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Bullpup Rifles (Auto & Semi-Auto Centerfire) => P90 / PS90 P90 icon => Topic started by: 300winmag on August 09, 2017, 04:14:18 PM



Title: How much velocity is lost when converting to an SBR?
Post by: 300winmag on August 09, 2017, 04:14:18 PM
Anyone have any confirmed data* on how much velocity is lost when converting a PS90 to an SBR?

*confirmed via chronograph.

Eric B.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: 300winmag on October 12, 2017, 10:31:03 PM
FOUND IT!

Wikipedia, in their 5.7 x 28 article has a chart that shows the SS197 (the current blue tip V-Max FN round) has a muzzle velocity of 1,0950 ft./sec. from a P90. A footnote to that chart says there is about 150 ft./sec. more velocity from a PS90.  So you're pretty close on that guesstimate.

Eric B.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: pilot4prophet on February 18, 2018, 01:18:32 PM
Buffman Range on YouTube does a lot of 5.7x28 chrono and gel testing. Check it out. From what I've seen it's about 150-200 FPS loosing 4" of barrel.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: 300winmag on May 26, 2018, 01:29:48 PM
That's actually a lot of velocity loss for a "handier" PS90 and a tactical look. What I like about the PS90 IS its god range.

This velocity loss is the main factor making me hesitate to get an SBR. I'm a long range rifle competitor and that kind of loss in a centerfire rifle is quite a bit. Maybe that's why I am so sensitive to this.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Hkbeltfed on May 26, 2018, 07:03:47 PM
The PS90 is a derivative of the P90, so one could argue it should be a SBR. Needs for a longer barrel/bigger gun are better addressed with a X95 or AUG in my opinion.

Current PS90 SBR owner as well as a X95 and AUG, both pinned and welded and slightly over 26" each.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: pilot4prophet on May 27, 2018, 08:03:46 AM
To be fair, the 5.7x28 was not really designed to be a long range killer. I've got my SBR sighted in for a maximum PBR of about 225 yds. I really don't think I'd take a shot over 150. If the expectation is big trouble then a full power rifle is the answer.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Dwill on June 23, 2018, 09:15:47 PM
The 5.7x28 was designed for the P90, which was an SBR in the first place.  The longer barreled civilian PS90 came later.  Any extra velocity from the longer barrel is just an incidental benefit.