warthog984

Magpul UBR uses AR15 carbine length buffer tube. I have a DPMS 308 Carbine buffer and spring from Midway USA. What I notice is when I hand cycle the round, it pops out of the magazine feed lips and goes at an awkward angle. The rounds seem to bind on top of the chamber. I have no problem with extracting and ejecting the ammo if i stick it in the chamber and close the bolt. The bolt carrier group was bought as a complete unit from Midway USA also.

Hello.....This issue is driving me nuts. I just built a new AR 308 and i cannot get the bullets to feed into the chamber when I charge the handle. I have tried three different ammo types. AE 150gr., Federal 168gr., Prvi 168gr. All of them strip from the magazine but hang-up about 3/4 into the chamber. It almost appears that the angle is too steep when being fed into the chamber. On the one side of the brass you can see rub marks when I pull the brass out. Also, the bot pushes so hard on the brass while it is in the chamber that I have to pull real hard on the charging handle to get it out. The weird thing is that it does not get to the point where the bolt extractor grips the bullet case. The bolt lugs are only touching the case. I have verified that the bolt does go back far enough into the buffer tube. The bolt catch works when the mag i empty. I tried using PMAG Gen 2 and Gen 3 mags. Parts are listed as the following: Aero Precision Upper and Lower combo Mega 16" barrel Rainier Raptor charging handle Magpul UBR DPMS carbine buffer DPMS Carbine buffer spring DPMS BCG I did head space the barrel and bolt and it passed. I can put a live round in the chamber and the bolt closes and extracts when I pull the charging handle. If I lay the gun down on its side resting on my table and pull and release the handle slowly, I can get it to feed on occasion. I broke one rule that I have never done in the past. I bought a product that just came to market (Aero Upper and Lower in 308). I have had really good luck in the past with Aero Ar15 lowers. I figured they are good to go. Not sure if this problem is related to the lower or not. The M4 feed ramp cut outs look like poop on the upper. I dont think this is the problem since the brass will feed 3/4 into the chamber. I dont know if the m4 feed ramps were cut at the wrong angle on the barrel extension. Seems to be at an odd angle. This is my first AR 308 build. I have build about 20 AR 15s with no issues like this. I have lubed the hell out of the bolt carrier. I used Brownells Action Lube. Very slick.I am running out of ideas.

Thanks...On page 3-4 it talks about my exact issue. I also have a DPMS bolt carrier. Not sure if I want the Phase 5 bolt catch. I like it simple. I may modify the Armalite if the DPMS fails. Also, the Aero upper does not have a large cut out for large head bolt catches. I dont know if the Phase 5 would fit.

Hello, This is my first post and first AR 308 build. So far everything has gone well. I purchased a new Aero Precision Upper and Lower combo. Aero says that the parts kit is DPMS compatible. Based on other topics on this forum, I gathered that the Armalite bolt catch is stronger than the DPMS. I bought two Armalite AR10A bolt catches, but neither will hold the bolt closed. I also have a DPMS 308 bolt catch and it works. The Armalite does not have enough travel. It seems like it is too thick on the area that touches the bolt catch plunger or the lower receiver. Just curious if anyone encounter this issue with other manufacture lowers. Also, is the current DPMS 308 bolt catch from Brownells any better than the ones in the past that broke?