16" 300blk with pistol gas system...

[Keyser Soze]

So I bought a barrel from Palmetto State Armory. It is 16" with a pistol length gas system. The gas port is about .070". I haven't fired it yet, as it isn't put together. Does anyone have experience with a similar configuration? How big is your gas port? Does .070 sound about right?

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[spectra]

I know my Noveske has a bigger gas port but at the same time other barrels have bigger gas ports. I think you just need to build it and see what happens.

I know Noveske states all barrels will only hold the bolt open on the last round with a suppressor installed... well mine works without one so who knows.

There are a few articles out there as that is one issue with the 300 is gas port size.

 

[IronMonster]

I dont have any experience with the .300, But I can tell you that a 16" barrel with a pistol gas system has some serious dwell time and that .070 is typical for a 5.56 16" barrel. I have read (in the Patrick Sweeney AR gunsmithing books) that enlarging the gas port is almost never required to make a gun run properly. That opening it up is always a "fix" to solve a problem that can be corrected without over gassing the system. Changing out buffers, springs and proper tweaking.

Like spectra said, build it and see how it runs.

 

[Keyser Soze]

Thanks for the advice guys. I'm waiting on a couple more parts and then, after I take a second mortgage on my house, I'll order a few rounds and test it out.

 

[spectra]

Start reloading that is the only way to shoot a 300blk. Ammo is coming down in price but still expensive.

 

[nwtech]

I have a 14.5 inch 300AAC barrel and I think the gas port is 0.750 pistol set up. It doesn't cycle with subsonic but will run fine with supersonic. But I've only tried a couple brands of ammo and haven't messed around with bullet size. My buffer is a pistol buffer also.

 

[PotshotJim]

My NEMO 16" barrel gas port is .073" and pistol length.
It cycles supers and subs reliably.
Disclaimer: I load my own ammo, so I can't say what results you will get with factory loads.

 

[Keyser Soze]

Thanks @PotshotJim. I will be trying factory loads, probably Remington, to start. I don't have the gear for hand loading. But I plan on getting a press some day.

 

[spectra]

What Rem loads? I started mine of with Rem Match ammo and it worked just fine. Then moved to reloads and no issues.

 

[spectra]

Keyser what area are you in?

 

[Keyser Soze]

Spectra, I am in Mill Creek Washington

 

[SCannon]

My 300blk had issues with cycling after I first built it. Would short stroke with 125gn bullets at ~2000fps. Tried a new buffer and spring, then I started cutting coils off of the buffer spring. I had read that the could help but only to cut 2" off of the spring. Nothing worked and I ended up widening the gas port from 0.07 to 0.08, and the problem became intermittent, widening out to 0.09 made the gun cycle perfectly. Subs will cycle most of the time, but I assume a suppressor they will work all the time. It does cycle very well with subs and the cut down spring.
That was my third 300 build, and all required fine tuning to get operational.

 

[Keyser Soze]

I just got mine finished last night. I haven't taken it to the range yet. I really hope it functions. Now that I have added up the total cost, I think I should have just bought a complete rifle.

 

[SCannon]

Yeah, but anyone can buy a complete one. Not many people can even break down an AR past taking the BCG out of the upper.

 

[Keyser Soze]

Haha. True... It has been a lot of fun. And picking out each part has been cool. I just hope I don't have too many problems.

 

[SCannon]

Message me if you have any problems, I've run into most of them.