300 AAC Blackout BCG not seating fully...

**redsnake** · 03-21-14, 21:36

I finally got to take my 2 AR's to the range today and break them in a bit. One being a 5.56 build that ran perfectly and was great to shoot. The other had some issues and I was hoping to get some input here.

The upper is a Noveske I ordered f/MidwayUSA
Specs:

Specifications:
Upper Receiver: A3 Flat-Top
Barrel Length: 16"
Barrel Contour: Medium
Barrel Material: 416R Stainless Steel
Muzzle Thread Pattern: 5/8"-24
Chrome Lined: No
Barrel Finish: Bead-Blasted Satin Grey
Twist Rate: 1 in 7" Polygonal
Chamber: 300 AAC Blackout
Bolt Carrier: Mil-Spec
M4 Feed Ramps: Yes
Muzzle Device: AAC Blackout 51-T Flash Hider
Gas System Length: Pistol
Gas Block Diameter: 0.750"
Handguard: NSR-13.5, Free Float
Sights: None
Extras: BCM Gunfighter Charging Handle (Noveske Marked)
Weight: 4 lbs, 7.6 oz

The Lower is one I assembled from a Rainer Arms lower, Geisselle Trigger, BAD Selector & Pins, Milspec Buffer Tube w/an H2 Buffer, Magpul Stock and using a Magpul Mag.

I was trying to shoot Factory loaded Remington Premier Match 125 Gr ammo and also trying a couple rounds of some reloads f/a local reloader. Not subsonic rounds. The Remington Rounds are pictured below. The first time I racked the BCG something felt off. The BCG didn't feel or look like it went into full lockup. I wasn't sure since this was the first time w/this rifle and I pulled the trigger and it just clicked... no boom. So I removed the mag, racked the action and reseated the round. This time the rifle fired, cycled the empty and chambered another round. That round fired and then the malfunction happened again. I couldn't get the round to seat fully. I removed the BCG and added some lub thinking perhaps I had it too dry. Still the round wouldn't chamber and now it was hard to actually pull the Charging handle and get the round out. Once I got the round out I put the gun away until I could get home and look it over.

So when I got home I pulled the BCG out, cleaned and lubed it up well w/some Frog Lube. Made sure there was nothing blocking the breach, barrel, or anything else. All looked good so I took her out in the backyard and tried to manually cycle a few rounds. I had the same problem. The BCG would not fully seat (not sure this is the proper terminology) and it appears the bullets are getting nicked up when trying to load them. I'm not sure if something is wrong w/the breach face or chamber or if it's something simple I could fix.

Hopefully these pics help. Here's the pics of the way the BCG locks up before fully seating the 300 AAC round. Also a couple pics of the bullets I tried to load and you can see how the brass looks a bit nicked up. Any ideas what could cause this? Is this something I should take up w/ MidwayUSA and possibly seek a replacement? I appreciate any help or suggestions.

**aguila327** · 03-21-14, 22:04

Switch bolt carrier groups in the rifles and see if it works in the 5.56 or if the 300blk Upper chokes the other bolt carrier.

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**VLODPG** · 03-21-14, 22:33

I don't know if this will be the same for your Noveske but my PSA had one of those "O" rings around the extractor spring. It would do exactly what you described
until I removed it.

.

**discreet** · 03-21-14, 23:02

You have a 2nd bcg, why did you waste time cycling rounds and chewing up rounds? Just put the 2nd bcg in and see if the issue is still there. If it's not, you have a good idea of what is causing it then. From there you'd see if it is a carrier or bolt issue etc.

If it chokes on the 2nd bcg you have narrowed it down quite a bit.

Unsure at how you didn't notice how far the carrier was out of battery before trying to shoot. Fairly quick and easy to see the bolt isn't locked.

**Iraqgunz** · 03-21-14, 23:29

Exactly what "milspec" BCG was this? Something like the AR Stoner line of trash?

**redsnake** · 03-22-14, 09:47

Thanks for the info. I am a bit of a newbie at the AR building game but not shooting. The picture I posted is somewhat over-exaggerated to what first happened at the range. It appeared to be fully in battery on the first shot attempt. I recycled the round and it functioned. After a couple attempts w/the failure to go into battery is when I put it back in the bag and didn't attempt another shot. When I got home I cleaned and lubed it up really well (even though the rifle was new) and got the rounds to malfunction as pictured. I'm not too worried about roughing up a couple rounds of ammo while trying to figure this out. The BCG cycles perfectly until I put a round in the mag and try to chamber.

Iraqgunz... No idea really who made the milspec BCG. I assumed (I know that's not always a good thing) that since this upper was assembled by Noveske it would be of good quality. Again, another assumption. :\

Since I spent the better part of the day at the range yesterday w/my 2 sons, today the wife and I are doing some running around and 'honey-dos' so I'll get back and try these suggestions later today and report back.

Again, I'm very appreciative of the suggestions and help. Best way to learn for me is hands-on.

**Onyx Z** · 03-22-14, 10:49

It sounds like you may have a tight, out-of-spec headspace or chamber. I loaded up some rounds that would chamber just fine in an older barrel that had to be replaced. They wouldn't chamber in the new barrel, which has a tighter, but still in-spec headspace. This is fairly unlikely since manufacturers headspace their brass well under the SAAMI limits, but I would look into it as a possibility.

This doesn't seem like something Noveske would let slip through QC though...

**redsnake** · 03-22-14, 19:33

Originally Posted by Onyx Z

It sounds like you may have a tight, out-of-spec headspace or chamber. I loaded up some rounds that would chamber just fine in an older barrel that had to be replaced. They wouldn't chamber in the new barrel, which has a tighter, but still in-spec headspace. This is fairly unlikely since manufacturers headspace their brass well under the SAAMI limits, but I would look into it as a possibility.

This doesn't seem like something Noveske would let slip through QC though...

I think you might be on to something. I swapped out the BCG from the 5.56 that functioned fine at the range. Put it into my 300 and tried the same procedure... and the BCG would not go into battery. Round felt a bit 'jammed' into the chamber.

So I laid the 2 rifles side by side and slid the 5.56 round into it's appropriate upper and did the same for the 300. The 5.56 seated fully whereas the 300 brass never seemed to seat into the chamber fully. I tried to capture the difference in the pics below. The 300 on the left and the 5.56 on the right.

If the chamber of the barrel is out of spec (too tight) is this something that should be returnable to the manufacturer or MidwayUSA or would I just need to replace the barrel? I'm not sure where to go from here. I would think that this upper being a Noveske Assembled unit this wouldn't happen.... but I know issues can slip by even the best companies.