Point of impact changes with various suppressors (shooting .22LR)

Those of you who don't have suppressors may not realise it, but there are point of impact changes which can be experienced when:

1) Shooting suppressed vs unsuppressed
2) Shooting with one suppressor vs another
3) Shooting with a thread adapter vs no adapter

I recently conducted a very rough-and-ready experiment using some of my suppressors. This was on a 25 yard range using one of my R55 Benchmark rifles and one batch of RWS Target Rifle ammunition. The barrel is threaded 1/2" x 28tpi (UNEF) and I have mainly UNEF cans, but some UNF ones too (for 1/2" x 20tpi threads):



I also have some barrel thread adapters (more on that later).

Firstly let me admit that this sort of test, if conducted formally, should be done with a chronograph and the rifle should be in some kind of rest.
Also the rifle should be cleaned, fouled and zeroed between tests so that a set number of unsuppressed rounds are fired on a clean gun and then the tested can is attached.

Also, it needs a better shooter than me (or me on a better day, because I shot badly on the day). But I think the test still has value, even with bad group sizes. It's the position of the groups I am interested in.

Anyway, here's what I did:

1) Using the Ontarget TDS software I printed 10 of the "style 31" targets. You can learn what that software does here: https://ontargetshooting.com/ontarget-tds/
2) Each target has 25 "bulls" or spots and I fired 1 round at each spot.
3) I then scanned the targets at home and imported them into the software to check the group positions.

Here's an example target (I have cropped the extra 5 sighter spots off, and the barcode).
Also not shown is the ruler I scanned with the target, in order to have a 1" reference to calibrate the image in the software:



Yes, I know, that is not great shooting. But it won't nullify the value of this post. Also, the suppressors that were tested all had low round counts. The lowest was 50 and the highest was 150. No chemicals had been sprayed into the suppressors beforehand.

Here are the combinations I tested:

1) No suppressor, no adapter or thread protector
2) Wildcat Predator 12 reflex suppressor with a 150cm reflex tube. That's the big one in the photo
3) ASE Utra Dual Rimfire suppressor (I have 3 of these, this is number 3)
4) ASE Utra Dual Rimfire suppressor as above, but with a UNEF to UNEF thread adapter (yes, same to same, to check for the influence of an adapter on the same rifle and suppressor)
5) Hausken SK156 suppressor
6) Hausken SK156 suppressor as above, but with a UNEF to UNEF thread adapter (yes, same to same, to check for the influence of an adapter on the same rifle and suppressor)
7) Finland Fine Machining SAK suppressor
8) Finland Fine Machining SAK suppressor as above, but with a UNEF to UNEF thread adapter (yes, same to same, to check for the influence of an adapter on the same rifle and suppressor)
9) A-TEC CMM4(6) suppressor (I have 2 of these, this is number 2)
10) A-TEC CMM4(6) suppressor as above, but with a UNEF to UNEF thread adapter (yes, same to same, to check for the influence of an adapter on the same rifle and suppressor)

For reference these are the suppressors, labelled (except for the Wildcat Predator which is not shown). I did not use all of them, but I plan to do more of these tests in the future:

Now for the results. Here are the Ontarget TDS calculations for the various combinations:

1) No suppressor:


2) Wildcat Predator 12 reflex suppressor with a 150cm reflex tube:


3) ASE Utra Dual Rimfire suppressor:


4) ASE Utra Dual Rimfire suppressor as above, but with a UNEF to UNEF thread adapter:


5) Hausken SK156 suppressor:


6) Hausken SK156 suppressor as above, but with a UNEF to UNEF thread adapter:


7) Finland Fine Machining SAK suppressor:


8) Finland Fine Machining SAK suppressor as above, but with a UNEF to UNEF thread adapter:


9) A-TEC CMM4(6) suppressor:


10) A-TEC CMM4(6) suppressor as above, but with a UNEF to UNEF thread adapter:

I didn't expect that either, before I bought the cans.
I plan to run more tests this weekend, after I have cleaned the rifle.

Our club just bought six brand new A-TEC CMM4(6) suppressors, each one threaded UNF (1/2" x 20tpi) to match the threads on the Ruger 10/22s we will be using them on, and also two Toz bolt action .22LRs.

These are the six suppressors:





That was an ideal opportunity for me to check point of impact differences, since I had to test them anyway.

My rifle of choice is the R55 Benchmark featured at the beginning of this thread. That rifle is threaded UNEF and these suppressors are UNF, so I had to use an adapter. I therefore zeroed the rifle with the adapter only, and used that configuration as my "unsupressed" setup.

Again, using Ontarget TDS, I shot seven of the "style 31" targets, to see how much point of impact change there would be when comparing the six cans.

Once again, I don't think this is good shooting on my part. There was a bit of wind but I can do better, there is no doubt about that. These are the groups:

Unsuppressed, but using a UNEF to UNF adapter:


Can 1 using a UNEF to UNF adapter:


Can 2 using a UNEF to UNF adapter:


Can 3 using a UNEF to UNF adapter:


Can 4 using a UNEF to UNF adapter:


Can 5 using a UNEF to UNF adapter:


Can 6 using a UNEF to UNF adapter:


I think, even with the bad group sizes, there is enough evidence here to suggest that there are point of impact changes even when comparing brand new suppressors of the same make and model.

Today I conducted a small experiment to see whether these point of impact changes are reproducible even after a rifle is stripped, cleaned and zeroed again. And this time I did not use the rifle's bipod, I fired using front sand bags.
I tested four suppressors from the batch in post 1. Once again I got the group positions using Ontarget TDS. I then prepared these side-by-side comparisons of the TDS plots for each scenario.

1) Control / unsuppressed / newly zeroed:


2) Ase Utra Dual Rimfire (I have three of these and this was number 3):


3) Hausken SK156:


4) Finland Fine Machining SAK:


5) A-TEC CMM4(6). I have two of these and this was number 2:


6) Wildcat Predator 12, using a long reflex tube:


The suppressors with the least change in POI seem to the the Hausken SK156 and the A-TEC CMM4(6).
The Wildcat Predator had a marked change in POI.
I'll be doing more of these, on bags and on the bipod to see what happens over time...

There is one other interesting comparison, which is the Wildcat Predator 12 with a long reflex tube vs the same suppressor using a short reflex tube, shot on bags under the same conditions in today's session.
For those of you who haven't heard of a modular reflex suppressor, there's a thread about this suppressor here:

https://www.thehighroad.org/index.p...op-limited-wildcat-predator-12-for-22.825498/

I scaled the TDS plots for the long tube result to match that of the short tube, since the POI change resulted in shots going out of perimeter for the test with the short tube.

Here is the scaled Wildcat Predator 12 with the long reflex tube:


And here is the same suppressor with the short reflex tube:


That's quite a difference!
The muzzle attachment remains the same for both cases, since it attaches to the muzzle via the bridge module. The diffuser portion of the suppressor (with the baffles) should therefore index the same way on the gun.
It may well be a case of the different weight having an effect on the barrel harmonics. There are other variables that may be relevant such as I could have messed something up when disassembling the can to change the reflex section.

Anyway, I thought it was interesting to see the POI shift so far south!

MachIVshooter said:

Are you able to report on the aperture size and clip style of each model?

Click to expand...

I have radiographs of all of these suppressors except the 6 A-TECs that the club bought. I'll post those images here, they are quite interesting!

MachIVshooter said:

I can't tell what, if any, clip style is used on it

Click to expand...

What do you mean by clip style?

MachIVshooter said:

I'd put money on the Sirocco being the quietest, especially on a short barrel. It's cross section is similar to my design.

Click to expand...

We are stuck here in the UK, with rifles or really long-barrelled pistols.
My testing on several .22 rifles has the cans rated for sound reduction as follows (top is best):

1. A-TEC CMM4(6)
2. ASE Utra Dual Rimfire
3. Hausken Sk156, ASE Utra Eco
4. Hogan Decimeater, Sirocco SM1116P, B&T Tiger, MAE LR22ST and Finland Fine Machining SAK
5. Phantom Power RF22 (no surprise this one comes last)

The Wildcat Predator 12 is somewhere between (3) and (4) above.

When I bought the 10 research cans I was convinced the Hausken would be the best, since it has the greatest internal volume and a complex symmetrical monocore baffle set-up. It was the most expensive of the 10 research cans also.

But the Sirocco does not impress.

I think the A-TEC guys have managed to model the baffles in such a way as to disrupt the gases in an optimum manner. They are a weird design, I will post images of the internals later. I haven't taken my A-TECs apart, but I know what the structure is because I have CT scans of the can.
I'll post pictures of the club's A-TEC internals next time I get a chance to photograph them.

Here's a CT reconstruction I made, of the first A-TEC can I bought:

Ah, I understand now. The Sirocco doesn't have clipped baffles, they are plain cones. It is manufactured in India and imported to the UK by Edgar Brothers. Here are the baffles:



All the components:



The other suppressor that could have had keyed baffles is the MAE LR22ST. But as you can see, these are also plain baffles:



The Hogan Decimeater has a combination of simple washers and felt padding:



The ASE Utra Dual Rimfire is a heavy steel double-skinned suppressor with 18 angled baffles, made in Finland by ASE Utra. It works very well, almost as quiet as the A-TEC CMM4(6). When reassembling the can, you have to index the baffles on a guide rod like so:



That would happen one-by-one as you slide them back into the inner tube of the suppressor. I generated this composite image showing how the baffles are arranged, from CT data:



There are holes in the inner tube towards the base of the suppressor, allowing gases access to the recess between the inner and outer tube.
It is a very solid suppressor, but is hard to disassemble and reassemble and there are serious manufacturing inconsistencies when comparing one ASE Utra Dual Rimfire to another. I found discrepancies in weight and dimensions when comparing the three units I have (and a fourth one for an air rifle).

Then the next category is the monocore design.

First is the Hausken SK156. This is a well made suppressor, manufactured in Norway:



The core has everything in it, even the thread receptacle (you specify the threads you want and they send you a steel thread adapter that sits flush in the unit).

The Wildcat Predator is similar, but it is a reflex suppressor. There's plenty of info on that one in the thread I referenced in post #9 above.

Next up is the Phantom RF22, made in New Zealand. It is a very cheap and small suppressor:



This next one is the Oulun Työstökeskus Oy SAK (Finland Fine Machining Ltd is a translation of the company name and the model of the suppressor is SAK). It has a monocore baffle arrangement secured inside the sleeve by a cap:





Those are cheap and popular here in the UK.

The ASE Utra Eco is interesting. The sleeve has the base thread and there is a retaining cap that screws onto the end, like the SAK. The monocore has a strange design:





Those round recesses arise from the baffles and therefore accommodate gases. Here's a composite image with the chambers indicated on one of my radiographs:

The last two cans are the ones with the weird baffles.

The Brugger and Thomet Tiger is made in Switzerland and is a non-serviceable can. They send the units out with the end caps Loctited and they do not support users opening the can. However, I found images of B&T baffles on SilencerTalk which match the structure of the baffles seen in my radiographs of the can. One image can be seen here:

http://www.silencertalk.com/albums/BT/BTsternlamelle1.jpg

They look like individual baffles stacked in the sleeve with the two end caps securing the stack from both sides.

The A-TEC CMM4(6) can be taken apart but the company does not recommend it. This is a well-made suppressor manufactured in Norway.
There is an old review of a 4 baffle version here, which shows the baffles:

https://www.gunmart.net/shooting-accessories/equipment/moderators/a-tec-cmm-4-alu-moderator

I have two of the better 6-baffle version and I also recommended that our club buy those suppressors because I know they can take a lot of abuse.
One of mine has had 35,000 rounds through it without any cleaning, and it is still going strong (although it has put on weight). You can see the story of that suppressor in my LinkedIn article, in my signature.

When I service the club cans tomorrow I will see if I can get some detailed photos of the baffles.

I just thought of another test I could run:

Point of impact changes with a suppressor where the baffles are asymmetrical and they can be aligned freely in the sleeve. I can do that with two of my ASE Utra Dual Rimfires.
It just means changing the orientation of the stack of baffles for each test.

Here's a photo of the A-TEC CMM series baffle (this is from one of the suppressors in post #6):

MachIVshooter said:

But alas, only LE/govt can import suppressors, so a side-by-side with those and what we have here would be hard to coordinate. Having dB readings gives some idea, but differences in hosts, ammo, and procedure can account for pretty dramatic SPL disparities, and even the environmental factors from one location to another, even day to day in the same place affect readings.

Click to expand...

I agree with you 100%.
I have a feeling if we had access to each others' suppressors and equipment, a bunch of interesting tests could be run! Not just that, but you would be my first choice to partner and manufacture a prototype I am working on.

Yesterday I tested two other suppressors I own. They are both ASE Utra Dual Rimfire suppressors and I have had them for some time. I open them up and clean them from time to time.
This suppressor has a double-tube design, and you can see pictures of the baffles and how they sit in the inner tube in post #18 above.

For this test I had two objectives:

1) To find out whether the orientation of the baffles within the tube could significantly affect POI.
2) To find out whether the POI changes (if any) exhibited by one suppressor were matched by the other.

First I stripped and cleaned my rifle, and I stripped both cans and cleaned the baffles carefully. I cleaned the part of the recess between the inner and outer tube as best I could, in both cases.

Next, I attached each can to my rifle and marked the 12 o'clock position of the can and used that mark as a reference point.

I then zeroed the rifle with no suppressor attached and no thread adapter. These ASE Utra Dual Rimfire suppressors were purchased with the same UNEF (1/2"x28 tpi) threads as my R55 Benchmark has. So there is no need for an adapter, but you will see later that an adapter did come into play for an added experiment.

Here is the control group, as mapped by Ontarget TDS:



The next group was shot using ASE Utra Dual Rimfire number 2. Before I fired the 25 rounds, I photographed the orientation of the baffles. Here's the end of the suppressor with the end cap off:



I used the longer of the three standoffs as an indicator of how the baffles were aligned, relative to the can and the gun. In the image above, I call that between 6 and 7 o' clock. Here's the TDS group:



I then took all the baffles out and laid them out blast side up and photographed those too. This is how much residue collects on these baffles from 25 rounds of RWS Target Rifle. Baffles are numbered from the muzzle out towards the end cap, so number 18 was under the end cap:



I then wiped down each baffle and cleaned the inner tube of the suppressor with a dry toothbrush and reassembled the suppressor with the baffles in a different orientation. For the next test I had them aligned like this, almost at 12 o' clock:



Here's the TDS group:



The baffles came out looking the same as before (I won't waste space by posting that photo). I wiped them down, cleaned the inner tube again and reinstalled the baffles with a different orientation. I think one photo will do, since you probably understand the architecture of the can by now. This is how the baffles were for the next test, they were sitting right at 9 o' clock:



Here's the TDS group:



The last test with this suppressor was with the baffles at 3 o' clock:



And this TDS group was remarkable because I found the POI to be very far to the right. I had to manually mark bullet holes in TDS, because the auto hole finder failed (which is understandable):



So it seems to me that in the case of the ASE Utra Dual Rimfire, the position of the baffles when the can is reassembled, can have a marked effect on POI.

In the next post I will show you how the tests went with the other suppressor...