DustinIL

Latest Update: Went to the range real quick yesterday to try out an Accuwedge and three other types of magazines (25 rd Pmag GenM3, DPMS, and CPD)...........No change. Charging handle keeps coming back. Even worse, things actually regressed, i.e. I even tried single loads again without a magazine inserted and the charging handle came back. FWIW I was using Austrian milsurp. I was still using the BCM charging handle. There's still enough of a ledge on the latch side that when I pull on the opposite side (non-ambi) that it won't release. At this point I don't know what the nuts to do besides take it to a gunsmith and see what can be done, if anything. The kicker is I even emailed the maker of the upper to see if they could give me the inside dimensions of their upper so I could try some measurements...just crickets, and no one answered their damn phone. So......yeah.

I've never used an Accuwedge, but $5 is a lot cheaper than what the heavier buffet and spring cost. The BCG I used today is phosphated. I used it to compare with my nickel boron one. Taking off some anodizing from the CH can't hurt at this point.

Update: Just got back from the range. I started with 5 rounds loaded without magazine inserted and using a buddy's DPMS BCG. Near as I can tell the charging handle didn't move back (was by myself so no way I could possibly record on phone and try to slowmo); had it braced against my bicep so I could keep my head back to watch. Second 5 rounds I used a magazine... charging handle for sure moved back. Magazine was not resting on table during shots. Moved during all 5 shots. For last 10 rounds in box I fired without magazine inserted. No movement as far as I can tell. Even shouldered normally and put a finger in front of CH to check for movement, none noticed. Magazine used was a 20 round pmag (few years old, but barely used). So I'm guessing either mag lips too tall for the DPMS lower? Or not enough space in upper where BCG and charging handle are on top of mag while I'm battery? What's my next move? Oh yeah, almost forgot. I had also put some white touch up paint on underside of CH and so no signs of rubbing or other contact.

I totally believe it and am most appreciative of the wealth of knowledge and help you guys have given me.

Thank you very much! I tried looking for the specs using the site search (I even read the thread on how to do it right, lol) and wasn't having any luck.

Good ideas Robocop. Out of curiosity are the specs for the BCG in a thread here so I can at least use a micrometer on mine? (Looking now too for specs)

I was able to go to the range real quick to try the new heavy buffer and spring and.......no change. Charging handle still comes back; not every time, but at least half the time. At this point I'm about to kick it to the curb. I even tried two different and new charging handles and still happened. I didn't feel any difference in recoil impulse with the new buffer and spring vs. the lighter one I have. All brass ejected just fine and bolt stayed back on empty mag. When I got home I didn't break it down to see if anything had rubbed due to being in a sour mood. Will try to take a look next day off. Short of taking it to a qualified gunsmith, any suggestions?

Sadly I didn't have time over this past weekend to measure or try out the heavy buffer and spring. But I do have a question: During the roughly 60 or so rounds I've put through it so far I didn't have any issues of short stroking, which according to this thread, https://forum.308ar.com/topic/16799-gas-tubes-and-barrel-gas-ports/, could be a symptom of a too short gas tube. Granted, my tube isn't nearly as short in the recess as others are. I'll still try to measure on my next day off, but I was just wondering. Thanks again.

Does it look like the gas tube is right length or tad short?

Current update: I went ahead and bought a new buffer and buffer spring after consulting with Clint from www.heavybuffers.com. According to usps.com it was delivered today. Not sure I'll have time tomorrow to try it out. But with that said, after reading up on the pinned posts about all the particulars regarding .308 ARs/AR-10s, is it possible that the gas tube I used is incorrect (too long)? Before coming here, I just realized I've never seen a gas tube labeled as AR15 only or AR10/LR308 only; just gas tube by length (pistol, carbine, mid-length, intermediate, rifle). I'm just starting to doubt myself on just about everything with this build (except the lower, I guess). Silly me, when I first started to buy parts to build my first .308 AR, thought the main differences between the top two contenders (AR-10 vs. DPMS-type) were the shape of the upper receiver and the magazines used. Holy crap was I wrong. Apologies for the lack of pics. Since all this began I've been working as much OT as I can get and also remodeling my basement on days off, so not too much spare time.

First of all, your Google-fu is better than mine 98Z5V. I have no idea why my searching for an answer didn't find this. Thanks. Second, I failed to mention in my last post that I had swapped out the ZEV for a BCM. Now, is the BCM also a bad design? Highly unlikely, but possible. Or two different charging handles with the same result indicate an issue elsewhere? Apologies for the lack of a pic. I'll try to post one tonight or for sure tomorrow.

Charging handle UPDATE: Finally got some spare time the last couple days to look the rifle over and look for any other signs of what could be going on with the charging handle coming back. I took the upper half off, turned it upside down, and moved the bcg back and forth by hand. No signs of the bcg dragging/binding on the charging handle. No signs of wear at all on underside of charging handle where gas key goes. Also no signs of abnormal wear on the top of the charging handle where it goes against the upper and vice versa. After moving the bcg back and forth by hand and with a varying the speed of movement, I noticed that the back of the gas key is striking the back end of the underside of the charging handle. I put a little bit of white touch-up appliance paint on back end of CH and moved the bcg back and forth again; noticed two small marks in paint. This point I decided to take the rifle and 10 rounds to the range and just watch the charging handle as I fired. As expected the charging handle came back a couple inches 6-8 times. I pulled the rear pin and checked the paint on C.H.; same two marks. So with that said, what are my options to fix it? With no standardization with 308 ARs do I try another brand of CH (with longer recess for gas key to travel, if available)? Different buffer weight, spring, both? By chance the gas key on the Brownell's bcg bigger/taller than others? Or is there something else I should check first? Midwest Industries Handguard update: after a helpful discussion with Andy from M.I. and obtaining some more Vibra-tite 548 (bedding compound) and a small torque plate for the handguard screws, I cleaned off the old 548 and applied again more thoroughly, used the torque plate and reinstalled. I let the 548 cure completely without doubt and to check to see if it moved during the 10 shots mentioned above I put a mark an indexing mark on it with sharpie. I'm happy to report that the handguard didn't move this go-round. Once I get the CH figured out (I really, really, really hope that it's not the upper receiver at fault) the next step is to do some groupings and hopefully run it in a training class to so if it's truly GTG. I would definitely like to give a shout out to M.I.'s customer service and Andy in particular. I'll make a post about it soon.

You are correct on good deals being out there, for all makes actually. I just kind of ballparked $200ish because I even scored my MI on a Black Friday sale for less than $200. I'll keep an eye on SLR.....not like I didn't buy an Aero lower for ~$100 on Brownells a couple weeks ago and might be "forced" to do another build.

Nice. I'll have to check them all out next day off. Weird part is that I wasn't over torquing the screws; rail started to rise beforehand. I fooled around with it again yesterday and got some insight from Andy at MI and I think found a solution.

Thanks for the tip. I forgot about Hera.

Yup, saw that one on MI's website.

Nice. Thanks for the tip. I'll keep an eye out for them.

Totally wish I could. Sadly, in my case, Aero's are all made for the "high" style from what I've seen. Oh darn, guess I'll have to snag an upper on sale sometime.

Good point about the brass. From what I remember I didn't see any issue with the brass when I picked it up, but I'll take a look at it again when I get home to confirm. I used a mix of some milsurp and commercial for the barrel break-in; they all felt the same and "normal" for a .308 to me.

It has indeed rounded the outside of the latch indent. That's when I looked at the design of the ZEV latch and its angles on front and back, vs. a more traditional style latch with the more square/90* profile like a BCM or mil-spec type. Oddly though, when I first had the rifle completely built I did have to use a little oomph to rack it for function checks because the ZEV's latch doesn't use a rotation pin to help unlock the latch. Assuming everything on my build is in spec and running fine, i.e. not over gassed, no parts binding etc., would the ZEV worked fine and not be forced back, or is there an issue somewhere that caused the ZEV to be pushed/pulled out of lock and hence wear down the CH ledge of CH indent?

Hello again. I'm looking for possible handguard options in the worst case scenario that I can't get the MI one I have now to work correctly (see other thread I started for info if interested). The upper it'd be going on is a Guntec USA "DPMS style low" type. Preferably mlok and $200-ish or less, if possible. Thanks.

Hey 98Z5V, thanks for the response. You are correct on the application of the Vibra-tite VC-3 and 548, and Loc-Tite. I didn't use the MI supplied Vibra-Tite 548 on the two screws to attach the rail, only on the surface of the barrel nut as per MI's instructions. I used blue (medium) Loc-Tite on the screws. Is dried 548 as easy to remove as VC-3, or do I have to do some light scrapping/chipping to get it off? Or can I apply another layer over the dried stuff and it'll still work, like when reapplying VC-3?

Hey washguy, thanks for the response. Yeah, I probably should have looked further into the ZEV; silly me thinking ZEV was a decent company and I got it for a reasonable price IMO. Well, according to the packaging from the upper receiver I used it says it's billet so I don't know. I've already swapped it out for a BCM I was able to find and the ZEV will go into the "Bin of Misfit Parts". Next day off I'll have to try the BCM and see if it comes back during firing. But the question remains, is the ZEV's latch design flawed and therefore would come back during firing no matter what, or is there still possibly an issue pushing it back? As far as the MI rail goes, I like the feel of it; it's lightweight, slim enough for me to get a comfortable grip, and plenty of places to put rails. BUT, MI should have put the issue with threads possibly showing depending on upper brand on the actual page of the rail itself and also on the packaging with the instructions, not somewhat hidden on their FAQ page. IIRC only about 1/16" was need to be removed from inside the barrel nut and pict rail on top for it to fit flush, so not really a deal killer overall, and I don't think its structural integrity was compromised. But, would have I bought it knowing ahead of time the thread thing? Doubtful. Again, like the ZEV, bought it for good price on Black Friday sale and from a reputable company. And question remains with it: why does the muzzle end now raise up when I tighten the rail screws when it didn't do anything like that the first time?

Hello all. I haven't posted in a long time, but have lurked now and then. As the title states I could use some help with diagnosing a couple issues with my Franken-build .308AR. I was hoping I had done enough research to avoid a post like this, but nope. I apologize if this post becomes long winded, but I wanted to make sure as many details are listed as possible for best educated guesses/diagnoses. So with that said I will list the parts I used for my build for background: Upper: Guntec USA (DPMS-style low, lightened with cutouts, Gen 1?) BCG: Brownell's, BRN-10 chrome Charging Handle: ZEV Technologies Handguard: Midwest Industries, MI-308SS15-DLM Lower: DPMS Lower Parts Group (minus FCG): DPMS FCG: ALG Defense ACT Stock/Buffer tube: ERGO F93 Buffer spring and buffer: unknown make/model bought in a kit (https://bkingsfirearms.com/shop/ar10-spare-parts-lower-parts-kit-upper-parts-kit-and-triggers/ar-10-308-six-position-buffer-tube-kit-w3-8-oz-buffer-mil-spec/) Barrel: Ballistic Advantage 16" Hanson profile, using their low-pro gas block and gas tube After buying parts during the course of a couple years (waiting for sales, etc.) and having parts Cerakoted, I finally put it together a couple months ago and did the barrel break-in per BA's instructions a couple weeks ago. NOTE: to make the handguard fit how I wanted (none of upper receiver threads showing, which can happen with some brands of uppers per MI's website, which I didn't know until first "mock up" assembly) I took it to a gunsmith and he removed just enough metal from inside the barrel nut to make it fit flush with the upper receiver and just enough metal from the top of handguard to match. After this was done everything went together just fine. ISSUES encountered: About half-way through the barrel break in I felt something touch my nose, and immediately checked the charging handle. Upon inspection I saw that the "shelf" that the CH "claw" rested on had been work, considerably (see pic). To be honest I only got the ZEV because it was an ambi CH for a reasonable price and because I couldn't find a BCM one at the time. Also, while looking closer and the ZEV CH's claw profile, I noticed that its profile is different than other CHs I've used/seen (see pic). Even with the different profile, I wouldn't expect the CH to go back with the bolt even everything as was running right, but I don't know what I don't know about .308AR particulars. Also, I noticed that the handguard had started creeping forward as well; simple fix I thought by re-tightening the two screw at bottom of handguard (the screws were torqued beforehand per MI specs). Nope, handguard creeped forward again. So dear readers and Wizards of .308AR Smart I come to you for help. Does the ZEV CH just have a bad claw design and therefore was destined to now work like other CHs (I did finally score a BCM charging handle after this, and it has the more "traditional" squared claw), or should it have worked correctly and something else is causing it to be forced back (over-gassed, gas leak, etc.)? I saw no abnormal wear on the CH or inside the upper that isn't out of the ordinary during typical use, especially after being racked a few times during assembly, etc. As for the handguard, I did email MI yesterday to pick their brain. Guy I was in contact in is thinking I might have not used enough of the bedding compound (Vibra-tite 548) that came with the handguard. To be fair they didn't say how much to use so too little use is definitely a possibility on my part, and possible need to score up the inside of the handguard that goes over their barrel nut for more surface area. With that, any suggestions on how to remove dried up bedding compound so I can apply a new layer of Vibra-tite, or do I try just getting more and putting it over bare spots and what's already dried on it? I responded to him that I'd check what he suggested, but the main issue I'm having with the HG is that when I tried to put it back on, when having it lie on a flat surface to make sure the upper and HG are square and flat with each other, when I start to tighten the two screws, and it doesn't matter which one, it causes the muzzle end of the HG to rise. I did NOT have that issue when I first put it together; not sure if i hand tightened the screws too much at the range (didn't have my torque wrench with me) or what. Again, my apologies for this novel. I have tried scouring posts here to find similar issues, but no luck so far. I hope they're simple fixes, but with me being a tad frustrated that I couldn't figure it out yet has my mind going down the rabbit hole and assuming the worst that I have to buy new parts and basically rebuild the thing.....sigh. I can't give any other detailed pics at the moment (at work), but can try to take some later, family time willing this weekend. If not then, for sure Mon. or Tues. Thanks again for sticking with me this far and for any/all help offered.

My question would be is it breaking because of the steel ammo, or were the extractors made of inferior steel and therefore would have broken eventually regardless of case material? Please don't get me wrong, I totally understand the reasons given for not using steel cased ammo, as mrraley stated. My only response would be that my guns aren't meant to be safe queens and therefore will only get XYZ type ammo through it. The only gun I have that I worry about what type of ammo I use is my M1 Garand, and that isn't about case type, put powder type and risk of damaging the oprod. Using the expensive car analogy, of course run what fuel is recommended, but they also recommend only form XYZ gas stations and even only ABC oil brand.....which is the same as nearly every other brand, but whoever made the deal with the automaker to be put in owner's manuals and some "advertising". If your gun maker starts mandating FGMM or Black Hills match ONLY in your gun are you going to do that? Until I see a thorough testing comparison of steel cased ammo being used; durability, reliability, etc. in an unbiased testing platform I'm taking the anti-steel cased opinions with a grain of salt, as all of us should do when reading info from the interwebs. Again, YMMV and it's your money and gun. If someone is willing to do some T&E with a donor gun, I'd be willing to chip in for the cost of ammo. But when I say a thorough test, I mean THOROUGH: using as many types of steel cased ammo as you/we could get our hands on; Wolf (WPA black box and mil. classic), Brown Bear, Tula, Silver Bear, Golden Bear, Golden Tiger, Ulyanovks (sp?), and others I don't know or forgot, with as many bullet types and weights as possible. Again, my thought is that with today's metallurgy knowledge and advances in manufacturing, ARs and AR bolts, bolt carriers, extractors, etc. can't be made of superior materials than "soft" steel used for ammo cases? Or how about this: instead of trying the polymer or lacquer coated steel cases, try the zinc plated (Silver Bear, MFS, etc.) or brass plated (Golden Bear) ammo?