abigfire Posted July 11, 2012 Report Share Posted July 11, 2012 I just finished my first build and tried to test it, and it will not pull the rounds off the mag. It only puts a dent on the casing or scrape marks. I've tried 3 different mags. Magpul, CMMG, and DPMS with the same results. Any one have ideas on what's going on? Could it be related to the bolt barely catching on the bolt catch? The bolt releases when I eject the mag (haven't figured that one out yet too). Quote Link to comment Share on other sites More sharing options...
Jgun Posted July 11, 2012 Report Share Posted July 11, 2012 Could you give us further information?, what bolt carrier group are you using, what mags did you test, etc. From what you've posted it sounds as though yours saying that the mag is too low and the bolt is not stripping a rd when it comes forward. Have you checked the mag catch to see if there might be something wrong with it that's allowing the mag to sit lower? You say you've tried 3 mags, how do you find their fit in the mag well to be, is there up and down play? If you use the charging handle to slowly allow the bolt carrier to come forward, do you see the bolt "ride" over the top of the back of the cartridge when it comes forward? Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted July 11, 2012 Report Share Posted July 11, 2012 Also, what ammo are you using? Some cartridges don't like feeding in auto rifles. Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted July 11, 2012 Report Share Posted July 11, 2012 Hi,Can you separate the upper from the lower and take pictures of the lower with a loaded magazine in the lower ?Also can you take a picture of the bottom of the upper ?THX Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 12, 2012 Report Share Posted July 12, 2012 Did you use a 308 specific bolt catch ?What buffer & spring do you have in there & are you sure its for a 308.Sounds like the bolt catch is catching on the bolt carrier & not the bolt . BCG may not be going far enough into the receiver extension . Some thing hanging it up or wrong parts , maybe ? Quote Link to comment Share on other sites More sharing options...
Jgun Posted July 12, 2012 Report Share Posted July 12, 2012 Good point, I've seen that before. but if the gun is short stroking, and the bolt/carrier is stopping before the bolt clears the back of the rd in the mag, and the bolt catch is catching the carrier and not the bolt, that would be a different thing than what he's describing, no? I think the first thing we need is for the OP to tell us, when the bolt is locked back manually,by the bolt catch, if he looks into the ejection port, is the bolt further back than the back of the top rd in the mag? If so, we go to what I said before, while holding the charging handle back, hit the bolt release, and then slowly let the carrier come forward, while controlling it with the charging handle, if it fails to strip a rd from the mag, while slowly/manually cycling it, I'm thinking that he's looking at a problem with the mag being too low, or possibly a problem with the mag itself. I'm thinking that if the same thing happened with 3 different mags, It's unlikely that it's mag related. I had a condition on one of my guns, where the gun cycled when manually operated with the charging handle, but when fired it, it didn't always pick up the next rd from the mag, or lock back on an empty mag. This was a newly built gun, using full power factory ammo. In my case all it took to remedy the problem was more lube to the BCG (I soaked it until it was dripping, but not heavy oil) and a few more break in rds to get the parts used to each other. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 12, 2012 Report Share Posted July 12, 2012 If the bolt carrier is feeding a round onto the feed ramp , instead of the bolt pushing it up ,(which happens for several reasons, none good ), the live round will be pined onto the feed ramp/chamber area , it will leave some real nice dents into the case. I have pulled the bullets from the ones I was getting from trying P-mags in my CMMG 308 build ( mag related feeding issue ), resized them with out a depriming stem , reloaded them & the dents fired out .Reasons have already been stated , Mag related problems ( as above ), BCG not stroking all the way ( not stroking back far enough & BCG stopping short ,but enough for the bolt carrier to engage the live round , too short of a feeding cycle or in some cases , extreeme BCG travel , bolt bounce . Wrong components or miss matched . Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted July 14, 2012 Report Share Posted July 14, 2012 If the bolt carrier is feeding a round onto the feed ramp , instead of the bolt pushing it up ,(which happens for several reasons, none good ), the live round will be pined onto the feed ramp/chamber area , it will leave some real nice dents into the case. I have pulled the bullets from the ones I was getting from trying P-mags in my CMMG 308 build ( mag related feeding issue ), resized them with out a depriming stem , reloaded them & the dents fired out .Reasons have already been stated , Mag related problems ( as above ), BCG not stroking all the way ( not stroking back far enough & BCG stopping short ,but enough for the bolt carrier to engage the live round , too short of a feeding cycle or in some cases , extreeme BCG travel , bolt bounce . Wrong components or miss matched .JGUN, I agree ,but want to see a picture of the bolt catch in the lower receiver. Quote Link to comment Share on other sites More sharing options...
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