Over torqued flash hiders? Accuracy?

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[ARCHIVED THREAD] - Over torqued flash hiders? Accuracy?

Posted: 4/18/2017 2:56:49 PM EDT

Hey boys, I was watching some brownell's videos on youtube and the one thing that was mentioned was that over torqued flash hiders can play havoc on accuracy.
I remember when I was putting my qd mounts on my 9" BCM 300 and a 16" BCM. When I did it, I just kinda tightened them until they were aligned and didn't give it too much though. Put the rock set on and called it a day.

How bad did I shit the bed? Do I just remove and go again? Or do I quit guns forever? Hang my head in shame, or just a learning experience?

Posted: 4/18/2017 3:31:34 PM EDT

[#1]

Just go shoot it.

Is it inaccurate? Maybe the flash hider's an issue. Probably something else.

Is it accurate? Sleep easy and keep shooting. Well not at the same time, but you get the point.

Posted: 4/18/2017 4:48:18 PM EDT

[#2]

Most of my QD mounts nowadays are on just tight enough to not unthread while the rockset does the rest of the work. My first QD mount (AAC 51T Brakeout) was on so tight that I had to take it to a gunsmith to get it off. He said he threw it under an x-ray to which he claims it appeared as if it had been welded. He also claims it took a hydraulic press and over 2 tons of pressure to break it off. Anyways, with that muzzle brake my rifle (Gen 1 Savage 10FCP-SR) was printing cloverleaf 5 shot groups at 100 yards with FGMM. It was holding consistent 6" groups at 776 yards (furthest target at my dad's range). Only a sample point of one, but my experience says it has to be one helluva torque value for it to effect accuracy big time.

Posted: 4/18/2017 6:26:48 PM EDT

[#3]

Shoot it. Deal with it only if accuracy is an issue.

Posted: 4/18/2017 10:24:20 PM EDT

[#4]

Don't worry about it, OP.

Posted: 4/19/2017 8:54:50 AM EDT

[#5]

I had an Imbel FAL kit that came with a barrel whose crown was bulged because that flash hider was cranked down like a mofo at the arsenal. I had it chopped to 18 and rethreaded. I did some other black magic to the FAL and 5-shot 168gr FGMM groups shrunk by ~50%.

I've entertained the thought of cutting it to 16in but it shoots so well I don't want to gamble.

So yes, overtorqued muzzle devices can screw with a barrel's mechanical accuracy. Shoot it. If it shoots well, leave it alone. If it shoots poorly with different loads, the muzzle device might be a contributing factor.

ETA: Fixing it isn't too bad. A simple recrown will usually suffice. Counterbore will be the next step if recrowning alone doesn't work.

Posted: 4/21/2017 2:09:37 PM EDT

[#6]

If you were using crush washers it should be ok, but why Rocksett?

Posted: 4/22/2017 10:56:41 PM EDT

[#7]

Quote History

Quoted:
If you were using crush washers it should be ok, but why Rocksett?

View Quote

Suppressor useage.

Posted: 4/24/2017 8:00:33 AM EDT

[#8]

For suppressor use you should have been using shim washers to get the correct timing at the correct torque.
There have been posts where muzzle devices were over torqued to the point where the barrel was damaged, but they are rare.
Only you know approximately how much torque you used; inspect the bore and if there are no visible defects then you will have to decide to redo it or not.
Obviously at some point you will have to test fire it and look for key holing or excessive group sizes.

Posted: 4/24/2017 10:09:37 PM EDT

[#9]

Quote History

Quoted:
For suppressor use you should have been using shim washers to get the correct timing at the correct torque.
There have been posts where muzzle devices were over torqued to the point where the barrel was damaged, but they are rare.
Only you know approximately how much torque you used; inspect the bore and if there are no visible defects then you will have to decide to redo it or not.
Obviously at some point you will have to test fire it and look for key holing or excessive group sizes.

View Quote

Thanks for the info. Yea I used shims and rockset. I don't think I over torqued them but I was worried for a little bit. This saturday I'm going to a 100 yard range so I'll be doing some accuracy testing.

Posted: 4/25/2017 12:34:42 AM EDT

[#10]

Unless you can SEE the damage inside the barrel you should be OK.

One of those old Guatemalan M16 kits I bought had an overtorqued flashhider. You could see a ring where the barrel stepped down inside the barrel, and the lands/grooves were visibly displaced a few degrees.

I don't know what kind of gorilla did that, but yeah, that barrel was toast for accuracy. Jungle rot inside that chrome lined barrel did not help matters, either.

I'll try to get pics next weekend, if I still have that barrel.

Posted: 4/25/2017 1:33:03 AM EDT

[#11]

I have a White Oak barrel that had been torqued so hard that the threads are a little tweaked. It shoots 5 shot groups in the .8" range on a regular basis which is as good as I can shoot an AR.

Posted: 4/25/2017 2:45:30 AM EDT

[#12]

Quoted:
Hey boys, I was watching some brownell's videos on youtube and the one thing that was mentioned was that over torqued flash hiders can play havoc on accuracy.
I remember when I was putting my qd mounts on my 9" BCM 300 and a 16" BCM. When I did it, I just kinda tightened them until they were aligned and didn't give it too much though. Put the rock set on and called it a day.

View Quote

Have you noticed an accuracy problem, or are you just having baseless worries based on something you saw/read/heard without any real reason?

At least....I assume you've shot these, because you say "I remember when..." about the assembly you did.

If not, get off the keyboard and on the range.

Posted: 4/25/2017 2:30:07 PM EDT

[#13]

Quote History

Quoted:
Have you noticed an accuracy problem, or are you just having baseless worries based on something you saw/read/heard without any real reason?

At least....I assume you've shot these, because you say "I remember when..." about the assembly you did.

If not, get off the keyboard and on the range.

View Quote

THis.

Posted: 4/25/2017 3:19:42 PM EDT

[#14]

For,the last few years, I have been using Rocksett and torquing to 20-30 ft pounds, no matter what device.

Posted: 4/25/2017 3:29:18 PM EDT

[#15]

I have personally seen an overtorqued flashhider negatively impact accuracy. I've also seen a loose one do it.

The overtorqued AAC blackout was installed with a crescent wrench. Don't know how tight. It wasn't tight enough to distort threads. I removed it, loctited it, torqued to 10ft/lbs, and accuracy improved pretty dramatically.

The loose flashhider was my fault. I installed it right before a range trip an never torqued it down. I shot ~20 shots and saw that the barrel was nowhere near as accurate as it had been the day before. Process of elimination led me to the flashhider which when checked was spinning freely. Retorqued it and the barrel went back to shooting like it was supposed to.

Barrel harmonics, barrel distortion, whatever it is it does make a difference.

[ARCHIVED THREAD] - Over torqued flash hiders? Accuracy?

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