BROWNELLS 308AR BOLT CARRIER GROUPS - BROWNELLS 308AR BOLT CARRIER GROUP 308 WIN NICKEL BORON MP

Good Looking BCG, packaged good and shipped quick, I was glad to see a JP style firing pin retaining pin on this BCG, GOOD Value on the sale price...

I was having headspace problem with my new build, aero M5E1 upper, ballistic advantage barrel & a aero precision bolt, while using a forster headspace guage the bolt would not turn on the GO guage so I decided to swap the bolt for the brownell's nickle boron & it worked perfect. Ran about 150 rounds (6.5 creedmore) & it worked flawless, no jams/malfunction what so ever, only downside is when I received the bolt it was full but after polishing it was amazing.

I purchased the BCG for a build off an Aero Upper and Lower set.



The BCG is nice for the money, however my gas key hole was .007" undersized which resulted in the destruction of a gas tube. Fortunatly I had a reamer (.1805") for gas tubes and was able to use the reamer to bring the gas key into spec.



I chambered and headspaced the barrel to this bolt with no problems and once I get the kinks worked out I believe this rifle will be very reliable and long lasting.



Overall I am happy with the bolt due to its price point and decent quality. I believe I got a gas key that simply had a little build up of NiB in the bore causing it to be out of spec.



I spoke to tech support about this issue and they were very helpful and willing to exchange it immediately, however I want to try and make this one work due to my barrel being headspace to this bolt.

I have several of these bolts and have had the same issue with both of them. Looking at the bolt face of the Extractor, the bevel on the Extractor does not line up with the diameter of the bolt recess. With the Extractor bevel not in the correct place the round is picked up and slammed into the chamber. The Extractor does not catch the edge of the shell and will not eject the shell. A simple fix is to remove the Extractor and increase the bevel so it will slip over the shell and seat it in the bolt recess. A good value BCG but not Military Spec. After the modification the bolt works without issue.

Actually Zero Stars - It was pretty, but on my specimen of this bolt, the individual bolt lugs measured .308" to .309" long and the bolt face recess measured .123" deep, which resulted in the bolt failing to reject a top quality NOGO gage in a well respected, high-end barrel brand. (WIN 308 headspace is 1.6300" to 1.6340", only .0040" total tolerance range and the barrel/extension combo gets part of that). I tried bolts from three other rifles in my shop and all firmly rejected the NOGO gage in this barrel. I talked with a Brownells' tech and he told me the lugs should be .312" and the recess should be .128" according to their manufacturer. My measurements showed this bolt to be way off the manufacturer dimensions. In my opinion, even if it were correct to the manufacturer's dimensions, it would likely still fail on the NOGO gage based on my experience (bolt face recess too deep). On many other AR-308 bolts and barrels used, I have found that bolt lugs measuring .312" to .313" long and bolt face recesses measuring .1245" to .1255" deep will headspace properly in good quality barrels. There is some info to support these dimensions on the web, but I could find no manufacturer dimensions. Rifle building hobbyists, BEWARE, there is no MIL SPEC for AR-308 rifles or parts, like on M4 and M16 parts used in AR-15s. Each AR-308 part maker chooses his own dimensions and tolerances. Every bolt/barrel combination should be headspaced for best quality, accuracy, and safety.

Got this BCG the other day for my Aero M5 build. The machining on this bolt is superb. Their are no sharp edges anywhere. I have not shot this but I do have previous experience with their AR-15 M16 nitride bolt, which runs flawlessly, and will continue to do business with brownells. I know the .308 is a completely different animal when it comes to parts but the quality of their products are barnone. This will hopefully be mating up with a ballistic advantage DPMS cut barrel extension. Can’t wait to get this rifle barking.

I bought this for my Aero Precision M5 build, and although I’m only half way through, this bolt looks great. There’s no sharp corners or edges and looks very well crafted. Thanks Brownells.

Runs flawlessly in my PSA10 gen 2. It’s runs smooother than the original bolt Carr group.

This carrier is made so well, the machining and finish are perfect, smooth, slick, no machining/ tool marks, no burrs. No sharp edges, fits perfect



I'm super impressed, and I'm a machinist, I haven't seen any others better than this in any way



Go brownells!!!!!!!!!

The nitride finish is perfect. Functions flawlessly in my 6.5 Creedmoor with Ballistic Advantage barrel. Forward Assist serrations are on this bolt carrier and work as expected.

Great product. Thanks Pete.

This bolt is made of the same high quality material as other more expensive ones. Fit and finish are top notch. Headspaced to my Ballistic Advantage 6.5 Creedmoor barrel perfectly. Haven't shot it yet, but the first impressions are phenominal.