FULL AMBI LOWERS W/Great R&D & WARRANTY

[Tokay444]

I’ve played with most of the fully ambi lowers on the market and I’ve personally owned two of them.

The absolute best in my opinion is the Radian lower. With that being said, it is horrifically overpriced. But the machining quality is second to none. The tolerances are super tight and every upper I’ve tried it on has had a nice, snug fit. The ADAC is a really clever, effective right side bolt catch and all the other controls are really nice. I especially like the machining and finish quality of the billet parts that are all included. It also comes with the Radian safety which isn’t my favorite but its nice to have in my spare parts collection. I really like how they look but some people think they are really over-styled.

The other lower I’ve had (now sold) is the ADM which is also very nice but I didn’t like the right side bolt lock as much as the Radian and the quality of the small parts wasn’t as nice (cast phosphate coated parts vs the billet nitride parts on the Radian). It also didn’t have as tight of a fit with my uppers. Some people like the fact that the ADM is black anodized vs the Radian’s Cerakote finish. If you insist on having anodizing, buy the ADM. I didn’t care about that because I like to rattle can my guns.

The LMT MARS lower is also very nice. A friend of mine has one and I’ve shot it quite a bit. My only issue with it is that the right side bolt paddle doesn’t fit with the Vltor stripped uppers which I use in many of my uppers. If you prefer the forged, milspec look, this lower is absolutely the way to go. Yes, LMT QC is very hit and miss but they do take care of you if you have a problem.

How do you know what their tolerances are?

 

[Leicafan1990]

if we are talking true full ambi, right side bolt catch

ADM
LMT
LWRCI

the new Daniel Defense lowers (idk if you can buy them by themselves currently)

the Radian is not full ambi in the way those others are

The Radian lower is absolutely fully ambidextrous. You can drop the magazine from both sides of the receiver. You can lock the bolt from both sides of the receiver and you drop the bolt from both sides of the receiver. It can do everything the LMT/LWRC and ADM can do.

 

[Leicafan1990]

How do you know what their tolerances are?

I don’t, but you can say the same about all AR manufacturers. All we have is anecdotal evidence. I’ve heard lots of examples from Radian owners of how tight uppers from various different brands fit on their lowers. Their build kits are also known to be extremely well made with little to no wobble.

I’ve also spoken on a number of occasions with an ex Radian employee who worked for half a dozen different brands before working at Radian and he said that Radian put more effort into machining quality and QC checks than any of the other brands he worked for. He also has legitimate complaints about some of the management decisions there and criticized their pricing model so I trust that he was telling the truth about their quality and tolerances.

From personal experience, my Radian lower is immaculate and all the uppers I’ve put on it have been super tight fitting.

There are certainly things to dislike about Radian lowers (expensive, overly stylized, no anodizing), but I’ve never heard someone complain about the quality of construction. Maybe there are examples out there but they are extremely rare.

 

[Tokay444]

Ok. That isn’t tolerance though.

 

[Leicafan1990]

Ok. That isn’t tolerance though.

It more or less confirms that they consistently hit their target tolerance.

If customers consistently make similar comments about fitment, that means the company is delivering a very dimensionally consistent product. This would mean that they have tight tolerances.

We don’t know the tolerances of Bartlein barrels but customers overwhelmingly talk about how consistently accurate they are so we can reasonably assume they have very tight tolerances during manufacturing.

 

[Tokay444]

Bartlien has tight tolerances on what? The outside diameter of a blank? The length? The depth of stamping on the end? People who don’t know anything about manufacturing have gotten quite comfortable using a term that doesn’t mean what they think it means.
I’m not saying Radian doesn’t, but I am willing to bet they’re no “tighter” than milspec, which is its own tolerance. Even if they deviate from milspec, a blanket statement like, “they have tight tolerances” is giveaway someone doesn’t know what a tolerance is.
Look up the definition of tolerance.
Let me ask in a different way. Are there any uppers that Radian lowers won’t work with, and if so, why?

 

[Ape_Factory]

POF Gen4 billet lowers or ADM. Everything else, including the Radian are a step below ergonomically. I'd throw the Sig LT lowers in there too but they're unobtanium without the rest of the gun and both the POF and ADM have a mechanism to tighten the lower to the upper. I think the bolt lock on the Sig is a bit more fragile than on the ADM and the POF is protected by the trigger guard. I personally think the ADM is now overpriced and the POF is definitely a better value and has a higher build quality.

Here's the POF. The bolt catch is the notch inside the trigger guard towards the front. The bolt release is the flat elongated paddle just above the mag release. Won't snag on anything. And there's a little finger cutout for when your index digit is not on the trigger. Nice touch and a tactile reference as to your finger's position in relation to the other controls. Both the POF and ADM can be operated with one finger on the same side of the gun.



The ADM. Bolt lock/release is the little triangle lever that moves up and down so like the POF, you can do everything with one finger.


Sig MCX Spear LT lower. The actual forging and anodizing is first rate. It looks and exudes quality other than being the color of baby poop. This is the best angle I have to show the bolt catch/release on the right side. I can see how it might get damaged. The ADM's lever is somewhat flush and protected while the POF is flush for the release and protected by the trigger guard. I could see a fluke accident happening with the Sig where it catches on clothing or another object and gets tweaked.

 

[Leicafan1990]

Bartlien has tight tolerances on what? The outside diameter of a blank? The length? The depth of stamping on the end? People who don’t know anything about manufacturing have gotten quite comfortable using a term that doesn’t mean what they think it means.
I’m not saying Radian doesn’t, but I am willing to bet they’re no “tighter” than milspec, which is its own tolerance. Even if they deviate from milspec, a blanket statement like, “they have tight tolerances” is giveaway someone doesn’t know what a tolerance is.
Look up the definition of tolerance.
Let me ask in a different way. Are there any uppers that Radian lowers won’t work with, and if so, why?

Tolerance is an acceptable range of dimensions for a manufactured part. If the part falls within that range, it will function properly, unless it has some kind of materials defect.

From the evidence we have, it appears that Radian do have tighter tolerances than milspec. Why? Well milspec tolerances don’t require a tight, no wobble fit between the upper and lower. Sure, you can get that if the takedown pin posts are at opposite ends of the tolerance range but it’s luck of the draw. If buy two receiver sets from Aero, one set could have a very tight fit and the other could be much more loose and they both fall within tolerance for Aero.

Randian build sets seem to consistently have a very tight fit between the upper and lower. I’ve handled about a dozen of them and they are all like this. In order to do this, you need to have your own tolerance that is tighter than what milspec calls for. This is the same for companies like JP, Icon Defense, Zev/Mega, Noveske, Seekins … any brands that advertise a tight fit between the upper and lower.

Granted, this is just one set of dimensions on a receiver set. Obviously there are lots of other holes and pockets that have their own tolerance range and I don’t know if Randian deviates from Milspec for those parts of the receiver.

And to answer your last question, yes there are probably some uppers that won’t initially fit on a Radian lower and will require material removal to fit but that upper would probably be on the extreme end of the tolerance range or possibly be outside it.

 

[Tokay444]

If Radian’s lowers will fit a milspec upper, then their tolerance has to accommodate the full range of allowable deviation of a milspec upper.
Matching sets being tight doesn’t necessarily confirm tight tolerances. They could simply be paring uppers on the high side of spec with lowers on the low side of spec and vice versa. Again, I can’t confirm nor deny that their tolerances are tight, but neither can anyone that hasn’t seen their drawings.

 

[Leicafan1990]

If Radian’s lowers will fit a milspec upper, then their tolerance has to accommodate the full range of allowable deviation of a milspec upper.
Matching sets being tight doesn’t necessarily confirm tight tolerances. They could simply be paring uppers on the high side of spec with lowers on the low side of spec and vice versa. Again, I can’t confirm nor deny that their tolerances are tight, but neither can anyone that hasn’t seen their drawings.

Their tolerance doesn’t necessarily need to accommodate the full range of milspec tolerances for upper receivers. Tolerance staking is a thing and customers generally understand that if you are mixing upper and lower brands, you might get a loose fit or you might need to remove a little material from one part to get them to fit together properly.

Radian’s spec is likely designed to have a tight fit between their upper and their lower and they don’t concern themselves too much with the tolerance range that other brands could potentially have.

I did ask the ex employee about set matching and he told me the only matching they really did was having all the build sets come from the same Cerakote batch. They kept the machining tolerances tight so they didn’t have to waste time matching sets and they also don’t sell receiver blems because they thought that hurt the brands premium image.

You bring up perfectly valid points but I think it’s reasonable to say that Radian have tighter tolerances than milspec because the extremely consistent product they deliver seems to back that up.

 

[JS8588]

Stop feeding the troll

 

[Delicatessen]

PWS/KAC/Noveske/SLR/FCD-SOLGW, MEGA etc all have

Just fyi; PWS has a newer version that is like the Lmt/lwrci with the right side catch/release paddle. Personally I prefer the Lwrc and Lmt mars style and have not had issues with either. Just realize that this style limits upper compatibility more than others (Bcm mk2, vltor etc are not going to work)

 

[HitEmHard]

The SanTan are nice, and matched upper/lower sets are rather affordable. I have 2 and like them. Everything works like it should! That said, anything beyond an ambi safety is a little bit of a waste. Standard controls are pretty easy to use left-handed. But that's just my 0.0002(tight tolerance)