Suppressor Point of Impact Shift

H82bogey

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I have a question, but let me set up the scenario.

Shooting a rem 308, vortex viper, factory ammo. Went out and sighted my scope in after changing the base plate. I'm not the worlds greatest shooter and was pretty windy, but was shooting 1 to 1-1/2" groups at 100. This was done without the can. Went home, cleaned said rifle and put away.

Went back the next week. Took a couple shots to warm up, same group as the week before. Then I attached the suppressor, which had been fully cleaned. My point of impact at 100 shifted completely off paper! So I checked to make sure it was threaded on tight and it was. Took a couple more shots, same result. Not on paper. Moved it back to fifty yards, took a couple shots and again off paper.

I didn't have anyone with me to give me an idea where I was hitting, but messed around and found if I held 5 Mil's low at 50 yards I could punch paper and was also 3" right of center.

So my question is, what would cause this much of a POI shift? I haven't had a chance to take the can apart and check for impact on the baffles. My knowledge on this subject is limited and my online research helped me understand barrel harmonics better, but I still don't see how adding a suppressor can change it that much. Suppressor was screwed on tight and was clean. Without suppressor groups were fine at 100. I do have a heavy barrel so not sure my harmonics would be off enough to completely throw my accuracy out the window.

Any insight is appreciated.

Thanks in advance.
 


JMF

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I've never seen any left/right shift with the can. My rifles are all about 4 minutes low with the can. If your barrel is free floated, make sure it still is after you add the weight of the can.
 

SupressYourself

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Thats messed up.
I see a shift of .5-2 MOA low with the can on vs not across all my rifles. More on lighter profile barrels, less on thicker ones.
The only time I had it move me off paper is when it somehow came 1/4 turn loose.

Do you have a crush washer or anything between the barrel and the can? If so, lose that and thread it straight on. I hold the rifle between my legs and crank it down tight with both hands.

JMF makes a good point about free floating. I had to sand some out of the barrel channel on my Rem 7mm stock so it would still float with the extra weight on the end.

Aside from that, could be that the threads on the barrel or can are messed up and it's not aligning directly with the bore. It may not be out of whack enough to cause a baffle or end cap strike, but enough to mess with the bullet on exit.
 

Obi-Wan

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I tried my varminter 3.0 for the first time last week on both my 5.56 & 270. The 5.56 I tried first and it was 6" high and 6" to right and the 270 was 3" high and 3" right. I adjusted both guns accordingly and both were shooting that what I consider decent groups. I did not shoot either gun without the suppressor that day. Both guns and suppressor has been cleaned and will give it another try this weekend shooting both with and without the can.

this was at the 100yd range
 
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Coyote Hunter

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Not sure on your problem. My 22-250 was sighted in before I added my suppressor. Once I added it, I was shooting 4" low. No change on left or right though... My guess is that JMF is on to it. If your barrel is free floated, the weight may have changed that.

Let us know what you figure out.
 


JMF

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Two people have mentioned cleaning their suppressors. I bet I have close to a thousand rounds through mine and have yet to clean it. Unless you are shooting rimfires they don't need to be cleaned much, unless you just need something to do.
 

SupressYourself

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Yeah, clean vs dirty should not affect POI at all. I have noticed that at a certain point of dirtiness, sound supression decreases and cleaning helps that. But this is at like thousands (not hundreds) of rounds. Centerfire of course. Rimfire is a whole other conversation -- those things run dirtier than <insert racial or sexual joke here>.
 

H82bogey

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Well thanks for all the insight. I will check on the free float with the weight being added.

On the cleaning, I have the varminter 3.0 and they recommend cleaning every 50-100 rounds? Are you finding you can shoot more rounds without cleaning? Also, what are you guys using to clean them? I've been using Hoppes #9 and if I have 50+ rounds through it, it takes 3 plus hours to get these things cleaned out. I feel like it takes way too long. Is there a better cleaner or method?
 

SupressYourself

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On the cleaning, I have the varminter 3.0 and they recommend cleaning every 50-100 rounds? Are you finding you can shoot more rounds without cleaning? Also, what are you guys using to clean them? I've been using Hoppes #9 and if I have 50+ rounds through it, it takes 3 plus hours to get these things cleaned out. I feel like it takes way too long. Is there a better cleaner or method?

Cleaning every 50 to 100 rounds is ridiculous.
It depends on the powder used + burn rate + barrel length, but you should be able to go like 1,000 rounds or more in most cases. Probably less if you're shooting military surplus or some other cheap / questionable ammo.

What I do is weigh my suppressors with a food or postage-type scale when they're clean, and then check them every so often. When they've gained a few ounces, it's probably time.

I let my baffles soak in CLR. It's great for taking carbon off of just about anything. It still takes time -- Let it soak, wipe with paper towel, soak again, repeat -- but if you're cleaning less often and you're not in a rush to get it done, it's no big deal.

I don't have one, but I'd think one of those brass tumblers with the stainless steel pins would be the cats-ass for cleaning the baffles.
 
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JMF

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Drop it in a container of mineral spirits over night, flush it out with water the next day and let it dry.

- - - Updated - - -

Suppress beat me too it.

- - - Updated - - -

And remember, these things are made of stainless steel and titanium, not porcelain.
 


Bed Wetter

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Clean your suppressor? Why?

Consider maybe not floating your barrel? I have a Barrett Fieldcraft with a skinny little 6.5 barrel. I put a suppressor on it and it shoots wonderfully. Action and barrel are glass bedded the entire length of the stock. No harmonic or barrel drooping issues I guess.
 

PrairieGhost

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My 300 am and my 308 win both shoot 3 inches low with suppressor, but I sight on with a suppressor and don't shoot without it. I don't get left and right, and that makes me think your barrel is contacting the stock. That or the threading is off center on rifle or suppressor. My 6.5s ate 2 inches low with a suppressor. The weight of your suppressor could also be changing barrel harmonics as someone already mentioned.
 

H82bogey

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I took a look at some things last night, based on everyone's input. Also had a chance to take the suppressor apart. I think I found my issue. For some reason the bullet is making contact with the end cap. I'm not sure what would cause this. I have included the picture. This is the cap where the bullet is exiting the can. You can see the wear on the top of the hole. There is also a wear mark inside the hole of the cap. I checked all the baffles and not one has an impact mark. Is it possible the end cap wasn't screwed in tight enough?
end cap.jpg
 

jr2280

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I would have your threads checked asap. That is not OK.
 


H82bogey

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Called Dakota silencer and they sent me a form to send in to Mack Brothers for repair. Sounds like I only need to pay for shipping.
 

SupressYourself

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Called Dakota silencer and they sent me a form to send in to Mack Brothers for repair. Sounds like I only need to pay for shipping.

Could be the threads on your rifle are out of alignment, which they would not be able to fix. I would want to check alignment on that rifle and then one other for comparison.

I know others have done this using an un-fletched carbon arrow. Finding one of the correct diameter for your bore is the only tricky part.

- - - Updated - - -

Clean your suppressor? Why?

I recently read in (I think) American Rifleman how you don't need to clean a centerfire suppressor because the next shot cleans up after the last one, or some such ignorant BS.

Weigh your suppressor now, and then weigh it 500-1000 rounds from now. Then you'll know.

How quickly it accumulates carbon depends on the baffle design, the powder you're shooting, and barrel length vs burn rate for said-powder.
I shoot mainly H4350 through my Varminter 2.0 30 cal, and there are times when I take the can off, knock it lightly against a chunk of wood a few times, and carbon chunks fall out.
I'm actually cleaning that one right now because it's up a few ounces.
 


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