Swap muzzle brake-change of impact.

[Jitterbug]

I have a Larue UU PredaTar upper and it shipped with a Tranquilo brake, installing an A2 wasn't an option, I asked. I'm currently zero'd and it may not be possible for me to get to a range any time in the near future to confirm zero if I swap it out for an A2 flash hider. I'm sure every individual situation is different but does anyone have any general ideas's on what I should for a change in zero? Off by a foot or two at a 100 yards or more like and inch or two?

I've heard the Tanquilo is like a flamethrower at night.

[gaijin]

Inches most likely at 100 yds.

And yeah, anytime you swap a MD it’s prudent to confirm, or “re”- zero.

[RHINOWSO]

Inches most likely at 100 yds.

And yeah, anytime you swap a MD it’s prudent to confirm, or “re”- zero.

And realize he said "most likely". I've seen it throw things further than that, especially if you get unlucky enough to have an outspec or mis-installed part.

Personally, if I change anything on the barrel or optic setup, it's no longer 'zeroed'. Sure, with a QD mount optics it is 'close', but if you move the mount forward / aft things have changed. A quality muzzle device shouldn't change 'much', but it has likely changed. Could be elevation, could be windage, could be both.

Until you shoot it, you really have no idea.

Another prudent reason to have more than 1 rifle. I'm never without a rifle that is 100% solid.

[gaijin]

^Agreed.

IME switching from a flash hider to an effective brake, or hybrid device, my gun is shooting appreciably lower and usually further left.

The point; any changes in MD or mount/optic- I confirm zero/re-zero.
I want to KNOW my POA/POI is where it’s supposed to be.

[lordmorgul]

Plan to change a weight hanging off the end of your barrel and don’t expect anything to change? Not a good plan.


Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!

[Jitterbug]

Thanks guys, I appreciate it.

Kind of what I expected but thought I'd ask. I was pleasantly surprised a while back to find out that the POI didn't change all that much at 100 yards for 55, 62 and 77 grain ammo with a RR, BCM stainless or the Larue. I have 3 uppers and 2 lowers.

The Rock River is ready to go but it's a 16" stainless, heavy contour. My wife was struggling with the weight while going through some dry fire drills recently. The Larue is "her gun" to replace her stainless BCM due to the weight. It's light, handy and ready to go with a 1.25 x 4 Leupold Patrol on it but I told her to expect to be blinded if you fire it at night.

I've had some medical issues for almost 2 years now that has set be back a bit. I shipped the first UU back due to accuracy issues and it took LaRue 3 months to ship the latest one back to me. I had a major surgery about the same time it finally arrived back and just couldn't get the TranQuilo off, test it, mount scopes and get it re-zeroed before this damn pandemic hit. I'm not getting in the range time or working up loads or keeping the "gun stuff" up to speed as much as I would prefer.

I did get her a new CZ Phantom and installed a an Olight Bald R pro on it for her...again a kicking myself moment, we could have picked up an AR pistol at the same time from our well stocked LGS, a pistol has been on the agenda ever since I handled a Mk18 a while ago. And I've been wanting to put my own together rather then purchasing off the shelf. You know what the say about hindsight.

[PatEgan]

Read what RHINOWSO said.

Now read it again.

It's kind of sounding like range time is a problem for you in terms of affirming/confirming POIs with your chosen load. If it's important to you, get to range and CONFIRM ZERO. This is not a criticism, just a solid, proven choice, but you knew that.

Like everyone else, I like LaRue and what they've done all these years. The reality is that they're not really the leading edge of innovation at this point, or really that far up there in terms of being at the leading edge of AR development now. Are they irrelevant? NO. That being said, I think you're better served with a different muzzle device. The next step for you is to define your mission/REALISTIC expectations. I.e., what are you REALLY going to do and expect to do, with THIS rifle? Do you really need to suppress flash? Are you trying to mitigate muzzle rise? Is recoil (5.56 now, come on...) impulse on your shoulder really an issue? An honest and sober assessment of that question should inform your decision accordingly.

Pat

[DMTJAGER]

Anyone feel free to correct me if I error but does not changing anything about a rifles barrel change it's harmonics and will with a 95%+ certainty change its POI?
as an example, I have a Savage 116 FCSS in 7mm STW that has a muzzle brake that can be twisted CW to vent gas and then twisted CCW to block gas from venting and if you sight in with set to vent gas, then shoot at or past 300 yards with the vent set to closed the difference in POI becomes significant.

[Stickman]

I was pleasantly surprised a while back to find out that the POI didn't change all that much at 100 yards for 55, 62 and 77 grain ammo with a RR, BCM stainless or the Larue. I have 3 uppers and 2 lowers.

I shipped the first UU back due to accuracy issues and it took LaRue 3 months to ship the latest one back to me.

I did get her a new CZ Phantom and installed a an Olight Bald R pro on it for her...again a kicking myself moment, we could have picked up an AR pistol at the same time from our well stocked LGS, a pistol has been on the agenda ever since I handled a Mk18 a while ago. And I've been wanting to put my own together rather then purchasing off the shelf. You know what the say about hindsight.

Changes in impact tend to be different than what a lot of people expect. Much like yourself, I don't see huge changes in varying ammo weights at most ranges, but that is more a matter of me just banging steel out to 500 yards or so. Out to 300 it doesn't make much difference at all, but again, its hitting steel not shooting bullseyes. Obviously shooting groups things become different.

What sort of issues were you seeing with accuracy? Did you try different ammo types?

Have you thought about using a pistol caliber subgun for your wife as opposed to an AR?

[Jitterbug]

My apologies for the late answer to your question.

I finally got in some range time with the A2 flash hider mounted and my zero was off less than an inch at 100 yards. But I agree with everyone who suggested that changing anything on the barrel requires one to re-zero. I can’t sleep at night not knowing where my load is zeroed.

Regarding accuracy issues with the original Larue upper, I tried 5 different factory loads including 77 gr. FGGM and 4 different reloads, 52 gr SMK to 77 gr SMK. I swapped three different optics and mounts and cleaned 3 times over the course of 300 rounds. The average 5 shot group was 1.83”. The issue was that I was getting first round flyers that opened up nice .5-1.25” groups. I was also getting significant brass shavings in the chamber area for the first 250 rounds.
I’m not sure what repair work Larue did to the upper, I marked the rail so I know that they returned it and I’m pretty sure I have a new BCG but I’m not sure about the barrel.

My first range trip with the Tranquillo brake I was able to shoot at 100 yards with a SWFA 3x15 using a 62 gr. Hornady BTHP handload that averaged 1.62” for 3x5 shot groups with no flyers. This is about what I get out of my 16” medium heavy contour Rock River which is the most accurate of the 3 uppers that I own.

I’ve since mounted a Leupold VXR 1.25 x 4 Patrol and a Burris RT-6 and shot 18, five shot groups off a bench with front and rear bags at 100 yards with 4 different hand loads utilizing 55 g. VMAX, 62 gr. Gold Dots, 62 gr. Hornady BTHP and 77 grain SMK., I’m averaging 1.67”, the barrel appears to have a preference for 77 SMK which is giving me 1.30” for a 4 group average.

1.20, 1.05, 1.85, and 1.10 the 1.85” group had four into .95” then a flyer ruined it. But, overall the flyer issue with the replacement upper appears to be resolved. We’ve shot a bit of steel with it out to 200 yards and I cleaned it for the first time yesterday, I’m guessing I have around 400 rounds through it. No brass shaving this time.

Yup, I’ve considered a pistol caliber subgun as well as an 11.5” AR15 pistol, or an even shorter 300 B.O. Right now I’m leaning towards a 14.5” P&W, either a DD or Centurion. I’ve read good things about the DD 14.5” lightweight carbine and might go that route if I could find one.

On the other hand the 11.5” 5.56 pistol really intrigues me, I’ve handled several at the LGS, but I am concerned about blast and flash with the short barrel. Some guy’s say it’s not bad others say it’s horrendous. I'd probably mount a red dot or Eotech on it and use it for under 200 yards, light and handy.