300 Whisper SBR AR

[gotgraham]

Hello all. My name is Jacob. I'm new to the forums, but have been playing around with 300 whisper for the last year or so.

Just about done with my SBR 300 whisper AR-15. It’s turning out nicely I think.

- 8.5" Krieger heavy barrel
- Pistol length gas system
- CMMG SBR registered lower
- Rock River upper
- DMPS hard chromed bolt
- Magpul MIAD grip
- Magpul CTR collapsible stock
- Troy Industries front and rear iron sights
- JP Mid-length handguard
- Gemtech HVT Quick Detach flash hider.

Waiting on Form 4 approval:
- Gemtech HVT .30 cal suppressor, quick detach

http://img241.imageshack.us/img241/6886/dsc01937smvl5.jpg

[Medic650]

Looks great! I'm thinking about building similar upper after first of the year. Where did you get your barrel? Also, did you use a adjustable gas block?

[gotgraham]

Thanks! I got the barrel from a friend of mine - don't know where he got it. It was originally 16" with a pistol length gas system. I had it cut down to 8.5". No adjustable gas block yet. I had pretty good luck with this gas system on the longer barrel; hopefully it still cycles well :).

[natec]

That is an excellent setup you have there.

Let us know how the Gemtech works -

Nate

[este]

That looks great. Almost exactly how I want mine to be set up.

What twist is the barrel and what do you plan on shooting through it ?

[Spook]

http://usera.ImageCave.com/Spook/2aarebarrels.jpg

Barrels in stock :smile:
1 in 8 , Brux,Stainless,threaded 5/8 X 24,3 way gas block fits under float tube

[este]

Is that a pistol gas setup?

What lengths do you have?

And how much ? :). (pm me if you would prefer to)

[gotgraham]

That looks great. Almost exactly how I want mine to be set up.

What twist is the barrel and what do you plan on shooting through it ?

It's a 1-8" twist barrel. I am current shooting 190gr prvi projectiles through it. It seems to be a pretty decent package.

Is that a pistol gas setup?
Yessir

[interceptor]

Making any progress...? I'm interested because mine is almost identical, except 1" longer barrel. But, I'm having some ammo issues at the moment. Using 147gn Winchesters over 8.4gn or 2400 this weekend, will eject but not load new round off mag. Using lightened buffer, still no go.

Frustrating to say the least. Tonight I will dissassemble and check to make sure the gas block is lined up directly over gas port.

[Medic650]

I assembled this SBR upper with a barrel purchased from Spook. Test fired today and it ran great. It's looking like it may actually be more accurate than my SSK upper with 220 SMKs. Barrel is high quality and Spook was good to deal with. :-)

http://i258.photobucket.com/albums/hh258/mictdave/IMG_1126.jpghttp://i258.photobucket.com/albums/hh258/mictdave/IMG_1127.jpg

[gotgraham]

I got my Gemtech HVT! It was approved on the 10th and I picked it up form the dealer today. Can't wait to try it out...

http://img19.imageshack.us/img19/2018/suppressoronze5.jpg
http://img142.imageshack.us/img142/2010/suppressoroffje0.jpg

[Colohunter]

Nice looking set up! Let us know how it shoots and how it sounds.

[stockshift]

Very nice. Please let us know how that HVT works out. I'm waiting on one myself.

[gotgraham]

I tested it out last night - worked awesome. I will get some video / audio this weekend to share.

[gotgraham]

Ok. Range report time...

Accuracy was great - about 1 moa with the super sonic load I tested. After drilling out my gas port to 0.093", function was flawless. Bolt speed was just right, the brass didn't get beat up. Here's a video of it in action. There's a .223 AR in the background about 100 yards away that you can hear at the same time, unfortunately. You'll get the idea.

Here's the video - suppressed with supersonic loads (~1250 fps). Ignore me jerking the trigger, i was just popping off some rounds for the video :) It was very much hearing safe. http://tinypic.com/player.php?v=2lihk6d&s=5

My wife posing with the whisper...
http://img54.imageshack.us/img54/6851/dsc02015a.jpg

[Casey]

That is possibly the nicest SBR setup i have seen. Nice work.

[lovdasnow]

very nice, thanks for posting the follow up.
what are the specs of the subsonic load are you using?

[gotgraham]

Thanks guys!

Bullet: 190gr. HPBT-M
Primer: WSR
Case: LC brass mixed year
Powder: Hodgdon's Lil'gun
Weight: 7.7 gr. @ 920 fps
7.5 gr. @ 875 fps
7.4 gr. @ 800 fps

Test elevation: 3200 ft.

Brass
Trim: 1.385"
Max: 1.395"

C.O.A.L.: average 2.080" perfect depth for PMAG

[Keith1863]

Very nice. If I wasn't totally invested in my current build I probably would have gone with your setup.

I have been working on a Daewoo DR200 SBR upper in 300 Whisper. I am getting ready to drill the gas port but I don't know what size to go with. It has an adjustable gas system (via rotating a gas plug in the gas block), so it really shouldn't matter too much? As long as it is not too small right?

The Daewoo DR200's in stock config with a 223 barrel have a gas port diameter of 0.102".

I figured if I stick with this diameter and hang a suppressor on the end of the 2 inches of barrel that sits past the gas port, I should be able to cycle the gas piston with subsonic loads.

Any suggestions as to making the hole bigger or smaller would be appreciated.

Sorry for hijacking the thread.

Thanks,
Keith

[gotgraham]

No problem. If you're going to have an adjustable gas block, I would suggest drilling the port out to the full inside diameter of your gas tube. Others can probably chime in. I think its not much beyond the 0.102". Is your gas system carbine length? As far as drilling the hole, I picked up an assortment of cobalt steel drill bits from local tool supplier. Pick the one closest to your desired final measurement. To prevent drilling through your barrel, you should insert a rod of sorts (or drive a bullet) down the barrel to drill down to. In my case, I used an old cleaning rod. Slowly drill through the existing hole, taking a small amount of material at a time. Eventually you will drill completely through the gas port. Knock out any excess 'flashing' from the drilling with a cleaning brush. You're done. Test it out.

[stockshift]

Thanks for posting the video. I'm still waiting on my HVT; will probably be another month or so before it comes in. :frown: