Ruger American 450 Bushmaster conversion

[southernpew]

BRAND NEW member here. I am usually an AR guy but I do want to get into Bolt Guns and some longer distant shooting (This build isn't for that)

I am looking to build a 458 SOCOM bolt gun. There's a company that makes a 458 bolt rifle but its $2k plus. For that price I can have an X Caliber barrel made and an MDT chassis, plus a trigger on a Ruger American for less. So that is the route I am attempting.
Casting and loading big 600gr projectiles and throwing them at a hog at 150-200 yards seems like a blast, its already fun shooting them suppressed through one of my ARs.

My question is, I'm aware that MDT makes the LSS-XL-GEN2 in a SA AR which utilizes AR magazines. But the Ruger American 450 Bushmaster comes standard as using the rotary magazines ( I believe). I know that with Preferred Barrels and X Caliber, they ask if the Ruger American used AR mags or not from the factory, can I use an action that had an rotary mag stock and swap it to feed out of AR mags? By buying the AR mag stock and opting for the longer tenon (AR mag option)

Thanks for any help. Just found this forum and there is entirely too much to read, but I do not mind sitting back and reading for a few weeks

 

[Birch7]

My 450b ranch has a single stack mag. AR mag rugers have a different bolt, but why would you need the AR mags? You could run the ruger in a chassis made for aics and be fine, maybe run a 6br spacer mag.

 

[southernpew]

My 450b ranch has a single stack mag. AR mag rugers have a different bolt, but why would you need the AR mags? You could run the ruger in a chassis made for aics and be fine, maybe run a 6br spacer mag.

I’ve been all over the RugerForums and have seen 1 guy convert his 450b Ranch rifle to 458 AR mags in a MDT chassis. A lot on that forum have called Ruger asking to swap from the flush mags to AICS or AR mags and Ruger sells then a drop in mag well to convert it to either or. So there’s a bunch of conflicting information

I just want AR mags for this build, for simplicity. I am used to loading 458 for my AR mags and have tons of them (Lancers)

But, I could order the MDT chassis for AICS mags I guess. I ordered an X Caliber barrel already for the build. They’re 20% off currently

Here are pictures of his build going from the Ranch to the MDT with AR mags.



So I guess my question would be, why AICS over AR magazines or vice versa?

 

[Birch7]

I guess an ar mag with socom is center feed, so the bolt wouldn't matter, so long as the cartridge sits at the correct height. You'd be stuck with the AR mag setup, which would limit upgrade path for long range shooting with a different cartridge using this build

 

[southernpew]

I guess an ar mag with socom is center feed, so the bolt wouldn't matter, so long as the cartridge sits at the correct height. You'd be stuck with the AR mag setup, which would limit upgrade path for long range shooting with a different cartridge using this build

I understand that. And if this rifle was chambered in basically anything else other than 458 SOCOM, I would prefer the longer AICS mag as the Ruger Ranch is a short action. Going to an AR magazine basically turns it into a “Mini action”

BUT say I went AICS. Being most of my loads are 2.25” ish long, if I could load some to maybe 2.35” and still chamber, would I have any issues with loading so much shorter rounds in the longer magazines?

Most of my cast bullets will be limited to 2.26” (AR mag length) anyway. Being ill mostly shoot big subsonic a through it anyway

I do plan on building a long ranger bolt rifle after this. Not sure what caliber just yet
This is a whole new world to me, I’m used to AR platforms

 

[Birch7]

6br aics mag, has spacer at rear to make shorter rounds feed better.

 

[southernpew]

6br aics mag, has spacer at rear to make shorter rounds feed better.

So other than being able to convert the rifle into something else later down the road, using 6br AICS mags for 458 and then swapping to a true SA caliber then using full length AICS mags.

I don’t plan on changing up this build later on down the road. This would be a hog gun and stretching out 600gr subs to as far as I can hit paper/gongs

 

[southernpew]

6br aics mag, has spacer at rear to make shorter rounds feed better.

Looking at the specs of the 6br COAL I may actually switch up and go that route.

308/6.5 AICS mag is 2.850” COAL
6BR AICS mag is 2.505” COAL

I wonder how many 458 would fit in the 10rd and the 12rd mag now, and if it would load reliably? Most of the bullets are pretty blunt, i do have 2 spitzer molds which i could load a little longer than usual.
A 30 round AR mag will hold 11. I wouldn’t use a 30 round, I’d use 20 to get 8ish

 

[southernpew]

6br aics mag, has spacer at rear to make shorter rounds feed better.

Well I may or may not have ordered a chassis in each mag type. Also ordered 2 stocks and a handful of different magazines from MDTs sale on Thanksgiving.
I know the AR mag will work, but the AICS mag I’m not sure of. So now I’ll be able to find out for myself

 

[AXMC]

Looks like unless you have gorilla arms you could benefit from a shorter LOP. If you don't want to give the folder up, OBI makes a shorter tube for that stock.
Looks like he's out of stock, but might be worth sending him a message.

MDT SHORT Skeleton Carbine Stock

This is a short replacement buffer tube for the MDT SCS and SCS-Lite butt stocks. It works perfectly for a shorter length of pull or if you want to include a folder in your stock set up.

oldballsinc.com

 

[southernpew]

Looks like unless you have gorilla arms you could benefit from a shorter LOP. If you don't want to give the folder up, OBI makes a shorter tube for that stock.
Looks like he's out of stock, but might be worth sending him a message.

MDT SHORT Skeleton Carbine Stock

This is a short replacement buffer tube for the MDT SCS and SCS-Lite butt stocks. It works perfectly for a shorter length of pull or if you want to include a folder in your stock set up.

oldballsinc.com

Yeah I thought that was weird too.
I’m not running a folder on mine when I get all my parts. But I am 6’1 and have longer arms, I don’t think it would be an issue. But I will install it just to see though, but won’t run a folder on this build.

I ended up buying 4 chassis, 2 stocks, and a couple mags from the big MDT sale.
So I’ll throw the folder on a 300BLK mini fix SBR style build.

 

[southernpew]

Ruger American Ranch 450 Bushmaster
16” 1:10 Stainless fluted X-Caliber barrel
MDT LSS-XL Gen 2 chassis (AR mag)
Glades Bolt handle and cover
SilencerCo Hybrid 46 with Bravo ASR mount and anchor brake

Next will be the permanent scope (still unsure of which one just yet), different grip, and possibly a Timney trigger

 

[JJ3]

How did this project perform?

 

[southernpew]

How did this project perform?

For me it’s great. I have not been able to stretch it beyond 100 yet. But being this was purpose built for hogs out to 150, it’s gonna be an awesome rifle! Especially with my 500gr spire point cast loads