SP5 Modifications for SBR?

[rayrevolver]

I found a solution. It's expensive though.

I got a F5MFG stock:

F5 MFG Modular Stock System (MSS) For MP5 and Variants

Shop F5 MFG Modular Stock System (MSS) For MP5 and Variants and other firearm products and accessories with exclusive online offers only at F5 MFG.

f5mfg.com

I found a used ACR Stock, like pictured above. I do not want to shoot with that monster LOP and in the off chance the ATF show up at the range, I wanted to be able to extend the stock to that last position.

I drilled a small hole in the mount part and used this spring plunger below. I was able to just screw it into that hole already in the stock portion. Works like a charm, now the stock is fully functional, just a pain to get it past the initial block where you need to pull the tab plus the 2 buttons on the stock.

Amazon product ASIN B098SWCBXL
I am not 100% sure its 29" but measuring it looks very close (aka I won't "make" the sbr until I get a stamp). If you say it is, I might start working the paperwork. Pics to follow.

 

[ST19AG_WGreymon]

I found a used ACR Stock, like pictured above. I do not want to shoot with that monster LOP and in the off chance the ATF show up at the range, I wanted to be able to extend the stock to that last position.

I drilled a small hole in the mount part and used this spring plunger below. I was able to just screw it into that hole already in the stock portion. Works like a charm, now the stock is fully functional, just a pain to get it past the initial block where you need to pull the tab plus the 2 buttons on the stock.

Amazon product ASIN B098SWCBXL
I am not 100% sure its 29" but measuring it looks very close (aka I won't "make" the sbr until I get a stamp). If you say it is, I might start working the paperwork. Pics to follow.

I'm not sure how close the F5MFG stock is to a true ACR stock, but like I said you will need to remove some material on the last block to reach 29".

 

[outrider58]

Have you guys seen this?

MSP advisory on AR pistols with braces

Ok my thought on the advisory. The way I see it Maryland is simply stating we see a braced pistol as a pistol, they did not change their definition. The rub is the points system, maryland cant not make the judgement call on a braced pistol being a sbr, only the atf can do that. So a cop cant see...

www.mdshooters.com

 

[Squaregrouper]

Have you guys seen this?

MSP advisory on AR pistols with braces

Ok my thought on the advisory. The way I see it Maryland is simply stating we see a braced pistol as a pistol, they did not change their definition. The rub is the points system, maryland cant not make the judgement call on a braced pistol being a sbr, only the atf can do that. So a cop cant see...

www.mdshooters.com

Yeah, and I'm hindsight 20/20 pissed I SBR'ed my AP5 to MD standards.

 

[outrider58]

Yeah, and I'm hindsight 20/20 pissed I SBR'ed my AP5 to MD standards.

It's awfully tempting, but think I'm just gonna hold off until I GTFO of Md.

 

[Mike OTDP]

I submitted the ATF paperwork for my PTR...with a copy of the MSP letter. We'll see how it turns out.

 

[ST19AG_WGreymon]

Yeah, and I'm hindsight 20/20 pissed I SBR'ed my AP5 to MD standards.

You are allowed to make changes to the form by submitting a letter to the ATF.

 

[Squaregrouper]

You are allowed to make changes to the form by submitting a letter to the ATF.

In anticipation of the brace ban, I paid the $200 and made a 29" SBR. As it turned out, I could have kept the brace and gotten a free tax stamp.

 

[Mike OTDP]

For what it's worth, I just got back an ATF Form 1 for a PTR9 with brace. I sent a copy of the MSP letter with the application, they seem to have accepted it.

 

[smdub]

Time for me to go public. I mentioned it to a few people at the MSI fundraiser yesterday. I've been working on an adapter for the new collapsible Magpul SL stock. I designed a spacer (about 2.75") to hit 29". Ok, so this is like all the other long LOP solutions? Nope! It can work like what I did for the MPX. I can cut another notch in the slider to stop about 2.75" shorter and maintain the orig LOP yet still be able to extend to 29".
Right now the spacer is only 10mm as it prints quick and I'm dialing in the fit on both sides (It's a PITA to fit all the curves and bends in the Magpul stock!) Have gen 5 on the printer now and I think it should be the one. Then I'll stretch it to the required length and print the first full length one - tomorrow hopefully. I still need to source screws but I have an idea for that.
One of the benefits is that as an extendible stock (and not a folder) it's not an evil feature and you can still use a suppressor.

 

[djcerna]

Time for me to go public. I mentioned it to a few people at the MSI fundraiser yesterday. I've been working on an adapter for the new collapsible Magpul SL stock. I designed a spacer (about 2.75") to hit 29". Ok, so this is like all the other long LOP solutions? Nope! It can work like what I did for the MPX. I can cut another notch in the slider to stop about 2.75" shorter and maintain the orig LOP yet still be able to extend to 29".
Right now the spacer is only 10mm as it prints quick and I'm dialing in the fit on both sides (It's a PITA to fit all the curves and bends in the Magpul stock!) Have gen 5 on the printer now and I think it should be the one. Then I'll stretch it to the required length and print the first full length one - tomorrow hopefully. I still need to source screws but I have an idea for that.
One of the benefits is that as an extendible stock (and not a folder) it's not an evil feature and you can still use a suppressor.

Thanks for the update. Please keep us posted.

 

[rayrevolver]

Have you guys seen this?

MSP advisory on AR pistols with braces

Ok my thought on the advisory. The way I see it Maryland is simply stating we see a braced pistol as a pistol, they did not change their definition. The rub is the points system, maryland cant not make the judgement call on a braced pistol being a sbr, only the atf can do that. So a cop cant see...

www.mdshooters.com

Thank you. News to me!

My issue is I have a trust, so even the free stamp means I would have an SBR outside of the trust. And cost $200 to transfer it in.

At this point I am waiting for the dust to settle. I have a very nice B&T collapsible brace that can be converted to a stock, but won't meet the 29" rule.

 

[Bander]

Time for me to go public. I mentioned it to a few people at the MSI fundraiser yesterday. I've been working on an adapter for the new collapsible Magpul SL stock. I designed a spacer (about 2.75") to hit 29". Ok, so this is like all the other long LOP solutions? Nope! It can work like what I did for the MPX. I can cut another notch in the slider to stop about 2.75" shorter and maintain the orig LOP yet still be able to extend to 29".
Right now the spacer is only 10mm as it prints quick and I'm dialing in the fit on both sides (It's a PITA to fit all the curves and bends in the Magpul stock!) Have gen 5 on the printer now and I think it should be the one. Then I'll stretch it to the required length and print the first full length one - tomorrow hopefully. I still need to source screws but I have an idea for that.
One of the benefits is that as an extendible stock (and not a folder) it's not an evil feature and you can still use a suppressor.

I bought the same stock thinking to do the same, but never quite got around to actually modeling this up in CAD - mostly because I am not that good at CAD.

If you ever do finish this I’d be interested in buying the STL from you so I could print this myself.

 

[outrider58]

Thank you. News to me!

My issue is I have a trust, so even the free stamp means I would have an SBR outside of the trust. And cost $200 to transfer it in.

At this point I am waiting for the dust to settle. I have a very nice B&T collapsible brace that can be converted to a stock, but won't meet the 29" rule.

Yeah, me too. Besides, I'd rather move out of the state and turn my AR9 pistols into righteous SBRs through my trust.

 

[AlBeight]

In anticipation of the brace ban, I paid the $200 and made a 29" SBR. As it turned out, I could have kept the brace and gotten a free tax stamp.

Finally caved in and aginst my better judgement I submitted my SP5K last night for a free tax stamp thru SilencerShop. MD braced pistol, federal SBR. Woefully short of 29”, would still love to figue out how to MD SBR this thing, but shouldered braced pistol will work for now I guess.

 

[jrumann59]

Finally caved in and aginst my better judgement I submitted my SP5K last night for a free tax stamp thru SilencerShop. MD braced pistol, federal SBR. Woefully short of 29”, would still love to figue out how to MD SBR this thing, but shouldered braced pistol will work for now I guess.

I did 11 stamps Sunday night, would not want to have visit and get nailed for constructive intent with non SBR lowers with SBR uppers near by

 

[AlBeight]

I did 11 stamps Sunday night, would not want to have visit and get nailed for constructive intent with non SBR lowers with SBR uppers near by

I did 3 (2 others in addition to the HK). Honestly didn’t really care at first and wasn’t going to do anything about any of them. I then thought, with how easy SilencerShop makes it, why not?

The HK will probably remain as the MD legal braced pistol, as will my 7-1/2” Springfield Saint, but I would really like to go full-blown SBR with my Zion-15 pistol.

 

[jrumann59]

I did 3 (2 others in addition to the HK). Honestly didn’t really care at first and wasn’t going to do anything about any of them. I then thought, with how easy SilencerShop makes it, why not?

The HK will probably remain as the MD legal braced pistol, as will my 7-1/2” Springfield Saint, but I would really like to go full-blown SBR with my Zion-15 pistol.

I thought about doing themm through Silencer shop but 11 @ $50 each added up quick, I went got my prints done to get an ETF file and once I navigated the ATF form it was pretty easy and not as time consuming as I thought.

 

[ken792]

I thought about doing themm through Silencer shop but 11 @ $50 each added up quick, I went got my prints done to get an ETF file and once I navigated the ATF form it was pretty easy and not as time consuming as I thought.

It’s believed that they don’t even run the prints. They accepted my smudged DIY prints on the fingerprint cards I got from them for free.

 

[jrumann59]

It’s believed that they don’t even run the prints. They accepted my smudged DIY prints on the fingerprint cards I got from them for free.

That is eleven set of DIY prints, now I have ETF for others in the future.