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Bill A. and ThunderBeast Suppressors have done some initial testing with the Ultra series cans on 6.5 Grendel.
The 5" Ultra seemed to be the quietest overall when taking the ejection port area and gas vent holes into consideration, since the 7" builds more back pressure. The 7" Ultra of course is more quiet at the muzzle, but louder at the bolt carrier gas vent holes.
Also, a 30 cal can might be the better choice for gassers since the 6.5mm Ultra's are so efficient, they build more back pressure in a gasser, causing more ejection port supersonic gas escape noise.
This is the can I wanted as soon as TBAC revealed the Ultra Series last year. At 7.4oz, you don't even notice you have a can on the end of the rifle.
If you are worried about repeatability, Ray actually won Steel Safari taking off one of their cans in between each stage, where you have to traverse rough terrain between stage locations, then make hits at long range with a precision rifle. Just to be able to place in the match with a rifle intact is one thing, but to remove a suppressor from the barrel after each stage, carry the rifle over distance, re-attach every time, and win the match is simply unheard of.
![[Image: D465_2888_img.jpg]](https://thunderbeastarms.com/photo/ULTRA/tbac430/D465_2888_img.jpg)
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Very interesting results considering back pressure and port noise. I have a TBAC CB9 that is quiet but the back pressure on my 16" is noticeable. I use an adjustable gas block and a Tubbs CWS to delay the unlocking as long as possible. I'd love to try one of the 5" or 7" Ultras!
- PA
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I have a ultra 7 that should be in my grubby hands any day now. But the ultra 5 does look sexy and would be great on my 8" blkout with subs. I have noticed the port noise on my ARs is much louder than the muzzle noise. I could see where the 5" would help this, but its a trade off with port and muzzle. Guess its still pick your poison.
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Any updates? Who's running a TBAC Ultra on their Grendel? My father in law and I are setting up a trust and splitting the cost of a suppressor. The 30. Cal Ultra is at the top of our list. I'll be running it on a 20" heavy (1") barrel .264 LBC and a future Grendel SBR. He has a 300 BlkOut w/16" barrel.
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Very interesting.
Out of interest how did you distinguish between the two sounds; the muzzle and the ejection port?
I was reading recently the results of one of our quasi government pest control teams doing sound trials with a Casella CEL63X sound pressure meter. They used two microphones; including a 165db high-range microphone for high-power supersonic loads. The meter samples pressure very 0.1sec which as you know is still fairly slow given the speed peak pressure waves are generated.
The results at the muzzle and 50meteres downrange were as you would expect.
Sometimes I wonder about these expensive fancy scientific instruments when the trusty 'ear' confirms what the instrument is saying. I guess when you are trying to convince others in a commercial/scientific forum suggesting you 'listened' only goes so far.
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ccasanova Wrote:Any updates? Who's running a TBAC Ultra on their Grendel? My father in law and I are setting up a trust and splitting the cost of a suppressor. The 30. Cal Ultra is at the top of our list. I'll be running it on a 20" heavy (1") barrel .264 LBC and a future Grendel SBR. He has a 300 BlkOut w/16" barrel.
I using a TBAC ultra 7 30 cal. Very light and sounds good.
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LRRPF52 Wrote:Also, a 30 cal can might be the better choice for gassers since the 6.5mm Ultra's are so efficient, they build more back pressure in a gasser, causing more ejection port supersonic gas escape noise.
I just tumbled across the TBAC web site and was highly interested since they are one of the few 6.5 cans out there ...
But I have to ask the dumb question here - gasser = gas piston?
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Gassee=semi. Currently have a 30 Cal ultra 7, might try the 6.5mm soon.
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I wouldn't use the 6.5mm can on an AR15, because it works too well, which means more supersonic noise from the vent holes in the BCG and close to the shooter.
A 30 cal can is best for the AR15 I think. 6.5mm is awesome on bolt guns. TBAC has one of the quietest cans on the market, the lightest, and is the standard for minimal POI shift between suppressed and unsuppressed.
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Do you know if Ray metered the test between 30 and 6.5 ultras?
And I'll probably try both just because I can, I'm also thinking about a 6.5 creedmoor bolt gun, so a 6.5 can would be best.
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I really hate living in Komifornia when people start talking about cans.
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LRR, since you have experience with these, is it worth the extra length and weight getting the 7"over the 5" in 30 cal for the 6.5g ar15? Is it noticably quieter?
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http://osssuppressors.com/suppressors/
This is a new design. As a pilot I understand high bypass fans and this is a new design in Suppressor's which reduces the back pressure. In a 300 blackout it needs it to operate in some models.
Worth a look. I am in the process of purchase 3 of their Suppressor's. 2 Bpr's and Srm 2's with a Ifm7 which is rated up to 300 win mag.
Give it a look.
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LRRPF52 Wrote:I wouldn't use the 6.5mm can on an AR15, because it works too well, which means more supersonic noise from the vent holes in the BCG and close to the shooter.
Would your opinion change if the Grendel was a gas piston instead of DI?
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Okay, finally ran through the ultra line.
[video]https://youtu.be/LJsG_NNOiTQ[/video]
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Proverbial newbie question here. Are the 'forward assist vents' are a gimmick that would exacerbate the noise issue or worthwhile in this case?
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That settles it, I'll use my SDN-6 and not buy a 6.5 can... Thanks for the info!
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wganz Wrote:Proverbial newbie question here. Are the 'forward assist vents' are a gimmick that would exacerbate the noise issue or worthwhile in this case?
Interesting, and never seen it used but what's to prevent gas being forced out of all the other cracks and holes. It's not like the rest of the receiver is now channelling all the gas exclusively out that machined bolt assist hole. Most of the suppressed pressure comes out the ejection port back via the chamber.
You could save yourself some money and drill a hole in the receiver, or take out the bolt assist altogether. The bolt assist hole now points back on an angle so as long as you are not a left-hander it should give you an idea what it would be like.
Personally I don't think it will change enough to be noticed.
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