Looks like I got an upper with a standard ejection port size so 450 Bushmaster is out. Someone suggested 350 Legend so I’m digging into that instead. 9mm bullets can be loaded for cheap plinking or practice. The bolt is the same. Magazines specific to the caliber are needed. What else is specific to 350 Legend? Will stiffer springs and/or heavier bullets be needed? Is there a standard barrel length and gas system? Is an adjustable gas block necessary or advised? I intend to reload it, so I’ll have to dig into that part. Are subsonic loads available?
Now Researching 350 Legend
- Thread starter DMW1116
- Start date
Barrel and mag are the only things that were different on my.350. Its a good solid short range round...still looking at getting another, just not an AR.
I believe there are some subsonic rounds available for the .350, but im not positive. Theoretically you could use 358 bullets in one, and 250s would probably be subsonic, but at least my example didnt have a wide enough neck for 358s...... interestingly i shot 180gr .358s loaded in 9mm shells out of my taurus 692......they wernt horrible....
I believe there are some subsonic rounds available for the .350, but im not positive. Theoretically you could use 358 bullets in one, and 250s would probably be subsonic, but at least my example didnt have a wide enough neck for 358s...... interestingly i shot 180gr .358s loaded in 9mm shells out of my taurus 692......they wernt horrible....
mcb
Member
Assuming the barrel is ported correctly those will not be needed. Start with standard and adjust if needed. A heavier buffer might lessen felt recoil if the gun is slightly over gassed as many manufacturers do to ensure reliability but should not be required.
As for 450 BM you can use a standard upper and open it up. The port opening is only slightly bigger, easy to do with a mill or even some files if you're handy. A standard port cover still works on a 450 BM upper.
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sevt_chevelle
Member
That would be fake news.
BCM upper modified for 450 and the door still works.
The XL uppers are nothing more than regular uppers with opened up ports.
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sevt_chevelle
Member
I'm not dedicated to either one really. Both will provide larger diameter capability out to 200 yards. 350 Legend is cheaper to shoot but has some reloading peculiarities. I'd rather not have to modify the upper though. I nearly have all the lower parts I want. The upper will have to wait a bit until I decide what I want to do with it.
mcb
Member
Here's is a slightly better photo.
The upper is a standard Bushmaster upper, the lower is a Factory Bushmaster 450 upper. As you can see the port is opened from the detent notch forward on the top, the front lower corner is square up some and a slight amount across most of the bottom.
bassjam
Member
I was briefly looking into both cartridges a few weeks ago, and like was posted above you can open the port yourself for 450BM. I settled on the 350 though. I've been using a 357mag lever action for deer, so I think the 350 legend should be perfectly adequate. The biggest reason I chose the 350 instead of the 450 was noise, I'm not running a suppressor and I figured the 350 will be safer for my ears. I had pretty much everything on hand except a barrel, muzzle device, and magazine, so I ordered a CMMG barrel and put it together and slapped it on another lower I have. No adjustable gas block. Rifle length buffer tube. I put a 9mm linear comp on to throw some more of that noise away from me.
After about 5 shots to bore sight these were the next 15 shots using a 3x prism, shooting winchester 145gr fmj's, at 50, 100, 200 (bore was pretty hot by 200 and a 3x prism with a 1MOA dot is hard to be precise with). Since then I've had a chance to run hunting loads, from 150gr to 180gr accuracy was about the same although I had a bunch of FTL's with HSM 170gr Spire Points. Personally I've never shot a deer further than 40 yards away, so I'm happy with the 1.5-2MOA I'm getting with my setup.
After about 5 shots to bore sight these were the next 15 shots using a 3x prism, shooting winchester 145gr fmj's, at 50, 100, 200 (bore was pretty hot by 200 and a 3x prism with a 1MOA dot is hard to be precise with). Since then I've had a chance to run hunting loads, from 150gr to 180gr accuracy was about the same although I had a bunch of FTL's with HSM 170gr Spire Points. Personally I've never shot a deer further than 40 yards away, so I'm happy with the 1.5-2MOA I'm getting with my setup.
If I elect to go the larger bore route for this build, I'm looking for a 200 yard or less setup with maybe a fixed 2.5x20 scope or prism. Basically, anything between 2x and 3x. I have a different couple of rifles for iron sight shooting if I feel the need. A KS-47 AK-15 from PSA would also fill the shorter-range slot. The steel case ammo of old is nearly gone, but I'd find some brass and reload it anyway. We'll see what comes up. What I decide ultimately depends on how well I can get my current DMR (discount marksman rifle) to shoot. I'm working on a load for it now that I hope will stay under 1.5" at 100 yards for 10 rounds, which I realize is a fairly tall order for a budget build rifle.
