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Posted: 7/25/2014 12:41:34 PM EDT
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Lower is a Tactical Machining .308 upper a DPMS LR308 LP and bolt is an armsunlimited NiB coated bolt made by APF Armory; the problem I'm having is that the bolt won't hold open on an empty magpul 10 round pmag.
I'd like to try swapping bolt catches but can't seem to melt the threadlocker blue. Any advice on getting the blue loctite out? Also by chance anyone know where I might find a .050 long arm t handle allen wrench? Edit: Bolt catch also does not manually hold open with no magazine. |
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Start by shotgunning the upper open, then inserting a empty mag.
Does the empty mag follower under it own spring tension cause the bolt catch to fully raise. If the catch is just tight in the lower receiver, and the problem at hand, then work the catch with some lube to loose it up in the lower receiver slot. If the problem is not a tight catch, but instead too much return spring pressure that the empty mag follower can not over come, then the catch will need to be pulled so the catch spring/detent channel can be cleaned up, and if needed, the return spring clipped a coil or two (or the channel correctly deepened) so the return spring tension is correct so the a good mag spring with follower can over ride it to get the catch up. As for removing the catch pin bolt, If loctite is in involved, then best to get two .05 allen wrenchs. Use one to transfer heat to the set screw to break the loctite bond with a torch (torch on the allen wrench to transfer heat from it to the set screw to break the bond first), then the new allen wrench to remove the bolt since you just annealed the first Wrench with the torch when you where transferring heat with it. Now back to the upper receiver and lower receiver combo. If the bolt catch is able to be pushed all the way up via the empty mag with the upper open and mag inserted into the well, and then with the upper locked back down you can not pull the charging handle back far enough for the face of the bolt to clear behind the bolt catch, the problems here is the wrong length buffer or buffer spring in play instead. When pulling back on the charging handle, the face of the bolt should be able to be retracted to flush with the back of the ejection port on the LP receiver (non ejection port cover type receiver) to clean the bolt catch. If this is the problem, then we need to know the receiver extension in play (telescoping or fixed stock type), as well as the length of the buffer and buffer spring. |
Most of the 308 receivers uses a threaded type pin, instead of the standard roll type pins on the 223 receives to hold the bolt catch in place.
Granted that is someone when buck wild with the loctite, they could have flowed it to the catch riding bearing area of the allen type threaded pin, but working the catch with lube on the bearing area between the two will break the Locktite free to solve the problem without having to pull the set screw type pin. |
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I've tried heating the wrench and either I'm not heating it long enough or the inside of the set screw may have been rounded.
If it is rounded what would be the way to go about getting it out? Edit: any specific lubricant you'd suggest? At thr moment seems all I can find that I have is rem oil and wd40. Wd40 just sounds like a bad idea. |
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Rem oil with teflon is CLP, and will work fine if there is loctite on the pin shaft/catch to break it loose so the catch does not bind when moving in the receiver slot, on the pin.
Is your bolt catch not moving freely in the lower receiver (with just the light spring return tension pulling it back down) now? When you shotgun the upper open, install a empty mag into the well, is the bolt catch not fully raising all the way up via the empty mag follower now? As for if you stripped the bolt catch bolt pin allen head socket, then it can be removed with a easy-out/screw extractort if needed. It gets a little tricky since you need to use one that will work with a long extension so you can stay straight with the threads using the extractor tool in the stripped out allen socket , and tape up the side of the receiver up so you don't scratch the side of the receiver when using the tool to remove and replace the threaded pin. 
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Quoted:
Bolt catch moves freely now but does not keep bolt locked back on empty mag well. Catch is raised on empty mag but rather than hold bolt back the bolt stops on the follower. Not sure if it make as a difference but I've got a magpul prs stock with an a2 spacer. Need to see a photo of the charging handle pulled all the way back,with the stopping position of the face of the bolt against the back edge of the ejection port window. Right now, it sounds like when you are pulling the charging handle all the way back/rifle cycling on its own, the face of the bolt is not getting behind the bolt catch, but instead stopping way in front of the back of ejection port window. If this is the case, then pull the butt stock back screw and try again. The butt stock screw may be too long, protruding into the back of the tube void, and what is limiting the rearward travel of the Buffer-B/C and why the face of the bolt can not travel past the bolt catch for it to retain the bolt via the face of the bolt. Also, are you using the PRS® Precision-Adjustable Stock – AR10/SR25, for the 308 platform? |
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Quoted:
I am using .308 version of the stock. took out rhe a2 spacer and bolt holds open properly. now I'm back to LoP not clearing the cheek comb if raised @_@ Thank you so much for the help I really appreciate the help I got here over reddits ridicule. Quoted:
I am using .308 version of the stock. took out rhe a2 spacer and bolt holds open properly. now I'm back to LoP not clearing the cheek comb if raised @_@ Thank you so much for the help I really appreciate the help I got here over reddits ridicule. You sure you have the 308 version*, and how did you manage to use a A-2 spacer and have the front of the stock mount up correctly with the back of the receiver ? Also to point out, the butt stock comes with a way shorter butt stock screw that you use without an A-2 receiver extension spacer, so make sure that you are using the correct butt stock screw, and not a longer A1 or A2 butt stock bolt. http://www.youtube.com/watch?v=tw6HnUa7f_o *From Magpul, DO NOT USE THE PRS AR15/M16 ON AR10-TYPE RIFLES DUE TO CHARGING HANDLE CLEARANCE ISSUES! Please order the the AR10/SR25 PRS: PRS Precision-Adjustable Butt Stock – AR10/SR25. Contact Magpul at 1.877.4MAGPUL if you need to convert your current PRS stock to the AR10/SR25 model. So on that note, might want to get Magpul on the phone to go over the problem, since it sounds like you received the wrong model in the package (received the 5.56 unit, and not for 308 unit, and they can get you the needed parts to correct it). |
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From what I understand the cheek comb in the .308 model measures 4 1/2 inches which is what I have.
Box is marked for .308 as well I know incorrect products sometimes get placed in boxes, on the chance it is the wrong one I'll give magpul a call. edit: looked under the sling attachment and it had ar10 stamped underneath. edit 2: spoke to both dpms and magpul the stock and charging handle measured to correct specs. Looks like about my only choice is to shave about 1/8th an inch off the cheek comb. |
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