300 whisper for AR15 questions

[tacgnut]

I have a few ??s concerning the building of a new upper chambered in 300 fireball/whisper.

The idea I had was a short barreled upper (I have the SBR stamped lower already), short as possible 10"? whatever needed to accomodate the gas system. I want the barrel/gas block shorter than the end of the forearm, whether mid length or standard tube does not matter. I have a Ti30 can from SAS.
This will be for sub loads only or primarily atleast.

Questions;
<span style="font-weight: bold">Minimum barrel length?
Twist for the 200-220 gr. bullets?
Any feeding issues from standard mags, M4 feed ramp needed?
Is the any negatives when shooting sub loads from a short barrel?</span>

And any other pertinent info you can provide.

Thanks in advance

 

[dksd39]

Re: 300 whisper for AR15 questions

I am a bolt gun only 300 whisper shooter so I can not comment on the gas system. As for twist- 1/8 is the best for subs and my understanding is 9" is the shortest you should go.

 

[zunrj5]

Re: 300 whisper for AR15 questions

Not sure about the barrel length/stability mine is a 16". I have no firsthand experience with anything shorter. I would recommend a pistol length gas system for better reliability w/ subs, plus with a short barrel it will give you more dwell time.

A 1-8-twist seems to be the standard for the larger subs. Mine is only a 1-10 (doner barrel) but I have shot up to 175's with it no key holing. A buddy of mine just yesterday shot some 180 grainers with the same set up and had no problems. It would topple a Larue out to 250m (had to stop there b/c of time so we didn't get any further). If you're set on the 200-220's I would still recommend the 1-8 though.

As far a feeding goes mine does fine w/o m4 cuts. Standard mags should feed no problem; the only issue you should find with them is capacity. The rib that goes down on either side pushes against the ogive (in standard 5.56 this is where the shoulder is) of the larger bullet and forces them to nose toward the center reducing mag capacity. What's worked for me is taking a p-mag a sanding or dremeling away the rib.

I hope this helps. Good luck.

-John

 

[Goin'Hot]

Re: 300 whisper for AR15 questions

This is probably the best source Quarterbore to get some answers.

1/8 twist is what you'll want for your barrel. IF you're going to run subs only, get the barrel ported in the pistol position and you won't need an adjustable gas block. If you'll run supers in it, you should really have an adjustable block.

Round seem to feed just fine in standard mags.

 

[IrishArrow]

Re: 300 whisper for AR15 questions

Buddy of mine did a whisper on a PRI 10" barrel with PRI low profile gas block and PRI full length PRI free float tube, also has the Thunderbeast 30p suppressor which fits perfectly inside the tube...looks pimp. Couldn't tell you what the twist is. You might have to check out your outside diameter of the SAS can first to see what free float system you can go with. Hope that helps some, really easy to put together.

 

[tacgnut]

Re: 300 whisper for AR15 questions

Thanks for the replies fellas.
I heard that someone makes 300 whisper brass, anyone know who that may be?

 

[RHutch]

Re: 300 whisper for AR15 questions

I bought some whisper brass from SSK...$48/100. Dont know who makes it. It's marked SSK/300 whisper.

 

[fast freddy]

Re: 300 whisper for AR15 questions

a guy named ranger dave on quarterbore forums used to sell it formed from mil brass for pretty cheap, might want to check there other than that its ssk or make it youreself.

 

[Ranb]

Re: 300 whisper for AR15 questions

My SSK upper has a 1-8 twist 18" barrel with an adjustable gas port 4.5 inches from the front of the receiver. I make the brass from once fired 223 remington by cutting off at the shoulder, sizing then trimming.

Ranb

 

[Zak Smith]

Re: 300 whisper for AR15 questions

Irisharrow,

Is this it? Do I know you?


............... Larger version of above photo.

This is the full size 30P. When we get some extra baffles and an extra short piece of tube, I'll make a short version so it sticks out less.

 

[johngfoster]

Re: 300 whisper for AR15 questions

Any more word on barrel length?

 

[MitchInOR]

Re: 300 whisper for AR15 questions

Noveske has barrels in stock now. As mentioned above Quarterbore seems to be the largest source of info on the subject.

From what I have gathered going over 16" is a waste, 1-8 twist for the heavy bullets and a gas block in the pistol position is best for subsonics.

The build I have visualized looks pretty much like Zak's

 

[Zak Smith]

Re: 300 whisper for AR15 questions

My build is bitchin' and the Noveske barrle works great. I use a slightly lightened bolt carrier and cut a couple coils off my op spring.

The only thing I would change is to use a shorter suppressor-- we'll get to it when we have a few extra baffles laying around one of these days.

 

[bribri]

Re: 300 whisper for AR15 questions

I am having my rem 700 rebarreled to 300 whisper with a 16.75 inch barrel and a 7 twist by kyle armament. He kind of specializes in the whisper. From my research the 8 twist is the most popular. What do you guys think is a 7 twist to fast? I would like to shoot the 125 gr bullets supersonic for hunting.

 

[Wild_Bill]

Re: 300 whisper for AR15 questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bebberson</div><div class="ubbcode-body">I am having my rem 700 rebarreled to 300 whisper with a 16.75 inch barrel and a 7 twist by kyle armament. He kind of specializes in the whisper. From my research the 8 twist is the most popular. What do you guys think is a 7 twist to fast? I would like to shoot the 125 gr bullets supersonic for hunting. </div></div>

If you want to shoot supersonic stick with an 8 twist they work in them but you might have issues with a 7 twist unless you want to shoot 240gr projectiles you dont need it an 8 twist will stabalise everything else and will also work with the 240's.

We are building an 18" wgisper at the moment just to make sure of barrel length legalities here for a guy on a model70 and he has an 8 twist it will work for anything he will ever try to shoot through it.

 

[Hoser]

Re: 300 whisper for AR15 questions

Get a Noveske 10.5 inch 8 twist barrel. The 220s are the easiest to work with and they wont break the bank like the 240s.

My 300 Whisper AR looks just like Zaks, but I have a Shark can.

My 300 Whisper bolt gun has a 16.25 inch barrel with a SF 338 can. Both sound like a pellet gun.

 

[Zak Smith]

Re: 300 whisper for AR15 questions

I found the 220's (and 210's) easier to get to run the action reliably at 1100 fps. The 240's have a steeper pressure curve that needed a little more tuning.

 

[aac_shooter]

Re: 300 whisper for AR15 questions

lou400a makes he brass on sh and it is good. i bought 1000 from him.

 

[1802]

Re: 300 whisper for AR15 questions

love the accuracy of my 16" Noveske! But as far as how short you can go??????????????

 

[brazos609]

Re: 300 whisper for AR15 questions

I think Noveske is down to one 16" barrel left right now.