New SP5 issues? - AR15.COM

Posted: 2/17/2020 9:28:30 PM EDT

I just got mine and noticed a few things and want to know if they are normal or not.
First the front hand guard wobbles a bit up and down. Not a ton but moves.
Second putting the sb collapsing brace on it was a huge pain in the ass. Like two guys fighting the end plate and trying to get the pin in. That took like ten minutes to do.
Third the brace is super stiff to slide. Like smack it on the table to collapse and strain to get it to extend.
These things normal? This is my first go at the mp5 thing.
I shot 200 rounds though it and it cycled perfect.

Attached File

Posted: 2/17/2020 9:35:43 PM EDT

[#1]

The first two items are relatively normal across all the MP5 clones, so I'm not surprised if it carries over to an actual HK. The end plate on the brace should loosen up with time, mine comes on and off without much force now a days (first time putting it on required a rubber mallet).

I can't speak to adjustment of your particular brace as I've never used it.

Posted: 2/17/2020 9:41:56 PM EDT

[#2]

All normal

Posted: 2/17/2020 9:43:57 PM EDT

[#3]

Quoted:
I just got mine and noticed a few things and want to know if they are normal or not.
First the front hand guard wobbles a bit up and down. Not a ton but moves.
Second putting the sb collapsing brace on it was a huge pain in the ass. Like two guys fighting the end plate and trying to get the pin in. That took like ten minutes to do.
Third the brace is super stiff to slide. Like smack it on the table to collapse and strain to get it to extend.
These things normal? This is my first go at the mp5 thing.
I shot 200 rounds though it and it cycled perfect.

https://www.AR15.Com/media/mediaFiles/296004/6AEBCBB4-8573-4583-95B5-CFACC9042CBC_jpe-1280654.JPG

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Cant speak to the SP5 but have a PTR and SB side folder. I had to massage the end cap of the stock with a file to fit the weapon. I did not want to scratch the OEM finish of the PTR. On top of that, no way would I ever "FORCE" something together. It may be snug, but should not need to be forced. I would not blame it on the weapon, you are putting an after market item on it. I bet a German made A3 stock would fit on there just fine. As far as the forearm, hard to say without comparing to another in person.

Posted: 2/17/2020 9:45:17 PM EDT

[#4]

Should I file or dremel the inside edge of the rail on the brace so it will slide more easy?

Posted: 2/17/2020 10:01:09 PM EDT

[#5]

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Quoted:
Should I file or dremel the inside edge of the rail on the brace so it will slide more easy?

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I'm not saying yes or no. You need to do what you are comfortable with. If it were mine, I would not be happy. I would start with the end plate and get that fitting better and then see whats causing the slider to bind. But that me. I'm confident in my abilities.

Posted: 2/17/2020 10:19:13 PM EDT

[#6]

The SB brace aluminum anodized mounts are terribly designed. The K mount side folder is excessively oversized. Much more attention should have been spent on fitment and the interior holes should have been chamfered like most other folding stock mounts and pistol end caps. Their interior hole on the SP5 version could have had a slight chamfer to aid in guiding the pin through. No attention to detail just fast machining steps to maximize profit.

Posted: 2/17/2020 10:27:51 PM EDT

[#7]

Anything related to the brace is the fault of the brace maker. HK didn’t design the MP5 to fit aftermarket braces, they made it to fit their MP5 stocks, which I’m 100% sure would work fine if you decided to SBR. Fit problems with SB braces on MP5s and clones are a known commodity.

Posted: 2/18/2020 8:07:06 AM EDT

[#8]

Does your brace have the buffer on the inside? I removed mine and my brace fit much easier.

Posted: 2/18/2020 9:22:31 AM EDT

[#9]

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Quoted:
Does your brace have the buffer on the inside? I removed mine and my brace fit much easier.

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That might be the issue. I was looking online and some people cut theirs down. What’s its purpose since the original endcap does not have one?

Posted: 2/18/2020 9:27:05 AM EDT

[#10]

Quote History

Quoted:
The SB brace aluminum anodized mounts are terribly designed. The K mount side folder is excessively oversized. Much more attention should have been spent on fitment and the interior holes should have been chamfered like most other folding stock mounts and pistol end caps. Their interior hole on the SP5 version could have had a slight chamfer to aid in guiding the pin through. No attention to detail just fast machining steps to maximize profit.

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I'll say this is the case on the MPX too, so that might be an SB thing. When SIG released their own collapsing brace I quickly switched to that as overall fitment was MUCH better than my SB one.

Posted: 2/18/2020 10:32:15 AM EDT

[#11]

The brace is out of spec. If you put a proper H&K stock on it it will slip on fine.

Posted: 2/18/2020 10:48:08 AM EDT

[#12]

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Quoted:

That might be the issue. I was looking online and some people cut theirs down. What’s its purpose since the original endcap does not have one?

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I don't know and I'm no expert on the platform. My Form 1 was recently approved and I put an A2 stock on that also does not have a buffer. My SP5 has run fine without a buffer in both the brace and stock.

Posted: 2/18/2020 11:02:07 AM EDT

[#13]

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Quoted:
The brace is out of spec. If you put a proper H&K stock on it it will slip on fine.

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I was in the store when I put that brace on. I tried three different ones and they were all the same

Posted: 2/18/2020 1:45:01 PM EDT

[#14]

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Quoted:

I'll say this is the case on the MPX too, so that might be an SB thing. When SIG released their own collapsing brace I quickly switched to that as overall fitment was MUCH better than my SB one.

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Manticore Arms was the marking on the earliest SB folding braces for MP5 and clones. Putting blame where it is earned.
We can thank M.A. for putting in the effort on the frustration about fitment. Come on guys a little more time spent fitment design makes all the difference. Then you can have the monkey push the button on the CNC machine.

Posted: 2/18/2020 4:48:36 PM EDT

[#15]

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Quoted:

I was in the store when I put that brace on. I tried three different ones and they were all the same

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@1911xdm

To the brace sliding on. They have a thick buffer and a cap screw that hit the welded block inside the receiver. On the clones it was designed for, that block isn’t there. You can make a minor modification.

1. Remove the hexhead/cap screw at the 7 o’clock position and leave it out

2. You need to cut a small notch out of the buffer where it hits the welded in block.

Part of you fitment issue may be your putting a lot of strain on the receiver and brace by smashing the buffer and screw into the block. Anytime it takes 2 people to force something its time to slow down and see what is going on.

Attached File

Attached File

I have had no fitment issues with that mod and the brace collapses and extends smooth as silk. The gun also functions fine.

Posted: 2/18/2020 5:44:37 PM EDT

[#16]

Quote History

Quoted:
@1911xdm

To the brace sliding on. They have a thick buffer and a cap screw that hit the welded block inside the receiver. On the clones it was designed for, that block isn’t there. You can make a minor modification.

1. Remove the hexhead/cap screw at the 7 o’clock position and leave it out

2. You need to cut a small notch out of the buffer where it hits the welded in block.

Part of you fitment issue may be your putting a lot of strain on the receiver and brace by smashing the buffer and screw into the block. Anytime it takes 2 people to force something its time to slow down and see what is going on.

https://www.AR15.Com/media/mediaFiles/185708/3AB5BB94-71B8-4768-9563-E11ABB3552AA_jpe-1281531.JPG

https://www.AR15.Com/media/mediaFiles/185708/BEB960FC-0F54-431C-BECE-D297C4FC1463_jpe-1281515.JPG

https://www.AR15.Com/media/mediaFiles/185708/760FB34B-FE21-48F2-A5F0-167D1F01F0DB_jpe-1281523.JPG

I have had no fitment issues with that mod and the brace collapses and extends smooth as silk. The gun also functions fine.

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Quoted:

Quoted:

I was in the store when I put that brace on. I tried three different ones and they were all the same

@1911xdm

To the brace sliding on. They have a thick buffer and a cap screw that hit the welded block inside the receiver. On the clones it was designed for, that block isn’t there. You can make a minor modification.

1. Remove the hexhead/cap screw at the 7 o’clock position and leave it out

2. You need to cut a small notch out of the buffer where it hits the welded in block.

Part of you fitment issue may be your putting a lot of strain on the receiver and brace by smashing the buffer and screw into the block. Anytime it takes 2 people to force something its time to slow down and see what is going on.

https://www.AR15.Com/media/mediaFiles/185708/3AB5BB94-71B8-4768-9563-E11ABB3552AA_jpe-1281531.JPG

https://www.AR15.Com/media/mediaFiles/185708/BEB960FC-0F54-431C-BECE-D297C4FC1463_jpe-1281515.JPG

https://www.AR15.Com/media/mediaFiles/185708/760FB34B-FE21-48F2-A5F0-167D1F01F0DB_jpe-1281523.JPG

I have had no fitment issues with that mod and the brace collapses and extends smooth as silk. The gun also functions fine.

Ya I saw that video. I bet that’s it. I’ll take it apart tonight and look. Hope I did not oval the take down hole.

Posted: 2/18/2020 7:15:20 PM EDT

[#17]

Yep you guys were right. Sucks Its kinda dinged. Maybe I should tell the gunshot guys about it before they do it again to someone else’s gun. I watched the two gunsmiths do it

Attached File

Posted: 2/18/2020 8:24:59 PM EDT

[#18]

As soon as I cut a little off where that dent is it went on with minimal effort. Kinda annoyed the gunshop guys did know know about this. They said it’s the first sp5 they have seen come in.
What is that piece of metal that has a dent on it even do?

Posted: 2/18/2020 8:27:07 PM EDT

[#19]

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Quoted:
As soon as I cut a little off where that dent is it went on with minimal effort. Kinda annoyed the gunshop guys did know know about this. They said it’s the first sp5 they have seen come in.
What is that piece of metal that has a dent on it even do?

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makes it so you can't run the full auto carrier. Did the collapse function improve?

Posted: 2/18/2020 8:43:16 PM EDT

[#20]

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Quoted:
makes it so you can't run the full auto carrier. Did the collapse function improve?

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Quoted:

Quoted:
As soon as I cut a little off where that dent is it went on with minimal effort. Kinda annoyed the gunshop guys did know know about this. They said it’s the first sp5 they have seen come in.
What is that piece of metal that has a dent on it even do?

makes it so you can't run the full auto carrier. Did the collapse function improve?

No still stiff. First two notices got less stiff the more I use it. Fully collapsed I would need to banging on something to get it there.
Moving it in and out has loosened it some.

So that little dent won’t hurt anything then. That’s good for the price tag this thing has.

Posted: 2/18/2020 8:51:00 PM EDT

[#21]

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Quoted:

I was in the store when I put that brace on. I tried three different ones and they were all the same

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Yes, they are manufactured out of spec.

Posted: 2/20/2020 10:52:09 PM EDT

[#22]

Thanks guys. Anything I can do about the hand guard?

Posted: 3/11/2020 8:16:55 PM EDT

[#23]

Consider changing to a KAC railed hand guard, though currently hard to find at msrp.

Posted: 3/13/2020 11:43:39 PM EDT

[#24]

@1911xdm

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Quoted:
Thanks guys. Anything I can do about the hand guard?

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Mine rattled a little.
If you get a thick o-ring at Ace, you can stretch it over the little shelf (finger?) that protrudes inside the handguard.
I tried a sink o-ring, about 1/2” diameter, made for a faucet. They are rated for 240 degrees according to the manufacturer website.

That worked pretty well but then I cut a thin slice of automotive hose.
I think it’s rated for higher temperature and I was able to cut it to the thickness I wanted.
Ideally, if it fits tight enough to make the pin a little difficult to pull out, the rattle should be gone.

Posted: 3/14/2020 9:23:03 AM EDT

[#25]

A eFiled stamp takes like 5 weeks to get back. SBR the thing and put an actual HK stock on there instead of the cheesy brace and you won’t have these problems

Posted: 3/14/2020 10:19:53 AM EDT

[#26]

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Quoted:
A eFiled stamp takes like 5 weeks to get back. SBR the thing and put an actual HK stock on there instead of the cheesy brace and you won’t have these problems

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Not sure how making a SBR will fix the handguard rattle.
Seems like an expensive fix.

Posted: 3/14/2020 2:47:10 PM EDT

[#27]

I shoot across state lines a lot. So I would have to get permission every time I go with the sbr. Suppressors do not need permission though.

Posted: 3/14/2020 2:51:10 PM EDT

[#28]

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Quoted:
I shoot across state lines a lot. So I would have to get permission every time I go with the sbr. Suppressors do not need permission though.

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I SBR'd my K to add a VFG for ergonomic hand placement and real stock to control recoil with the binary trigger. I would not SBR a full size because it doesn't seem necessary.

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