cad_man
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Posts posted by cad_man
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I know what my next upgrade is.
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I'd say my dry firing hasn't been excessive, but at every step along the way of my build I rack & dry fire as part of function testing. Most of the dry firing was during magazine feed lip tuning, and that took a while to get the bolt open function working on all of my magazines. The ever loosening choke is the only issue I've seen, and it doesn't take many handle pulls to get it loose. The wall thickness of the barrel seems too thin to allow a threaded lock ring, so I'll probably just use a drop of high temp thread locker and call it a day.
This is my first and only shotgun. Are loose chokes an issue on other shotguns?
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Not heavy.
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8 months after buying my MKA I finally get to shoot it.
I added a Magpul B.A.D. lever, swapped the Trulock Tactical Choke for the stock choke with three notches on it, and went with the Magpul MOE Fixed Carbine Stock.
Very very nice.
Let us know about the Mako GLWith the added weight of the FB lower and standard length handguard, the Mako GL was a little too heavy and had to go. It also loosened up a little just from pushing it in and out before I even shot the MKA, and I just couldn't get over that looseness. I like my firearms nice and solid. The Magpul MOE Fixed Carbine Stock it turns out is the perfect length and is rock solid.
The B.A.D. lever is a must. Releasing the bolt with the bolt catch alone was a bitch with some magazines. The leverage of the B.A.D. lever makes that a thing of the past.
Didn't get to shoot it until the tail end of our time at the range, so I only ran a couple boxes through it (Federal Power Shok rifled slugs, 1610 fps) with a factory 10 round magazine.
I had 2 FTEs, and when I got home I found I could twist the barrel side to side easily by hand. The retaining nut & the gas spring retainer came loose, so I'll chalk up the FTEs to that. The other rounds went boom and ejected just fine. I'm going to modify the retaining nut to prevent it from coming loose in the future.
All of my shots grouped to the lower left corner of the target and I'll contribute most of that to the barrel. The bore in the upper receiver is a loose fit for the barrel extension, and the barrel angles downward slightly because of it. When the gas spring retainer is tightened it pulls the barrel downward. I don't see any good fix for that other than see if RAAC will replace the upper. FB has posted pictures of their MKA upper and that may be the direction to go. Better machining and the slick receiver/handguard interface FTW.
The stock choke tube also worked loose. Dry firing would transmit shock through the barrel and the Trulock would become loose from that alone, so that's the reason for running the stock choke. But it looks like anything will work loose unless there is some sort of mechanical means to tighten it.
FTEs aside, the MKA is a blast to shoot with a nice bit of recoil to keep you honest. We where shooting at an indoor range and my wife said other shooters would walk by really slow behind me to check out what was making the kabooms versus their pops, and they would comment on the length of the 10 round magazine. There apparently are not many MKAs in California.
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I've been collaborating with Lew on a design for my MKA that will function with the standard length FB handguard, larger aftermarket charging handle, and access to the bullet button (magazine release button for you lucky free state people) and finally got it delivered.
The fit is perfect and there is access to everything. I was supposed to use it yesterday and give him feedback, but didn't get a chance so it'll be some time next month. I did use the other MKA brass (hull) catcher on our ARs and filled the bag up. Works great and looks good too.
These are pictures of Lew's new design:
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There is no provision for the retainer & spring. It's only function it is to retain the buffer in the extension tube of ARs. The tab of an endplate aligns the buffer tube, and yes you will want to use one of those.
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No. The MKA does not use a buffer & spring.
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My TBC was waiting for me when I got home today. Nice unit.
Mounted it on the MKA and the charging handle hits the curved plastic strip that mounts the bag to the lower part of the frame. Unbolting the strip and turning it upside down solves that issue.
Now I pull the left side charging handle and......
the right side handle cannot pull all the way back. In the picture the MKA is in bolt open condition and you can see the handle does not fit in the frame/bag.
Looking carefully at the pics ToysRUs posted I see the problem. The catcher was modified around his MKA; short FB handguard and stock charging handle. I have the standard length FB handguard and T&N handle. The side rails on my standard handguard stop almost 1.25" from the front of the receiver, and that looks like what I'm short for the handle to work with the catcher. The larger handle is also why it hits the frame as set up.
I'm going to keep this catcher to use on our ARs and contact Lew about getting one made for my particular MKA configuration. They have a model with a longer frame for ARs with exactly this issue.
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You will probably want to contact the BATF and get a letter from them before removing that tag.
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Not a good idea.
Page 43 (also on page 10) of the ATF Federal Firearms Regulations Reference Guide:
§ 478.34 Removed, obliterated, or altered
serial number.
No person shall knowingly transport,
ship, or receive in interstate or foreign
commerce any firearm which has had the
importer's or manufacturer's serial number
removed, obliterated, or altered, or possess
or receive any firearm which has had
the importer's or manufacturer's serial
number removed, obliterated, or altered
and has, at any time, been shipped or
transported
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Hanging on to mine.
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Ordered. Plan to use it on both my MKA & our ARs.
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Definitely interested.
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Magazine issue. The bolt open tab on 2 of my 10 rounders and half of my 5 rounders does not sit high enough to lift the bolt catch. Like duggr mentioned, opening the front of the feed lips will allow the follower to rise and the tab will lift the bolt catch. This worked for me. You will need to be careful so the bolt open tab doesn't hit the top of the window it protrudes through.
These magazines are all over the place, with the same ones either not fitting correctly or not at all in my stock lower. They all fit the TAC-12 lower just fine. Most of the feed lips are also not the same length on both sides of the magazines. They definitely need fine tuning to be 100% reliable.
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Ouch, more than the part itself. I had other items in the same order.
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Yes, a positive feel without any stiffness when moving out of the detents. With the longer nose you are able to preload the plunger without bottoming out the ball. Part # 84985A52 has a slightly higher spring rate.
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Will do. The Mako is a loose fit on the Vltor extension since its made to also fit commercial spec tubes. To fix that, I put a 1" wide strip of .022" thick UHMW tape along the top of the tube and a strip of PTFE tap in the receiver channel of the stock and that eliminated all but the slightest hint of wobble, and the stock still slides back & forth freely.
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One other note, I did not use the safety detent FB included with the lower. Instead I bought a long nose spring plunger from McMaster, part# 84985A13. You don't need a plunger wrench like it says in the product description, it is slotted for a screw driver.
http://www.mcmaster.com/#catalog/119/3345/=mtovvl
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After much anticipation, my TAC-12 lower finally made it's way home on Thursday. As a machinist and programmer, I can say this is a very nicely machined part. No chatter marks, funky edge breaks, engineering shortcuts or mediocre workmanship. A very nice component. The only thing I would note to FB is add some material to the top of the bosses that the bolt lock roll pin goes through. Scary thin in the event the pin needs to be removed for any reason.
My MKA is not the light weight it once was, but not that heavy either. Definitely a very solid gun without feeling awkward or overweight. I bought a Magpul CTR stock that was supposed to go on the MKA, but it wound up on my Daniel Defense M4v5 instead. If I don't like the Mako I'll get another CTR for the MKA and drop some weight in the process.
So far, my build consists of:
Pre XN MKA
FB TAC-12 lower with Ambi-Safety assembly
FB Handguard with charging handle, standard length
Tromix trigger with disconnector
FB Hammer
Salem6 gas piston
T&N Charger Handle
Primary Arms Micro Dot sight with UTG lower 1/3 co-witness riser
Magpul MOE +Grip
Magpul MBUS front & rear sights
Magpul Angled Fore-Grip
Magpul Rail Sling Attachment
Noveske rear sling mount
Trulock Tactical Choke
Mako GL Shock stock
Vltor shotgun receiver extension
Thordsen Bilateral Magazine Lock
The next up is to install the Thordsen Bilateral Magazine Lock. This requires drilling and tapping. I need to get an electrician to install a subpanel in my garage and hook up my phase converter so I can get my mill and lathe up and running.
I'm also going to make a new magazine release/bullet button assembly. The stock one is a loose piece of garbage.
The stock needs to be drilled and pinned before I venture onto any public land out here.
The FB handguard needed some Dremel work to fit over the barrel extension. Apparently the extension diameter varied on earlier MKAs, and mine was one of the bigger ones.
The Vltor extension has a cap that screws off and on so you can use it for storage, but there is no way to reach it without removing the stock. I'll drill, tap and permanently attach a low or button head screw to the cap so I can just remove the stock pad and unscrew the cap with a short allen key.
I ran into the same issue others have with the bolt catch not engaging the bolt and did some minor filing. This did not help, and the TAC-12 lower exposes an issue with the factory MKA magazines. I'll make a separate post for this.
Now I need to get time off from work to go shooting.
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My lower & Ambi-Safety kit is shipping Monday
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You need a 1/4-28 screw.
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SOLD
TAC-12 Receiver Set
in MKA-1919
Posted
I believe that will be the TAC-12 A1 model. On their Facebook page they mention it is a few months out for the A1.