Great price on BCG
Seems to be a great quality BCG and at a great price! I have not fired it yet, because I still need more parts to finish my build, but with Brownell's warranty I am confident that this BCG will work just fine!
Would you recommend this?
Yes, I would recommend to a friend
New AR Build
The BCG is the heart of my new build (.458 Socom) I have not finished the build yet. But, Brownells BCG looks flawless. Looking forward to completing it soon.
Works
Works as intended. Finish is a little splotchy on the bolt but doesnt matter.
It's your magazine.
I put this BCG in an anderson XL upper, MOS-tek 18" carbine length gassed barrel, rifle buffer/tube (it's off of a MK12 MOD 1 build) and i use C-products .450 duramags. Runs flawlessly and shoots 1/2 MOA with honaday black. Just wanted to clear the air on the 4 reviews that are currently on this page.
600 rounds and counting
ZERO issues in 600 rounds of 458 reloads. HOWEVER I removed the outer rubber donut/extractor booster before I ever used it. Just like in 223, you only donut if you get failures to extract (leave the little insert and spring in the usual places). Very happy with this BCG, especially at the sale price.
REQUIRES SIMPLE MODIFICATION TO FEED 458
This BCG caused fail-to-feed and fail-to-extract issues in my .458 SOCOM. Rounds were jamming nose-up half way into the chamber and I noticed small brass shavings coming from the case rim. The bolt would often close but not go fully into battery, and rounds would be difficult to extract. I learned these are known issues with aftermarket bolts for this caliber, and fortunately there is an easy fix thanks to Tony of Tromix (who developed the original .458 SOCOM). The issue is the extractor. Specifically, too much spring tension. As the round is stripped from the mag moving at an upward angle along the feed ramp, the rear of the case needs to lift into a horizontal position and smoothly center into the bolt face so it will chamber properly. The extractor needs to snap onto the rim easily for reliable feeding as well as extracting. If it doesn't, try this simple modification. 1. Strip the bolt and remove the extractor. 2. Remove the rubber o-ring. 3. Remove the extractor spring from the extractor. 4. Remove the rubber extractor spring buffer from the extractor spring. 5. Invert the extractor spring and reinstall it UPSIDE DOWN. It will no longer seat firmly into the recess in the extractor, so be sure to keep it aligned as you reattach the extractor to the bolt. 6. You're done! Reassemble the BCG, and save that tiny rubber buffer and o-ring in your spare parts collection. You should now be able to wiggle your extractor with a finger. I'm giving this BCG four stars because despite this little hiccup it seems to be a quality part at a good price. My rifle is now cycling reliably. Hope this helps out a frustrated shooter or two!
Poor machine quality
Does not cycle rounds chamfer on the bolt face is way to large leaving little material between the lugs rounds hang up on it
Wrong Bolt in BCG
I Purchased two of these bolt carrier groups a few months back and had nothing but issues with it. Every time I attempted to chamber around it would dent it dramatically. Also the firing pin would puncture the round when fired. I was having nothing but issues with this until I finally did online research and found the issue.. it appears Brownells is using the incorrect Bolt in the BCG. Only after purchasing new bolts from Tromix was my issue fixed. Now everything functions correctly.
Dont buy this bolt. It doesnt feed.
This bolt will not feed reliably, the face and lugs are not cut correctly and the extractor is way too weak. I purchased two of these for different projects and neither one would reliably feed and wouldnt extract every 3rd or 4th round. I tried 7 different types of mags, 4 different brands of barrels and extensions in 3 different receivers (including in some .458 SOCOM rifles that previously ran perfectly) and the result was always the same. When I swapped bolt heads the problems went away and both rifles ran perfectly with any type of ammo including some notoriously finicky RNFP cast bullets.
