I realize that Arsenal 107FR is arguably the most popular arsenal builds in America. It is under 1 grand and is packed with features. What I dont understand is the other models and their prices. Why are SAMs and pistol versions so much more expensive than SLR series? And what is it that 107UR has that 107FR doesnt? 107 UR has a shorter sight raidus. Help me understand the benefits of those models.

The UR has always been meant to SBR, that's the only real benefit IMO

The SAM7's have milled receivers, while the 107's have 1mm thickness stamped receivers.
Stamped receiver AK's are quickly bent into shape and heat treated. Milled receiver AK's take about 5 1/2 hours to mill out before heat treating. More time = More cost.

The 107UR is a SBR-ready Krinkov, while the 107CR is an SBR-ready mid size AK-104.
If you look close are the UR and CR, you will notice that they have a combined Gas Block and Front Site Base, while the 107FR has a separate GB and FSB.
Technically, neither should cost more than a full size FR, but Arsenal Las Vegas imports, meaning they can resell them at a premium

The 107FR is so popular because its a  factory built Bulgarian-made AK, which means high quality, light weight, and somewhat reasonable price at $950 - $1k

Many first time AK buyers get suckered into believing that milled guns are better and not just heavier.  They ARE more accurate so if you are planning on entering a bench rest competition with your AK they may be worth the extra coin...  

Thank you for the comments you all.
Are there really any difference to performance/significant strength if the receiver is milled? Arent they still just around 1mm thick? Arsenals claim is that the barrel is produced differently and time consumingly. So how is the accuracy of UR or SR with the higher quality barrel? Is it really significantly different than 107fr? I hear 107f hits average 2MOA. Is UR like submoa or something?

The standard for a Stamped receiver is 1mm thickness. However, some are thicker, such as the Chicoms, which are 1.5mm-1.6mm. Also the Russian Vepr's which are in the same general neighborhood. Thicker stamper receivers were designed to mimic the increased Torsional Ridgidity of milled receivers at the same reduced cost over milled. You can never ask which is better or which is more accurate (milled or stamped) without starting an argument. However, considering same manufacture, same shooter, same ammo, milled are typically viewed as being a TAD bit more accurate. But we're talking maybe 1/4" to 1/2" at best. MAC did an accuracy test  on the SAM7SF and got 1 3/4" at 100yds with regular Wolf ammo if that helps. That's in line with the accuracy for an AK-74 which is general a bit more accurate than a 47.

F vs FR...............The "F" refers to Folder............The "R" refers to a side scope rail.

Don't over-analyze all of this. Just buy what you like and can afford

I see that milled AKs seem more bad ass. I just bought a 107 and I hope it is worth over a SAM.
Thanks

Your 107 will be great and have accuracy that is more than adequate for anything situation in which you would use an AK.

Don't worry. You did good. And I'm sure your next AK will be a milled.

The magic of the SA/SAM series is that Arsenal can discontinue one model, then several years later reintroduce it with a different model designation, with only minor differences, and sell for hundreds of dollars more.

Or reintroduce the same model with the same name, after they find a "limited number forgotten in the back of the warehouse" at 2x the original price.

But hey, whatever works. I might bitch about Arsenal-KVAR, but they're the only game in town for Arsenal Kazanlak stuff.

Now someone correct me if I'm wrong but the SAM7s currently made are hundreds of dollars LESS than the previous ones.

I remember hearing that the originals had US made receivers or something and the Bulgarian made receiver drops the price significantly.

The SAM7 series is made by Arsenal of Bulgaria, then imported, and made 922r compliant.
The SA M-7 series was made by Arsenal of Las Vegas. They made their own receivers to Bulgarian spec.
The added cost of making their own receives added to the cost.
The similarity of the two series part number designations confuses many people
With regard to price........Arsenal's have not been priced well since the late 90's.

I witnessed someone paying around $1600-1700 for a new milled arsenal underfolder about 10-12 years ago.   It might have had banned features too...   so when the latest model came out and I could buy it for $1200-1300, I jumped at it.

The SLR-101S was identical to the SAM7 rifles in all ways except for the name. They sold for $999 new.

 
For some reason the new SAM underfolders are less well liked by some due to not having a 45 degree gas block.


As for stamped/milled? I've shot many of both and frankly prefer stamped due to less weight....but then again I'm the odd ball out because I also really like underfolders.

Except for the rare SAM7 Classic, all SAM rifles had milled receivers with AKM parts. This means skinny AKM barrels, & the 90 degree gas block. Nice guns, but not a true type 3 like the Classic was.  GARY

The advantage of a milled receiver is that it's a single chunk of metal so the spatial relationship between the receiver, interior rails, barrel, etc. is precise and fixed.  However, with a stamped receiver, the trunnions (the front trunnion holds the barrel) are riveted into the stamped receiver and the interior rails are separate assemblies that are mounted into the receiver.  If these parts are perfectly aligned during installation and the rivets hold, a stamped receiver can approach the precision of a milled receiver.  I wouldn't be concerned with something like an Arsenal 107 or a Saiga based AK because the Bulgarian and Russian factories know what they're doing.  With guns built from parts kits, the quality can vary.

The advantage of a stamped receiver is lower cost.  A milled receiver is roughly three times the cost of a stamped receiver.  Also, I've found that the milled receiver AKs have a smoother action than stamped receiver AKs.