450 Bushmaster Build

[303 hunter]

I’ve started a 450 Bushmaster build. Parts list so fat is: XXTreme Barrel Company 18” mid gas 1-24 barrel, Toolcraft BCG, KAW Valley linear comp, Acme Machine 12” keymod tube, low profile gas block and tube, and Burris Fullfield II 3-9x40 scope with PEPR mount. Aero XL upper should be here by the weekend. I’m going to use an Aero gen II lower with EFX rifle stock I already have.

This will be my first venture into the big bore AR world, and I’m excited! I bought 2 boxes of Hornady 250 grain FTX to get me started, but I’m collecting the components to reload this thumper.

 

[adcoch1]

I recently built a rifle and a pistol upper in 458 SOCOM, so I understand the excitement! Had to spend a month in the hospital due to a stomach problem though, so I havent had a chance to shoot them yet. Good luck on your build, and take lots of pictures!

 

[Trey Veston]

Sweet! Mine is fun for about 10 rounds. After that, it starts to get painful, lol.

I ordered a set of the Lee dies for $43 and one of them was so undersized that the cartridge would only go in half-way. I checked with my micrometer and confirmed it was wrong. I sent a detailed email to Lee, along with pictures of the offending die. Their response was to ask me what kind of case lube I was using and how long I'd been reloading. Basically accused me of being incompetent and stupid.

I replied that they had just lost a customer and I would be purchasing my dies from Hornady and RCBS in the future.

Bought the Hornady set for $70 and it works great...

 

[GunnyUSMC]

I love shooting my big bore AR. The only thing more fun then shooting it is the look on the face of others I let shoot it.
Your going to love it.

 

[303 hunter]

Aero upper is due for delivery tomorrow. I’ll lap the upper and likely have it together Saturday evening. Hoping I’ll be able to shoot my “thumper” this weekend. I’ll be sure to post pics.

 

[Trey Veston]

I'm bringing mine down to the cabin after the weekend since I have to burn slash piles and have had lots of predator activity in the area lately.

I added this magazine pouch to it last week and really like it...

 

[alfsauve]

I built the 458S and it's not bad on the shoulder at all. You will love shooting the big bore. I'm going on a hog hunt soon with mine soon.

 

[Riomouse911]

Since the .450 is a lightly tapered case (non-necked), do they make carbide dies for it?

 

[303 hunter]

Since the .450 is a lightly tapered case (non-necked), do they make carbide dies for it?

I don’t know. My Lee dies are not carbide, and I didn’t think about that before ordering.

 

[303 hunter]

Got it finished today, and shot it for function. Everything seems GTG. Recoil isn’t as bad as I’ve been told; it’s about like my 20 gauge pump shotgun. My 13 year old daughter shot it with no problems. Hopefully I’ll be able to shoot it more tomorrow, because we ran out of light today.

 

[Riomouse911]

Nice lookin' rig!

Let us know how accuracy was for you. I have several lowers and would probably go for a big-bore upper if the right combo came along...

Stay safe!

 

[303 hunter]

Nice lookin' rig!

Let us know how accuracy was for you. I have several lowers and would probably go for a big-bore upper if the right combo came along...

Stay safe!

Delta Team Tactical had some killer deals using this same barrel, check them out. I prefer to assemble my own. With a bolt hogged out to .308 size, everything needs to be right. I lap the face of my uppers, and this Aero needed it. With thin bolt lugs you need everything to be aligned. I started lapping uppers when I started building 7.62x39, and I’ve never had a bolt failure.

 

[303 hunter]

Well, I tried it out today and was extremely happy! I was shooting Hornady 250 gr FTX at 100 yards. The shot on the left and 2 on the right were final sighting in of my scope. 13 shots altogether and my shoulder feels it!

 

[GunnyUSMC]

View attachment 811959 Well, I tried it out today and was extremely happy! I was shooting Hornady 250 gr FTX at 100 yards. The shot on the left and 2 on the right were final sighting in of my scope. 13 shots altogether and my shoulder feels it!

Well done.