused by excessive heat or gas escaping past the rings. |
|
|
|
Posted: 2/16/2013 9:27:21 PM EDT
[#2]
I think once you clean it with a brush and solvent or breakfree clp it will look fine.
|
|
|
|
Posted: 2/16/2013 9:33:43 PM EDT
[#3]
Quoted:
Can you post a few photos of the barrel extension? I've seen bolt wear like that when the barrel assembly was not indexed properly, causing the edges of the bolt lugs to hit the extension lugs while cycling. ETA: That BCG looks like it is in serious need of lube. Unless it is a NiB BCG, the discoloration is abnormal and could possibly be caused by excessive heat or gas escaping past the rings. Thanks for you answer. I used a lot of lube : Break Free with CLP. The BCG I think it might come from Chez Republic and it has that odd finish. Here are some pics of the barrel extension http://img17.imageshack.us/img17/8761/p1020071tj.jpg http://img24.imageshack.us/img24/7052/p1020072u.jpg http://img20.imageshack.us/img20/640/p1020073an.jpg |
|
|
|
Posted: 2/16/2013 9:34:38 PM EDT
[#4]
Quoted:
I think once you clean it with a brush and solvent or breakfree clp it will look fine. Thanks, I was not referring to the spots over the bolt but just the rounded corners of the stars. |
|
|
|
Posted: 2/16/2013 9:45:44 PM EDT
[#5]
Quoted:
Quoted:
I think once you clean it with a brush and solvent or breakfree clp it will look fine. Thanks, I was not referring to the spots over the bolt but just the rounded corners of the stars. It may just be the way the photos look, but the extension appears to me that the barrel assembly may be slightly indexed to the right. It also looks like there may be some areas of wear on the extension lugs that correspond with the ones on the bolt. I may be wrong because I am viewing these photos on a smaller screen, can you verify this? |
|
|
|
Posted: 2/16/2013 9:49:59 PM EDT
[#6]
Quoted:
Quoted:
I think once you clean it with a brush and solvent or breakfree clp it will look fine. Thanks, I was not referring to the spots over the bolt but just the rounded corners of the stars. Are there burrs on the corners? Rub your finger nail over the areas in question. If no burrs, I feel your OK. Just lube the bolt heavier next time. Oil every part of the bolt well, including the rings. However, keep the bolt face area as dry as possible. |
|
|
|
Posted: 2/16/2013 9:55:57 PM EDT
[#7]
Also, the gas tube looks like it is seated further inward than normal. Does the BCG slide into battery easily, or do you have to force it?
|
|
|
|
Posted: 2/16/2013 10:06:33 PM EDT
[#8]
After looking at everything on a larger screen now, I am confident that the gas tube is causing the issue. It is much too long. You can also see the impact wear on the end of the tube. When the carrier key engages the tube, it is being lifted and directed along the angle of the tube due to its excessive length, causing the bolt lugs to enter the extension at a very slight angle. Take it back to the guy who assembled it and point this out to him. Also ensure that the barrel is indexed correctly.
|
|
|
|
Posted: 2/16/2013 10:24:47 PM EDT
[#9]
Quoted:
Are there burrs on the corners? Rub your finger nail over the areas in question. If no burrs, I feel your OK. Just lube the bolt heavier next time. Oil every part of the bolt well, including the rings. However, keep the bolt face area as dry as possible. Apparently there are nu burrs on the corners. Thank you for your good suggestions, Pain. |
|
|
|
Posted: 2/16/2013 10:25:35 PM EDT
[#10]
Quoted:
Also, the gas tube looks like it is seated further inward than normal. Does the BCG slide into battery easily, or do you have to force it? The BCG slides easily, no need to force it. |
|
|
|
Posted: 2/16/2013 10:27:44 PM EDT
[#11]
Quoted:
After looking at everything on a larger screen now, I am confident that the gas tube is causing the issue. It is much too long. You can also see the impact wear on the end of the tube. When the carrier key engages the tube, it is being lifted and directed along the angle of the tube due to its excessive length, causing the bolt lugs to enter the extension at a very slight angle. Take it back to the guy who assembled it and point this out to him. Also ensure that the barrel is indexed correctly. Thank you, Mike_Anthony. I will ask him to check all the parts you suggested. |
|
|
|
Posted: 2/16/2013 10:29:41 PM EDT
[#12]
Quoted:
Quoted:
Also, the gas tube looks like it is seated further inward than normal. Does the BCG slide into battery easily, or do you have to force it? The BCG slides easily, no need to force it. Can you post a pic of the gas tube, taken while looking straight down through the bottom of the receiver? From the other photos, the tube almost appears to extend past the cam recess and almost to the ejection port door recess. It may just be an optical illusion, but that's how it appears in those photos. |
|
|
|
Posted: 2/16/2013 10:39:02 PM EDT
[#13]
Here are the gas tube pics.
If needed I can measure its lenght from the barrel extension. 
|
|
|
|
Posted: 2/16/2013 10:43:31 PM EDT
[#14]
The top of the gas tube is 26.1 mm from the barrel extension ( about 1.027")
|
|
|
|
Posted: 2/16/2013 10:48:29 PM EDT
[#15]
Quoted:
Here are the gas tube pics. If needed I can measure its lenght from the barrel extension. http://img38.imageshack.us/img38/9067/p1020074.JPG http://img836.imageshack.us/img836/9558/p1020075d.jpg Actually, it appears to be the correct length now that I can see it from above. The photos threw the appearance of the angles off a bit. If you can manually insert the BCG into battery easily and do not feel any resistance at all, and there are no matching marks on the extension lugs, then those marks on the bolt lugs may not be wear marks at all. They may have been machined into the bolt as part of the design from the manufacturer. You did state that the bolt was from the Czech Republic, correct? |
|
|
|
Posted: 2/16/2013 10:55:12 PM EDT
[#16]
Quoted:
Actually, it appears to be the correct length now that I can see it from above. The photos threw the appearance of the angles off a bit. If you can manually insert the BCG into battery easily and do not feel any resistance at all, and there are no matching marks on the extension lugs, then those marks on the bolt lugs may not be wear marks at all. They may have been machined into the bolt as part of the design from the manufacturer. You did state that the bolt was from the Czech Republic, correct? I tryed to make the bolt carrier falling for gravity keeping the upper receiver vertical with the muzzle downwards and the bolt carrier seats in place easily but not for the last 2 mm, I have to push it with finger but not resistence. I said above that I think it might come from Czech Republic, same as the upper, but I am not sure since the dealer is not willing disclose from where he gets parts. Odd but true. I am in Italy and we must be happy with what we can get here. Here some more pics of the BCG with that odd finish. 
|
|
|
|
Posted: 2/16/2013 11:09:13 PM EDT
[#17]
Quoted:
Quoted:
Actually, it appears to be the correct length now that I can see it from above. The photos threw the appearance of the angles off a bit. If you can manually insert the BCG into battery easily and do not feel any resistance at all, and there are no matching marks on the extension lugs, then those marks on the bolt lugs may not be wear marks at all. They may have been machined into the bolt as part of the design from the manufacturer. You did state that the bolt was from the Czech Republic, correct? I tryed to make the bolt carrier falling for gravity keeping the upper receiver vertical with the muzzle downwards and the bolt carrier seats in place easily but not for the last 2 mm, I have to push it with finger but not resistence. I said above that I think it might come from Czech Republic, same as the upper, but I am not sure since the dealer is not willing disclose from where he gets parts. Odd but true. I am in Italy and we must be happy with what we can get here. Here some more pics of the BCG with that odd finish. http://img690.imageshack.us/img690/6366/img6109g.jpg http://img600.imageshack.us/img600/8516/img6110k.jpg http://img259.imageshack.us/img259/310/img6111yz.jpg The resistance for the last two mm is normal, especially for a new BCG. It is the force of the front of the bolt lugs pressing against the chamber face in order to move the cam and initiate bolt rotation/locking on an empty chamber. Normally, the resistance would be between the contact of the bolt face and the case rim when a round is chambered. If the marks on your bolt lugs appear even, then I would suspect that it was machined by the manufacturer and there is no issue. |
|
|
|
Posted: 2/16/2013 11:11:29 PM EDT
[#18]
Quoted:
Quoted:
Actually, it appears to be the correct length now that I can see it from above. The photos threw the appearance of the angles off a bit. If you can manually insert the BCG into battery easily and do not feel any resistance at all, and there are no matching marks on the extension lugs, then those marks on the bolt lugs may not be wear marks at all. They may have been machined into the bolt as part of the design from the manufacturer. You did state that the bolt was from the Czech Republic, correct? I tryed to make the bolt carrier falling for gravity keeping the upper receiver vertical with the muzzle downwards and the bolt carrier seats in place easily but not for the last 2 mm, I have to push it with finger but not resistence. I said above that I think it might come from Czech Republic, same as the upper, but I am not sure since the dealer is not willing disclose from where he gets parts. Odd but true. I am in Italy and we must be happy with what we can get here. Here some more pics of the BCG with that odd finish. http://img690.imageshack.us/img690/6366/img6109g.jpg http://img600.imageshack.us/img600/8516/img6110k.jpg http://img259.imageshack.us/img259/310/img6111yz.jpg I have never seen a BCG like that. Did the dealer disclose what type of material it was manufactured from? |
|
|
|
Posted: 2/16/2013 11:13:51 PM EDT
[#19]
Quoted: Quoted: Can you post a few photos of the barrel extension? I've seen bolt wear like that when the barrel assembly was not indexed properly, causing the edges of the bolt lugs to hit the extension lugs while cycling. ETA: That BCG looks like it is in serious need of lube. Unless it is a NiB BCG, the discoloration is abnormal and could possibly be caused by excessive heat or gas escaping past the rings. Thanks for you answer. I used a lot of lube : Break Free with CLP. The BCG I think it might come from Chez Republic and it has that odd finish. Here are some pics of the barrel extension http://img17.imageshack.us/img17/8761/p1020071tj.jpg http://img24.imageshack.us/img24/7052/p1020072u.jpg http://img20.imageshack.us/img20/640/p1020073an.jpg Are the silver specs in those pics metal shavings, reflections from lube, wear spots, or something else? |
|
|
|
Posted: 2/16/2013 11:39:56 PM EDT
[#20]
Quoted:
I have never seen a BCG like that. Did the dealer disclose what type of material it was manufactured from? He did not. I think it might be a product which has not been finished. The odd thing is that I tryed to apply some Birchwood Perma Blue but invain, the product does not blue the surface. Probably it is steel chrome metal. |
|
|
|
Posted: 2/16/2013 11:41:35 PM EDT
[#21]
Quoted:
Are the silver specs in those pics metal shavings, reflections from lube, wear spots, or something else? Those are permanent spots over the finish. The BCG was as you can see even when it was brand new in mint conditions. |
|
|
|
Posted: 2/16/2013 11:43:08 PM EDT
[#22]
Quoted:
The resistance for the last two mm is normal, especially for a new BCG. It is the force of the front of the bolt lugs pressing against the chamber face in order to move the cam and initiate bolt rotation/locking on an empty chamber. Normally, the resistance would be between the contact of the bolt face and the case rim when a round is chambered. If the marks on your bolt lugs appear even, then I would suspect that it was machined by the manufacturer and there is no issue. Thank you again for your time and your help, Mike_Anthony. |
|
|
|
Posted: 2/17/2013 5:51:21 AM EDT
[#23]
Biz,
I don't see anything out of place....all looks normal to me. It appears that the Czechs are using a "dry film lubricant" on the carrier and bolt. They must think that it helps during the break-in period. We use a dry film lubricant on some of our military-type magazines. I've never seen it on a carrier or bolt. It will come off as you use and clean the weapon. For your own satisfaction, why not take the bolt to the dealer and compare it to a new bolt ? |
|
|
|
Posted: 2/17/2013 7:28:40 AM EDT
[#24]
If its not taking gun blue then its maybe a stainless or chromed steel its either a non ferrous coating or steel otherwise it would take blue.
|
|
|
|
Posted: 2/17/2013 7:53:54 AM EDT
[#25]
I'm with the guy above. The rounded edge you see on that bolt lug sure does look like it corresponds to the top left (11 o'clock) opening of the barrel extension. I'd say they are hitting each other and material is being removed. It's very close if the bolt isn't giving much resistance, but it appears that the lugs and the extension were coming into contact at the wrong angle. Either the lugs were slightly out of spec or the extension was slightly out of spec. Being in Italy may make it tough to get high quality stuff but I'd take it back to the dealer and see if a new bolt correctly matched the extension. Then you'd know if it was the barrel extension or your bolt causing the problem. If you shoot it a bit more and the parts look no different then you may not have any further issues, but it wouldn't be worth chancing if it were me. If those lugs get worse you may begin to have cycling issues because of the gas timing being thrown off due to the lugs letting gas escape too early.
|
|
|
|
Posted: 2/17/2013 8:12:15 AM EDT
[#26]
Bizio,
It looks like your feed ramps on your barrel extension might be a fraction off-center, but I doubt it should be a problem. Your bolt carrier appears to be of a very hard alloy. Birchwood Casey liquid blue may not color it due to its hardess -- again, should not be a problem. I would shoot that rifle as much as you like. I see no extensive wear on the sides of either lugs you highlighted, and they do not align with the left and right feed ramp edges. Ciao. |
|
|
|
Posted: 2/17/2013 8:48:11 AM EDT
[#27]
Quoted:
Biz, I don't see anything out of place....all looks normal to me. It appears that the Czechs are using a "dry film lubricant" on the carrier and bolt. They must think that it helps during the break-in period. We use a dry film lubricant on some of our military-type magazines. I've never seen it on a carrier or bolt. It will come off as you use and clean the weapon. For your own satisfaction, why not take the bolt to the dealer and compare it to a new bolt ? Thank you, Direct-Drive. I have 2 colt BCG and 2 Bushmaster ones to compare with and there is no wear at the corner I circled with red anyway. You are talking of Molikote which is used on Colt mags for example. |
|
|
|
Posted: 2/17/2013 8:51:03 AM EDT
[#28]
Quoted:
Bizio, It looks like your feed ramps on your barrel extension might be a fraction off-center, but I doubt it should be a problem. Your bolt carrier appears to be of a very hard alloy. Birchwood Casey liquid blue may not color it due to its hardess -- again, should not be a problem. I would shoot that rifle as much as you like. I see no extensive wear on the sides of either lugs you highlighted, and they do not align with the left and right feed ramp edges. Ciao. Thank you, Sinister. I will keep on shooting. |
|
|
|
Posted: 2/17/2013 9:58:12 AM EDT
[#29]
Quoted:
Quoted:
Hil, I bought an upper receiver with 10" 1/2 barrel which has been assembled by dealer, so unfortunatly I don't know the exact brand of each part he used. I tested it with 200 rounds of Sellier & Bellot commercial rounds. Do you think such wear over the stars of the bolt is normal, I mean for example the rounded edge corner marked with red circles ? Thank you. http://img89.imageshack.us/img89/96/p10200691.jpg Salu2 a to2 Bizio Can you post a few photos of the barrel extension? I've seen bolt wear like that when the barrel assembly was not indexed properly, causing the edges of the bolt lugs to hit the extension lugs while cycling. ETA: That BCG looks like it is in serious need of lube. Unless it is a NiB BCG, the discoloration is abnormal and could possibly be caused by excessive heat or gas escaping past the rings. That is exactly what I was thinking! I have a FN barrel going back to "PSA" for the same issue. The barrel extension is rotated to far to the right too, causing the bolt head to come in contact slightly with the barrel extension lugs before going into battery. Thankfully I noticed this before I started shooting it. Better yet the FSB is notably canted to the right. I know PSA drilled the barrel for the FSB so that is not FN's fault but the improper barrel extension index IS FN's fault. I couldn't believe they put shit like this out. All manufacturers put out a shitty product from time to time though... |
|
|
|
Posted: 2/17/2013 10:01:02 AM EDT
[#30]
Quoted:
Quoted:
Can you post a few photos of the barrel extension? I've seen bolt wear like that when the barrel assembly was not indexed properly, causing the edges of the bolt lugs to hit the extension lugs while cycling. ETA: That BCG looks like it is in serious need of lube. Unless it is a NiB BCG, the discoloration is abnormal and could possibly be caused by excessive heat or gas escaping past the rings. Thanks for you answer. I used a lot of lube : Break Free with CLP. The BCG I think it might come from Chez Republic and it has that odd finish. Here are some pics of the barrel extension http://img17.imageshack.us/img17/8761/p1020071tj.jpg http://img24.imageshack.us/img24/7052/p1020072u.jpg http://img20.imageshack.us/img20/640/p1020073an.jpg From the above pics the barrel extension appears to be ever so slightly indexed a hair or two to the right. Mine is two hairs more than yours OP and is easier to see. That's why it's going back to PSA... |
|
|
|
Posted: 2/17/2013 10:42:05 AM EDT
[#31]
You' re right. I checked and my barrel extension, just looking it from the receiver side, should be twisted counter clockwise of about 2°
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
