My 7.62x39 build (UPDATE with Range Report and minor issue....need help!)

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[ARCHIVED THREAD] - My 7.62x39 build (UPDATE with Range Report and minor issue....need help!)

Posted: 9/30/2013 3:51:42 PM EDT

I've been contemplating doing one of these builds for quite some time

Due to a number of things I decided now is the time.

Figured i'd keep a log of the build as I go

So far I have

YHM Phantom 5c2 in .30 cal
PSA full auto BCG
Rubber City Armory 7.62x39 bolt (carpenter 158 steel and nitrided)
Cobra Tactical Systems 16" 7.62x39 melonited barrel 1x10
YHM quick deploy buis
PA micro dot

Still need

stripped upper
low pro gas block and tube
charging handle
forend

Hope this helps some of the people looking to do their own build

i'll try to keep updated on the build and how the bolt holds out

Posted: 10/8/2013 7:38:50 AM EDT

[#1]

recently purchased

yhm clamp on gas block
yhm black carbine gas tube
bcm barrrel nut
bcm blem/demo upper
bcm gunfighter charging handle
fortis rev 12" rail

for the time being I am gonna use one of my other lowers

hope to have this built by the weekend and get it headspaced, want to get it to the range while I still have a few weekends left before winter sets in

Posted: 10/8/2013 9:24:01 AM EDT

[#2]

Gonna need pics when it's all together.

Posted: 10/10/2013 7:13:27 PM EDT

[#3]

deleted

Posted: 10/11/2013 11:11:27 AM EDT

[#4]

Quote History

Quoted:
Gonna need pics when it's all together.

View Quote

pics added

Posted: 10/11/2013 5:19:23 PM EDT

[#5]

Looks good brother. Go shoot it. I had mine out today again. Very addictive.

Posted: 10/11/2013 5:22:01 PM EDT

[#6]

Quote History

Quoted:
Looks good brother. Go shoot it. I had mine out today again. Very addictive.

View Quote

Thanks!

it's going out tomorrow

my buddy is gonna bring his cordless dremel so we can modify mags at the range

Posted: 10/11/2013 7:22:35 PM EDT

[#7]

Nicely done.

Posted: 10/12/2013 5:14:11 PM EDT

[#8]

Range Report

Hit the range today....awesome gun!!!

Buddy of mine modified magazines before we put any rounds through it.

No FTFire or FTFeed

I did have a problem that kept happening about 20% of the time

I added some pics but I know they suck so i'll try to explain. I would get a FTE where the case was still grabbed by the extractor and it would jam up against a round from the magazine.

Each time it seemed like the round was loose from the mag, like it had bypassed the feed lips.

The only thing I could think of is that the follower or spring in the mag would hang up and there wasn't enough tension on the round which would cause cartridge to bypass feed lips and jam up against extracting round.

Other problem but possibly related was that every so often a casing would extract almost next to me on the bench...the rest would launch behind me in a pretty consistent pile about 10' or so behind me. Our thought was that this could be due to the same problem as above where a cartridge from the mag was catching the extracting round but it didn't jam in there it would just get slowed down(if that makes sense)

What do you guys think?

Anyone hear of this kind of thing?

Thanks
Paul

Posted: 10/12/2013 6:07:36 PM EDT

[#9]

Post a pic of your mags. The only thing I modified on mine was the front lip where the cartridges feed from the mag. I just took the dremel to them a bit. I didn't grind anything internal on the mags like the youtube video specified. Did you grind anything else other than the front lip? I have had zero feed issues with my ASCs after doing this other than the previously discussed tension issue.

Posted: 10/12/2013 6:11:46 PM EDT

[#10]

Quote History

Quoted:
Post a pic of your mags. The only thing I modified on mine was the front lip where the cartridges feed from the mag. I just took the dremel to them a bit. I didn't grind anything internal on the mags like the youtube video specified. Did you grind anything else other than the front lip? I have had zero feed issues with my ASCs after doing this other than the previously discussed tension issue.

View Quote

I touched the indents on the feed lips a little bit

I also touched the followers a little bit with a polishing wheel....it hasn't fully helped

the reason I touched up the followers is because when i would hand empty the mags I could feel where there was hardly any tension on the cartridges...like the follower was catching on something inside...id have to bang the magazine to kind of get the tension back on em again

Posted: 10/13/2013 6:41:31 AM EDT

[#11]

I have the exact same problem. From what I read from H over at 6.8 Forum is that we have an extractor issue. I took my extractor spring out and it looked too short or compressed so I replaced it with an extra power extractor spring. I have not had time to test it yet. Keep us posted on what you find out. I may be able to get out this week and test my rifle and see if I fixed it.

Posted: 10/13/2013 6:47:08 AM EDT

[#12]

I was having this same problem with one of my mags. I removed the floorplate and spring and noticed that the follower did seem to hang up a bit in the body of the magazine. I took some sandpaper to the outside edges of the follower until it would slide easily inside the magazine. So far so good.

Posted: 10/13/2013 6:50:50 AM EDT

[#13]

Quote History

Quoted:
I was having this same problem with one of my mags. I removed the floorplate and spring and noticed that the follower did seem to hang up a bit in the body of the magazine. I took some sandpaper to the outside edges of the follower until it would slide easily inside the magazine. So far so good.

View Quote

I did touch the follower with a polishing bit when I had the dremel out

one of the followers out of my 2 mags was noticeably larger and didn't want to feed reliably

I still was having an issue though where it seemed like it would hang up

I ordered some extra power AK mag springs from brownells yesterday and another 30 round ASC mag and I will see if that helps

gonna look into the extractor issue...also gonna see about the spring...

any more ideas?

good to know i'm not the only one

Thanks!!

Posted: 10/13/2013 12:54:24 PM EDT

[#14]

Thank you for your post. Could you be more specific on the magazine modifications? I have been having FTF issues with my ASC magazines for over a year.

Thank you.

ETA: FTFeed

Posted: 10/13/2013 1:47:38 PM EDT

[#15]

Quote History

Quoted:
Thank you for your post. Could you be more specific on the magazine modifications? I have been having FTF issues with my ASC magazines for over a year.

Thank you.

ETA: FTFeed

View Quote

check out this thread

many have altered their mags this way with much sucess

I dremeled out the front of mine and took the front two dimples off the feed lips...I had absolutely no FTFeed yesterday

good luck!

Paul

Posted: 10/13/2013 3:03:37 PM EDT

[#16]

Quote History

Quoted:

check out this thread

many have altered their mags this way with much sucess

I dremeled out the front of mine and took the front two dimples off the feed lips...I had absolutely no FTFeed yesterday

good luck!

Paul

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Thank you for your post. Could you be more specific on the magazine modifications? I have been having FTF issues with my ASC magazines for over a year.

Thank you.

ETA: FTFeed

check out this thread

many have altered their mags this way with much sucess

I dremeled out the front of mine and took the front two dimples off the feed lips...I had absolutely no FTFeed yesterday

good luck!

Paul

Thanks!

Posted: 10/13/2013 3:11:46 PM EDT

[#17]

Quote History

Quoted:

Thanks!

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Thank you for your post. Could you be more specific on the magazine modifications? I have been having FTF issues with my ASC magazines for over a year.

Thank you.

ETA: FTFeed

check out this thread

many have altered their mags this way with much sucess

I dremeled out the front of mine and took the front two dimples off the feed lips...I had absolutely no FTFeed yesterday

good luck!

Paul

Thanks!

Holy SHit!!! I love the internet!! What a simple fix!!! Thank you so much! When I get off work I know what I will be doing!

Thank you so much!

Posted: 10/15/2013 3:23:51 PM EDT

[#18]

happy to help

Posted: 10/16/2013 5:27:12 PM EDT

[#19]

Quick question. How did you get rid of the forward dimple on the lips? Grind them or hammer flat? Thanks!

Posted: 10/16/2013 6:00:36 PM EDT

[#20]

Quote History

Quoted:
Quick question. How did you get rid of the forward dimple on the lips? Grind them or hammer flat? Thanks!

View Quote

we hit it with a skinny dremel bit

kind of a pain...just go slow and keep checking

it doesn't take much to grind em down

eta: what kind of rifle do you have? pics?

Posted: 10/16/2013 6:40:20 PM EDT

[#21]

Quote History

Quoted:

we hit it with a skinny dremel bit

kind of a pain...just go slow and keep checking

it doesn't take much to grind em down

eta: what kind of rifle do you have? pics?

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Quick question. How did you get rid of the forward dimple on the lips? Grind them or hammer flat? Thanks!

we hit it with a skinny dremel bit

kind of a pain...just go slow and keep checking

it doesn't take much to grind em down

eta: what kind of rifle do you have? pics?

I will take some pics. It is nothing special a Franken gun.

ETA: Pic

14.5" barrel 1x10 twist
YHM Phantom FHC -pinned so I didn't have to get a stamp
DPMS Lower
DSA Upper
YHM Specter length diamond lightweight handguard
CMMG Stock trigger and parts kit
YHM flip up BUIS

It feels AWSOME to shoot and is decently accurate....when it feeds.

I love it more than my 5.56 AR's just need to fix the reliability issue.

Posted: 10/23/2013 1:12:16 PM EDT

[#22]

Update:

Quote History

Quoted:
I have the exact same problem. From what I read from H over at 6.8 Forum is that we have an extractor issue. I took my extractor spring out and it looked too short or compressed so I replaced it with an extra power extractor spring. I have not had time to test it yet. Keep us posted on what you find out. I may be able to get out this week and test my rifle and see if I fixed it.

View Quote

I went to the range today and replacing my factory extractor spring with an extra power spring fixed the problem. My mags have not been modified. Just relacing the extractor spring with an extra power one and now it runs like a swiss watch.
Hope your fix is as easy.

Posted: 10/23/2013 1:14:12 PM EDT

[#23]

Quote History

Quoted:
Update:

I went to the range today and replacing my factory extractor spring with an extra power spring fixed the problem. My mags have not been modified. Just relacing the extractor spring with an extra power one and now it runs like a swiss watch.
Hope your fix is as easy.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:
Update:

Quoted:
I have the exact same problem. From what I read from H over at 6.8 Forum is that we have an extractor issue. I took my extractor spring out and it looked too short or compressed so I replaced it with an extra power extractor spring. I have not had time to test it yet. Keep us posted on what you find out. I may be able to get out this week and test my rifle and see if I fixed it.

I went to the range today and replacing my factory extractor spring with an extra power spring fixed the problem. My mags have not been modified. Just relacing the extractor spring with an extra power one and now it runs like a swiss watch.
Hope your fix is as easy.

how do you know it's too short or compressed?

Posted: 10/26/2013 6:43:33 PM EDT

[#24]

Just compare it to a new one. Make sure you have an extractor buffer insert installed or an O ring, but not both. The buffer is the blue or black piece of plastic inside the spring. My spring was just shorter than a standard spring. It came that way from the mfgr.

Hope that helps.

Posted: 10/27/2013 4:23:08 PM EDT

[#25]

Who made your barrel? DO the make 7.62x39 specific mags? I have an AK ,but the 7.62x39 AR intrigues me. Iam still waiting on my lower so I got time to think about it.

Quote History

Quoted:

I will take some pics. It is nothing special a Franken gun.

ETA: Pic
http://i1162.photobucket.com/albums/q531/Cmarks77/0118D8BF-C8C3-4F62-9268-88FFDACEA830-3775-00000380E655EAB4_zps32842b70.jpg

14.5" barrel 1x10 twist
YHM Phantom FHC -pinned so I didn't have to get a stamp
DPMS Lower
DSA Upper
YHM Specter length diamond lightweight handguard
CMMG Stock trigger and parts kit
YHM flip up BUIS

It feels AWSOME to shoot and is decently accurate....when it feeds.

I love it more than my 5.56 AR's just need to fix the reliability issue.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Quick question. How did you get rid of the forward dimple on the lips? Grind them or hammer flat? Thanks!

we hit it with a skinny dremel bit

kind of a pain...just go slow and keep checking

it doesn't take much to grind em down

eta: what kind of rifle do you have? pics?

I will take some pics. It is nothing special a Franken gun.

ETA: Pic
http://i1162.photobucket.com/albums/q531/Cmarks77/0118D8BF-C8C3-4F62-9268-88FFDACEA830-3775-00000380E655EAB4_zps32842b70.jpg

14.5" barrel 1x10 twist
YHM Phantom FHC -pinned so I didn't have to get a stamp
DPMS Lower
DSA Upper
YHM Specter length diamond lightweight handguard
CMMG Stock trigger and parts kit
YHM flip up BUIS

It feels AWSOME to shoot and is decently accurate....when it feeds.

I love it more than my 5.56 AR's just need to fix the reliability issue.

Posted: 10/28/2013 7:13:24 PM EDT

[#26]

Quote History

Quoted:
Who made your barrel? DO the make 7.62x39 specific mags? I have an AK ,but the 7.62x39 AR intrigues me. Iam still waiting on my lower so I got time to think about it.

-"snip"

View Quote

Not quite sure. I bought the barrel from Sportsmans Guide on a wim. Works great! Love the 7.62x39 in the AR platform. It has the little more "umph" that everyone talks about with the 6.8 but much cheaper. If I would have built this before all my others I probably would have built more of these. Also, love the smaller barrel with the lightweight handguards. My lightest rifle.

Posted: 10/28/2013 7:20:49 PM EDT

[#27]

Quote History

Quoted:

Not quite sure. I bought the barrel from Sportsmans Guide on a wim. Works great! Love the 7.62x39 in the AR platform. It has the little more "umph" that everyone talks about with the 6.8 but much cheaper. If I would have built this before all my others I probably would have built more of these. Also, love the smaller barrel with the lightweight handguards. My lightest rifle.

View Quote

i think it is an ess barrel

Posted: 10/28/2013 7:57:15 PM EDT

[#28]

Quote History

Quoted:

i think it is an ess barrel

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Not quite sure. I bought the barrel from Sportsmans Guide on a wim. Works great! Love the 7.62x39 in the AR platform. It has the little more "umph" that everyone talks about with the 6.8 but much cheaper. If I would have built this before all my others I probably would have built more of these. Also, love the smaller barrel with the lightweight handguards. My lightest rifle.

i think it is an ess barrel

Guess I should look. Does ESS have a stamp on it?

Posted: 10/28/2013 10:36:34 PM EDT

[#29]

Quote History

Quoted:

Guess I should look. Does ESS have a stamp on it?

View Quote

No stamp on it, but a similar font to known ess barrels. In the end it really doesn't matter who made the sg barrels because they will hold minute of cabbage all day long.

Posted: 10/28/2013 11:10:14 PM EDT

[#30]

Quote History

Quoted:
No stamp on it, but a similar font to known ess barrels. In the end it really doesn't matter who made the sg barrels because they will hold minute of cabbage all day long.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Guess I should look. Does ESS have a stamp on it?

No stamp on it, but a similar font to known ess barrels. In the end it really doesn't matter who made the sg barrels because they will hold minute of cabbage all day long.

It shoots 2MOA at 200yds, which is good for me. Was researching online & the 5.56 barrels from SG are made by Mossberg. Probably not the 7.62 barrels though.

Posted: 10/29/2013 12:38:59 PM EDT

[#31]

cool ! I really wanted to do a 300 blk ,but ammo is outrageous & hard to find .I have an Ak & that round is very close. My main concern is the mags . I wish magpul made some.

[ARCHIVED THREAD] - My 7.62x39 build (UPDATE with Range Report and minor issue....need help!)

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