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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.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Andygold on January 25, 2019, 04:46:55 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.

Looking at the number above, there seems to be a mistake.  The SS197 coming out of a P90 has a muzzle velocity of 1,950 fps, not 1,0950 fps as posted.  Big difference an extra zero makes in the wrong place.  Just wanted to set the record straight.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: whiskey91lima on January 25, 2019, 05:42:59 PM
1,950 fps is so low to begin with. The P90 was only designed for QCB range. I doubt that 150 fps is worth making the rifle worse for QCB maneuverability. 2,100 fps ain't something to be proud of either compared to 5.56 chambered rifles.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Andygold on January 28, 2019, 05:02:16 PM
1,950 fps is so low to begin with. The P90 was only designed for QCB range. I doubt that 150 fps is worth making the rifle worse for QCB maneuverability. 2,100 fps ain't something to be proud of either compared to 5.56 chambered rifles.

Agreed that the P90 was designed for CQB.   In regards to bullet velocity...this isn't a 5.56 chambered rifle...It's a 5.7x28 chambered PDW.  It's not designed to compete with a main battle rifle!  For zany comparison sake, compare it then to a 9mm pistol for example, using 147 gr. bullets where you only get less than 1,000 fps.  You could then say that the 9mm is no 5.7x28mm chambered PDW.  What I'm getting at is that they are not competitors and can't be compared as competitors.  What I can say is that I can keep 50 rounds of P90 on a 10" pie plate at 50 feet with a single pull, while I cannot do the same with my AR.  2,000 fps of accurate shot placement has to count for something!   ;)


Title: Re: How much velocity is lost when converting to an SBR?
Post by: jaflowers on March 06, 2019, 05:37:45 PM
Also remember, the SS197 is very watered down ammo. It'll kill varmits and such easily, even seen successful hog and deer videos with it, but you can get quite a bit more out of specialty ammo or handloads. My own loads have a 36gr Barnes VG getting out the barrel at almost 2700 fps, a considerable improvement over the factory offerings.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Andygold on March 06, 2019, 06:18:47 PM
SS197 may be "watered down" ammunition as you say.  With that in mind, it along with some SS192 was used by Nidal Hasan to kill 13 and wound 30 at Fort Hood back in 2009.  And, that was with a 5.7 pistol, not a 16" barreled rifle.  Even an SBR-converted PS90 is going to have a barrel well over twice as long as the 5.7 pistol which caused so much death and injuries.


Title: Re: How much velocity is lost when converting to an SBR?
Post by: jaflowers on March 06, 2019, 09:28:12 PM
SS197 may be "watered down" ammunition as you say.  With that in mind, it along with some SS192 was used by Nidal Hasan to kill 13 and wound 30 at Fort Hood back in 2009.  And, that was with a 5.7 pistol, not a 16" barreled rifle.  Even an SBR-converted PS90 is going to have a barrel well over twice as long as the 5.7 pistol which caused so much death and injuries.

Oh, I'm very aware. The abilities of the cartridge is one of the reasons I've become a true fanboy. Three FiveSevens, two PS90s, an AR57 and custom 15" Encore...... :)


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Andygold on March 07, 2019, 08:47:56 AM
SS197 may be "watered down" ammunition as you say.  With that in mind, it along with some SS192 was used by Nidal Hasan to kill 13 and wound 30 at Fort Hood back in 2009.  And, that was with a 5.7 pistol, not a 16" barreled rifle.  Even an SBR-converted PS90 is going to have a barrel well over twice as long as the 5.7 pistol which caused so much death and injuries.

Oh, I'm very aware. The abilities of the cartridge is one of the reasons I've become a true fanboy. Three FiveSevens, two PS90s, an AR57 and custom 15" Encore...... :)
👍


Title: Re: How much velocity is lost when converting to an SBR?
Post by: Zeiram3f on March 08, 2019, 05:33:09 AM
Iíve taken two whitetail deer with my PS90 SBR. Itís surprisingly effective. Both were taken between 60-80 yards, no further or closer. The wound channels were unlike that of a battle rifle and actually quite ehhh... impressive and unusual. Personally, I plan to hunt with my MDR from here on, but am sold on the 5.7ís capabilities.

I used SS197 but intend to switch to something hotter fairly soon.