School me on the 450 Bushmaster AR platform

[Lloyd Smale]

I want a 10.5 inch 450 pistol. Ive got a 50 beo 16 inch and its been a darned good gun but its on the heavy side. Problem is everyone seems to be pretty proud of there 450 and 50 beo pistol uppers. Easy to find a 556 or 9mm pistol upper for around 300 bucks but a 450 or 50beo is closer to a grand.

[Earlwb]

I want a 10.5 inch 450 pistol. Ive got a 50 beo 16 inch and its been a darned good gun but its on the heavy side. Problem is everyone seems to be pretty proud of there 450 and 50 beo pistol uppers. Easy to find a 556 or 9mm pistol upper for around 300 bucks but a 450 or 50beo is closer to a grand.

You should be able to buy the barrel and bolt or BCG for it. The other parts are pretty much standard stuff. I am not sure if you need to open up the ejection port on the upper receiver.If it needs to be a little larger it isn't by much.

I took a quick look and there are some companies that make pistol barrels for the 450 BM. Granted the price is higher, but there may not be much of any demand for pistol barrels though. Thus low volume.

[Lloyd Smale]

I know on my beo they opened up the ejection port.

[Pipefitter]

Update: After mounting the scope I got the head cold from the devil, about a week and a half with not enough energy to get off of the couch. Finally made it to the range this weekend, posted targets at 50 & 100 yards during a break in the shooting, set up the spotting scope, bench bags, and loaded one round in the magazine. Lined up the scope on the 50 yard target and CLICK! Worked the charging handle and ejected a live round without any marks whatsoever on the primer. Broke the rifle down, pulled the bolt and then the firing pin and found that the tip of the firing pin was ground off (not sheared or broken, ground off flat).
I had another AR in the truck so I switched firing pins and proceeded to get the scope sighted in. Ended up shooting one box of factory Hornady ammo, getting 3 shot 1" groups at the end.
This morning I called GLFA in Sparta and the owner said "We have been waiting on this call". It seems that they had ground the tip off of one firing pin to use as function and feeding testing on their uppers (to avoid accidental discharges in the shop) and it had somehow made it into the upper I bought. For my troubles a new firing pin and a free box of ammo is in the mail to me.
The upper drops the brass about 4-6 feet away at the 4 0'clock position, recoil is on par with a in-line muzzleloader loaded with 150gns of black powder and a 250gn bullet.

[43PU]

Not a AR but I have the Ruger Ranch in 450 bushy I shoot the lee 255 RF Or the 320 grn with IMR 4198 at 100 they shoot just fine for deer or pop cans

[Idaho45guy]

Resurrecting a dead thread to get some more feedback on the .450 Bushmaster.

I've been scouring the internet and have found dozens of folks who built .450 Bushmaster rifles for either deer hunting in the midwest, or pig hunting in the south. No one has built one for the purpose that I'm building mine.

I live on the border of Washington state and Idaho. I go into the Idaho woods nearly every weekend to go hiking, ATV riding, fishing, or just enjoying the family cabin. I don't hunt in Washington where the libs have made it a huge hassle, and I don't hunt in Idaho where it is ridiculously expensive to hunt for elk as a non-resident.

So, I don't need a hunting rifle. But since the re-introduction of wolves and a growing predator population, I do have a need for a handy carbine for defense against predators. I normally carry a Glock 29 in 10mm. I wanted something with a bit more range and oomph, so I bought a Marlin 1894 in .45 Colt and modified into a great little rifle. The problem is that it's a pig. Over 11lbs with all the goodies on it and loaded up.

I have a couple of ARs that I rarely shoot. I like them. But the .223 really is a fairly limited round. Great as a coyote and ground squirrel round, but not so much as a hard hitting defensive round.

I got a notice from Midway that they had a clearance special on an AR-Stoner .450 Bushmaster upper with a 16" barrel and optics ready for $399. I started looking at the numbers for the .450 Bushmaster and it seemed ideal for my needs. I already cast and load for the .45 Colt and am also a fan of the Hornady XTP 250gr J-word for wolves and cougars. We also have a lot of black bears and a a few grizzlies, but bears really aren't that big of a concern; every run in I've had with them has them running the other way post haste.

So, I hope to build a sub 8lb carbine that is hard-hitting and reliable.

I've got some cases ordered and already have some Lil' Gun on the shelf. I also ordered some of the special magazine followers needed to convert USGI 30-rounders into reliable 10-round .450 Bushmaster magazines.

[Moleman-]

Should be able to get under the 8# mark with an optic without too much effort. This 44x1.8" wildcat came in at 8#3 oz with the scope and magazine but without the suppressor. It has a fairly heavy barrel profile at .980" to the .875" gas block, .845" to the 11/16"-24tpi muzzle threads.

[Idaho45guy]

That's good to hear...

The way the upper is shipped it is set up for optics only. If I want to run iron sights, then I need to upgrade the hand guard...

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[gnostic]

I just bought a 458 Socom, 450 BM upper from Primary Arms for seventy dollars to my door. I'm going cheap on this build, as I think, all AR's are pretty much the same. I built my 5.56 AR with a Spikes lower, JP trigger group, Nitride barrel, Toolcraft Nitride bolt carrier group and free floating handguard. This rifle shoots 3/4" groups and in four years, hasn't malfunctioned a single time.

[Tackleberry41]

Just finished putting a 450 together. Had an AR stoner upper I had bought, tried to sell it, but we have all seen the prices anymore. Short of giving it way not going to sell it. I went back and forth this cal or that. Yea I like the 458 socom, already have several 458 molds. But they aint cheap. Box of 20 is $60, brass not much less. I also cast several 452 bullets for various 45 pistols. A box of 20 Hornady are $25. So I went w 450BM. Not done much more than get it running at this point, get some dies next month. Already blew my budget on getting set up for my 41 swiss and the barrel for the 450.

Had the upper, just enlarged the ejection port. Had the wrench to get the M4 barrel out. A barrel was $90, gasblock and tube. Yea can buy a bolt, but I own a lathe, opened the 5.56 one, what everybody else is doing. Maybe someone is making them from scratch. I dremmeled the 5.56 extractor, works fine. No muzzle brake yet, debating about a tap to make one or buy one.

One thing I did to mine that made a huge difference was more weight in the buffer. Really needs an adjustable gas block. I had a bar of 1/2in tungsten left over from making a really heavy 9mm buffer. Epoxied a chunk in there, huge difference in the recoil. Forgot I had it out and touched one off, yea you feel it alot more with a factory rifle buffer.

Have a 250gr NOE RNFP mold, will use that, and plan on a 300gr or so. Have a Lee, but does not make the best bullets. Maybe a heavier NOE w HP pins. Powder coat them as I do with everything else.

[Idaho45guy]

Got in the upper today and am really happy with the quality. Fitted it to my my Ruger lower and it is nice and tight.

Had a Magpul FDE forend sitting around so installed it. Will have to upgrade the stock to a Magpul FDE model and add a recoil pad. Will have to look into getting a heavier buffer as well.

I had a bunch of army issued 30-round mags from 30 years ago that I brought home and so I ordered a couple of .450 Bushmaster followers for them from Chamber Tactical. That's supposed to be the most reliable route to go for magazines. I don't have any rounds, but I could get 10 shell cases in it and the lip tension was perfect.

As for actual ammo... This may be the hottest AR round in Texas and the Midwest, but the guy at my local gun shop had never even heard of it before, much less have any ammo in stock for it.

Driving 50 miles on saturday to go to a GSSF match and will see if the gun shops have any down there. Not enough time to order online as I'm leaving for Japan next week for a couple of weeks and don't want to have ammo sitting on my porch for that long. If I can find some ammo Saturday, then I'll shoot it on Saturday. Otherwise, I'll have to wait for my new dies to arrive.

Weighed it and with a fairly heavy 3x9 tactical scope, it is just over 7.5 lbs, so with a sling, light, and reflex sight, it should be under 8 lbs.

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[Moleman-]

Nice, I'm sure you'll like it. I'm in a "Limited Firearms Zone" which translates to straight wall cartridge under 1.8" long and larger than .35" or shotgun, muzzleloader, archery only. I can get 450BM ammo at the grocery store.

[Earlwb]

It is looking good. I did load up a few dummy rounds to test the magazines at home with before I went to the range. I had to do a little hand filing on my magazines before the rounds would feed OK. Other than that no problems. I did a fair amount of pig hunting in south Texas with my 450 Bushmaster.

[Idaho45guy]

It is looking good. I did load up a few dummy rounds to test the magazines at home with before I went to the range. I had to do a little hand filing on my magazines before the rounds would feed OK. Other than that no problems. I did a fair amount of pig hunting in south Texas with my 450 Bushmaster.

Picked up another lower from Palmetto State Armory, a PA10 gen 2 with Magpul furniture on Friday from the Ace Hardware/sporting goods store, I was checking out their collection of dies and they actually had a set of Lee for the .450 Bushmaster, so I grabbed it. went to the nearby Sportsman's Warehouse and they had a couple boxes of Hornady Black in .450 Bushmaster for $29.99. Bought a box.

Headed home and tried to makes some loads and realized I had two major issues. First, I forgot to get the appropriate CCI 400 small rifle primers. Second, the sizing die from Lee was seriously undersized.

Headed to the family cabin on Saturday to at least function test the rifle and get the scope relatively sighted in. Decided to use a smaller and lighter Nikon rather than the heavy "tactical" 3x9.

I also did some filing on my magazine feed lips and cycled a bunch of rounds prior to heading to the range; everything seemed to work fine.

At the range, all rounds cycled and fed perfectly with both of my converted magazines. Did not try standard USGI mags with stock black followers; will do that when I have a bunch more ammo loaded.

Recoil was substantial compared to a regular AR and noticeably harsher than my current woods gun; a Marlin 1894 in .45 Colt. But, it really wasn't all that bad and I fired a box of ammo with no ill effects to my shoulder. My elderly father also shot it and said it felt like his Marlin 1894 in .44 Magnum.

Since it was only a 25yd range and I had limited ammo, didn't do any real accuracy testing, but dad was able to get a 3-shot group into one ragged hole.

Overall, very, very happy with the performance and feel of this rifle. Can't wait to get back from Japan next month and get it totally kitted for carry in the woods.

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[Cosmic_Charlie]

The prices on the 450 Bushmaster uppers has been coming down. I'd like a 10" pistol set up for subsonic loads. Make a great light weight deer gun with power like a .44 mag. With those SB tactical braces, you can really put the rounds on target quickly. A 300 gr. boolit @ 1000 fps is big medicine.

Well, that idea didn't last long. Seems the 450 is not a good choice for subsonic in an AR. Guess I better stick to 45 acp and keep it simple.