Bbl length?

[TacDoc]

I'm suffering from terminal BRD at its final stages... I've build yet a 20" A2, 16" A4 midlenghth, 18" SPR Mod me and now I'm planning for a SBR.

I've read about the advantages of the midlength over the carbine gas system, so my first question is what's the shortest lenght for a barrel to be functional with a midlength gas system?

Also I want to know if someone here have tried the PRi fat boy gas tube? It really works? Does it really reduces cycle time?

Any input on this subjects will be GREATLY APPRECIATED! Also I'll like to know what bbl length/gas system configurations have worked for you.

Thanks in advance!

[Forest]

I have a PRI Fat Boy on one of my 14.5" carbines. Yes it works as advertised.

I should note I orginally bought it to try on a 16" 'lightweight' (.625" barrel), it ran as advertised on that one as well.

Both carbines were run with Wolf 55gr, Black Hills 75gr, and Q3131A with no issues noted.

[bigbore]

so my first question is what's the shortest lenght for a barrel to be functional with a midlength gas system?
___________________________
12.5" is pushing it unless you are running a suppressor

Also I want to know if someone here have tried the PRi fat boy gas tube? It really works? Does it really reduces cycle time?
______________________________
To an extent, but its just a band-aid.


Any input on this subjects will be GREATLY APPRECIATED! Also I'll like to know what bbl length/gas system configurations have worked for you.
_____________________________________
For just playing, most any length can be made to work good enough.
I have 11.5" with the gas port moved 1" forward. Has worked great suppressed and not suppressed.

[CapnCrunch]

I've ran a few 12.5" barrels with midlength ports, and I dig the setup. Some have gotten 11.5" guns to run reliably, but I don't know to what extent they had to go to get proper function.

The EXT gas system Steve does is well thought out, and while I haven't use one on an 11.5", I've ran something very similar in a 14.5". I think that it is worth looking into.

[TacDoc]

_____________________________________
For just playing, most any length can be made to work good enough.
I have 11.5" with the gas port moved 1" forward. Has worked great suppressed and not suppressed.

I already have 3 AR's for playing... I want this one to be my SHTF rifle. I'm planning to use it for home defense and want to have it in my Truck when night checking my horses and cattle. So I really want a compact and RELIABLE rifle. Probably it'll be supressed.

[K.L. Davis]

CnC - I know at least one other guy that uses the proper sizes... and cuts them with a reamer, not a drill

TacDoc - The reliability standard for a military rifle will almost have it "over gassed" when compared to what the average person really needs. When I do design work on an barrel, I often will get something that shoots just great, then I load the rifle and stick it in a chest freezer for the night, let'er get down to about 0 to -10 and pull it out, stick it in a shoot-tube and see what happens. Often the results are not what one would hope

The AR has a few temp ranges that it does not like... if you are building something that may ever have to be used in these, you have to do what you have to do to make sure it will work there.

[CapnCrunch]

CnC - I know at least one other guy that uses the proper sizes... and cuts them with a reamer, not a drill

Last I heard, reaming was illegal in Texas

[KevinB]

I have a FAT BOY on a 11.5 Colt - works well and really slows down the system when using a Can.



Some basic velocity readings from 14.5-16-20 - I was for somethign work rleated so I did not do 10-10.5-11.5-12.5 - but I will when I have some spare time between contracts.

[SuicideHz]

After seeing Bigbore's "see what I can fit in one case" thread, I find myself wanting to have my 16" SS WOA midlength he put together cut down to 12.5". It will end up looking just like his SBR in that thread, but with 2" more of rail space. This idea is just a setup up for a future OPSINC 15th model like he has on that 11.5"...

It's nice to know it's possible and will run!

[Raith]

Anyone have any experience with a 14.5" barrel with a midlength gas system?