Point of impact shift using a suppressor


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1858
January 18, 2014, 03:06 PM
I dropped by Thunder Beast Arms' booth during the SHOT show to ask about their muzzle brakes and suppressors and they mentioned that their products are "immune" to a common problem encountered with many suppressors, namely point of impact shift. Ray talked about POI shift when removing/attaching a suppressor and the same issue as the suppressor heats up. The QD variants are supposedly the biggest offenders. The guys at TBAC are experienced long range shooters and competitors so their requirements are not necessarily those of the average shooter. However, I'm curious if anyone here has any input on this. What suppressor do you own/use and have you seen or experienced a significant POI shift due to heat or removing/attaching the suppressor?

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hq
January 18, 2014, 04:02 PM
What suppressor do you own/use and have you seen or experienced a significant POI shift due to heat or removing/attaching the suppressor?

After over a quarter of a century and several dozens of suppressors, POI shift is pretty much inevitable and in some rare cases when it doesn't happen, it's unpredictable, random and dependent on gun-suppressor combo. Suppressors have a similar effect as donut-shaped barrel "tuners" that are used on some rifles. They WILL change the harmonic frequency of the barrel, there's no way around it.

I'd take all claims that a particular suppressor doesn't shift POI with a grain of salt.

1858
January 18, 2014, 04:56 PM
TBAC folks didn't provide any data and I didn't ask but Ray mentioned that he won a steel match recently during which he removed and attached the suppressor after each stage. Their game requires first round hits on small moa targets at long range. This is anecdotal and it's obvious that a max POI shift spec would be different for different people and applications.

I'm new to suppressor ownership and went the AAC QD route so am wondering what to expect.

Bartholomew Roberts
January 18, 2014, 05:19 PM
My Ops Inc. 16th model has a zero shift when you attach it; but the shift is consistent and repeatable (about 1" low and 1" left at 100yds)

rjrivero
January 18, 2014, 05:24 PM
My Ops Inc. 16th model has a zero shift when you attach it; but the shift is consistent and repeatable (about 1" low and 1" left at 100yds)

A little off topic: Did you hear that Ron Allen (former contract suppressor builder for Ops Inc) is now making suppressors under his own label? Allen Engineering is the name of the company. I haven't heard of anything shipping from Ops Inc in a good while. (maybe 6 months or so.)

The Allen Engineering suppressors are going for 2/3 the price of the Ops Inc suppressors.

hq
January 18, 2014, 05:33 PM
TBAC folks didn't provide any data and I didn't ask but Ray mentioned that he won a steel match recently during which he removed and attached the suppressor after each stage.

Ah, this ment that the POI won't shift when the suppressor is removed and attached again. That's normal, pretty much a given for all quality suppressors. While POI shift can be significant compared to shooting without a suppressor, it shouldn't occur at all when shooting suppressed, no matter how many times you remove and install the can. I do that all the time and if shift occurs, it indicates that something is seriously wrong.

TIMC
January 20, 2014, 09:52 PM
What suppressor do you own/use and have you seen or experienced a significant POI shift due to heat or removing/attaching the suppressor?


My thunderbeast 30P1 has a several inch POI change on my .308's.

The 5.56 Liberty Torch QA has almost no POI change on 2 different AR's

Bartholomew Roberts
January 21, 2014, 11:32 AM
Had not heard that.

Arizona_Mike
January 21, 2014, 12:04 PM
Assuming perfect concentrically, you are hanging a weight on the end of your barrel. The harmonics are going to change. A good load might become a bad load and a bad load might become a good load.

I don't see how a company can guarantee no POI shift unless they provide the barrel.

Mike

1858
January 22, 2014, 05:38 PM
I probably wasn't clear on this but my concern is the POI shift each time the suppressor is reattached. I understand that some POI shift with and without a suppressor is to be expected, but my question is more about POI shift with the suppressor on, not so much the difference between on and off. I've invested fairly heavily in AAC QD suppressors and their QD muzzle brakes/flash hiders so this is why I asked the question. Also, is anyone seeing a "significant" POI shift as the suppressor heats up?

Arizona_Mike
January 22, 2014, 06:16 PM
You mean a difference in POI shift with each (re)attachment? This would be a sign of a concentrically problem with the suppressor or barrel threading. Some suppressors allow you to rotate the body to compensate for this to a degree.

Mike

1858
January 22, 2014, 06:20 PM
You mean a difference in POI shift with each (re)attachment?

Exactly! The good folks at TBAC mentioned that this is a problem with many (all) of the QD variants. As I mentioned, how significant a problem this is will depend on what you're trying to hit.

Arizona_Mike
January 22, 2014, 06:43 PM
I was not thinking about QD attachment as I have put an emphasis on multi-gun use and gone all threaded (so far).

Mike

hq
January 23, 2014, 07:14 AM
QD? I haven't experienced any POI shift whatsoever with BR (T8S), ASE Utra Borelock/CQB(S)-BL and various HK MP5 bayonet-style QD suppressors. A solid mount is a solid mount, regardless of whether it uses threads or some other kind of attachment method, and once the suppressor is installed and properly aligned with the barrel, it keeps its POI consistent.

In any case, it's good to hear that TBAC has managed to develop another solid QD mount for suppressor market. It may not be as unique as they want buyers to believe, but they have so much confidence in their product that I'd be surprised if it wasn't good. Too bad exporting a suppressor from the US requires so much red tape, otherwise I'd might get one for some unofficial personal field testing.

donaldspark
February 1, 2014, 11:47 AM
POI shift is common.

Adjustable POI shift compensation was one factor in settling on the YHM Cobra. The piston/LID is hex shaped and can be indexed in six different positions to bring suppressed POI as close to unsuppressed POI as possible.

Arizona_Mike
February 6, 2014, 11:55 AM
Hq, a concentric solidly mounted suppressor still changes barrel harmonics.

Mike

rjrivero
February 26, 2014, 04:30 PM
A little off topic: Did you hear that Ron Allen (former contract suppressor builder for Ops Inc) is now making suppressors under his own label? Allen Engineering is the name of the company. I haven't heard of anything shipping from Ops Inc in a good while. (maybe 6 months or so.)

The Allen Engineering suppressors are going for 2/3 the price of the Ops Inc suppressors.
Turns out the rumor I heard in January is true. www.aesuppressors.com/suppressors

1858
February 26, 2014, 08:36 PM
That's all we need, another firearms related company generating income for a state that doesn't allow its residents to own the product made in the state. No thanks! :barf:

Bubbles
February 27, 2014, 10:47 AM
A little off topic: Did you hear that Ron Allen (former contract suppressor builder for Ops Inc) is now making suppressors under his own label? Allen Engineering is the name of the company. I haven't heard of anything shipping from Ops Inc in a good while. (maybe 6 months or so.)
OPS, Inc gave up their SOT a few weeks ago.

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