RDIAS compatible receivers (2022 edition)

[Brockak47]

Hi everyone, I just picked up a RDIAS. It fits and works like a glove in my SP1 that it came with but I do not want to shoot it out. I’ve tried looking up what receivers are rdias compatible but it seems all of threads are very dated so I’m worried to buy based on old
News. My sear is a SWD steel dias.

Thanks!

Going to copy and add your responses to this post

Bushmaster ( I don't know about Wyndham Weaponry)

Spike's Tactical

DPMS

Aero Precision m4e1 - pocket is .59" deep

Sendra

SGW

Radian Ax556 ambi - tried it out at the gunshop

Anderson - pocket is .63" deep

colt Sp1 - pocket is .64" deep

 

[brenbuilds]

A few brands that I know are "low shelf" are:

Bushmaster ( I don't know about Wyndham Weaponry)

Spike's Tactical

DPMS

Aero Precision

Sendra

SGW

Many current manufacturers have moved to "low shelf", as there is little reason not to. This list is far from complete, but those are a few off the top of my head.

 

[amphibian]

For a RDIAS, I would try to get your hands on an MGI lower for maximum modularity.

Unfortunately, MGI had various companies make their lowers for them so some are low shelf and some are not.

 

[Brockak47]

For a RDIAS, I would try to get your hands on an MGI lower for maximum modularity.

Unfortunately, MGI had various companies make their lowers for them so some are low shelf and some are not.

Hey, yeah you selling ? I don’t mind swapping triggers it takes but a few seconds. The mgi lowers are nice but no longer made so not really an option for me

 

[amphibian]

I know but there are several on Gunbroker.

 

[mattnh]

I’m using old Bushmaster receivers

MGI is def cool option to leave lower alone.
I wish they were still in production
as prices seem kind’a high on GB.

 

[mattnh]

Will any upper worn on MGI lower?
I don’t think i’d bother with just hot-swapping
Barrel and bolt into their custom upper now that new
Spares get a Premium

 

[amphibian]

Will any upper worn on MGI lower?
I don’t think i’d bother with just hot-swapping
Barrel and bolt into their custom upper now that new
Spares get a Premium

Yes, any upper that works on a standard AR lower works on the MGI lower...including the Shrike/MCR.
I agree that I see no point in their quick change barrel upper. Yes, it uses standard barrels and bolts but the issue is that front sites that are adjustable for windage are basically non-existant (I do know Ares has one for their Shrike). So when you quick change a barrel now your zero is off. I know there are some optics you can have multiple zero's but I'd rather just swap uppers.

Picture below is my Shrike on an MGI lower. Notice that the magwell has been cut to directly accept a full size 249 SAW box and with the grip pod deployed, the stock can still contact the ground. Additionally this magwell still accepts regular mags/drums.

Most of the pics on my site are using the MGI lower: https://c3junkie.com/?page_id=164

Picture below of the 7.62 AK magwell setup. I like the push button mag release over the typical AK flapper style.

Some have posted about getting custom magwells made. I know someone out there had one made to take Thompson SMG mags.

Also, if you are not aware the Colt 901 (556/308) and DPMS G2 is standard AR15 pattern on the back half of the lower receiver. Only the magwell area is stretched to take the larger mag.
The G2 was copied by Adams Arms and I think several others.

So you could get a custom magwell made for .308.
If nobody does this, I may try to mill one out myself or maybe even 3D print magwells for whatever and if they break who cares.

Or make your own Tommy15 magwell:

 

[A&S Conversions]

Windham Weaponry (the original Bushmaster that was sold to Remington) shows that their multi caliber is out of stock. They made uppers and lowers for MGI. They sold MGI style products with their name on them after the MGI patent went away. I would call and see if they have a lower and some magwells. I agree with "mattnh" that the upper is pricey. It is certainly easier to change complete uppers than to pull barrels and bolt groups. The modular magwells are great. I prefer 7.62x39 using AK mags. Like "amphibian" I was fortunate enough to get some of the oddball magwells that MGI offered. I shaved 0.010" off the Grease Gun magwell's catch to use with CMMG RDB .45 caliber upper. I need to try my custom Thompson magwell with the RDB. I need to buy some 10mm Glock mags for the large frame Glock magwell I have for use with a 10mm direct impingement upper I bought. The stuff is out there. Switching fire control at the range is a PITA and messy. I am glad that I have a MGI lower for my DIAS. I have been focused on our M16 magwell adapter for the M10 RR.

Scott

ETA, The only real application that I have used the MGI upper for is with the Valkyrie belt fed conversion. I had an original MGI upper modified for use with the belt fed system. I also had three Bushmaster 14.5" heavy fluted chrome lined barrels fitted with modified piston kits. Lock back the bolt, pull the hot barrel, incert a cool barrel and load another 200 round belt. The H-BAR barrels are 1/3 the price of the Ares/Fightlite barrels.

 

[amphibian]

Scott, interesting that you had to mod your GG mag catch for your 45 CMMG RDB upper. I didn't have to mod mine at all.

Also, I did get a small frame Glock magwell but the height and angle doesn't work with the CMMG RDB for 9mm or .40SW.
I would think you would have the same problem in 10mm or .45 for DI since the feed height/angle I would think is the same as the CMMG RDB.??