I purchased this block in the set with the upper clamp, due to it's popularity, although I've noticed most gun smiths seem to be moving away from it. Once home, I discovered that the lower block does not fit into any of my AR lowers, which covers 4 (top) AR models. Looking at the shape of the block, I can see that it is concave (wider on the ends). It's not just snug, it doesn't fit at all - any of the lowers I tried. Reading more about the block, I learned that it does require fitting before use. That means in order to use this tool, I have to permanently modify it's shape. No tool should require permanent modification before it can be used; that's a design flaw. Fitting custom parts makes sense...but a tool? My concern now is if I modify it enough to fit 1 lower, that might not work for another. I'll possibly have to modify it for each lower, but once you take material off, you can't add it back on. I'm tossing this in the junk pile and already ordered a competitive product. I'm giving this 2 stars, because it doesn't work out of the box, but seems like if it did fit your lower, then it would be a strong vise.

I used this for a recent build that used the Aero Precision Enhanced Upper receiver, and an Anderson Manufacturing lower. There with issues with both main parts.



The part of the upper receiver where the front pivot pin goes through collides with the action block and doesn't allow it to close correctly. I was still able to get it gripped on the upper well enough for attaching the barrel and flash hider, but it made me feel uneasy to say the least. As others have said, the lower block is too large to slide into the magazine well. I'll probably go back and use a file to shave off the collisions areas, but I shouldn't have to. If you're planning on using the same upper as me be aware of it not closing completely. It might work fine with regular uppers, but I can't attest to that. The price is great, but I'd strongly consider buying better quality for more money if I had to do it over.

The upper block works great on both my Sig 556 upper and my fiances DPMS Oracle upper but the lower magazine block is too large for both of our lowers..

Can hardly get in in there and I do not want to risk pounding it in and causing too much stress on the magazine well.

I know it is meant to hold it down but this seems almost too tight..



I would suggest only getting the upper block and finding a lower block elsewhere.

Just received this today, the upper action block is fine as well as the internal support, however the lower vice block is a very tight fit in to the mag well. I will trim it down some. That being said, the price for the set is great considering each piece individually costs about as much as the set.

I have had this set for four years and it has worked very well. A must have for Barrel removal/ installs. It was designed for Mil-Spec. Recievers. They have a different type of mag release than a Stag and some others, so be careful when ordering the Kit vs. the upper block It may not fit(lower mag. block) some billet lowers, depending on the tolerance. Overall I find it an indispensable tool. well worth the purchase price! Stag sells there own Lower vise block that fits their lowers as well as many others, I have found that if the brownells block is tight or does not fit the Stag block will. Just something I have learned over the trials and errors in years of Gunsmithing.

I have a colt le6920 and this block was to big on both ends. I took a large file, and while watching football, carefully removed a little material on both sides for a nice tight fit. I know every ar maker will have slight differences in the mag well so this block being to big for my ar was no surprise. It was easy for me to fit it to my mag well and I would recommend it to anyone. Just remember that not everything will fit perfectly and in this case that's perfectly fine.

Had to file it to fit my 1st. lower! Got it snug! Dropped right in the 2nd. lower like a GI mag! Works great! Thanks Brownells!

Does what it's intended to do. The only thing I gave it a 4 is that I have to shave a lot on the lower receiver vise block in order for it to fit on my Colt lower receiver. I had no issues with the upper vise block.

I was just hoping that for the price, both blocks should fit perfectly, or they make different blocks for different receiver sizes.

Does not fit. I needed to use it or I would have returned it. I had to use a sander in order to make it fit. Sanding a little at a time until it would fit then it wobbled front to back.

Would give it 4 stars, but...I had to take a file to it to reduce it in size to get it to fit in the magazine well. It was too thick. Tried it in 3 lowers and it was too large in all. Once fitted, it works great.

Did not fit my Spikes Tactical Lower. I am returning it now i will update later on how Brownells handles the claim.

Does not fit all lowers. Had to take some off the sides to get it to fit my AXTS lowers. Slipped right in to a Daniel Defense lower though.

Fit nice and tight in my Rock River, and no sanding or modification was needed. This makes working on my AR platform rifles so much easier. My first use was to use along with the Brownells buttstock wrench, and I could not be happier with both. Well worth the money.

I ordered this product to use for building a Stag Arms lower receiver. I had to spend about 30 minutes with a Dremel tool and sandpaper to remove enough material for it to fit within my lower mag well. I used calipers to measure the block and compare it to the dimensions of a real magazine, and the block was about .02" too thick. Just enough so that it wouldn't fit inside the mag well. I definitely didn't want to "force" it to fit. Now it fits snugly and securely.

The product works well, but coming from Brownells I would've expected a little better quality, which is why I only gave it three stars. This is just a molded piece of heavy plastic, and the mold is apparently slightly too large.

Purchased in a pack that included upper receiver vice block. The lower block did not fit as others stated but 15-minutes with a file fixed that problem. Product now works with no problems and is still tight. You will need to work on it before using but I still say that it is a great buy.

Works as designed, though it is an extremely tight fit on my Spike's Tactical lower. As with many of the other reviews, will have to sand down the sides.

It was super snug in my Spike's lower but it went in with some tapping. Well, I got the magwell down to the stops, and they sheared right off, and it's not like I hit it very hard. The nylon is really slippery as well and didn't seem to want to stay clamped in the vice.

I really wish they'd just modify their design for their hammer drop block and make it extend below the magwell, so you could clamp onto it.

Given this one is double ended, I don't know why they couldn't have made one end slightly smaller than the other so that hopefully people don't have to sand them. I don't know why with a milspec receiver why you should have to modify the thing at all. It should just work.

This is a great set, at a great price. I had concerns it wouldn't work with a VLTOR upper but just assembled a new AR with a VLTOR and had no problems whatsoever.

Just completed my first AR lower build. Spikes tactical lower, RRA LPK. As many reviewers stated, I needed to sand the vice block to get it to fit into my lower receiver. That's why I gave it 4 instead of 5. With minor sanding, it is a great product.

Another product that does what its intended for. If it doesn't fit maybe its not the receiver block, maybe its your rifle.

Overall it worked great.

The kit came as advertised. The mag block fits tight in my billeted lower, but it serves the purpose. The upper insert worked on both my billeted and forged uppers. The vise block only worked on the mil spec forged upper and not the billeted upper. Do not get this kit expecting the upper vise block to work on a billeted upper, go another route.

Well made product better than rednecking it by hand

I purchased this set and am happy I did. It is affordable and works great. It fit my A2 and M4 flattop upper snugly with no problems. The receiver vise block was a little tight getting it in the first time or so but works great now. I highly suggest this set for the price.

This product is too large to fit into the magwell of Stag, Sig, Noveske, RRA, S&W, and Colt lower receivers. It requires significant force to correctly install to prevent crushing, but gets stuck when it's time to remove. This can be remedied by sanding down the sides, but if you pay [$] for something it should work without having to fix manufacturing or design defects. I will not buy another Brownell's product again.

Well I havent checked the upper block yet cus I dont want to take off my EOTECH, but the magwell block does not fit on my Rock River Arms lower. I will most likely have to take the grinder to it and get it down to a slimmer size. Does not fit front to back but clears ok side to side. I dont know what model lower they used to make these but I cant believe how off it is.

It's a solid piece, but I'm going to have to do the standard sanding. They should sell it either at spec sizes or undersized and include shims of different sizes.

Well like others have stated it requires sanding to fit. While I both understand and like the fact that it come a little big to accept differant tolerances that should be stated when purchasing the product. I would expect better from Brownells. Once sanded down it does fit nicely.

Bought these blocks to make sure I get the job done, and done right when putting together or doing extensive maintenance work on my AR15s.

Just completed installing a free float handguard on my BCM. This kit works great! I knew what to expect with the lower receiver vice block from prior reviews, so before I used it, I filed it down to insure it wouldn't get stuck in the magwell. The vice block worked great on the flat top receiver.

Works well on the standard AR rifles but my son and I are both left-handed so we have built a few left handed rifles using Stag left handed parts. The vise block will not properly grip a left sided upper. The block has specific cut outs to fit around the ejection port and the forward assist. The lower block still works though the mag catch does not engage. Wish that it was universal for those of us that build for both sides.

This is one of those tools you don't know how you did without. Great product on the upper receiver block set. The lower mag well block is a different story. It doesn't fit.

I've used this a handful of times since receiving it a few days ago. I used to use the "Plastix Plus" stand to do general maintenance/cleaning/lubing, but now I prefer this vise block. You'll read some reviews complaining of the block being too large for the mag well. I don't think that this is a problem or design flaw at all. Think about it--not all manufacturers will end up with lower receivers (hence mag wells) that are within design specs. I think Brownells did us consumers right by using a larger-than-spec mold. It took me a few swipes with a file to get a snug fit with my lowers (CMMG). There's no play. Just be careful and don't go overboard with sandpaper or a file.

I bought the set. Tried just hand fitting the lower block in the receiver-it got stuck. Really stuck. I had to put it in cradle and hammer it out. Should either be made better or have a warning that it needs to be sanded, with sanding instructions. I expected better from Brownells

It fits very tight, which is good. That being said, it fits so tight that it requires a lot of force to mount the lower. When I was pushing the lower down on it, part of the side stop broke off. I have tried "super glue" twice now to effect a repair. The first time it didn't hold. So far the second time it has held. If it breaks again, I will return it.

I found out about this set when I attended an armorers course a few years ago. It is an absolute must for the AR15/M16 armorer, and the hobbyist alike.
The upper clamp will keep you from trashing your upper on those over torqued, or in some cases damaged barrel nuts.
The only thing that keeps me from giving this a 5 star rating is the mag. well block is hit and miss as far as which lowers it will fit into, some fit, some don't, though luckily I don't use it as much as the upper clamp; so it's not a big deal.
Overall an excellent addition to any serious AR users tool kit!

This tool is a must if you work on AR-15 rifles. It's a very simple tool. Very easy to use. Just need a 4 inch, or bigger bench vise.

I purchased this set to use on my latest AR project. My AR's old barrel nut was very difficult to remove and I am absolutely convinced that I would have destroyed my upper without the use of this tool. It held my barreled upper firmly in the vise, even under what would have been way more torque than necessary, under normal conditions. There was absolutely no damage to my upper after the project was completed. The lower block was also used to remove the buffer tube from my lower. It also worked very well under heavier torque to remove the staked castle nut. An all around great product.

worked great but for the money could have been alot cheaper

Awesome tool. Absolutely necessary to remove AR barrels

I had to sand mine a little to get it to fit in the mag well of my lower. Took all of 5 minutes with some sandpaper I had lying around. Even with that slight nurgle, I found it an indispensable tool.

I got the "itch" to put together an AR from scratch. Other than carrying a M16A2 for a while it was my first experience in actually starting from a stripped lower. This package was the perfect choice. It more than does the job, for less than the price of others.

This product is a great concept for working on your AR without damging your rifle. It is durable and very easy to use, but as a previous reviewer stated I too had to sand the block in order to get it to fit in the magazine housing. I would still recommend to a friend, but I hope that Brownells will address the problem and correct it for other customers that make this purchase. For the price, the product should be ready to use out of the package.

Would not fit into the mag well. Had to sand down the sides of the block. Took me about 5 minutes. But for the price, it should fit the first time. My lower is not the issue. All my mags fit fine including pmags. This was just too thick.

Is a great set. I love the protection it gives to both upper and lower receivers. I did have one small snag. The upper receiver block can crush receiver slightly, which can throw off torque of barrel nut. After some minor fitting it was perfect. Should have baught when I first started job position.

A must have for armorer level repairs and modifications to the AR family.

If you are serious about working on your AR15/M16 platform this tool needs to be on your "Need List"
versus your "Want List". Very rugged and solid when placed into the vice to hold your lower assembly or complete rifle. I use it for cleaning,scope mounting, or any task requiring solid holding capabilities. I rarely use my gun cradles for AR's anymore after purchasing this. And since you are considering this go ahead and purchase the "Upper Receiver Action Vice Block" Brownell's Part # 702-003-015.
And if you really want to save a few bucks buy the set! Brownell's Part #702-000-001.
These are both required for any serious AR Owner!
They are like having an extra pair of hands that are not connected to a mouth. :^)

If you do any of your own work on an AR-15 you need this set. It will protect and secure both the upper and lower for any work that you need to do. I had to modify my upper receiver clamp to work with a Daniel Defense rail as the screws wouldn't allow the block to close but it works just fine now.

Have this product for years now and performs as it should. The upper block shrouds and supports the receiver with the insert in place to torque the barrel nut to specs without stress on the upper. The lower block inserts in the mag well and firmly holds the lower to perform tasks that might otherwise take up one hand. Excellent product.