SBR and AOW Questions

[H22ate]

OK as for question 1.
I have a lower and all of the appropriate paper work on the way to make a SBR, which of course will be an AR style gun.
Now my question is, should I go with a 7.5" of 10.25" barrel? I heard without modification .223 doesnt like to cycle very well out of the 7.5" upper, is there any truth to that? Im liking the idea of the 7.5" upper that way when I throw the can on it, its still nice and compact. I contacted POF and he said the 10.25 would be alot more reliable but does anybody have any experience with both of these uppers? Another thing I would like to add is I will be shooting alot more .22 rds out of it than .223 and with that recoil based setup I should have NO problems at all, am I correct?

Question 2.
I just got a mossberg J.I.C. (Factory pistol grip shotgun). Ive been wanting to build shorty shotgun so I got one of those that way its only a $5 AOW stamp rather than the $200 SBS stamp. Instead of buying a serbu I figured Id save ALOT of money by building the same thing myself. Has anybody done this? I realized the feed tube will have to be cut down and threaded but also what type of pump did you make/buy to cycle it. I have the tools and "know-how" to do it, Im just wondering if its going to be a PITA for my first attempt.
Any input on that would also be greatly appreciated!
Thanks, H22ate

[ithinkimamedic]

#1. There have been varying accounts of reliability shorter than 10.5 inches, it all depends on gas port size and gas tubes, there is also a "pig tail" tube out there to increase the tube length, length of lock up time and reliability. The other problem you have is the suppressor... I may not be up on all the suppressor manufactures but I don't believe any of them recommend a barrel that short at all, in fact it will void any warranty that they have, I believe this is the case of AAC, SWR, Gemtech, SilencerCo and others. Again, check with the mfg of the can before you kill it the first time you are out.

#2. It will still cost you $200 to do the Form 1 on the Mossburg, yes, even if you are making the AOW since you will be the Manufacturer. Now if you did that and then decided to sell down the line it would only be $5.

[ithinkimamedic]

oh and I will add, if you are only shooting 22LR then 7.5 should be fine for the AR, even suppressed.

[H22ate]

#1. There have been varying accounts of reliability shorter than 10.5 inches, it all depends on gas port size and gas tubes, there is also a "pig tail" tube out there to increase the tube length, length of lock up time and reliability. The other problem you have is the suppressor... I may not be up on all the suppressor manufactures but I don't believe any of them recommend a barrel that short at all, in fact it will void any warranty that they have, I believe this is the case of AAC, SWR, Gemtech, SilencerCo and others. Again, check with the mfg of the can before you kill it the first time you are out.

#2. It will still cost you $200 to do the Form 1 on the Mossburg, yes, even if you are making the AOW since you will be the Manufacturer. Now if you did that and then decided to sell down the line it would only be $5.

1.
I just read you last post as well. Yes it will be primarily used for .22lr. But Id like the peace of mind to know that if I throw in .223 its going to work, ya know. I contacted POF about a year ago about this and the fellow there brought that stuff to my attention. Hes the one that suggested that I go with the 10.25 in barreled upper. Ill probably be buying the upper from "model 1 sales" and I know they'll put on whatever gas block you want, is it possible that an adjustable GB would help the 7.5" upper? I dont know the first thing about the gas workings and pressure inside of these things. Im going to put a 13.5" rail on it so the barrel will be hidden at all times but I wanted the can to be inside as much as possible. Im going to have to contact AAC and see whats what with that, I wasnt aware that they wouldnt warranty it if something goes wrong........ What would the shorter barrel have to do with that?
P.S. I read your write up on your build a while ago and because of that its saving me alot of headaches so thank you for that! Where did you buy your upper from, and hows that rifle workin out for you

2.
DAMN you're absolutely right! That definitely a big spoiler for that idea! So I guess the serbu isnt all that bad of a price since it does save you $195!

[Kramer]

1.
I'm going to have to contact AAC and see whats what with that, I wasn't aware that they wouldn't warranty it if something goes wrong.What would the shorter barrel have to do with that?

As mentioned, you should not go lower than 10.5 for reliability issues. The reason they will not warranty a can on a shorter barrel, usually 10.5 or 11" is minimum, is due to the severe blast and erosion on the baffles. You will wear them out a lot quicker than a regular length barrel.

[H22ate]

As mentioned, you should not go lower than 10.5 for reliability issues. The reason they will not warranty a can on a shorter barrel, usually 10.5 or 11" is minimum, is due to the severe blast and erosion on the baffles. You will wear them out a lot quicker than a regular length barrel.

OK, that makes absolute sense.

[ithinkimamedic]

Maybe warranty wasn't the best word, there was a time when, if you managed to destroy the suppressor somehow, that some of the companies would rebuild/replace it depending upon the damage and how/why it was damaged. As of current, if the tube is destroyed nothing can be done and the suppressor can not be repaired, this changed after a letter was sent to the BATFE by Gemtech and created quite the shitstorm at the time.

Honestly if you are primarily going to be shooting 22lr then a 7.5 is fine as I believe they are blow back operated and don't need the gas system. I don't think an adjustable gas block would really be necessary. When you first get the upper, make sure it works with 556 if it doesn't send it back, do that until it works right. I've shot a DPMS kittykat and it didn't have any problems, usually the mfg's of these shorter uppers make sure they are over gasses so that there aren't problems with functionality.

As to the suppressor, I hope you aren't buying a 556 suppressor and then planning on putting a ton of 22lr through it! That being said, I hope you aren't putting 556 through a 22lr suppressors too. yes, I know there are some videos out there of mfg's doing that just to prove how tough their can's are but it is NOT recommended and wouldn't even sound good. I have a AAC Omni and the shortest they recommend it on is a 10.5, the 7.5 isn't going to kill it but it will erode the blast baffle at an alarmingly faster rate than 10.5, 11.5, 14.5, 16 or 20. I don't believe it is know exactly HOW much faster but it has been proven that it will be significant. Based on your discription I would guess you are going with a screw on suppressor or M1000/M2000 type QD.


As to my build, it's remained pretty much unchanged since I built it. I bought the upper off of a forum, I don't recall which one. It's a Colt A2 with SOCOM barrel cut down to 11.5 inches, I've paired it with a AAC Omni which can mount to any A2 flash hider so it can change guns easily. I still have the entry stock on it and a hydraulic buffer in there for use with the 9mm set up, though I haven't shot that set up in years. In short, she runs like a raped ape, everyone at the range always wants to shot it. It feeds everything I've fed it and the only stoppages I've had have been magazine related, even when it's dirty as a french hooker. Glad to hear that the write up is still helping people!

[ithinkimamedic]

As mentioned, you should not go lower than 10.5 for reliability issues. The reason they will not warranty a can on a shorter barrel, usually 10.5 or 11" is minimum, is due to the severe blast and erosion on the baffles. You will wear them out a lot quicker than a regular length barrel.

What he said... apparently I have the attention span of a lab with a new tube of tennis balls.

[H22ate]

Yea its still helping. When I recieve my paperwork and all that fun stuff I may have a question or 2 for ya but for now I think I know how to do it

[Nate7667]

Some thing to think about.
What can are going with? If you use a QD can and still want it buried down inside a quad rail make sure its a thread on or spring pressure lock and does not require a lever flipped or ratchet button to be depressed to release the can. Or unless you like taking your rail off a lot. LOL

Here are a few pics that Bryon at Maj Malf posted about erosion. These are AAC Break outs, which seem to work great as a replaceable blast baffle rather than your can. Cant remember if this was a 10.5" or 11.5" upper and im sure they saw full auto.
And the last one of a can's blast baffle.