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Discussion Starter · #1 ·
Hi, I have been shooting a r's for 2 decades and I built many of them. I'm having problems with this build and looking for some help.

When trying to load a round, either with the bolt closed, or by using the bolt catch, the first round will jam into the feed ramp-barrel extension and jam. Sometimes the first will feed but the next will jam.

So far I have Field stripped and cleaned the entire rifle and BCG, did a little polishing on the feed ramps, removed and replaced the mag catch to make sure it is fully seated, replaced the buffer and buffer Spring, Tried multiple types of ammo and and at least 5 different makes of magazines. No luck.

At one

time I had a magazine that would actually feed but I have no idea where it is or what brand it was.

Suggestions please
 

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Update.. i tried the upper on a different lower and with a diffefent BCG, still jams on 1st or 2nd round. Any suggestions?
Just a couple thougths and a couple of question.
1. Does the first round propery chamble and does if fire the first round everey time?
2. Have you tried 1 round in mag, fire , and dertermine the clock posistion it ejects at?
3. Are you used a std Buffer and sping?
4 What ammo and grain
 

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Discussion Starter · #5 ·
Thanks

1 trying to load a round, either with the bolt closed, or by using the bolt catch, the first round will jam into the feed ramp-barrel extension and jam. Sometimes the first will feed but the next will jam. This is without firing, just cycling

2. no I have not looked at eject position

3. I put in a upgraded buffer and spring with same result

4. 55 grain fmj ammo, various brands. Also tried with Magpul dummy rounds.

Any suggestions are appreciated
 

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Thanks

1 trying to load a round, either with the bolt closed, or by using the bolt catch, the first round will jam into the feed ramp-barrel extension and jam. Sometimes the first will feed but the next will jam. This is without firing, just cycling

2. no I have not looked at eject position

3. I put in a upgraded buffer and spring with same result

4. 55 grain fmj ammo, various brands. Also tried with Magpul dummy rounds.

Any suggestions are appreciated
The usual suspect is the magazine. Did you try different mags? try a 20 round, or don't load to capacity and see if it chambers with just 3-5 rounds, or 1 or 2 rounds less than capacity. Thats the most likely, also make sure its fully seated, and can't be pulled out, also If the spring is too strong or too weak it can cause chambering issues. What are the specs on the buffer/spring, as in length, weight, carbine or rifle tube? not likely but if completely out of spec in weight/spring length there can be an issue.

Theres always a possibility of machining issues, did you try a different upper with the same lower and bcg? what are the gun specs?
 
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