General silencer discussion. If you want to talk about a specific silenced rifle or pistol, it is best to do that in the rifle or pistol section for that brand.
I finally got approved of my AAC SR-7. After my first several boxes of sobsonic ammo, I noticed some baffle strike...
Setup:
Tikka T3x Lite SS in .308 Win, muzzle threaded by Pierce Engineering here in Lansing, M.
AAC Blackout 90T brake, direct screw on without a washer.
Beck Ammunition 168gr A-Max Subsonic load
The first several shot through the can groups around 1.5 MOA@100yard then I noticed some keyholling so I stoped and swap to supersonic Freedomunition 155gr A-Max, keyholling even worse.
I dig up some information here and there. The Beck Ammunition said 1in11 twist and 1in12 twist is fine. And I didn't notice any keyholing shooting without the can.
I do find a review under the reviews of this Midway USA product page: https://www.midwayusa.com/product/10181 ... -box-of-50
So I am thinking about if it's possible that the 90T brake mess things up, I do think I mount the can on the brake right and tight.
If you're getting baffle strikes the suppressor bore is not correctly aligned with the rifle bore. Period. Something isn't correctly machined, whether it's the barrel thread, mount, shoulder, or the can itself. One can easily eliminate each of these with simple tests and possibly machine operations on a lathe, though of course skill is required to check and correct properly. A test rod of the appropriate caliber and known straightness can be inserted into the bore and the barrel and clearance checked all around at the end cap. But don't just keep shooting through it until the source of the problem is found and corrected.
I finally got approved of my AAC SR-7. After my first several boxes of sobsonic ammo, I noticed some baffle strike...
Setup:
Tikka T3x Lite SS in .308 Win, muzzle threaded by Pierce Engineering here in Lansing, M.
AAC Blackout 90T brake, direct screw on without a washer.
Beck Ammunition 168gr A-Max Subsonic load
The first several shot through the can groups around 1.5 MOA@100yard then I noticed some keyholling so I stoped and swap to supersonic Freedomunition 155gr A-Max, keyholling even worse.
I dig up some information here and there. The Beck Ammunition said 1in11 twist and 1in12 twist is fine. And I didn't notice any keyholing shooting without the can.
I do find a review under the reviews of this Midway USA product page: https://www.midwayusa.com/product/10181 ... -box-of-50
So I am thinking about if it's possible that the 90T brake mess things up, I do think I mount the can on the brake right and tight.
Any ideas why this would happend?
Threads were not cut concentric, I've seen it before on non factory threaded barrels.... or your 90T mount was not torqued to specs.
It's so important that not only are the threads cut perfectly concentrically but that the shoulder that is left is perfectly, and I mean perfectly squared to the barrel.
I shoot an AAC SR-5 and a SR-7 all the time and the only problem I had was when I did not Rockset and torque my 90T flash suppressor down properly and the mount worked loose and I got an end port hole strike. It hammered flat again with a 3 pound brass hammer.
From the looks of your baffles the striking occurred almost immediately out of the barrel, most baffel strikes from loose connectors are towards the end or often only just the end exit hole, which indicates non concentric threads cut on your barrel.
AAC is pretty good about things like that. When you call them listen carefully to the menu and DO Not pick the first choice, wait until you get a choice for repair, then you will actually be talking to a real AAC suppressor person and not a Remington person who usually knows nothing and will just f up your issue. Request an RMA or get their permission to just send it in with your Form 3 or 4
Thank you!
I am also wondering how long will it take for the suppressor to be repaired for AAC
gsyoung54 wrote:
trcloud wrote:
I finally got approved of my AAC SR-7. After my first several boxes of sobsonic ammo, I noticed some baffle strike...
Setup:
Tikka T3x Lite SS in .308 Win, muzzle threaded by Pierce Engineering here in Lansing, M.
AAC Blackout 90T brake, direct screw on without a washer.
Beck Ammunition 168gr A-Max Subsonic load
The first several shot through the can groups around 1.5 MOA@100yard then I noticed some keyholling so I stoped and swap to supersonic Freedomunition 155gr A-Max, keyholling even worse.
I dig up some information here and there. The Beck Ammunition said 1in11 twist and 1in12 twist is fine. And I didn't notice any keyholing shooting without the can.
I do find a review under the reviews of this Midway USA product page: https://www.midwayusa.com/product/10181 ... -box-of-50
So I am thinking about if it's possible that the 90T brake mess things up, I do think I mount the can on the brake right and tight.
Any ideas why this would happend?
Threads were not cut concentric, I've seen it before on non factory threaded barrels.... or your 90T mount was not torqued to specs.
It's so important that not only are the threads cut perfectly concentrically but that the shoulder that is left is perfectly, and I mean perfectly squared to the barrel.
I shoot an AAC SR-5 and a SR-7 all the time and the only problem I had was when I did not Rockset and torque my 90T flash suppressor down properly and the mount worked loose and I got an end port hole strike. It hammered flat again with a 3 pound brass hammer.
From the looks of your baffles the striking occurred almost immediately out of the barrel, most baffel strikes from loose connectors are towards the end or often only just the end exit hole, which indicates non concentric threads cut on your barrel.
AAC is pretty good about things like that. When you call them listen carefully to the menu and DO Not pick the first choice, wait until you get a choice for repair, then you will actually be talking to a real AAC suppressor person and not a Remington person who usually knows nothing and will just f up your issue. Request an RMA or get their permission to just send it in with your Form 3 or 4
Sounds like this is your first an only can. When you call, be polite but say you waited the better part of a year, bla, bla. You know the pitch. If they email you a shipping label ask them if it is overnite.
Most will fix it for free, or at least that would be what I would expect.
Most likely they will want to know details about ammo, barrel, reloads, etc. I had a baffle strike once with some Hornady pulls I bought because they were cheap. Had jacket separation in the can. The manufacturer fixed for free. They said everyone was intitled to one freeby.
There are a couple ways posted here over the years to determine if it was you parts or if it was ammo.
hardcase wrote:Sounds like this is your first an only can. When you call, be polite but say you waited the better part of a year, bla, bla. You know the pitch. If they email you a shipping label ask them if it is overnite.
Most will fix it for free, or at least that would be what I would expect.
Would you expect an automaker to repair body damage to your car under warranty because you scraped along the divider on the highway?
Maybe they'll be nice and take care of it, but a baffle strike is 100% on the end user. It's the owner's responsibility to ensure axial & concentric bore alignment. If you can't get it aligned, then you send it back to be checked by the manufacturer. Once you put bullets through it and cause a strike, misalignment of the can on known-true threads & shoulders after the fact can be attributable to the strike.
Warranties are against defects or failures which occur under normal use. Abuse and damage caused by user error are generally not going to be covered.
Good to hear you say that, as I've often felt that these sorts of 'warranty repair' discussions seem to express a considerable sense of inappropriate entitlement. I don't care how excellent the can might be, how perfect in every respect down to 0.00001" on everything - if the threads and shoulder aren't absolutely concentric to the last inch of bore, baffle strikes become almost inevitable. Did AAC make the threads on your barrel? If not, blame the machinist who did, not AAC, as it's that shoddy workmanship which caused damage to the can.
a_canadian wrote: if the threads and shoulder aren't absolutely concentric to the last inch of bore, baffle strikes become almost inevitable.
Axial alignment is where the problem usually resides. Concentricity could be off by a decent amount, but any more than about .002" per inch axial misalignment creates a problem. .003" per inch translates to .024" with an 8" can, which is about all the more clearance you'll ever see radially with the maximum bullet diameter a can is rated for.
I turn brass rods to fit the last 2" of bore with 3" hanging out past, and I don't cut until I'm within .0005" radial concentricity and .001" radial runout over that 3" length. I also won't guarantee against baffle strikes if there's less than .040" shoulder, so I do a lot of 1/2-28 threads or custom collars on sporting weight barrels.
Maybe it's just me, but I'm not seeing a baffle strike.
The jagged looking edge you're seeing is the clipping of the baffle. Half of the first bit of the cone is cut off to create the clip. The baffle has 8 pressed in flutes and the cut from the clip cutting into those flutes is what I'm seeing. But maybe I'm just not seeing exactly what you're talking about.
Yeah, I don’t see any baffle strikes. Like Paco said, that’s just the way the baffles are designed. I had a customer at my old shop who had the same misconception. His SDN-6 (precursor to the SR-7) has a similar baffle design. He thought those cuts were baffle strikes when that’s actually the way they’re made.
The baffles in my SR-7 look different with respect to the notch cuts, his have a jagged little thing at the bottom... especially the last baffle in his can and it even looks like it is bent out a bit on the right hand side as you look at it. However, if the bullet really did make those groves then it certainly boltwould have hit the end and deformed the exit hole. So now I think I agree with you but not sure why his notch cuts look so different than mine... I saw a SR-7 blown off the end of a brand new Remington I think it was in 300 Black after the first two shots from the already zeroed at the range that day gun hit the dirt 25 yards in front of a target at 50 yards. Have no idea why it blew off but we told him to stop shooting after the second shot and thought the idiot was making his gun safe when he fired a third time and the SR-7 and adapter went flying into a puddle. He was to inconsolable to answer any questions about how he torqued his mount. He left the range and I never saw him again. His friend said he may have just put the adapter on loosely "until he was happy with the setup" IDK
gsyoung54 wrote:So now I think I agree with you but not sure why his notch cuts look so different than mine...
Either the angle of the picture he posted gives an illusion of being different or AAC has made some minor changes to that baffle design (they made design changes to the SDN-6, so it's possible they did the same to the SR-7). Either, way nothing in the picture the OP posted looks anything like a baffle strike; it simply looks like the notched baffle design that AAC uses in their rifle cans.
You don't necessarily need actual baffle contact for a misaligned can to cause projectile instability. Surface effects kick in with too-close proximity of the bullet to the baffles, such that pressure waves can build to a degree where an air cushion actually pushes back against the bullet, deflecting it slightly. While it may seem unlikely at the kinds of velocities involved from a rifle with supersonic ammunition, one needs to understand that the greater the forces, the greater the effects. For example, think of what's happening when a fighter goes through the sound barrier. The pressure effects on air are so great that often we see vapour clouds condensing out of clear blue sky right at the nose cone of the jet. Imagine that sort of turbulence at the nose of your bullet... then imagine that being right up close to a series of steel barriers. Closer it gets, the higher the likelihood of some very fast kick-back before the bullet has completely passed each baffle, hitting the back end of the bullet and causing it to start tumbling.
I've noted a few experts talking about .22lr and bore size, suggesting that going too tight not only doesn't increase suppression, but considering the powerful cross-bore jetting involved with K baffles there's an increasing likelihood of causing inaccuracy as the bullet gets tossed back and forth while still inside the stack. Opening out from 0.25" to 0.28" and even 0.30" baffle bores has certainly helped accuracy in my experience, without significant increase in noise. Any asymmetry can cause accuracy issues, and while your bore may be adequately large, it could still be a small alignment problem.
"...I've noted a few experts talking about .22lr and bore size, suggesting that going too tight not only doesn't increase suppression, but considering the powerful cross-bore jetting involved with K baffles there's an increasing likelihood of causing inaccuracy as the bullet gets tossed back and forth while still inside the stack. Opening out from 0.25" to 0.28" and even 0.30" baffle bores has certainly helped accuracy in my experience, without significant increase in noise. Any asymmetry can cause accuracy issues, and while your bore may be adequately large, it could still be a small alignment problem...."
+1
Referring back to specs on the U.K. Parker Hale can in 1965 they made the diameter
of the 'snorkel/no_baffles' can 0.30".
For example in the case of the estimable Ray Brandes 1:8 twist S&W M41 barrel I have not heard of any 'wobble' in the 0.28" =>.030" diameter cans ... even with the Aquila fatties.
Sorry for replying to an old post, but I just spoke to an engineer this afternoon from V Seven Weapon Systems. I had requested a 1:5 twist barrel for a 5.625" barrel for 300BLK.
The engineer assumed I was fighting a bullet stability problem that I was attempting to solve with tighter spin. I was just looking to buy a shorter barrel and didn't know that the twist was irrelevant to barrel length.
He told me they've seen issues where bullet stability was a problem out of a silencer at short range, but would clear up at 100 yards. They tested it quite a bit and found the gases were outrunnig the bullet, bouncing off the baffles, and causing a wobble in the bullet. It would stabilize later, but if you removed the can the problem would go away.
They only saw this in cans with asymmetrical baffles. This has me a bit worried, because I bought an SR-7 for my rig and found this thread searching for info on whether the SR-7 baffles were symmetrical or not.
He did mention that during the testing, they'd see the occasional bullet that would just barley contact the can as it exited, causing a flier, but not actually damaging the end of the can.
