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Questions & Answers
WEIGHT OVER ALL FOR 450UPPER HOW MUCH TOCHANGE A.223 TO450 Expert Answer

This upper receiver weighs 5.22lbs. You should not need to change anything other than the upper to use this on a .223 lower receiver.

by Ethan C., Gear Expert, August 9, 2019
What is the thread pitch of the barrel? Expert Answer

It is 11/16"-24.

by Carly R., Gear Expert, December 12, 2017
Customer Reviews
Helpful Positive Review 450 Bushmaster is awesome! by sixtysix, Verified Owner, November 11, 2017
Was not really interested in AR platform until 450 Bushmaster was becoming popular. This upper shoots amazing with shots touching at 100 yards. Very happy with purchase! I did have an issue with shells not ejecting with any force at about 75 rounds, ...
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5/9 found this helpful
Helpful Positive Review Rick's rview by Rick, Verified Owner, March 20, 2018
got my bushmaster upper and immediately installed it on my stag arms lower. Easy to just push two pins and drop upper into frame and push pins back in.. i bought everything to reload as factory ammo is pricey. i have not sighted the gun in for accu...
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1/1 found this helpful
Helpful Positive Review .450 Bushmaster Upper by MiHunter, November 8, 2017
Very happy with this purchase. Ordered Saturday November 4 2017. Delivered to my door (signature required) Wednesday November 8. Still waiting on my Palmetto State Armory Lower (sku 37403) to ship. I also ordered a Vortex Crossfire II 1-4x 24mm op...
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1/4 found this helpful
Helpful Negative Review The good, the bad, and the ugly by Chipmaker330, September 25, 2018
I would like to first address a few technical notes. The two 91700 uppers I received in August 2018 arrived with .750in low profile, dimpled gas blocks, NOT the miniature Picatinny block featured on most websites. As mentioned in other reviews, the h...
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12/13 found this helpful
Most Recent Reviews Great choice by onebadhunter, Verified Owner, April 29, 2018
How are you all, I am very happy with the choice I made buying the 450bushmaster. it is A great shooting gun with all the knock down power I would need to get the job done. Plus you can buy the ammo for about $23.00 a box. And hit what ever you aim a...
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0/2 found this helpful
Most Recent Reviews description by robert, Verified Owner, November 29, 2017
photo is not the actual upper the upper i received had a 8" float and different barrel with different gas block location when i contacted optics planet i was told that it is normal to receive a upper that is different than pictured but the biggest ...
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3/6 found this helpful
Read All 9 Reviews

Product Discontinued by Manufacturer

Bushmaster .450 Bushmaster Upper Assembly w/5-Round Magazine has been discontinued by Bushmaster and is no longer available. Our product experts have helped us select these available replacements below.You can also explore other items in the Gun Parts, Magazines, AR 15 Parts, Rifle Parts, Rifle Magazines, AR15 Upper Receivers, AR Rifle Magazines yourself to try and find the perfect replacement for you!

Certain firearm magazines and extensions are subject to maximum capacity restrictions based on state and local laws. Currently, we are unable to sell these products to some locations. For a complete list of these restrictions, please visit our policy page.

By continuing with your purchase, you agree to adhere to all applicable laws and regulations.  

Product Info for Bushmaster .450 Bushmaster Upper Assembly w/5-Round Magazine

This drop-in A3 upper will mount to virtually any standard AR-15 mil-spec lower receiver. With a velocity of 2200 FPS the Hornady 250 Grain SST/FT bullet in the 450 Bushmaster "Thumper" is designed for all large North American game. Though not a long distance cartridge accuracy has proved to be exceptional out to 200 yards with felt recoil similar to a 20 gauge shotgun. The tubular aluminum forend allows the barrel to free float from the nut forward and chrome lining in both bore and chamber makes for long barrel life and easy cleaning. This upper receiver assembly comes complete with a charging handle forward assist ejection port cover bolt and bolt carrier assembly. The upper also features a versatile flat top for mounting optical devices or accessories. Includes a 5 round magazine.image

Features of Bushmaster .450 Bushmaster Upper Assembly w/5-Round Magazine, 91700:

  • Aluminum forearm free-floats the barrel for optimum accuracy
  • Heavy barrel is hard-chrome lined in bore and chamber for exceptional durability and has 1 in 24" twist rifling, optimized for the .450 bullet
  • Includes 5-round 450 Bushmaster magazine (1)
  • Bolt carrier assembly

Package Contents:

  • Bushmaster .450 Bushmaster Upper Assembly, 91700
  • 5-Round Magazine

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Related Products to Bushmaster .450 Bushmaster Upper Assembly w/5-Round Magazine

Bushmaster .450 Bushmaster Upper Assembly w/5-Round Magazine Unavailable & Discontinued Models

List of Unorderable Models

Bushmaster Upper Assembly, .450 Bushmaster, 16 inch Barrel, Carbine Length, 1-24 Twist, 11/16x24 Thread, Izzy Muzzle Brake, BCG, 5-Round Magazine, Black, 91700 , MPN: 91700 , UPC: 604206917003 , Code: 6C5-URC-91700-5RD
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