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First build...possibly complex issue


kazuaki

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I'm thinking I checked headspace incorrectly originally.  I used the bolt by itself and tried to rotate it closed in the chamber by hand.  I just rechecked with the bolt in the carrier (still no ejector), so that the carrier would do the work of rotating the bolt.  With a gentle press on the back of the BCG, I can get it to close on a NO-GO guage.  I've got so many problems :(

 

BTW, the BCG is from AIM Surplus and the barrel is from Mega.

Edited by kazuaki
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Regarding the buffer, there is absolutely zero contact between the BCG and buffer when closing the rifle. Clearly, that is an issue. It seems we've narrowed that issue down to the lower not being correct. The buffer retainer hole is not to spec. I'm weighing my options on resolving that issue still.

 

 

The Tubb Carrier Weight System adds 0.080" to the length of the BCG body - that's you're only solution for a fix, with keeping all the same parts you have.

 

The only ammo that's getting pierced primers is the Eagle Eye, and it's probably their primer selection that is the problem.  Run what you have of it, and don't use it in the future - but reload the brass and see how it is, reloaded.

 

Firing pin hole in the bolt face - check that out.  If it's too large, that can cause pierced primers.  It'll usually do that on all your ammo, though.

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I

 

I'm thinking I checked headspace incorrectly originally.  I used the bolt by itself and tried to rotate it closed in the chamber by hand.  I just rechecked with the bolt in the carrier (still no ejector), so that the carrier would do the work of rotating the bolt.  With a gentle press on the back of the BCG, I can get it to close on a NO-GO guage.  I've got so many problems :(

 

BTW, the BCG is from AIM Surplus and the barrel is from Mega.

Do you have another Bolt to try ?  That would be the first thing to try . 

 I check Head space both ways , I check it before the Barrel is installed & afterwards , but a "No Go " fit may not be good , but may still be with in spec's , for a older Military rifle  or    what is the designation of your bbl. ? .308 or 7.62x51 ?

How does the fired Brass look , from the side. How long is it , is it stretching much .

 

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Agreed.  I'm not suggesting the bolt or barrel is the cause of my issues, but the fact that I can close the bolt on a NOGO gauge is less than ideal.  They gave me some measurements to check on the bolt and it seems to check out.  So they said, just ship it back and we'll swap it.  Very happy with that service.  They also recommended Rubber City Armory bolts to me.  Apparently they use the smaller firing pin design (like the JP high pressure bolt) to better handle high pressure loads.  I may look into that, especially since my bolt has now had a dozen or more metal discs shoved through the firing pin hole.

Edited by kazuaki
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  That is good service , I would buy a bolt & send it to them with the Barrel & they can check the HS . 

 

  There sure are a lot of us using just 308 Bolts with out a problem & I have loaded some real HP rounds , with out a problem  <dontknow>  Thing is , if you need a replacement for one of their Bolts , or if it needs replacing the Firing Pin , you have to get it only from them  <dontknow>

  If you clean the Firing Pin channel in the Bolt, that copper from the Primer , should have no effect , but I would question the Bolt , if pieces of copper getting by the Firing Pin & its hole in the Bolt face ..

Edited by survivalshop
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Just dealt with Mega thinking I had a chamber problem.  They were absolutely superb to deal with.  My problem turned out to be the Ares Armor BCG.  Extraction problems led me to suspect the barrel.  Both Rainier, where I bought the barrel, and later Mega, verified headspace with my Ares Armor BCG and bolt.  Test firing resulted in numerous FTF, ejection problems, and some cratered primers with Harnady and Federal ammo.

 

I ended up dumping the Ares Armor BCG with, per Mega's recommendation, a Rubber City Armory BCG.  Problem(s) solved!  Mine is also an 80% (purchased from 80percentarms.com, finished with their jig by me).  Mine now runs like a watch.  Zero FTF, clean ejection, etc. etc. and it is quite accurate.  I'm loving it.

 

I am now a huge fan of Mega.  Have used a lot of their parts on various rifles, as have other family members, and their service is amazing.

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Well, one problem solved :)  I filled the buffer retainer hole with JB Weld, let it set, then milled a new hole where Juggernaut should have put it in the first place.  Used a 1/4" center cutting endmill in the mill to make a nice perfect hole at a 6 degree angle.

 

 

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post-16116-0-11984000-1438808732_thumb.j

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So, the replacement Mega barrel showed up, as did the Rubber City Armory high pressure bolt.  I assembled the upper and checked headspace, all is good.  I had disassembled the lower to fix my buffer retainer issue.  Somehow while reassembling the lower, a Geissele Hi-Speed Match trigger showed up in there ::). This forum is already costing me money... Anyway, when I put the upper onto the lower, the buffer is slightly pressed off of the retainer, as it should be.  The trigger hammer does not make contact with the bolt catch. I believe I've addressed all the issues up to this point.  I'm planning a quick trip to the range Sunday morning. Hopefully I've got a reliable and accurate rifle now :unsure:

 

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Kaz you said      " The trigger hammer does not make contact with the bolt catch."   I thought that didnt sound right...so I just now got off my azz and went to the bunker and pulled out five of my 308's..all different configs except the "twins". every one has the hammer making contact with the bolt catch when shotgunned open with all kinds of different trigger groups...of course when the bcg is present when the rifle is closed its a different story. What you dont  want is the hammer making contact with the lower receiver ...is that what you mean? cause if the hammer even slightly touches the lower that can cause light strikes. the hammer touching the catch where it wont even move is what I have...and my $hit works flawless   :) Wash

Oh and you said this on the first post

 

I found a post on another forum, where a guy had issues with light strikes due to the hammer hitting the bolt catch, thus not putting full force into the firing pin.  I checked mine and, sure enough, with the hammer dropped, the bolt catch is binding.  The hammer rests on the bolt catch, not the firing pin.  Obviously it strike the firing pin hard enough to send it flying forward and hitting the primer.  Most of the time it ignites.  My fix for this was simple, I machined a very small amount (0.025") off the back of the bolt catch.  Basically, I removed the small lip on the rear of it.  I can now drop the hammer and still move the bolt catch freely.  Success, right?

 

NOPE    it aint got nuthin to do with the hammer binding the bolt catch...if its a standard ar308 bolt catch or ar10 bolt catch.... hammer hitting the lower maybe yes    :) Wash

80% lower...hmmmmmmm

Edited by washguy
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Wash, when my rifle was fully assembled, and dry firing (or live firing) the hammer would strike the bolt catch at the same time or slightly before it bottomed on the firing pin. That is not correct. That should never happen. The hammer contacting the bolt catch during operation is taking power away from the firing pin strike. There were two root causes to this. First, this Juggernaut Tactical lower has been a crap investment. The fire control group is slightly too close to the bolt catch. I have verified over and over again that my pin holes line up exactly with their jig. When comparing to drawings if other LR308 lowers I've found, the space from bolt catch to hammer pin is slightly less in mine. Second, the profile of the hammer on the Wilson Combat TTU I was using may have slightly contributed to it. Although a standard milspec hammer I had looked like it had the same profile.

Just to be clear, my hammer did not contact the lower, only the bolt catch. I verified this by marking the parts with ink and then watching where the ink was rubbed off.

Edited by kazuaki
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  Kaz said :   

 

First, this Juggernaut Tactical lower has been a crap investment. The fire control group is slightly too close to the bolt catch. I have verified over and over again that my pin holes line up exactly with their jig. When comparing to drawings if other LR308 lowers I've found, the space from bolt catch to hammer pin is slightly less in mine.

 

Well, that bout sums it up then...you had to fiddle with the tolerance of the 80% lower....I gotcha  :) Wash

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