+1-800-504-5897 Help Center Check Order Status
About Us Policies Reviews How To
Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Enjoy free shipping during the holidays! Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC and to all U.S. Military APO/FPO/DPO addresses.

Enjoy Our Extended FREE RETURNS

We want to ensure that making a return is as easy as possible! With our Hassle-Free, Extended Holiday Returns, eligible orders placed from November 12, 2025 on will benefit from an extended return deadline (January 13, 2026 or 30 days after receipt of your order - whichever is later). We'll even cover the cost of return shipping. Learn more about our Return Policy.

  • Entire Store
  • ...
  • Apparel & Footwear
  • Astronomy
  • Everything Else
  • Eyewear
  • Hunting Gear
  • Lab Equipment
  • Military Gear
  • Outdoor Gear
  • Photography Equipment
  • Police, EMS & Fire
  • Shooting
  • Sport Optics
  • Sports & Hobbies
TIP
Shopping Cart

Reviews & Ratings for Maxim Defense Industries Universal 9mm Bolt Carrier Group (BCG) w/Weight Plug — 15 reviews

(15 reviews)
Maxim Defense Industries Universal 9mm Bolt Carrier Group (BCG) w/Weight Plug
Maxim Defense Industries Universal 9mm Bolt Carrier Group (BCG) w/Weight Plug
Currently Unavailable View Product
Write a Review
Compare (0)
1 item has been added
Add at least two items to compare
Most Helpful Positive Review Maxim Defense Industries Universal 9mm Bolt Carrier Group w/Weight Plug
Maxim Defense Industries Universal NB 9mm Bolt Carrier Group w/Weight Plug demo units. Mine looked LNIB, functioned perfect in a 9mm carbine as well as a 9mm pistol build using colt SMG type magazines, NB coated for easy cleanup which important in a blowback type firearm.
Most Helpful Negative Review unimpressed
Ran about 100 rounds through an ar 9 build with this bcg. Ran fine but it wasn’t until I tried to unload the gun that I notice the extractor came out at some point and disappeared. The gun actually ran on just blow back and the ejector. Pretty disappointed that it came out that quick though. Injury ...
Read More...
Show
Sort by
Filter by

Maxim Defense Industries Universal 9mm Bolt Carrier Group w/Weight Plug

by Luke, Verified Owner from TX, United States Written on March 25, 2020
Best 9mm BCG for the money! Can’t find It anymore affordable then what Optics Planet offers it for! It’s listed as a demo unit, mine looked brand new! Functions flawlessly in my build using parts also purchased from here.
Pros:
  • Did not have to spend $300 for a quality BCG
  • Did not have to spend $350.00 for a quality BCG. Functions Flawlessly!
Cons:
  • None
Would recommend: Yes
0 of 1 found the following review helpful.
Was it helpful to you? Yes | No
Share

Great priduct

by Dan, from KY, United States Written on March 1, 2020
great price and great quality. Fast shipping.. shipped out next day and received in 2 days. Highly recommend this BCG. Fit into upper receiver perfectly. Head speced perfect to my stainless steal barrel.
Would recommend: Yes
1 of 1 found the following review helpful.
Was it helpful to you? Yes | No
Share

Ok, chalking it to demo

by Gerald, Verified Owner from NC, United States Written on February 8, 2020
I had failure to fire after about 300 rounds using rhis bcg. After pulling apart the bolt carrier group, i found the firing pin spring had compressed and broken off towards the end.
Ordering a new spring and will see how it goes
Would recommend: No
1 of 2 found the following review helpful.
Was it helpful to you? Yes | No
Share

works flawlwssly on AR9 build

by tro jansky, Verified Owner from CA, United States Written on December 16, 2019
Built a 16” AR9 with this BCG (demo version). Item came with a few marks but runs perfectly fine. Used the following:

1) this bcg
2) 6.5 oz buffer
3) normal carbine spring
4 stern defense adapter

Rifle runs flawless from first shot to over 100 in a brand new barrel. Was very pleased with the build. Would recommend.
Would recommend: Yes
2 of 2 found the following review helpful.
Was it helpful to you? Yes | No
Share

Maxim ar9 NiB BCG looks great

by Ev, from CA, United States Written on November 9, 2019
Solid, hefty BCG from MD. The NiB coating appears to cover evenly, feels smooth to the touch, with no obvious course/pitting spots. The weight in the rear I understand to be removable for using a heavy buffer like H9 or H3, but it rattles slightly. Unsure what the weight case is made of, as I'm happy to report the weight is not pressed or molded in place. Will need to fire test, but so far, looks great. Shipping must have gone out the next day, because it got here in two days. Optics Planet is a phenomenal company
Pros:
  • Weight, Quality, Detail, Finish
Cons:
  • None
Best Used for:
  • AR-9
Would recommend: Yes
2 of 2 found the following review helpful.
Was it helpful to you? Yes | No
Share

9mm ar bolt

by Paladin, from IN, United States Written on October 20, 2019
Great price on a upscale bolt for a 9mm ar. Demo but like new! Will watch for more of the same such bargains to be had at optics planet! The go to site for all your sporting needs. Put it on your favorite list, and sign up for the email specials.
Pros:
  • great quality
Cons:
  • None
Would recommend: Yes
Was it helpful to you? Yes | No
Share

Great price but cut wrong for dust cover.

by dagother, from FL, United States Written on July 21, 2019
Demo model is a great price and has a good nib finish, the one I received looked brand new. Just be aware that your dust cover won't work as the relief cut is to shallow for it to close. If you are looking for a good deal this is it.
Pros:
  • Nib coated
  • Works with bcp glock lower
Cons:
  • Will not let dust cover close
Would recommend: Yes
4 of 4 found the following review helpful.
Was it helpful to you? Yes | No
Share

Maxim-um Quality

by Rainman, from AZ, United States Written on July 14, 2019
I've had so so luck with other 9mm BCG's so was leery with this purchase, especially since it said it was a factory "demo". Well, I couldn't find any tool marks or usage/handling marks of any kind. Installed in my upper with a Wyndom Weaponry multi cal lower. Using Mean Arms Endomag conversions on both Gen 2 and Gen 3 30 round Pmags. Call me impressed!! Runs like a million, no ftl, no ftf and no fte in over 100 rounds with Win FMJ 115 gr.
Pros:
  • IT WORKS !!!
Cons:
  • None
Would recommend: Yes
7 of 7 found the following review helpful.
Was it helpful to you? Yes | No
Share

Doesn't fit with ATI hammer/ trigger

by Kev, Verified Owner from AZ, United States Written on June 27, 2019
Haven't used it yet but it doesn't fit the ATI lower parts kit hammer correctly. Disappointing. Must be why it was on sale. Hopefully it works well after I get a different trigger. I'll update my review after I've used it if possible.
Would recommend: No
1 of 4 found the following review helpful.
Was it helpful to you? Yes | No
Share

great bcg for PCC

by bisrael, Verified Owner from VA, United States Written on May 23, 2019
this is a beautiful bcg and at the price listed on optics planet it's an even better deal. I've purchased three of these so far and I have used them on PDW and PCC builds...flawless in both. get one of these before the price goes up.
Would recommend: Yes
4 of 4 found the following review helpful.
Was it helpful to you? Yes | No
Share
There are no reviews that match your criteria. Would you like to review this product?