Modern Sporter - Build Discussions

Rayf01 said:
With the talk regarding buffer tube length and cycling, am I going to run in to an issue using a standard mil spec tube, buffer and spring? I was trying to budget a little less and found a set from True North, but want to make sure it will work. Unless I need to go with the PWS tub which is substantially more.
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Try the aero enhanced buffer tube, it’s much cheaper than PWS but offers the lip. Realistically 98-99 percent of the time you won’t notice it but using mil spec mine is actually on the shorter end of the travel and did cause problems twice.
 
What I found was using a milspec buffer tube once the gun broke in I was having failures to lock back around 80 percent of the time. When I would check clearance pulling the charging handle back it looked like I had about 2mm of clearance. But to really test it I took the upper off the lower and put the buffer in the buffer tube without a spring, then pushed the bolt as far as it would go forward in the carrier, then slid the bcg into the buffer tube. This showed me clearly that without modification the bolt face wasn't clearing the catch by about half 1mm. When you pull the charging handle to check clearance your not actually getting the bolt pushed all the way forward in the carrier unless you physically do push forward while holding the charging handle back. Also have to consider play in the bolt catch because it will tilt slightly back when the magazine pushes on the front of it. This is just my experience with the problem and think it is too bad Atrs has this oversight. Either way the pws tube worked good for me but it does bother me that I am missing 1 thread of engagement on the buffer tube to make my gun function with an unmodified buffer. Also on modified buffers be careful on how much you cut off the bumper because the bolt may contact the rear of the reciever. Mine contacted after I trimmed a 1/4 inch off. No contact and locks back now with pws tube turned out 1 turn with regular buffer.
 
J.L.C. said:
Are guys with the JP SCS system facing the same problems?
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I haven't experienced any issues with my JP SCS, but..... I also haven't encountered any issues on the standard buffer systems we've assembled, nor has anyone brought one in to show us this issue.

I'm not saying it doesn't exist, but I am saying I haven't seen it, and we have not been able to duplicate the issue in house.

I have not seen any evidence, so if one of you guys who are experiencing this is in the Calgary area, please stop by the shop so we can take a look at it.


What I have seen that could contribute to this, and why perhaps I am overly skeptical:

I HAVE seen that a shipment of US made, commercial spec receiver extensions came into the country that are not properly sized internally with a large bump inside and have seen buffers get jammed up in them.

I HAVE seen several commonly available Canadian barrels with undersized gas ports that we've had to open up.

and

I HAVE seen people using AR10 buffers and springs, without knowing it. (the buffer is visibly different, the spring is harder to tell)

And seperately, I have also seen that a huge number of LAR15 magazines using orange followers came into the country, where the magazine was deformed during production causing the front corners to actually be crushed making pointed tips that stick outwards and scratch up the inside of any receiver they are used in. If you have them, check them, if they are pointed, file them. [We do not carry them, nor have we ever sold them]
 
ATRS Shaun said:
And seperately, I have also seen that a huge number of LAR15 magazines using orange followers came into the country, where the magazine was deformed during production causing the front corners to actually be crushed making pointed tips that stick outwards and scratch up the inside of any receiver they are used in. If you have them, check them, if they are pointed, file them. [We do not carry them, nor have we ever sold them]
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Sanded down the sharp points a long time ago with 220 and 1000 wet sandpaper.

These came from SFRC in 2013.


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Yeah there's got to be a million of those things in the country, some are fine, some appear to have gotten slightly crunched when being folded in to shape.
 
Finally got to assembling my ss upper/lower the fitment is a little looser then I would have liked, but the more bothersome issue is that pmags and Mil-Spec mags have to be jammed in and pulled out,it seems like too much material in the front of the upper receiver mag well area
 
5HoursNorth said:
Finally got to assembling my ss upper/lower the fitment is a little looser then I would have liked, but the more bothersome issue is that pmags and Mil-Spec mags have to be jammed in and pulled out,it seems like too much material in the front of the upper receiver mag well area
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Sorry to hear that, mag fit issues seem to pop up often. Gotta say that’s my biggest concern with the receiver set I’ve got on order.
 
5HoursNorth said:
Finally got to assembling my ss upper/lower the fitment is a little looser then I would have liked, but the more bothersome issue is that pmags and Mil-Spec mags have to be jammed in and pulled out,it seems like too much material in the front of the upper receiver mag well area
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My buddy has 2 uppers his slick side upper has this sameproblem ( too much material in the front magwell area- colt 5/20s dont fit at all). His forward assist upper accepts mags much better. Seems like not all upper receivers are the same dimensionally
 
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It might just be a fluke of a problem. All my SS and FA uppers don't have an issue with accepting or dropping mags, even if I interchange the lowers. I'd say just contact ATRS.
 
Zero issues with my buddies.
All mags fit and drop free.
Not much of any wiggle.
Superb overall quality and anodizing.

Only issue was a mil spec buffer tube that was a touch too short causing failures to lock back on empty. Since corrected.

Theres a few I have read about some mag fitment issues related to the mating of the upper and lower and I'm pretty sure that ATRS was quick to offer support and remedies.
 
5HoursNorth said:
Finally got to assembling my ss upper/lower the fitment is a little looser then I would have liked, but the more bothersome issue is that pmags and Mil-Spec mags have to be jammed in and pulled out,it seems like too much material in the front of the upper receiver mag well area
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G#% Da%#!^&... I thought we got all of those, but one or two keep popping up. Please send an email to info@albertatacticalrifle.com with a picture of the inside of the magwell with upper attached, focusing primarily on the front wall of the inside of the magwell. We'll get you taken care of.

G.Mitchell said:
Sorry to hear that, mag fit issues seem to pop up often. Gotta say that’s my biggest concern with the receiver set I’ve got on order.
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2 Criteria:

(1) Slick side upper,
(2) produced during a small period of time where if I recall the 4th axis on the machine was not repeating properly. [This later resulted in a complete rebuild of the 4th axis, putting that machine out of service for over two months].

Now the fact we are making uppers in one batch, then changing machines over and making lowers, then switching back and forth, is what has resulted in maybe about 20 of these getting mixed and distributed to all random areas of orders, so I can't just say 'orders between here and here, check for this'. :(

The good news for anyone waiting on a slick side, is we are completely and utterly OUT of slick sides right now, so there are no more with the magazine issue that could inadvertently get mixed in... The drawback is that by the time we realized there was a problem, they had all left already.



auracle said:
My buddy has 2 uppers his slick side upper has this sameproblem ( too much material in the front magwell area- colt 5/20s dont fit at all). His forward assist upper accepts mags much better. Seems like not all upper receivers are the same dimensionally
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Tell him to send an email to info@albertatacticalrifle.com with a picture of the inside of the front of the magwell, and I'll get him taken care of. Thanks.
 
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