brn-180 ?

[Catbrain]

anyone running the brn-180 18.5 in 223 ?
I am getting sub moa groups with 60 grain v-max--- so I think I have potential for precision. I often get a 1/4 to 1/3 moa group with 1 or 2 fliers that bring it out to 3/4 moa. May try an accuwedge----
curious to know if anyone else is getting good accuracy ? handloading and seating the bullet to max mag length.

 

[Darryle]

I don't see how the accuwedge will increase accuracy in a blowback design AR style upper.

If the accuracy is in the upper, it's there, if not, no amount of tinkering with the with the fit between the upper and lower will fix it.

Are the fliers consistent or are they random, are you eliminating every other variable and have you determined it's the fit between the upper and lower causing the fliers?

Be satisfied with your current results or move to a platform that provides it. Your best option is to tweak the load until you squeeze every bit of accuracy out of it first.

 

[DSheetz]

The accuwedge is designed to take the movement out between the upper and lower receivers. Movement between the two allows the sights to move as the upper moves even if the lower and stock are stable movement between the two is like you shaking with a bolt gun or having a loose fit on a double-barreled shot gun, or a loose barrel on a lever action rifle. It's not so much that the upper isn't accurate as it is that the sights are allowed to move by movement between the upper and lower receivers. Some manufactures have even drilled and tapped the lower receiver to fit a set screw with a rubber or plastic tip to keep the movement between the two to a minimum. When a person studies on the AR platform there are several things that can be done to increase their accuracy. Often the flyer isn't so much the rifle movement as it is heating of a light weigh barrel, an untrue fitting of the barrel to the upper receiver, torque of the barrel nut or a handguard interfering with the barrel, bolt tilt, or one of many other things, the same as with a lot of bolt action rifles. Mr. Stoners rifles are here as is the AK style rifle and a bunch of people enjoy tinkering with them just to see how accurate they can make them like we play with our bolt action rifles, cars or trucks. I'm not sure but I believe that they are so popular because they are modular and can have so many things changed by the owner because we just plane and simply like to tinker with things.

 

[Rob67gmc]

I've tried it and had friends try it and have never seen an accuwedge improve accuracy. But, it's never hurt the accuracy either. I'm running a brn-180 in 300 blackout with a suppressed 10" barrel. Love the brn.

 

[Catbrain]

I am fine tuning the 60 gr v-max load now. There is no bolt tilt. not possible because there is no buffer. I have been trying to imagine where the fliers are coming from.
It seems like some moving part has two home positions- very slightly different. The fliers are usually about 1/2 moa off the tight cluster. The cluster is usually about 1/3 moa. Often 3 in cluster and two fliers right beside each other but displaced a bit. If I could figure out what is causing that - I could put 5 in about 3/8 inch consistantly. Soooooo close ......... to perfect------

 

[Catbrain]

and- unlike some other style guns-- the sights are both on the upper. So any slop could be affecting maybe the magazine position ? Might try shimming the mag in the mag well and see if the fliers are helped. could be changing the feed angle very slightly....

 

[Rob67gmc]

Try loading a single round, drop the mag, then shoot.

 

[Catbrain]

its a short stroke gas piston system. Maybe something in that part--- but all of that looks co-linear.
Rob---- how would that help ? (in terms of trouble shooting?) What is the thought there ?

 

[Rob67gmc]

You said you might try shimming the mag, this would eliminate the mag altogether.

 

[Catbrain]

if I load a single round from the mag-- shoot--- load a single round from the mag----
the mag could still be moving around.
I might they adding some of that aluminum AC duct tape to the front of back of the mag till it will barely go in. maybe a bit on the sides too.

 

[Darryle]

Try this

JP Enterprises Rear Tensioning Takedown Pin AR-15 SS

This two-piece rear take-down pin expands when the inside screw is turned and locks the upper and lower receivers together. The result is a rock-solid...

www.midwayusa.com

 

[Darryle]

While fun, blowback style AR rifles are not as popular as their traditional brethren for this reason. The reviews I saw on Brownells site listed a myriad of issues, accuracy among them.

I am well aware of the intricacies and accurizing of the the AR platform.

Good luck with your tinkering

 

[Catbrain]

While fun, blowback style AR rifles are not as popular as their traditional brethren for this reason. The reviews I saw on Brownells site listed a myriad of issues, accuracy among them.

I am well aware of the intricacies and accurizing of the the AR platform.

Good luck with your tinkering

I would not say it is inaccurate. It is as good as most off the shelf bolt guns as is. It's just a tiny bit away from fantastic. Does brownells have a forum ?
i know piston guns are generally expected to be a but less accurate than DI. But I think that all depends on the details of the particular mechanism. The long stroke types are generally kind of sloppy and loosey-goosey and have several degrees of freedom. The BRN 180 appears to me to eliminate much of that. I think one of the best features is that the bolt carrier does not tilt-- and it also does not touch the upper rcvr. so that makes everything nice and linear. And it
can not tilt much because of the rail the carrier rides on. (unlike other piston designs) So its got a lot going for it. It still have some things that could be done better. Just small things though. I think its a way better design than the ar-15. many of us forget that it took until the 1980's or 90's to really get the ar-15 platform completely smoothed out. Thats 60 years of refinement. Other designs have not had that opportunity.

 

[Mike6158]

I'm not sure but I believe that they are so popular because they are modular and can have so many things changed by the owner because we just plane and simply like to tinker with things.

I believe this. I've always said that I hate every AR platform rifle that I've built. I enjoy building them. I don't "really" hate them. They have their place in my shooting world. The are annoying in my reloading world. I STILL watch the brass when I shoot. Especially now.