Anyone running a 7in barrel on their ar15?

[Medic650]

I just want to confirm my understanding on these threads. 300 whisper with gas block in pistol position will not cycle reliably without the can with barrel lengths in the 8-8.5 inch range? I was thinking of shortening my 12 inch barrel down to reduce overall length. I do have a PRI adjustable gas block so maybe I could open up my gas port more for unsuppressed. I rarely shoot it without the can though.

[mak91]

Medic650, My barrel was 7 inches to start with and I move the gas port in 1 1/2 inches to get it to run with or without a can. From what others have said the 8 - 81/2 inch barrels do not run well without a can with the standard pistol position gas port but I have no personal experience with that length. I do not know what loads they were running but my setup will run subsonic with bullets as light as 110 grain. I've not tried any super loads yet as I am still working things out with it but it does show promise.

[redtazdog]

Originally Posted by mak91

Medic650, My barrel was 7 inches to start with and I move the gas port in 1 1/2 inches to get it to run with or without a can. From what others have said the 8 - 81/2 inch barrels do not run well without a can with the standard pistol position gas port but I have no personal experience with that length. I do not know what loads they were running but my setup will run subsonic with bullets as light as 110 grain. I've not tried any super loads yet as I am still working things out with it but it does show promise.

I'm waiting for a update from you and Spook as how well the
7" and 8" barrels with the shorter position gas blocks are cycling with
the heavy lead sub ammo.
I'm thinking maybe a 7" to 8" barrel for a form 1 integral I have
plans for and the shorter the gas tube means the longer the can

[Spook]

rtd, I've got no complaints thus far shooting 220's right at 1050fps. You cant tell that you're not shooting a 10+" barrel.
I'd like to hear maks accuracy results and Jon had pm'd me with really good groups from his "evo" barrel.
My next step is an adj gas block, or a more restricted port for the high vel loads.
I've been thinking some 110VMax's loaded up screaming fast would make a pretty decent personal defense weapon set up as an AR- pistol w/red dot optic? I've got one of those old ChiCom 100+ round drum mags around here somewhere........

[mak91]

Sorry Spook no accuracy reports yet but here is a picture of the little guy. I've opened up the gas port to .120 and put on a adjustable gas block. I've run 110/147/150/175/180/200/220/240 grain subsonic loads using 5 different powders that I have on hand. Adjusting the gas port 2 - 3 1/2 turns (depending on the load) and all the loads cycle with no issues with a 9mm can. This is roughly 1/2 to full open on the gas port. For the heavy loads of the powders that I have the best load seems to be 240 smk with 8.5 grain accurate #9 running right at 1000fps and making the least amount of noise. Lil Gun coming in second for the heavy bullets. For the real light bullets I tried IMI sr 4759. It is slightly slower than lilgun but takes up much more room in the case. It seems to work well so far but looks to be not as clean.

[JFettig]

Here is mine

[Titleiiredneck]

Damn this has me wanting spook to build me another whisper, I have a sbr lower and a dias, but dont wana run it on fa with my 30 cal can. Possibly a .308x39? Wonder about reliability with that round with the mag and bolt problems everyone had in the past. I heard some issues were fixed but have heard mixed results with the mags jamming and having to tune them along with the boltfaces breaking off still.

Oh I emailed SWR if anyone is interested and he said ok aslong as I understand my can life may decrease some more than normal.

I may just fins a howa 223 and flip it into a whisper or a 308x39 instead especially with the cdi and ai mags out now.

[JFettig]

My friend saw mine and begged me to build him one



We're just waiting for his gas block to get in so I can fit it to give him a nice tight seal. I am supposed to have it tomorrow.

I've now shot mine with the gas system in 2 different locations, both worked flawlessly.

[Spook]

Nice work JF ........has anyone figured out how short they can go yet?

mak is that a Krink flash suppressor on your SBR?

[mak91]

Spook, that is just a 1/2x28 - 10x3/4 thread adapter. I was using my m11 9mm can on it while I waited for advanced armament to make me a custom 18t 1/2x28 -308 adapter for the 7.62SD can I have of theirs. I originally got the 7 inch barrel from M1S years back when they were threading them 1/2x28.