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Discussion Starter · #1 ·
Hello all,
I have a Vector MP5/40. If I wanted to replace the US made bolt/carrier group with genuine HK/German, which parts would I need to look for? I assume a complete bolt head. I am not sure which locking piece I need (Hi/Lo). I also assume fireing pin and spring. What about carrier and recoil rod? I thought I read somewhere that if I was going from US to German parts that if I wanted to replace the bolt head, I would also have to replace something else, but I cant remember what exactly. I don't want to just get the complete bolt head, and realize that I also needed to get something else because certain german and US parts are not compatible with each other.

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The US carrier should be fine. If you swap out the bolt head, the locking piece may need to be changed also. If you're using standard 180 grain ammo, low lock piece should be fine. Some US bolts and locking pieces did not fit correctly. One builder placed two small tack welds on the US bolt heads to take up some slop between that and the US locking piece. If you have a US/SW bolt carrier recoil rod, I'd suggest installing an HK assembly.
 

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I replaced everything but the carrier on mine. I'm not sure it was necessary because I never fired it before I changed everything out. The only thing I noticed was the german LP would not fit in the US carrier and it had to be opened up a bit. Everything else seemed to interchange okay. Are you having a problem you are trying to repair?
 

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I would tend to follow the logic that if it's not broken, don't "fix" it. With my Coharie (K model .40), I was having issues running it with my sear pack so I made some changes. The bolt wiggled quite a bit in the carrier and was quite sloppy so I replaced with the following:
HK bolt head (only because I got it for about $200)
RCM bolt carrier (no HK exists and the RCM is an excellent choice)
HK #26 locking piece (later replaced with HK #24 LO for more positive extraction/ejection). I'll use the #26 when suppressed.
MP5K recoil rod works nicely as well

If you have that same sloppy bolt to carrier wiggle, I would recommend that you replace bolt head & carrier and locking piece at a minimum. I also recommend RCM parts unless you can obtain HK parts at a decent price. I know there was a HK bolt head available on this board for a little over $300 but that is about the best I have seen in a couple of years (except for one that came up recently for $175). I don't believe that you absolutely need original HK parts to make this run nicely as you could very easily spend more on the major parts (HK) then you spent on the whole gun to begin with.
 

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Discussion Starter · #5 ·
How are the US made OP/Recoil Rods? I see that the HK counterpart costs about $100. Do you think that the US made one is just as good? I guess since I have replaced everything in this rifle with german made parts, whats the last $100 for an OP Rod. LoL

Thanks

insin
 

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I had to replace the whole carrier/head/LP on mine, the German head and LP would absolutely not fit the US carrier. The factory recoil rod/spring seems to work fine though. If I run across a German offering for the right price, I'd probably nail it, but I'm not going to actively search one out.

The RCM parts I used in my 9mm k gun are flawless, so I'd start there as far as replacement parts.

ETA:
Just re-read that this was for a vector. Mine is a cohaire, sorry for the confusion, but I think they are the same
 

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So what would the #25 LP be used for then? Is it for heavier bullets that go slower or lighter bullets that go faster?
 

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So what would the #25 LP be used for then? Is it for heavier bullets that go slower or lighter bullets that go faster?
With regards to this thread, the #25 LP would be used strictly for "Hi-impulse" 10mm loads and would probably never be used in .40 S&W. Of course I'm sure someone will point out some exception, but I don't think it would even be necessary when firing .40 S&W suppressed.
To answer your question, using the HK LP guide, it would appear that generally speaking, the #25 LP is used for shooting lighter bullets moving faster.
 

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#25 is for high impulse 10mm and probably not required for 40. It might help suppressed but I don't know if it is necessary. The op rod is the same as the mp5f. They are 9mm in diameter as opposed to the standard 8mm with a stronger spring and black retainers. I've seen them on gunbroker and other places for $40 to $50. It seems like HKspecialists had them for $60 but it could have been another source where I saw those.
 

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Awesome. Just what I needed to know. I am only planning to shoot el cheapo through my 40 so I should be good with the #24. Those little buggers are expensive!!
 

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To the OP: I have a CA89-10mm. I'm waiting for TB's bolt head upgrade and had to purchase an HK bolt head. In the last 600 rounds I've had one FTE & that may be due to the E&L brass catcher. The Low impulse LP that came with the gun would not properly cycle certain 180gr so I have to use the Hi impulse. Personally I would start with the bolt head. My guess is the carrier is fine.
 
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