.300 whisper AR pistol build

[JFettig]

Hey, new to the forum but not new to the shooting community.
I'm in the process of building an AR pistol in a caliber thats legal to deer hunt in MN slug season. Originally it was gonna be 6.8spc but I think I like .300 whisper a lot better.
I machined the lower myself from a 0% forging and have a dpms parts kit right now, will likely put a 2 stage trigger in it. I started machining the 6.8 barrel from a .270 rem 700 barrel that I picked up for $10 but don't have a chamber reamer nor the funds to pick one up right now. I also include the price of a new bolt, brass and mags into that price I can't afford directly.

So being that I'm in MN and I can't own silencers, most loads would be supersonic, especially for knocking down deer.

Looking at other short barrels I'm seeing around here, I'm seeing gas ports in pistol location regardless of the length, I'm wondering if thats a subsonic thing or if thats the overall optimal location?
I'm looking to have a 10-12" barrel on this, supersonic loads primarily but want to be able to run subsonic loads.
Cost is also an issue(and machine time, living almost 200 miles from my shop right now). I have some servos I'll be selling to fund the remainder of this project. I'm hoping to come by a barrel or upper, another thing I'm considering is getting a model 1 sales barrel or barreled upper and cut it down, turn the end, crown or thread it.
Gas port: How is the gas port sized for .300 whisper? I'd imagine that placement and size depends a lot on barrel length just as much as it does going between supersonic and subsonic.

Anything else to consider that I haven't mentioned?


Thanks,
Jon

[pug]

If you buy a Model1 barrel it is ported in the carbine position. For the barrel length range you mentioned you will need the gas port in the pistol position regardless of sub or super. Therefore you would need to plug the old port and redrill a new one. Oly barrels are already ported in their own pistol position but do come with the gas block/sight tower and their own gas tube (don't know current availability). My current 10" auto pistol is ported .086". The power generated by a 10" 300/221 is close to a 44 mag but the recoil is so much better you can actually shoot the thing all day and of course the bullets are better. My personal opinion of AR pistols is a barrel over 10.5" is a little long but it is just an opinion. The 6.5" makes a sweet little blaster but the hunters don't seem to take to it for some reason...hehe.

[JFettig]

Thanks for the reply and info,

I'm having trouble finding the oly .300 whisper or fireball barrels. Could you point me in the right direction? I checked the website and catolog with no luck.

Thanks,
Jon

[pug]

When checking on Oly parts you want to call them on the phone to verify that they have what you want in stock ready to ship. Mike Milli (Dtech) at www.dtechsuperstore.com did have some oly barrels so you could check with him. Tony at del-ton.com also had them but was out of stock last I heard but maybe he has picked up another supplier.

[JFettig]

I'm quite a few steps closer to this build!
I have a barrel blank in the mail, my dies are in the mail and I have a chambering reamer.

Is there an optimal barrel length and gas port size? I'm looking for a rather accurate pistol, I'm hoping to be able to take deer out to 300 yards(probably more realisticly 200-250). A 6" barrel would be lots of fun, and if I make a 10" barrel I'd have enough material for a 6" too.

Is anyone running a gas piston on their .300 whisper? I'd like to make a gas piston setup for it.

This is still primarily for supersonic, but I want to be able to load up subsonic and make it capable of cycling them too.

What is the best way to port the barrel and not create burrs on the inside? I'd imagine that I'd start small and work my way out and ream the final size? There would probably still be burrs though wouldn't there?

There will be more questions soon. This project is finally starting to take off.

Thanks,
Jon

[Pitt300]

This may be too late.
I think M1S will drill your port wherever you want it but once they do it's totally yours.
Mine's in carbine position & I've gotten excellent support/response on questions to them.

[JFettig]

Thanks, i've since gotten a nice shilen blank and found the port location.
I'm going with 3.6" from the extension and I'll start with a .08" hole.
I think I've decided on a 10.5" barrel.

Jon