Foot long Grendel

[bwaites]

You're lucky to get 10-15fps suppressor boost.

Interesting, I would have thought it was more than that. From what others have said, its close to 2-3 inches of suppressor equal 1 inch of barrel. Not so much, though?

I yield to superior knowledge!

[lou400a]

Next time I'm out I'll measure with and without. I was in a hurry today to get her dialed in.

[LRRPF52]

If it's on a longer barrel, you get very little suppressor boost. I haven't chrono'd SBR's with and without, but I called Thunderbeast for some definitive information on it, and they have only seen a negligible fps increase.

With a .30 cal can on a smaller bore blaster, I would imagine there isn't much boost at all, but it would be interesting to see with and without in this case with the 11.5" SBR.

[Variable]

I'll have to go back and dig, but I got more boost than that with my AAC 762SD.

[Variable]

Nope, I was mostly wrong. I didn't get much more boost than your stated 10-15fps.

My averages for 10 shot strings with Factory 123 Amax out of my 10.5" barrel were:

Suppressed: 2198fps
Unsuppressed: 2179fps

So my boost was a whopping 19fps with Hornady factory 123s shot through an AAC 762SD. A tiny bit more, but not much.

I'd swear I got more boost with something Grendel, but I can't find the numbers if I did.

I had another string with the same setup going an avg. of 2214fps suppressed, but that was on a different day and in warmer weather. I didn't fire an unsuppressed string, so that data is pretty useless.


Me:

[Variable]

Well I went to test fire my new stick today and since I'm waiting on a bolt I've robbed one from my Beowulf.
First I've bore sighted at 50 yards and zeroed the scope with four shots while adjusting the gas block. I've been using JP adjustable gas block on all of my builds, but on this build I've tried SLR clamp on adjustable gb. Here's a link: http://www.slrrifleworks.com/index.p...&product_id=74
It uses spring loaded detent that will not move out of adjustment. It was a piece of cake to set it up and I like it so much I'll probably replace it on all of my rifles down the road.
At 100 yard line I've re-zeroed the scope w/suppressor on and chronoed some loads.

123gr Amax: 11.5" Sabre Defence - 2348.8; 17.5" Satern - 2535
90gr TNT: 11.5" Sabre Defence - 2450; 17.5" Satern - 2733.3

These were factory loads and the 11.5" SB barrel was suppressed w/Tornado Technology suppressor. I've used the 17.5" Satern barrel for comparison, but it wasn't suppressed.
This will get me 1,000 ft/lbs at 250 yards w/123gr Amax. Look out coyotes and whitetails!
I've only put 30 rounds down the pipe, but it was without any malfunctions and I'm extremely happy with the rifle and its performance so far. 9 round sting of 123 Amax under 2" with a bipod with few 3 round shots under 1" with 6x scope
Let's get some fur!

Boosted/Unboosted issues aside, what type of chronograph are you using? Distance from your muzzle (or suppressor endcap) to the skyscreens? Temperature?

Not saying that your chrono didn't report those numbers, but they do seem inordinately high...

[lou400a]

CED M2, 8' about 82 degrees F.

[Variable]

CED M2, 8' about 82 degrees F.

I use 15ft. FWIW. Too close can sometimes give you screwy numbers because of muzzle blast. I'm not saying that happened to you, but it's worth checking perhaps.