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Discussion Starter #1 (Edited)
Ive been working on getting all the parts together for the barreled k upper that I picked up a couple months ago, and today was the maiden voyage.



assembled it with a unknown manufacturer 0-1-30 lower, RCM/HK bolt carrier group(both from HKparts), and a semi group I had laying around.

the lower needed the front opened up just a bit to clear the shelf, HKparts did the clip job, so Id guess the shelf was just a touch off.

ETA: the HKparts clip job was great, the uneven trim job is ALL me. this is not indicative of their work. outside it looks great!




there was also some tabs on the receiver where the lower meets up with it that needed to be milled (read dremeled) off, these little tabs are present on my bobcat clone, but they are barely there, so it didnt phase me at all to grind away on my new receiver.

the shiny parts in this photo.


the RCM carrier group was pretty much exactly what I expected, Id be hard pressed to tell it from genuine HK.

seen here..... http://www.hkparts.net/shop/pc/MP5K-SP89-Bolt-Group-US-German-HK-144p2202.htm

when I got everything ready to assemble, the receiver was filled with what appeared to be blasting media, so it was gritty to the touch, course it kind of worked like a lapping compound at first, which may have eased any fitting.

after cleaning it again with all of my cleaning arsenal I got most of the grit out, and then oiled it quite a bit for final assembly.

when I hit the range, I wasnt really expecting much, as Ive owned one or two mp5 clones, and from my experience they ALL needed tweaking to get to run correctly.

I loaded up a POF mag, HK mag, and an original SW mag and proceeded to get on with my day.

to my amazement, it ran, 100%, right out of the gate. I put about 400 rounds through it today, 115gr, 124 gr, and 147gr. accuracy was great, ejection was strong, no stoppages, not even a strange feeling extraction or bobble at all.

I dont know if Im the luckiest clone buyer in the world, or maybe I just found the right combination of parts. finally.

all told, Im into this thing for $1200, a little more than I wanted to pay, and a little more than the MKE's were going for 6 months ago when I started this trip. but for my investment, I ended up with a 3 lug, zero 922r fears, and the ability to add a sear if I ever happen across one.

I've always wanted a k gun, and now that itch is scratched.

whats next???
 

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Absolutely need pics! You know we're pic whores!
 

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Thanks for the writeup.

Looking to do a "K" gun this year myself, after the ARX160 was a bust at SHOT.
 

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Congratulations! My two Painted Barreled receivers had the same success. I also have two unpainted barreled receivers that needed a little tweaking, but in the end, they all run great with HK/RCM bolt groups.

Enjoy it!
 

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thx for the review...I have not had such luck...BMP upper, standard lower, RCM bolt group. Initial bolt gap .9mm, yes, almost double what it should be. I changed locking pieces with a spare and get the same thing. Suggestions before I buy some smaller rollers?
 

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thx for the review...I have not had such luck...BMP upper, standard lower, RCM bolt group. Initial bolt gap .9mm, yes, almost double what it should be. I changed locking pieces with a spare and get the same thing. Suggestions before I buy some smaller rollers?
Contact BMP and see if they will check it out under warranty.
 

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robag99,
Do you have any german BCG's? Or is anyone near you to try a german BCG before you go any further.
Dj
 

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thx for the review...I have not had such luck...BMP upper, standard lower, RCM bolt group. Initial bolt gap .9mm, yes, almost double what it should be. I changed locking pieces with a spare and get the same thing. Suggestions before I buy some smaller rollers?
I 2nd DJF's suggestion of trying another bolt group, but that is some gap... Will the gun fire? How does it run? The 9mm round doesn't do much to bolt gap over time, but if it fires properly, I'd shoot a few hundred rounds through it to see if there is a change. By all means contact BMP, but instead of looking for a German BCG, I'd look for a Coharie/SW bolt group to test it with. Oddly enough, I had a SW bolt group that came with -6 rollers in it to get the bolt gap correct. It's fine, just odd to see in a new gun.

Post some updates!

J
 

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Well I took the advice given and borrowed another bolt group...not a german or RCM group (not sure who made it)...insert, slap... bolt gap remained the same. No I have not fired the gun yet and with this bolt gap I might not (The upper is brand spanking new!) I guess the next step is to contact BMP to see if they will take a look at it. I think -8 rollers may fix the gap but the upper may need reworked but again, it's new. Man, I really don't want to go down a rabbit hole here! Any other suggestions?
 

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robag99,
I didn't see this in your explaination, but I have to ask.......are you dropping the hammer before you measure your BG?
Dj
 

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Dj, Yes, I am fully assembling, dropping the hammer and releasing the trigger before measuring. The rollers are about half way extracted I’d say, maybe a bit more. The action is nice and smooth, but the BG needs to go forward just a tad more!
 

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Robag99, if the rollers dont't help and you not satisfied with the gun sent it back. I had some major issues with my K, a rotated trunnion that amongst other things, prevented it from being sighted in. One email to Nikki at BMP, I had a UPS ticket for the upper's trip to the gunsmith for warranty work. I fully expected a shoestring/duct tape fix but once it was returned (yesterday) I was impressed to find the gun was rebuilt (trunnion is no longer rotated and other issues fixed), functions great with RCM parts, locks up tight with cheap mags, has tight groups (300 hundred rounds) @ 15yds...Thumbs up and kudos for Nikki and whomever reworked the upper!!!!
 
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