Gunsmithing 300 blackout gas system?

[rugerdiggs]

Ok here is my intent. I plan on building a 300blackout from scratch since model 1 sales is 6 months behind on there kits. I have a stripped JD machine upper and lower and looking for the rest of the parts. I believe I have a 16" barrel found with a 3/32" gas port and OD of barrel is .750 at the gas port. My first intention is to let my girls deer hunt with it at a range of 100yds or less with 130-150gr bullets at 2000fps, I may want to put a can on it later and shoot some subs out of it. My question is what kind of gas system, buffer, and buffer spring is needed to get good function? I have read about some using pistol gas systems but I don't know much on how to "tune" the gas system and whats needed here, thanks alot

 

[rjacobs]

pistol gas in any barrel length is the way to go. Supers, subs, can on, can off, it will run them all. Carbine gas in 16" has an issue with subs with no can.

 

[rugerdiggs]

Ok thanks, will I need a special buffer and spring or just a mil spec work fine?

 

[rjacobs]

regular spring and c buffer for 16" guns. Dont over think things. I am fairly active on 300blktalk and see guys all the time having issues with their setups and they are always running some weird extra power spring and super heavy buffer and then wonder why the gun doesnt cycle. Its just like every other AR, start with the lightest of everything and step up buffers if you need. I run an H in my 9" and AAC recommends an H2, but my gun runs everything so I am hesitant to change it up.

 

[Delta4-3]

pistol gas in any barrel length is the way to go. Supers, subs, can on, can off, it will run them all. Carbine gas in 16" has an issue with subs with no can.

Negative sir, .300 blk 16" runs like a scalded dog with a carine length gas system, subs or supers so long as the gas port is .116". I have a lot of load data for both. The above statement for subs and supers.

 

[Delta4-3]

In fact it will cycle a lot smoother with carbine, and you won't have to use an adjustable block.

 

[Delta4-3]

For 9"-10.5" you want a pistol length tube with a 0.093" port. 7.5" barrels need a 0.103" port. 12.5" bbls do well with a 0.89" port. All the specs I listed will run subs or supers with or without a can as long as you use fitting powders.
I prefer reloader 7 for subs, it is clean, accurate, and consistent.

 

[rjacobs]

Negative sir, .300 blk 16" runs like a scalded dog with a carine length gas system, subs or supers so long as the gas port is .116". I have a lot of load data for both. The above statement for subs and supers.

You spend much time on 300blktalk? There are guys over there running carbine gas with the ports opened to .125 and still having issues with subs, unsuppressed(not sure why you would ever run a sub unsuppressed, but thats just me). I would NEVER personally choose a carbine gas system if there were pistol gas systems available. It also says something when the two big makers(aac and noveske) are only running pistol gas systems.

In fact it will cycle a lot smoother with carbine, and you won't have to use an adjustable block.

What on 300blk would you have to run an adjustable gas block on? Pistol gas? No way... No reason on either gas system on 300blk to run adjustable gas.

 

[Delta4-3]

You spend much time on 300blktalk? There are guys over there running carbine gas with the ports opened to .125 and still having issues with subs, unsuppressed(not sure why you would ever run a sub unsuppressed, but thats just me). I would NEVER personally choose a carbine gas system if there were pistol gas systems available. It also says something when the two big makers(aac and noveske) are only running pistol gas systems.



What on 300blk would you have to run an adjustable gas block on? Pistol gas? No way... No reason on either gas system on 300blk to run adjustable gas.

No, this is the only forum I am on. I don't mean to sound abrasive or condescending either, I apologize if it came off that way. I have built around 950 .300 blk's though, and that's just my personal experience with the system. However, I will admit that I am very seldom 100% accurate in my statements. There are a lot of factors though that don't get discussed much. Lat time I checked AAC used carbine length gas systems on there 16" bbls. I have worked on a lot of their barrels. I took in one of their 700 barrels that had the chamber 0.065" off center!

 

[Killswitch Engage]

I've ran a pistol length gp and carbine length gp on black out and by far pistol length is the way to go. It will cycle absolutley everything and considering the platform was really designed around heavy subsonics cycling in a gas gun that's where it should be. My buffers and springs have all been just straight carbine junk and my guns shoot flawlessly even cycling and lock open 100% with 178amax subsonic.