KAC vs Geissele Handguard

[WarriorPoet19]

Looking at getting either a KAC URX 3.1 or Geissele MK4/8. What are some of everyone's thoughts on each of these hand guards in general and in more specific details also as to pros and cons. I am very interested in trying out both at some point and am trying to decide which to start with. If you have any pictures of any of your setups with them please feel free to share them. As always thanks for everyone's opinions and input.

 

[TheOE800]

The $120 URX wrench is a good reason to go with the Geissele.

 

[MtnCreek]

I have a 13" mk8 on a 16" carbine and really like it. No barrel nut timing, light weight, feels solid, rail up top and m- loc everywhere. If there's better out there, I'm not aware of it.

 

[longshot2000]

They are both very solid. I have most of the KAC rails, and a few Geissele. I am a KAC fan, but unless you are building off a KAC weapon, I would go with Geissele. The Mk4 has more Picitinny rail sections. Mk8 is more of a tube. Also, look at the Mk13, which is a little tighter fit.

 

[padom]

I'm also a huge fan of the Daniel Defense MFR mlok Handguard and SLR's mlok. Very solid. I specifically love the MFR nut/attachment design. Extremely solid. Same with the SLR

 

[longshot2000]

Just a brief follow-up. I changed out two of my SBR rails at home, on personal firearms from DD Mk18 upper rails to Geissele Mk4 and Mk8. WOW ! What an amazing set of rails from Geissele. I have heard that one of their rails might be on the Army's new CSASS. I can see why. The Mk18 is so 2004.

Now, for my clone builds, I am keeping the Mk18 rails, because you have to have a DD rail for a true Mk18.

 

[WarriorPoet19]

Thats true. I've come to settle on the geissele route. The whole 14.5 will utilize almost all geissele parts and after playing with the mk8 more i really like it

 

[BangBangBlatBlat]

The Geissele handguard is the best out there. No barrel nut timing. Very simple to line up. Clamping design that uses steel bolts to thread into steel. No aluminum on aluminum threading holding the handguard on. There's a reason that they are going on the new CSASS.

 

[.30kal]

Geissele's are nice, but a bit on the heavy side. BCM has a new MLOK rail (MMR) coming out that is almost as light as its KeyMod Rails (KMR). Also, the BCM rails feel a little more round in the hand than Geissele's rails. I'd wait for the MMR if you are trying to save weight.

 

[MSTN]

Both are fantastic designs.

The URX is one of the more challenging forends with which to work. The Geissele is the easiest forend to install, ever, in my experience.

 

[WarriorPoet19]

Thank you so much for all the input and help everyone. Makes things so much easier hearing from all of you and your thoughts and experiences

 

[plong]

Both are fantastic designs.


The URX is one of the more challenging forends with which to work. The Geissele is the easiest forend to install, ever, in my experience.

^^^ This, definitely this... and... Most Definitely THIS ^^^

 

[Frontsightfocus86]

I’ve had a couple of G rails- Mk1, Mk1 mod1 rev a, and a Mk4... the mk1 were cool because they were 10” and a rarity. However the mk4 is my favorite Geissele rail. I do love me some KAC though- the 3.1 is a solid rail and as far as the wrench goes- you can find them used on the EE’s in the community for a lot less than retail.

Good luck- you won’t go wrong either way.

 

[WarriorPoet19]

I went with the Geissele MK4 and I absolutely love it. Ended up putting every Geissele part offered into it and it is just phenomenal

 

[wareagle700]

Geissele is top notch. I have a few of their rails and will continue to replace the rest with more G.

 

[Bill3508x]

Both are fantastic designs.

The URX is one of the more challenging forends with which to work. The Geissele is the easiest forend to install, ever, in my experience.

Is that a mk8 with the proof barrel?

 

[MSTN]

Is that a mk8 with the proof barrel?

Yes!

 

[padom]

Yes!

What AGB are you using with the MK8? I have one sitting here and both my SLR Sentry 7 set screw and Seekins AGB hit the ID of the handguard on the top left side of the gas block if looking down the handguard from the muzzle....

 

[Bill3508x]

Yes!

How much room do you have around the gas block? Doing a similar build here shortly.

Thanks.

 

[MSTN]

What AGB are you using with the MK8? I have one sitting here and both my SLR Sentry 7 set screw and Seekins AGB hit the ID of the handguard on the top left side of the gas block if looking down the handguard from the muzzle....

That is an SLR 7S.

I ran into the same problem. Geissele forends do not play well with any adjustable gas block I've tried. That corner of the gas tube channel Has to be relieved to provide clearance.

 

[padom]

That is an SLR 7S.

I ran into the same problem. Geissele forends do not play well with any adjustable gas block I've tried. That corner of the gas tube channel Has to be relieved to provide clearance.

Ok your findings are the same as mine. I am going to give the JP Low Profile AGB a try as they seem to fit on other handguards that SLR and Seekins dont.

 

[TheOE800]

I'll have to look at my DMR because I don't recall the Mk8 hitting the SLR AGB I'm using and it should be the same model you're using.

 

[padom]

I'll have to look at my DMR because I don't recall the Mk8 hitting the SLR AGB I'm using and it should be the same model you're using.

I can assure you it hits. Only one I have on hand that doesnt touch is the Geissele low pro non adjustable.

 

[TheOE800]

I can assure you it hits. Only one I have on hand that doesnt touch is the Geissele low pro non adjustable.

Nope just checked. Larue barrel, Sentry 7 .450" spacing, Geissele MK8 15" MLOK.

 

[padom]

Nope just checked. Larue barrel, Sentry 7 .450" spacing, Geissele MK8 15" MLOK.

20" Bartlein compass lake .750 gas tenon SLR Sentry 7 set screw and Seekins AGB both contact ID of rail on top left side of gas block. MSTN is saying he is having the same issue so I am so not sure what you are doing differently with the same gas block and Handguard to clear...

 

[TheOE800]

20" Bartlein compass lake .750 gas tenon SLR Sentry 7 set screw and Seekins AGB both contact ID of rail on top left side of gas block. MSTN is saying he is having the same issue so I am so not sure what you are doing differently with the same gas block and Handguard to clear...

Your gas block on straight?

I just verified with a flashlight and it seems real tight, possibly even touching during recoil perhaps, but I don't see rub marks or anything. I DO have a theory: I suspect you have your gas adjusted to a further out/more open position and the side of the gas block/set screw is further outboard than mine is. I run this upper with high pressure ammo and suppressed; being a Larue barrel it is also likely overgassed to begin with.

 

[padom]

My gas block on straight? Lmao..i hope I know how to install a gas block after 100+ AR's

seems tight? Can you fit a feeler gauge between the gas block and the rail?

 

[TheOE800]

It's a bit inconvenient to get in there and I only have the short 2" feelers, but let me try when I get back.

 

[boelt63A]

I have both and at this point I doubt I would go with another KAC rail. I have several Geissele rails and will continue to buy more.

 

[TheOE800]

My gas block on straight? Lmao..i hope I know how to install a gas block after 100+ AR's

seems tight? Can you fit a feeler gauge between the gas block and the rail?

It was difficult with my feelers, but it's only a few thou. No/little resistance at .006, but can shove a .012 through with some force. Oodles more room between the GB and the gas block channel, but the screw at the back of the GB on the ejection port side is quite a bit closer to the curvature of the handguard where the channel starts.

 

[Strykervet]

The URX2's and 3's are a bit of a bitch with that goddamn aluminum lock ring that is essentially a one use item --it almost ALWAYS strips the lugs when assembled and has to be roughnecked off and replaced with a new $50 lock ring. Not to mention the tool costs extra. I love my URX2's with built in front sights, but goddamn they are a hassle, especially if the need to be removed. I suspect that's why they were constantly upgrading them and finally replaced them with URX4 in a short time.

Try the URX 4. It's only real caveat is that for pinned gas blocks, you may have to dremel out a small window to line up the pin and punch for the gas block. No biggie, it's just one of many keymod or mlok slots, modding one won't hurt anything. They lock on at around 140ft.lbs. using shims to line up the gas tube. It basically forms a light monolithic upper, it's solid and it's light and one piece. I didn't like 'em at first, but after being forced to get one on the new SR25's I was won over and use 'em on several rifles now. URX4 comes with the wrench, costs far less overall, is probably more solid under stress and is obviously far more user friendly, not to mention much lighter due to lack of barrel nuts, rails and other shit.

Anybody has KAC rails and needs rail covers, I have a SHIT TON of them and will let them go for good prices and I have all sizes and models and can custom cut new sizes to spec. PM me if interested.