PS90 Owners I Need Your HELP!

Discuss rifles chambered for the 5.7x28mm; P90, PS90, and AR57.
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starfury
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Re: PS90 Owners I Need Your HELP!

Post by starfury » 10 Jul 2011, 16:30

Here is my PS90 (pictures looking forward and reward on the latch hole). I have about 2000+ rds through it. I haven't had any "pop up" issues with any rounds I have fire through it including some of my hotter reloads.

Regarding the bounce weight on the bolt, when I was talking to ninthining regarding this about a year ago I did some spreadsheet calculations with his bounce weight (1.66oz) and it appeared to me that the stock bounce weight is made of an ~ 17 gm/cc machinable tungsten (or heavy alloy) material. Going to the square design will add about 1oz at the same density. Heavier alloys are available up to about 18.5 gm/cc (http://www.mi-techmetals.com/hd-typical.htm" onclick="window.open(this.href);return false;).


As viewed to the rear:
Image

As viewed to the front:
Image
Last edited by starfury on 10 Jul 2011, 19:11, edited 1 time in total.

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Re: PS90 Owners I Need Your HELP!

Post by Buffman » 10 Jul 2011, 19:02

Jay what materials have you tried so far?

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 10 Jul 2011, 20:33

starfury wrote:Here is my PS90 (pictures looking forward and reward on the latch hole). I have about 2000+ rds through it. I haven't had any "pop up" issues with any rounds I have fire through it including some of my hotter reloads.

Regarding the bounce weight on the bolt, when I was talking to ninthining regarding this about a year ago I did some spreadsheet calculations with his bounce weight (1.66oz) and it appeared to me that the stock bounce weight is made of an ~ 17 gm/cc machinable tungsten (or heavy alloy) material. Going to the square design will add about 1oz at the same density. Heavier alloys are available up to about 18.5 gm/cc (http://www.mi-techmetals.com/hd-typical.htm" onclick="window.open(this.href);return false;).


As viewed to the rear:
Image

As viewed to the front:
Image

Well we know for a fact it is Magnetic Stainless Steel. So what out there would be denser?
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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 10 Jul 2011, 20:35

Buffman wrote:Jay what materials have you tried so far?

High grade SS. If I have to get the same type of magnetic stainless the this reducer will be really expensive.
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Buffman
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Re: PS90 Owners I Need Your HELP!

Post by Buffman » 10 Jul 2011, 21:24

Jay do you need sqaure stock or can you can you use round stock? Sending you a PM

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Re: PS90 Owners I Need Your HELP!

Post by ninthinning » 11 Jul 2011, 04:01

I sure hope you can solve the popping mag problem.
9th
Last edited by ninthinning on 12 Jul 2011, 03:27, edited 2 times in total.
God bless John Browning.

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 11 Jul 2011, 10:04

Well I have talked to some folkes. I have a source for the 17-4 magnetic SS and our next batch of reducers will be made of it.

Eric you will be one of the first to get a prototype. Heck I will send you one of the failed SS ones also just to have.
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Re: PS90 Owners I Need Your HELP!

Post by Grantness » 11 Jul 2011, 12:02

oooo free paper weights! :lmao: J/K all of this stuff is fascinating to me, and Im jealous I can't afford a PS90 yet :wall: .

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starfury
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Re: PS90 Owners I Need Your HELP!

Post by starfury » 11 Jul 2011, 20:45

I just pulled my PS90 stock bounce weight and weighed it at 47.2 gms. From the measurements I just took on it (OD= 14.2mm, ID=8.13mm L= 26.04mm) it comes out to 2.78 cc. The stock density is then 47.2/2.78 (gm/cc) = 16.97 gm/cc. This is ~2x the density of stainless steel and very close to the machinable tungsten alloy HD17 (also slightly magnetic). 17-4 PH SS is only ~7.8 gm/cc.

I will have to talk to some of my materials folks but even pure tungsten (which is way too brittle and hard to work with) is at the 18.5 gm/cc or so – not buying much.

What are the external dimensions of your square bounce weight? With that we can figure out what is would weight if using HD17 or maybe HD18 material.

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 11 Jul 2011, 22:43

Well it's stainless and magnetic. I did not do the mass calculations though.

My current rate reducer is .557x1.185 and came out to .03 ounces lighter then the factory reducer. I wonder if what looks like a machined lip inside the reducer is really an insert. Say a tungsten tube inside the 17-4? The 17-4 shell would protect the tungsten.
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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 11 Jul 2011, 22:59

I have a 60x non refracting micro scope and it's hard to tell. It looks like there could be a seam there. The metal is porous, it has turn marks but they look more like they where ground.
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starfury
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Re: PS90 Owners I Need Your HELP!

Post by starfury » 12 Jul 2011, 18:30

I did a quick calculation assuming your reducer dimensions of 0.557”x0.557”x1.185” with a hole down the center that I assume is a 0.32” diameter. If I assume ~8gm/cc for the stainless steel it comes to 1.26 oz about 0.4oz lighter than the factory 1.66oz bounce weight so that is in fairly good agreement with your numbers. Using your numbers, if you made it from HD17 it would weight 2.67oz an increase of 1oz, using HD18 would push the weight up to 2.83oz.

I didn’t look close enough at the surface of the reducer or the transition on the inside (it was too late and I have now put the thing back together) but you might be onto something there… especially it looks more like it is ground that would be a refractory metal like Tungsten or one of its machinables alloys. I have seen many times were they have cladded pure tungsten parts at work but usually using something like a plasma spray prior to a HIPING cycle (we are doing that on CERMET based fuel elements for NTP engines) then centerless grind them down.

Could you take a small magnet and put it on the inside and see how magnetic it is… there is only a few %Fe in the tungsten alloy so it will be much weaker - that might tell you something. Honestly, I believe the HD17/18 alloys are tough enough to handle the abuse of the bounce weight application without any cladding.

Also can you take some pictures of the view through your 60x of the outside clad, the "seam" area, and if you can see any of the ID area.
Last edited by starfury on 13 Jul 2011, 05:17, edited 2 times in total.

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 12 Jul 2011, 22:20

I will try to take a pic. The reducer is lightly magnetized now. Most likely from being passed through one of my strong shop magnets. Using a floating steel needle there is no discernible difference in the magnetic pull on the outside and inside of the reducer.
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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 28 Sep 2011, 11:19

Update, well the new rate reducer is an abject failure.

They aren't heavy enough. I am going to have to order a rate reducer form FNH so I can have it cut lengthwise to figure out what combination of metals FNH is using for them. This will be awhile though since these two sets have cost me almost 3 grand with absolutely no return on investment. I believe they are tungsten cored SS and the only way to verify is be destruction.

Next time you wonder why I or other companies charge 10 dollars for a 1 dollar piece of plastic it's best to keep this in mind and the cost of R&D


FYI I promised some of these if they worked to some member's. Since they don't I am sending out the HD recoil and mag catch springs to them.


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Re: PS90 Owners I Need Your HELP!

Post by f3rr37 » 28 Sep 2011, 18:23

If it helps any... they look nice. :)

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 28 Sep 2011, 20:20

Expensive paperweights.
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Re: PS90 Owners I Need Your HELP!

Post by f3rr37 » 28 Sep 2011, 20:33

If they weigh the same or even slightly more than the factory ones you could have the EA logo engraved and sell them as just replacement's or even novelty paper weights. That way you don't have product taking up space and your recoup some of the R&D costs.

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 28 Sep 2011, 20:48

1.50 each to be laser engraved. At this point with the legal bills piling up they are unlabeled paper weights.

Although I could sell them to full auto guys who want a higher rate of fire.
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Re: PS90 Owners I Need Your HELP!

Post by SoCal Gunner » 30 Sep 2011, 09:34

Engrave one, sell it to me and I'll buy another raffle ticket!

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Re: PS90 Owners I Need Your HELP!

Post by panzermk2 » 30 Sep 2011, 11:24

SoCal Gunner wrote:Engrave one, sell it to me and I'll buy another raffle ticket!

We are about to send out case gauges to be laser engraved. I will send out about 10 of the weights and have them done.
Jay Wolf
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