Severe Impact Shift due to wet suppressors

[3wolves]

Hey folks, this is my first post here but I asked around on another forum and they thought it would be wise to ask around on this forum. I just copied and pasted the text from my other forum page so here it goes.



So recently I did some deer hunting with my ldubs. I carried my 16" REPR and my brother carried my 14.7" IC. Both were suppressed. The REPR had the AAC MK13-SD, the IC had the Surefire Socom rc. Here's what happened.

We went to the island and hiked all day long. We saw about 6 does, but no bucks, and right now it's bucks only season. It rained cats and dogs the entire time, but we both carried muzzle down about 90% of the time, only carrying muzzle up when some climbing was required.

After returning to town, I went to the shooting range and attempted to shoot a 8" gong at 300 meters. My REPR impacted about 4 feet right but was the same elevation. The suppressor was on tight, and the scope hadn't been bumped and everything was tight. By the end of the 20rd mag, I was finally getting good hits. About the last 5 or 6 rounds were within 4 or 5 inches of eachother.

Then came the IC. I did the same with the IC and got the same results. I also got blasted in the face with water mixed with carbon. The REPR did the same thing but wasn't quite as bad because of the receiver design.

It appeared to me that the suppressors got some water in them, but I wouldn't have imagined that it would throw the impact off that much. I have since taken both rifles out and shot them dry and they shoot as they always have before.

I contacted surefire and AAC to ask if they had ever received a call about this, and neither one could really answer my question as to why it happened, but said they hadn't heard of that before. I wondered if maybe water had run down the barrel and got past the mount and into the suppressor, or possibly into the gas block and down the bore to the suppressor. We were soaking wet from rain, but didn't submerge the rifles underwater at all.

Has anybody had this happen, and is there a remedy to this?

A few weeks later I went on another hunt with the REPR, but this time I left the suppressor off until I reached the top of the mountain. I affixed it and shortly after shot a running buck in the neck at about 200 yards. I look forward to hearing the theories, and I'll try to duplicate this soon since we're getting a steady 8" of rain per day.


Second post:

Yeah, my ejection port was closed. I'm pretty religious about that. And yes, before EVERY hunt I go on, I go to the range the previous day, in this case at 6am that morning, to check my zero for my cold bore shot. I made a 630 yard cold bore shot with it the morning of the hunt, followed by a 3 shot group at 100 yards and it was under 1moa and zeroed perfect. I only shoot suppressed, but I do know that my point of impact shift from suppressed to unsuppressed is usually about 1.5moa down to the left. In case anyone thinks of this, yes I made sure the suppressor was on tight. The water in the bore theory mentioned makes sense to me, I'm wondering how so much water got into it in the first place. As mentioned before, it returned to zero after most the mag was fired with no scope adjustment. I then took it home and cleaned the piss out of it and fired it again the next day and it was still zeroed. I've pretty much narrowed it down to either water in the suppressor, or in the barrel. My next trip to the range I'll add a little water to my surefire can and see if it makes a difference. Thanks

Third Post:

I pretty much concluded that it couldn't have been due to something getting bumped since it did the same thing on both rifles. Each with very different optics. The IC has an Elcan SpecterDr 1-4x, which the way the mount is, I could see the possibility of it being bumped because you can move the scope up with little force. The REPR has a Nightforce NXS 2.5-10 on a larue mount. I checked the levers on both optics and they were still on solid, and after shooting both guns until they got hot they both returned to zero. I've been procrastinating getting to the range to test this out, but I will post the results with pictures of my groups. It will most likely be a 100 yard target for each.

Fourth Post:

I should have clarified. I've never experienced anything close to this kind of impact shift without a suppressor. On both rifles, they returned to zero after what I can only assume was caused by burning(evaporating) all the water out of the suppressors. I'm going to the range tomorrow, so I'll post some pics with my findings. Thanks!

Fifth Post:

Ok folks, I finally got out to the range to test this out. I'm not a scientist so this might not exactly be a scientific test, but it's pretty conclusive if you ask me. First I shot the m6-IC 14.7" with the surefire socom attached DRY. I used Hornady 55 gr Vmax and an Elcan Specter DR 1-4x. 6 rounds on the upper left diamond. You can see on the target it was a fairly acceptable group. It normally shoots a little tighter than this but it was still in the 1.25moa range. Distance was 100 yards. I then removed the suppressor and poured water into it until it poured out, then shook it pointed down until no more water poured out. I then fired 10 rounds of the same ammo from the same lot at the lower left diamond. I didn't think to measure the group because it was so bad.

The next target was 5 rounds of 168 gr Federal Gold Medal Match on the upper left diamond. This was with the 16" REPR with a 2.5-10x Nightforce and larue mount and an AAC Mk-13sd. It was under 1moa. I then repeated the same process as I did with the IC and fired 10 rounds at the lower left diamond. The group was so bad that I was amazed to discover that I didn't have a baffle strike. Hopefully these findings helps those who live in rainy places like here. Keep that can dry!

The images aren't right side up so if you tilt your head 90 degrees to the left you will see the correct orientation of the targets, lol.




Has anybody experienced this, or does anybody on here know why this severe of an impact shift would occur? If so, any other recommended means of keeping water out of the cans? Thanks!

[a_canadian]

You could just make a si.ple neoprene cover. A rectangle and a disc and the right glue and sew it to make sure it stays together. Keep it in place until you need to take a shot. Shouldn't let any rain in if it's a decent fit. Even a baggie would work with an elastic band for that matter.

[rimshaker]

I was always under the impression that rifle cans aren't meant to be shot wet. Shooting wet is primarily for giggles on pistol rounds.

Muzzle uncorking pressures are so much greater out of a rifle. Any unexpected thermodynamic behaviors inside a wet rifle can could be affecting bullet path or even its spin.

I wouldn't worry about baffle strikes. They're caused by physical misalignments of some nature, not by simply shooting wet.

[Capt. Link.]

I don't think the water caused any shift.I've shot to many of them without all of the horror stories coming true.Almost all major impact shifts are due to a baffle strike even if none can be found.
Suppressor designs range from wet to dry with today's dry cans now being shot wet.A wet suppressor can be used in rifle calibers without all of the hubbub.

[a_canadian]

And yet, unless the guy who started this thread is lying, his always-reliable suppressor which allows for fairly impressive precision shooting at great range has in fact displayed a severe impact shift when exposed for hours to heavy rain. Not before. Not after. Only when wet. Would the Captain care to attempt an explanation which addresses this anomaly? Or simply leave it at that, dismissing his real-world experience as impossible? It seems unlikely to a point approaching approaching impossibility that he's having baffle strikes dry, with around 1" groups at 100 yards and no change in scope zero in the before and after the wet can bad POI experience.

[Capt. Link.]

I have never seen a shift of that magnitude that was not caused by a strike.How many times was that suppressor taken off or at least tightened during this event.This alone can correct a unseen problem.People paid me good money for my expertise for 30 years diagnosing such problems.On a professional level I'm pointing out that water is a very unlikely candidate unless it was enough to quench your thirst.Even a defect in the suppressor that was exacerbated by the presence of water would need to result in a baffle or end cap being stuck for a major POI shift.
I would be interested in your opinion on how a 4' shift happens.I'm guessing you have seen this in your experience with suppressors.

PS: I have built rifle caliber suppressors that are run wet 100% of the time without any poi change between wet and dry.

[a_canadian]

Far from assaulting your professional experience, what I'm saying is that OP states quite thoroughly and clearly that the only change involved with this much-used suppressor was the rain water going into it and perhaps the barrel itself. If he was packing the rifle muzzle-upwards I'd guess quite a lot of water went into the barrel. If the projectile has a tapering nose, and guessing here that it did considering the intended usage, I suspect that gravity, on lowering the muzzle to shoot, would place the ALL of that water along the bottom of the barrel. If there was a significant plug of water, say a volume greater than that of the bullet, and considering that the bullet seals rather efficiently against the walls of the barrel, it seems fairly likely that there would be a bias in the location of most of the water as the bullet travelled down it. Rifling spins the bullet, some of that spin gets imparted to the water being pressed forward but considering water compresses not at all regardless of pressures involved, most would be travelling straight forward. While the enormous pressure hitting the water would spread it out fairly evenly, if the baffles were likewise very wet it seems somewhat likely that the downside-biased location of most of the water would push upwards on the bullet as it left the muzzle, causing a baffle graze. Not enough to cause damage, but enough to influence the path. How, exactly, would be a matter of extraordinary complexity in the calculation. And of course my notional understanding of the behaviour of the water may be far off base. But you're suggesting there's an alignment problem causing a baffle strike, and the rest of his reporting of the can's history of very fine accuracy and only a tiny and predictable POI shift as compared to firing the same rifle unsuppressed seem to contradict that. If firing his particular suppressor with his particular baffle setup and a LOT of water in the system is the ONLY situation where this weapon is showing dramatic inaccuracy, does it not seem logical to admit that the water is the problem? And then to do something about it, as I suggested in sheltering the can and barrel between shots with a slip-on sleeve of some sort?

[driver6814]

Simple, Put a condom on it. For the can you might need a magnum lol

[3wolves]

Thanks for the replies gents. I'll say it again, both of the rifles are acceptably accurate for what I use them for. I've shot the M6IC 14.7" 5.56 out to 800 yards with the 55gr Vmax. I've shot the 16" REPR out to 1000 yards with 178gr Hornday Amax home loads. Granted, after about 700 yards neither of them are outstandingly accurate like a bolt gun. The suppressors are both made by reputable companies that I have had nothing but good experiences with. This is just SO strange to me. I'm not technically educated on the dynamics of their operation, and I never shoot wet on purpose. All I know is the signature is reduced and the accuracy is unaffected, if not increased.

In the field, I was unable to determine whether it was caused by water in the bore, or water in the suppressor. We carried the rifles muzzle down the entire time except for a couple brief moments when some climbing was necessary.

During my test, I shot a group with each rifle DRY which showed they were both still zeroed and shot pretty consistently. I then walked my dog for half an hour by the range before doing my wet test. For the wet tests, I only put water into the suppressors(not the barrels), again muzzle down. I then kept them pointed down and shook as much of the water out as I could, then flipped it the other direction and there was no additional water pouring out.

First was the M6IC. I had the rifle in a rest and attached the suppressor. I then got behind it and pointed it downward on the rest while I chambered a round and began the test group, which was an epic fail. The same procedures were followed for the next rifle with similar results.

I literally can't make this up. If anybody doubts me, or is skeptical to my findings, please try for yourself and tell me what I'm doing wrong. Either way, my test concluded to me that water in the suppressor does severely impact POI, at least on suppressors not intended to shoot wet.

I have no way of knowing for sure if it's the actual suppressor, or if perhaps when I fired the first round wet the shot was only a little bit off, but the pressure from the first round forced some water into the bore and made each subsequent shot less accurate until it was evaporated out.

I guess something I could have done better in this test would be to record the placement of each wet shot in order to determine if it exponentially got worse from the first shot, or vice versa. Thanks for the input folks, I appreciate the collaborative knowledge on this subject. I'm not a scientist, lol. They don't make everything marine proof.

The neoprene cover is an interesting idea, but I don't know how the water is getting in there. It could be through the suppressor mount, gas block, or down the barrel from the chamber. There is no question that the entire rifles got wet themselves. Possibly water got in between the upper/lower or by the charging handles and somehow made it past the round in the chamber to run down the barrel?

[Historian]

3Wolves, a most intriguing problem you have had which
many of us have fortunately never encountered.

I must admit the I got STEAMED reading this
thread.

" ...I have no way of knowing for sure if it's the actual suppressor, or if perhaps when
I fired the first round wet the shot was only a little bit off,
but the pressure from the first round forced some water
into the bore and made each subsequent shot less accurate until it was evaporated out."

Steam does some weird things in a closed container as I recently discovered using a Michael Graves
teapot when I negligently had not seen that there was very little water in it.

Asymmetry on steroids, popping the cover and going off
like a Claymore. Never happened when there was plenty of water.
But the rapid build up was an explosive mixture.

With all other variables fixed and accounted for I believe you have converged on the culprit.

Using a condom on the can in the field, a time tested and proven efficiency
as was advised above, will put an ENZ to your scattering.