Suppressed Vs, Unsupressed: Is Velocity Lost?

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jgreenberg01
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Suppressed Vs, Unsupressed: Is Velocity Lost?

Post by jgreenberg01 » 17 May 2012, 04:37

Thought this might be interesting to some of you.

I had posted some youtube videos a while back about POA/POI shift when using a suppressor and it led to a bunch-o-questions from viewers as to whether or not using a suppressor would lower the fps of the round being fired. Most people were adamant that it would. I wasn't so sure, but I wasn't about to go spouting off because I hadn't actually tested it. I figured I would give it a try. While this is certainly not a definitive answer - I only tested two rifle rounds and two pistol rounds suppressed & unsuppressed - it was certainly an interesting result.





Summary:

AR57 (12"sbr)

SS197 40gr VMAX 5.7x28
Unsuppressed 1986fps @ 350ft-lb
Suppressed 1983fps @ 349ft-lb

Elite Ammunition 40gr VMAX 5.7x28
Unsuppressed 2350 @ 491ft-lb
Suppressed 2361 @ 495ft-lb

FNP-45 Tactical

Remington 230gr JHP .45acp
Unsuppressed 797fpf @ 325ft-lb
Suppressed 847fpf @ 373ft-lb

Federal Hydra-shok 230gr JHP .45acp
Unsuppressed 855fps @ 373ft-lb
Suppressed 905fps @ 419ft-lb

In every case except the SS197, the suppressed round was faster than the unsuppressed round. And the SS197 difference was too close to be significant. Now I'm wondering... does the suppressor have the effect of making the barrel longer? The pistol difference was significant and certainly suggests that.
Last edited by jgreenberg01 on 18 May 2012, 04:09, edited 1 time in total.
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Re: Suppressed Vs, Unsupressed: Is Velocity Lost?

Post by Esteves » 17 May 2012, 05:03

"Freebore boost" is the term that's used to describe the effect.
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Re: Suppressed Vs, Unsupressed: Is Velocity Lost?

Post by Rapier1772 » 17 May 2012, 07:00

I too did some testing about this with reloads on May 11 & posted it here: viewtopic.php?f=19&t=5715" onclick="window.open(this.href);return false;

No set result really, it depended on the load - some were faster & some were slower.
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Re: Suppressed Vs, Unsupressed: Is Velocity Lost?

Post by jgreenberg01 » 17 May 2012, 07:30

Thanks for sharing, I never would have seen that because it's in the reloading section. That's quite a bit of data you gathered too.

It just dawned on me that I should have included 5.56 rounds as well to see if a 16" barrel makes a difference. 5" barrel was substantially faster suppressed, 12" barrel was marginally faster (or about the same with SS197) - I wonder if adding 4" will change anything (yeah Blue, I knw... TWSS)?

I will try it next week with 2 or three different types of ammo as a follow-up.
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