9mm SBR Thread

[JoeLiberty]

It works great, never had an problems with it. The side charger is much nicer to use, if they weren't so expensive I'd get more.

If you use a regular lower, you could use a mag block type holder in a vice. My lower is a dedicated 9mm. so carpet or a barrel vice were my only options. There's no brass deflector or forward assist on the upper, so a vice worked fine.

I don't have a 9mm but I have had good luck with a block from Wheeler that clamps onto the Picatinny Rail. I bought it to use for my AR-10 but now I use the pic rail clamp for every barrel install I do.

[farm use]

All great points gents! And all great things to think about and consider when building one. Iv put together to many regular AR 15 to count, but when messing with the 9mm AR there are things that arnt like a regular AR when it comes to assembling. I went with a Runner Runner guns billet 9mm lower, a Spartan 9mm side charger (only because Matrix could never answer my questions when I called). I also got a NFA bolt from Runner Runner guns also. I must say and im not connected to Runner Runner Guns in any way, but they was very helpful answering the phone and questions I had. I will deal with them in the future. The pic rail clamp would work great I think, depends on how far it comes down on the upper and not hit the charging handle. I would think you could remove the side charging handle and put on the barrel then re-assemble the upper. Food for thought and we'll see.

[golfindia]

The rail holder will probably work fine. In my opinion, many people over tighten barrel nuts anyway. I always just line up the gas tube hole to the closest notch in the nut and call it good.

I have handled the Spartan uppers, they are nicely made. I got the matrix version mainly because I preferred the small ejection port hole. The large 223 size ejection hole is more versatile, I suppose.

You may need to experiment with buffer weight with a short barrel. I get occasional FTE with 147 grainers in my 7" using a 9mm buffer and no can. With a can on it, or no can + an H2 buffer it is 100% rock solid.

[farm use]

The rail holder will probably work fine. In my opinion, many people over tighten barrel nuts anyway. I always just line up the gas tube hole to the closest notch in the nut and call it good.

I have handled the Spartan uppers, they are nicely made. I got the matrix version mainly because I preferred the small ejection port hole. The large 223 size ejection hole is more versatile, I suppose.

You may need to experiment with buffer weight with a short barrel. I get occasional FTE with 147 grainers in my 7" using a 9mm buffer and no can. With a can on it, or no can + an H2 buffer it is 100% rock solid.

With how I'm setting it up I'll be suppressed 100% of the time. Iv got plenty of different weight buffers from old AR builds, and ordered a 9mm buffer and spacer to use with regular AR buffers. I'll play with it some to tune it with the best weight I hope. But at some point I'll put a JP silent capture spring in it. Thanks for all the info and advice golfindia! It's much appreciated!

[Sithlord]

The rail holder will probably work fine. In my opinion, many people over tighten barrel nuts anyway. I always just line up the gas tube hole to the closest notch in the nut and call it good.

I have handled the Spartan uppers, they are nicely made. I got the matrix version mainly because I preferred the small ejection port hole. The large 223 size ejection hole is more versatile, I suppose.

You may need to experiment with buffer weight with a short barrel. I get occasional FTE with 147 grainers in my 7" using a 9mm buffer and no can. With a can on it, or no can + an H2 buffer it is 100% rock solid.

With how I'm setting it up I'll be suppressed 100% of the time. Iv got plenty of different weight buffers from old AR builds, and ordered a 9mm buffer and spacer to use with regular AR buffers. I'll play with it some to tune it with the best weight I hope. But at some point I'll put a JP silent capture spring in it. Thanks for all the info and advice golfindia! It's much appreciated!

If you're going to use the JP silent capture spring, you might as well get the JP 9mm bolt carrier.

As with the AR-15 equivalent capture spring, there is a central rod which must pass through the center of the bolt carrier. Most 9mm bolt carriers have additional weight there (generally held in with a roll pin, so they ARE removable). However, by removing that weight, you now have less mass in the bolt carrier, which means it will take less back pressure to unlock, and will possibly be traveling faster.

The JP 9mm bolt carrier and capture spring are 'designed' to work together correctly.

Note - I have 2 AR-9's; one with the JP bolt/capture, one without. The JP bolt + capture runs very smoothly, perhaps slightly better than a regular bolt and buffer/spring [9mm Q buffer + Wolff XP spring].

[TMD]

golfindia,

Thank you for educating me. I have never had in hand a 9mm ar, and did not know about the different extension. Been toying with the idea of building one, and I am glad to have that information. Rules out a side charge for me.

Side charger upper is no different than any other upper when mounting a barrel. Difference is a 9mm barrel don't have an alignment key because it's a blowback and not di. Plenty of vice blocks that secure an upper from the top and bottom that will work.

[farm use]

The rail holder will probably work fine. In my opinion, many people over tighten barrel nuts anyway. I always just line up the gas tube hole to the closest notch in the nut and call it good.

I have handled the Spartan uppers, they are nicely made. I got the matrix version mainly because I preferred the small ejection port hole. The large 223 size ejection hole is more versatile, I suppose.

You may need to experiment with buffer weight with a short barrel. I get occasional FTE with 147 grainers in my 7" using a 9mm buffer and no can. With a can on it, or no can + an H2 buffer it is 100% rock solid.

With how I'm setting it up I'll be suppressed 100% of the time. Iv got plenty of different weight buffers from old AR builds, and ordered a 9mm buffer and spacer to use with regular AR buffers. I'll play with it some to tune it with the best weight I hope. But at some point I'll put a JP silent capture spring in it. Thanks for all the info and advice golfindia! It's much appreciated!

If you're going to use the JP silent capture spring, you might as well get the JP 9mm bolt carrier.

As with the AR-15 equivalent capture spring, there is a central rod which must pass through the center of the bolt carrier. Most 9mm bolt carriers have additional weight there (generally held in with a roll pin, so they ARE removable). However, by removing that weight, you now have less mass in the bolt carrier, which means it will take less back pressure to unlock, and will possibly be traveling faster.

The JP 9mm bolt carrier and capture spring are 'designed' to work together correctly.

Note - I have 2 AR-9's; one with the JP bolt/capture, one without. The JP bolt + capture runs very smoothly, perhaps slightly better than a regular bolt and buffer/spring [9mm Q buffer + Wolff XP spring].

Aww... There you go, I never even thought about the JP SCS's rod needing to go up through the carrier. I have 2 in my other ARs but didn't think about it for the 9. Man iv done ordered a NFA 9mm bolt, well I guess if I go with a JP SCS I'll be buying another bolt then. Maybe a buddy will want to build a 9 AR and I'll make him a great deal on a bolt then. Thanks sithlord for bring that to my attention! And hurting my feelings and wallet. Lol...

[farm use]

Ok gents, what 9mm buffer are you using? Im using a 9mm 5.6 oz buffer but its slinging my brass a good distance and at 5 Oclock with subs and suppers suppressed. Im thinking and looking at the 9mm Q buffer from heavy buffers.com. Whats the skinny on them?

[certifiable]

I put the JP SCS in my wife's sbr. That being said, I have a 8.6oz buffer from a JR carbine "upgrade kit" I need to try out

[farm use]

I put the JP SCS in my wife's sbr. That being said, I have a 8.6oz buffer from a JR carbine "upgrade kit" I need to try out

Id love to put a JP SCS in this one but im not gona buy the spring and a new bolt for it. I talked to clint from heavy buffers yesterday and he recommended the 12 oz buffer since im going to be suppressed 100% of the time. So I may give that a try.