Big Bore AR-15

[Yondering]

I have 16" uppers in both 350 Legend and 450 Bushmaster. Vortex 3-9x44 scopes on both.

The magazines can be problematic, depending on the ones used. I needed to modify the front of the magazine so the bullet wouldn't catch on them as their sliding forward. It's relatively easy to do with a Dremel. Most AR magazines are flat across and it needs more of a U shape to clear. Doesn't need much. Go slow and test often.
You can buy magazines for both calibers that are already "fixed".

Both are fun to shoot. I shoot the 350 Legend more since the local Walmart usually has ammo cheaper. 450 Bushmaster is harder to find and fairly expensive.

Just curious, does your 350 Legend barrel have a single center feed ramp, like the Bushmaster, or dual feed ramps like most other AR barrels? They are a dual feed magazine of course, but I've noticed some companies making the barrels with a single feed ramp and have to wonder if some of the mag issues stem from that.

I haven't seen any need to modify my C-Products Legend mags, but my barrel is set up for dual feed as it should be. What is important though is using a magazine without the internal ribs that a 5.56 mag has; either actual Legend magazines or 5.56 mags can be modified. Lancer 300 Blk mags might work too, but I haven't tried mine in the Legend. Probably should do that.

[USN-PO2]

Just curious, does your 350 Legend barrel have a single center feed ramp, like the Bushmaster, or dual feed ramps like most other AR barrels? They are a dual feed magazine of course, but I've noticed some companies making the barrels with a single feed ramp and have to wonder if some of the mag issues stem from that.

I haven't seen any need to modify my C-Products Legend mags, but my barrel is set up for dual feed as it should be. What is important though is using a magazine without the internal ribs that a 5.56 mag has; either actual Legend magazines or 5.56 mags can be modified. Lancer 300 Blk mags might work too, but I haven't tried mine in the Legend. Probably should do that.

Looks like a modified dual feed where they just removed the center lug between the two 5.56 style feed ramps. Haven't had a problem with it feeding so I guess it works

[Yondering]

Looks like a modified dual feed where they just removed the center lug between the two 5.56 style feed ramps. Haven't had a problem with it feeding so I guess it works

OK, yeah I've seen some like that too. Some of them remove the center lug (for no good reason that I can tell) but don't widen the other end of each feed ramp. What the feed ramps really need is to be widened more than 5.56 feed ramps, but most companies jumping on the bandwagon, the "follow the leader" companies, don't seem to understand this. When it's done correctly the magazines don't need any modification, other than to remove the ribs if you have 5.56 mags.

[LawDog]

I built a mold to cast 82gr wadcutters, with the idea to stack several of them in a case. the 460 will take 7 of them, although I usually use 6. In the Raptor it'll depend on the internal case taper of your brass, but you should be able to fit 4 of them or so behind a 200gr FTX (I doubt you'd get the full wadcutters to feed otherwise). Since the barrel is rifled, they do stay square to the target and leave round holes. Even a mild load with these is a bit much for a small game load though, and I'm not sure what other purpose they'd serve unless you're trying to clear a room maybe :) but they're interesting to experiment with.

You should add to your prayer list that I become Daddy Warbucks level rich. If I were floating in money, or just in charge of my own lucrative gun company, I would hire you to just build crazy stuff in a lab. I'd make sure you had all of the tools and the tax stamps, and I'd want a monthly report of what we had learned.

[Yondering]

You should add to your prayer list that I become Daddy Warbucks level rich. If I were floating in money, or just in charge of my own lucrative gun company, I would hire you to just build crazy stuff in a lab. I'd make sure you had all of the tools and the tax stamps, and I'd want a monthly report of what we had learned.

Sounds good brother, let's do it!

[KarlinPhoenix]

I found another 'big bore' AR-15 caliber:
"The 500 Auto Max is a rimless 500 S&W Magnum that is easy to obtain or reload. A very versatile cartridge, It can be had in loaded ammunition with bullets ranging from 350grns to an amazing 600grns. The handloader can utilize bullets ranging from 275grns to 700grns in almost any bullet type imaginable, hardcast, jacket hollow points, monolithic solids, etc. This unprecedented range of bullets weight and design make the AR500 suitable for anything from prairie dogs to pachyderms to Peterbilts. Truck stopping power in a platform weighing less than 10 pounds. AR500 – 500 AUTO MAX RIFLE

https://www.bighornarmory.com/produc...eid=f2e9024346

[Paul Groth]

So test fired the 450 bushmaster over the weekend. Forgot to do one thing and that was open up the ejection port. Did that then test fired it again. It cycles very nicely. The recoil is extremely manageable and pleasant while running a H3 buffer and a extra power flat coil spring. I will be testing for accuracy next time I take it out. I just wanted to get the reliability testing out of the way first. If a firearm isnt reliable, then it isnt worth having.

[Fat]

What magazine(s) are you using? I primarily run straight 20 round GI 5.56 with single feed followers from Fulton. I have read interwebs rumors that 20 round Lancers work un-modified and I have a few but they always seem to stay packed with 5.56 and forgotten when the 450 comes out to play.

[Paul Groth]

What magazine(s) are you using? I primarily run straight 20 round GI 5.56 with single feed followers from Fulton. I have read interwebs rumors that 20 round Lancers work un-modified and I have a few but they always seem to stay packed with 5.56 and forgotten when the 450 comes out to play.

I have two of the duramag 450 bushmaster specific 7rd mags that i have used so far. I modified one GI mag that manually cycles fine but i havent shot it yet. I will testing it this week.