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FINALLY joining the KAC club - KS-3 & KS-1 (Page 2 of 3)
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Originally Posted By thedownzero: Am I reading this right? Port erosion at 150 rds?  It's pretty typical/expected and is fine. This is a KAC 11.5" MOD 2 at 8K rounds: Attached File DDM4 barrel at 1-200 rounds: Attached File |
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Originally Posted By JohnDough: It's pretty typical/expected and is fine. Originally Posted By JohnDough: It's pretty typical/expected and is fine. not at that round count…maybe a couple thousand sure, but a couple hundred?! Looking at initial pic of port, it appears there was some runout/wear already. Originally Posted By Video: The Preston Moore test video had the same looking gas port. Sure, but at what round count? Op has 150 in that picture… |
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Originally Posted By thedownzero: Absolutely not at that round count…maybe a couple thousand sure, but a couple hundred?! Looking at initial pic of port, it appears there was some runout/wear already. That gas port was and is just fine and is wearing as expected. I have another KS3 with the same round count that I can scope for you if you really need a second sample. |
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Originally Posted By Brahmzy: How does the port erosion / round count conversion change with, say, nitrided 416R SS? The only real issue with port erosion is if it changes gas drive significantly, or if it gets too close to the muzzle (mk18s are a case study here). Otherwise, its just more or less nice to see it has no burrs and if it does/did that it polished out. Gas port erosion has very little to do with anything, otherwise. |
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I just bore-scoped 5 of my many AR rifles. These all are nitrided barrels. Not one of them has under 250 rounds - the 2 lowest still look brand new. A barrel I know that has over 2,500rds has nothing close to the erosion “appearance” of the above KAC. I bet it’s a chrome lining / plating thing and that the chrome just chips off right there, but it’s just that very superficial chrome layer and no real barrel metal erosion has taken place yet. I’ll borescope my 2 when I finally get ‘em and keep an eye on them. These will be the first chrome-lined rifles / barrels I’ve owned in a long time. Just bought a Griffin Armament 416R SS 5R middy nitrided barrel for a new 12.5 upper I’m building. It looks like a really nice barrel. Looking forward to it as a suppressor host. |
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Hodge MOD 2 FN barrel 14.5 middy with @500-1k or so on it. Circa 2015. Attached File |
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Originally Posted By JohnDough: Ive tried t2/g33,unity4x,g45, and keep coming back to LPVO/P2 stacks. The 10oz savings is nice, but you just give up too much. Gun control/cheek weld, wind holds, etched reticle, perfect nv beight piggyback, it's just too good to give up for 10oz After coming to the same conclusion as you I decided to set up another AMG/P2 combo for the KS3. If weather behaves I’ll be sighting it in tomorrow. 
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“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Originally Posted By ErikTaylor: After coming to the same conclusion as you I decided to set up another AMG/P2 combo for the KS3. If weather behaves I’ll be sighting it in tomorrow. https://www.ar15.com/media/mediaFiles/112986/IMG_2777-3797048.jpg Excellence! The AMG/P2 finally actually checked my boxes. I messed with so many combos trying to find optimal. |
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Originally Posted By JohnDough: Excellence! The AMG/P2 finally actually checked my boxes. I messed with so many combos trying to find optimal. I agree. Last weekend running the KS3 with the T2/3x mag-1 during open gym I wasn’t really excited with engagements at 300ish yards. It was hard to PID the plate. It was a white plate with white sugar sand in the background with taller grass as the foreground. I really enjoy the AMG/P2 combo so after seeing your post I was like why not, just get another one for the KS3 and call it a day! |
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Originally Posted By Brahmzy: You guys are gonna make me buy an AMG dammit. NXS1-4 K16i MK6 1-6 VCOG 1-6 NX8 1-8 ATACR 1-8/P2 T2/G33 T2/G45 T2/UNITY4X EXPS3-0/G33 TA02C-P2 NX8/Leupold DPP-NV NX8/RCR NX8/P2 AMG1-10/RMR HD-2 This is most of what I've gone through before settling on AMG 1-10/P2, and it's better than any of the above, IMO. For the dollar, NX8/P2 comes the closest. |
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Broke 'em out of jail last night!!! Attached File |
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Originally Posted By Brahmzy: Broke 'em out of jail last night!!! https://www.ar15.com/media/mediaFiles/50907/IMG_7280_jpeg-3799859.JPG So the fun begins!! 
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“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Originally Posted By Brahmzy: Broke 'em out of jail last night!!! https://www.ar15.com/media/mediaFiles/50907/IMG_7280_jpeg-3799859.JPG @Brahmzy How's the fitment between the upper and lower, is the lock up tight OR is it loose and rattle? Thanks |
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Originally Posted By Brahmzy: It’s not bad. That said, I already had 2 accuwedges waiting for these. Call me silly but I don’t do sloppy receivers. I standardized my builds on receiver sets that have tension screws like 20 years ago, lol. Flame suit on. I noticed the same thing with mine and just had several accuwedges arrive today! |
“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Originally Posted By ErikTaylor: I noticed the same thing with mine and just had several accuwedges arrive today! Both of my KS3s have identical lateral play, but zero vertical. Im quite pleased. Perfect mesh between precision and ease of proper assembly/disassembly. |
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Originally Posted By JohnDough: Both of my KS3s have identical lateral play, but zero vertical. Im quite pleased. Perfect mesh between precision and ease of proper assembly/disassembly. That’s about where mine are - definitely the tightest off the shelf rifles I’ve handled in awhile. These things are just tough feeling. Definitely ready for war. Just need to figure out my optics and sling setups. Oh and I’ve got SIX cans in jail right now, including the 2 2026 KAC ones. Sure be nice if the approvals would get batch approved in the next week. |
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Originally Posted By Marksman14: National match shim is something almost every rifle I own gets. Agreed on slop. Cannot stand it. The shim is a better solution than the accuwedge. @Marksman14 Ordered a 2-pack! THANK YOU! I was thinking to myself when I stuck the Accuwedges in that in 2026 this seems kinda ridiculous that nobody’s come up with something better. I remember my very first AR - brand new ban-era Colt 20”HBAR and weeks later brand new Bushmaster 16”. Both were sloppy pigs. Then I discovered Accuwedges and was very happy. Then I’d buy tons of lowers and uppers and match the sets for builds. Then as soon MEGA started the tension screw thing ..oh man. |
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Originally Posted By Brahmzy: @Marksman14 Ordered a 2-pack! THANK YOU! I was thinking to myself when I stuck the Accuwedges in that in 2026 this seems kinda ridiculous that nobody’s come up with something better. I remember my very first AR - brand new ban-era Colt 20”HBAR and weeks later brand new Bushmaster 16”. Both were sloppy pigs. Then I discovered Accuwedges and was very happy. Then I’d buy tons of lowers and uppers and match the sets for builds. Then as soon MEGA started the tension screw thing ..oh man. When you fit them, once the pins start to go in, go slow. It’s possible to get them to the point where they slide in and out as expected (easily) with NO slop. It’s also possible to go too far. It doesn’t take much. When you get close, make sure you clean the shim and the recess completely, and add a little oil to the pin. I’ve gotten them close, not cleaned the recess or the shim, then cleaned it, reinstalled, and it was perfect. I’ve also failed to clean it everything, then removed more material….then cleaned…and took too much off  . But yes, they are great. Glad you snagged some! |
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I could not stand the stock lens covers so I ordered a pair from MKM and they are sooooooo much much better. This is how the AMG should have come out of the box. For those interested the size you need are Front: 1.339 Rear: 1.700 They fit like a glove! 
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It’s such a big difference considering it’s just a scope cap. When you open the Vortex ones the rubber slides around and cants the cap, etc. The MKM’s are rock solid and stay put. |
“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Originally Posted By ErikTaylor: It’s such a big difference considering it’s just a scope cap. When you open the Vortex ones the rubber slides around and cants the cap, etc. The MKM’s are rock solid and stay put. @ErikTaylor Good to know - I need these for my Vortex Razor HD LHT 3-15x42 and NF NX6 1-6 and hopefully soon AMG. Just realized my inbound PA RDB 1-8 doesn't come with freaking scope covers! Are these 3D printed like some of their other stuff? How's the finish on them? EDIT: Yes, they're 3D printed - just had to read the description, lol. I have one of their throw levers and it is pretty rough as far as the texture. I wonder if they have improved that on their throw levers. |
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Originally Posted By Brahmzy: @ErikTaylor Good to know - I need these for my Vortex Razor HD LHT 3-15x42 and NF NX6 1-6 and hopefully soon AMG. Just realized my inbound PA RDB 1-8 doesn't come with freaking scope covers! Are these 3D printed like some of their other stuff? How's the finish on them? EDIT: Yes, they're 3D printed - just had to read the description, lol. I have one of their throw levers and it is pretty rough as far as the texture. I wonder if they have improved that on their throw levers. How can a scope not come with caps lol. I have one of their levers too and I think the finish is a little smoother overall on the caps. I didn’t notice, or think to myself, wow these are rough, when installing them on the AMG’s. |
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So, a little update on the MKM covers. I just got back from the range sighting the AMG’s in and I kept having the rear cap slip loose, either through sustained recoil or getting bumped. Damn. So my solution is electrical tape. The very most rear of the ocular is tapered (about 3/8” from rear of ocular housing forward) so I put a piece of electrical tape about that same width around the scope housing to help make up the difference and match the diameter forward of that 3/8” taper. I then put a tape inside the inner diameter of the rear cap. After getting the cap as far forward as possible I tightened the cap cross bolt down and it appears to be a much more secure fit, even though I thought I had one before. It’s not budging now. I hope this helps with the people with AMG’s and want to use the MKM caps. |
“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Originally Posted By ErikTaylor: So, a little update on the MKM covers. I just got back from the range sighting the AMG’s in and I kept having the rear cap slip loose, either through sustained recoil or getting bumped. Damn. So my solution is electrical tape. The very most rear of the ocular is tapered (about 3/8” from rear of ocular housing forward) so I put a piece of electrical tape about that same width around the scope housing to help make up the difference and match the diameter forward of that 3/8” taper. I then put a tape inside the inner diameter of the rear cap. After getting the cap as far forward as possible I tightened the cap cross bolt down and it appears to be a much more secure fit, even though I thought I had one before. It’s not budging now. I hope this helps with the people with AMG’s and want to use the MKM caps. Thanks for the update! Did the stock ones slip n slide like that at all? They make a 1.695 vs the 1.700 you bought - wonder if that’d be any better? |
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Originally Posted By Brahmzy: Thanks for the update! Did the stock ones slip n slide like that at all? They make a 1.695 vs the 1.700 you bought - wonder if that’d be any better? The stock ones do move around simply by flipping the cover on and off. However I don’t think they would have popped off from recoil because the rubber sleeve is much longer than the MKM caps. I’m not sure if the smaller cap would make a huge difference. Looking closer the taper built into the AMG ocular housing is roughly 1/2 of the length of the ID of the scope cap. So I think tape, or some medium, would need to be used to help make the diameter consistent. In this case I think the 1.700 would still make the most sense so it’s large enough to install the cap with the tape on both the ocular and the ID of the cap. I can’t say for sure if the 1.695 would allow this to happen. I think at minimum it would allow for room for the tape to be on the ocular housing, but possibly not inside the scope cap. I hope that all makes sense. This weekend I am running open gym at my range (basically CrossFit with dynamic shooting) so the caps will be put to the test. I’ll report back how they held up. |
“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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As promised I put these caps through open gym. They didn’t pop off at all and you can see here I was bouncing around with the rifle, running, etc for several hours. This is a new IG page I started last week so I don’t mix my shooting vids on my company page. This video is a cool 1st/3rd person view of the same stage. The KS1/AMG was an awesome combo. While 200 yards isn’t a crazy range for either component the grass was so tall you could only see the head box of the target. So thankful I was able to dial up to 6x. I couldn’t imagine trying to find the target that quickly with a 3x magnifier or a red dot only. KS1/AMG/MKM Caps at Open Gym ETA: Especially with my eyes. |
“The beauty about the second amendment is it won’t be needed until they try to take it.” -Thomas Jefferson
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Re-zeroed the KS3 today with some 70gr TSX. The gun seems to really like it even if I can't shoot for beans.Attached File |
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Originally Posted By Marksman14: When you fit them, once the pins start to go in, go slow. It’s possible to get them to the point where they slide in and out as expected (easily) with NO slop. It’s also possible to go too far. It doesn’t take much. When you get close, make sure you clean the shim and the recess completely, and add a little oil to the pin. I’ve gotten them close, not cleaned the recess or the shim, then cleaned it, reinstalled, and it was perfect. I’ve also failed to clean it everything, then removed more material….then cleaned…and took too much off . But yes, they are great. Glad you snagged some! Holy crap. Been at this for HOURS - just on the KS-3. I’m out of sandpaper, lol. Mine fit fairly tight vertically which means I’m having to remove a ton of the shim and I’ve still got a long way to go. They need to provide about 4x the sandpaper and maybe a separate sheet of 160 or something. Bummer is really I need to get this handled before mounting optics and all that. @Marksman14 |
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Originally Posted By Brahmzy: Holy crap. Been at this for HOURS - just on the KS-3. I’m out of sandpaper, lol. Mine fit fairly tight vertically which means I’m having to remove a ton of the shim and I’ve still got a long way to go. They need to provide about 4x the sandpaper and maybe a separate sheet of 160 or something. Bummer is really I need to get this handled before mounting optics and all that. @Marksman14 I had to grind the fuck out of one on my Geissele tabbed MK16/upper blem I just bought. The depth of the cut in the upper was very shallow. Seems like you’re dealing with the same thing. If you have a set of calipers, measure the depth of that channel versus the thickness of the shim and it will give you an idea of how much further to go. The G upper took me about 45 min to do. Most other uppers have been in the 15-20 min range. It’s worth the time though. Just don’t go too far |
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Got it! Super tight now! Starting to come together finally. Tough call between the NX6 1-6 or AGM for the KS-3. Think I'll save the AGM for the KS-1. Attached File |
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Originally Posted By Brahmzy: Got it! Super tight now! Starting to come together finally. Tough call between the NX6 1-6 or AGM for the KS-3. Think I'll save the AGM for the KS-1. https://www.ar15.com/media/mediaFiles/50907/IMG_7351_jpeg-3805332.JPG That to me, is the logical choice. Glad you got it fit! |
| I really think that if KAC meant to make these a slip fit, they would have. They give them the clearances/tolerances they intended to, and KAC tests things more than most. For example, if you look at the notch in your rail/upper where the two join, you will see the gap is wider on the (from shooter's perspective), right side while solid/touching on the left. This is so that the rails line up perfectly as the hand-guard nut is torqued solid. This is the level of detail KAC machines into these rifles. I'd not muck with it with shims and whatnot to alter it. |
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I think it’s more .mil rifles vs civilian rifles. .mil rifles always have looser tolerances. All rando uppers need to interface will all rando lowers without creating friction for the armorers. Same with Colt, same with every other .mil rifle. That said, my KS-3 is nice and tight now and that’s the way it’s staying. Will be working on the KS-1 next. Same as it always was. Or is it. |
FINALLY joining the KAC club - KS-3 & KS-1 (Page 2 of 3)
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