Same polymer throughout? (SBR project)

[BigWaylon]

First post, not counting the one I put in the classifieds. I tried to search, but you can imagine the number of results I got when searching for "polymer". I did scan the last 6 months or so of results, but didn't see the answer I was looking for.

I have a MOE 15-22 that I've filed a Form 1 on in order to SBR it. That means I need to get it engraved sometime soon. The place I've used in the past has only done aluminum receivers.

I'm going to shorten the handguard as well, so I'll have some extra material around. Plus, I have the whole non-functional buffer tube that is covered by the stock.

Does anybody know if it's the same polymer used throughout the rifle? Just curious if testing on the quadrail and/or buffer tube would give me accurate results before marking up the receiver.


Obligatory photo attached.

Thanks.
Greg

 

[Zax]

The lower receiver and buffer tube should be the same, but would engraving the polymer meet the requirements? I know they specify the depth of engraving and size etc.

Could you engrave a plate and permanently attach it?

 

[BillyJack2012]

How short are you going with the barrel? Just wondering why you would want to shorten the rail.

Also, If I were going to SBR the 15-22, I'd consider a barrel nut swap to the AR standard nut and a FF rail. Don't ask for justification as I don't have one. Just what I would do.

 

[BigWaylon]

4.5" for the barrel. Generally accepted length to keep all bulk ammo subsonic. Going to cut the quadrail so that it's 4" longer than the barrel (meaning about 3" to remove), so that my suppressor sticks out ~1.5".

No issues with engraving the polymer as far as standards go. Has to meet the .003" depth requirement. Heck, I could do it with a dremel, but I'd like it to look a little better.

For now, I can go with the factory rail and not spend any money. Not to say I won't convert to an aftermarket product down the road. Also, this lets me specify barrel length and then cut the rail to the exact length I want. As opposed to the AR57 monolithic upper I'm doing at the same time, where the rail length is set and I just have to cut the barrel 4" shorter to that random (7.75") length.

I'm figuring the buffer tube is probably the same. Was curious about the quadrail.

What I'm after is basically the black version of the pic attached, but with factory rail.

 

[BigWaylon]

BTW...got the idea to cut it down from this forum: http://smith-wessonforum.com/smith-...cut-their-hand-guard-sbr-whatever-reason.html

(Which also assured me the polymer was indeed black all the way through).

 

[Kayback]

And yes, you can engrave the polymer. There isn't anything about the material, just size and depth requirements.

KBK

 

[BigWaylon]

And yes, you can engrave the polymer. There isn't anything about the material, just size and depth requirements.

KBK

Figured I'd come back and add to this topic for a minute. First off...there is not a size requirement for the engraving, only minimum depth of .003". Had several places say they wouldn't engrave it because it's polymer. So, me being one more concerned about function over form...I pulled out the Dremel.

Might not be pretty...but it's completely legal and had no negative impact on accuracy or reliability.

Form 1 was approved this morning, and the barrel has been shipped off to ADCO. They're going to cut it down to 4.5" and thread it to meet SiCo's o-ring engagement specs. The Form 4 for my Spectre II ought to be approved in 2-4 weeks.

Barrel should be back in a week or so, and I'll cut the handguard down once I have the barrel back. Pretty excited about the project.

 

[BigWaylon]

Barrel came back today. Excellent work as expected.

A couple of pics...

Comparing ADCO's version of SiCo's thread specs to one of SiCo's adapters:

(Note that ADCO's actually match the specs more accurately than SiCo does

)


When you ask for 4.5"...that's exactly what you get.

The barrel mocked up in the 15-22:

(Have to get the handguard cut down this week)


The barrel in my hand:

(And I thought my 6" AR57 barrel was small)

 

[RedNeck Jim]

Did you remove the ejector before sending it off? I remember you said you cut something like 10" off the barrel prior to sending.

 

[BigWaylon]

Did you remove the ejector before sending it off? I remember you said you cut something like 10" off the barrel prior to sending.

I did not. Didn't really even think about checking to see how easy it came off.

I did cut ~10" off before I sent it. I put the piece I did send into a piece of PVC pipe about 8" long, which protected the ejector.

The pipe was just tight enough that I had to cut a little slit in it for one of the "tabs" on the barrel to slide into. ADCO actually sent the barrel back in the same PVC pipe inside the original box.

 

[BigWaylon]

Just thought I'd come back to wrap this up with a couple more pics. Got the factory polymer handguard cut down yesterday and the rifle put back together. It's just a hair over 24" to the end of the suppressor with stock collapsed.

I don't know that I could be any more pleased at this point, assuming it still shoots straight. now just waiting to replace the replica Spectre II with the real thing.

 

[RedNeck Jim]

What did you cut it with & how much did you take off? Also, how long is that replica?

Looks great! Very curious how it shoots.

 

[BigWaylon]

What did you cut it with & how much did you take off? Also, how long is that replica?

Looks great! Very curious how it shoots.

Band saw. Then just hit it with some fine grit sandpaper and a little gun oil.

I actually had two of them I cut, to see which worked better. I ended up able to use the longer one to cover more barrel and suppressor. The issue with length is the big holes in the handguard more than anything else. I didn't want an open semi-circle, so there are only a couple places I could actually choose to cut. I probably took off an inch or two?...but don't know exactly. The rail is now 8" from the seam with the upper receiver to the end, so you could compare it to yours and see.

The replica is identical to the Spectre II. 6" long, 1" diameter. Even weighs within a half ounce of the real one.

 

[RedNeck Jim]

Band saw.

That is what I was planning on using.

 

[BigWaylon]

That is what I was planning on using.

Only little bit of advice I'll give is cut a little sliver off first as a practice cut. And then no matter how well it turns out, take your time and don't rush the real cut.

 

[FiremanFrank]

Looks awesome. I may just follow your lead and pick up a second M&P to do this too.

 

[BigWaylon]

Still not too bulky of a package with a 50rd mag...

 

[BigWaylon]

...and makes a nice pair with the M&P 22.

 

[DUKnCVR]

Where did you get the replica spectre

 

[brucev]

Just found this thread. Very interesting. Been shooting my 15-22 w/ the stock collapsed all the way down. Get better results in general when shooting. As pictured in the preceding post, this rifle would be most interesting and useful. As I am not a gifted machinist, this is a project that I will not likely undertake. But, more power to those who have the skills and are able to handle the legal steps required!