Q:

Review: Rapid Compact P-Rod bullpup kit

As promised here’s a small review of the compact P-Rod bullpup kit being produced in Spain by our buddy Rapid..

Although I have built my own compact walnut stock for a P-rod I felt the urge for another one.. I figured one in .22 and one in .177 should cover all bases.. :mrgreen:
My first emails to Rapid were to satisfy my curiosity requesting pictures of the trigger set up etc but he did not share this with me.. I ended up placing an order anyway for his “Walnut look” compact kit and he kept me well informed of its build progress and shipping status once sent.

The kit in my opinion is very reasonably priced at $350 USD + postage. With the price you can pick up a Marauder pistol that makes for a very cheap little mid powered multi shot minipup. I will probably keep this one tuned at 13-14ftlbs but the P-rod can be wound up to about 20ftlbs if desired.
Realistically this is a 30-50 yard gun and a great back yard plinker so I dont see any point in tuning it so hot that your shot count crashes..

The package showed up well marked and the kit well packed. No damage and all complete.


The stock is made from Kiln dried (vaporized) European Beech Wood. This timber is stable, resistant to warping, lightweight and easy to work. There are no knots. As I said earlier I ordered the “walnut look” which means this stock has a light walnut coloured stain on it and has been finished with a satin varnish.
The stock is well made and shaped right but could benefit from a little more sanding work before finishing. My stock has a few signs tool burning and “blunt CNC tooling trauma” that tends to chip out some of the grain when tools are dull or the machine speed is to slow. I will fill them back to level with a clear resin and lightly sand the whole stock with 1200 grit paper then give it a coat or two of true oil or similar to satisfy the OCD in me. 😉



Once I had the kit in hand Rapid sent me a word document of instructions to fit it.
After a quick browse through I set to work and stripped the Maurauder pistol. The safety catch needs to be removed and pistol grip requires some major surgery that may not sit well with the guys that buy with “originality or re-sale value” in mind but with all parts including the complete pistol grip available from Crosman at a very reasonable price I soon found myself halfway through the pistol grip with a hacksaw… 😯 I had considered originally milling a new trigger block that was just big enough to retain the trigger components but the hacksaw dulled that urge.


With that job complete I moved onto fitting the small brass gauge extension that drops the gauge low enough to run the trigger linkage “wishbone” parts either side of it.
This is where my first problem came up… the thread on the Marauder gauge and cylinder is 1/8″BSP tapered but the thread on the brass extension is a 1/8″NPT tapered, a non tapered male 1/8″ BSP thread will thread loosely into a female 1/8″NPT but a Male NPT straight thread wont thread into a female BSP. Because the threads on the Marauder are tapered it will allow this extension to be fitted but no matter how much thread tape I put on it I couldn’t get it to seal! I tried 3 different loctite products and even a couple of O rings but it still leaked bad.

I soon worked out that it was bottoming out on the air tube before the “slightly loser” tapered NPT thread could lock up and seal on the female BSP..

I put the part in the lathe and removed about an 1/8″ from above the thread so more of the taper could screw into the cylinder..
With a small amount to thread sealant this did the trick and the “hiss” stopped.

The gauge does sit a little too recessed in its viewing port for my liking which shows a large void and will probably let crap into the trigger parts so I will eventually machine a new extension to bring the gauge almost flush with the stock.

From there I fitted the weaver rail and trigger linkage which as a whole is nicely designed and functions well.


Once the trigger was set up I wasnt happy with the heavy raspy feel to it, I tracked the grittiness down to where the threaded rod runs through the trigger block and washer held under load with the return spring.. the thread rod was grinding up and down the washer which felt and sounded terrible..

…back to the lathe I filed and polished the thread off the accused section and now it runs smooth.

With a bit of fine tuning I now have a very acceptable adjustable trigger. Just dont expect any miracle match triggers from it as it is only as good as the factory P-Rod trigger it mirrors.


The metal parts are well machined and the fit is great, the shroud remains floating within the new front riser mount but it does not have the internal Oring that the factory one has. Again a little more time taken on the polishing before anodising process would leave a better finish at least on the Weaver rail and riser that are visible.

The riser mount and weaver rail are machined from 7075 “alzintok 75”. (Duralumin with alloy aluminium and zinc) and the other parts are 6063-T5 “simagaltok 63”. (alloy: aluminium, magnesium and silicon.) Both materials are up to the job they carry out but the finish on the 7075 parts are a shade of steely blue which often happens when anodizing this harder 7000 series alloy.


Rapid, if you want to get a better finish on these parts you should bead blast them before the anodizing process, this will hide all the machining /de-buring marks and aid a more durable coating also match the matt black finish of the P- rod better.

The last small mod I made was to the rear stock mounting cap screws. The stock is countersunk for the smaller oddball factory dome head screws that hold the plastic pistol grips on but I saw no point in needing a Allen key to remove the front cap screws then a flat head screwdriver to remove the rear screws so I have drilled and tapped the pistol grip frame to 4mm and countersunk the stock with a 5/32″ piloted countersink tool, after a spot of touch up stain I fitted some countersunk cap screws to match the front.




So all in all I think its a great little product and makes a very compact little pup out of a relativity inexpensive pistol.
Well done to you Rapid for an all round nice product that will provide us with loads of fun and nice work on your great follow up service with your sales.
:thumb:

I am yet to sight it and shoot it as I ran out of light while trying to fix the leak but Ill do that tomorrow and group it with a bunch of different pellet to see what diet it prefers. Id imagine it will shoot like every other P-Rod out there and certainly not break any records but If anyone is interested in that I can post a few pics here too..
Here it is all mounted up with some compact Burris 4X glass.



Other BullPups

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Viewing 15 replies - 1 through 15 (of 25 total)

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I also used heavy duty Teflon tape.. Mine was pink roll though. Has held air fine for around 6 months now. Tried the liquid Teflon multiple times before becoming frustrated. Teflon tape worked first try. A forum friend of mine was also having problems with the liquid and used the tape as I suggested, and problem instantly solved.
Here she is now, in all her glory..


Thank you Javier!!

I just built a p-rod bullpup using Rapid70’s kit. Shipping took a bit over 2 weeks. My wood specimen was better than Wingman’s. Everything went together pretty easy between using this guide and Rapid70’s pdf he provides. It is not exactly step by step, but easy enough to fill in the spaces. For the step that Wingman used teflon tape, and Rapid70 recommends liquid thread sealant, I used this http://www.oatey.com/doc/Yellow_Gas_Line_Tape.pdf. Teflon tape is only rated to a few hundred PSI. This yellow tape is rated for 10000psi. It went on quick and seems to be holding well. I bought it at lowes or home dept in the plumbing section.

Before announcing the kits in the forums; I test the kits in my airguns.
To verify that everything is working properly.

In this photo my Marauder Pistol. With “NPT-BSP Hex” that I supply with the kit.
Pressure: 2750 PSI

Kind regards,

Rapid-70

Hello everyone:
As I mentioned here in the forum and emial with Wihgman; all kits I’ve assembled in Spain; neither loses air.
And customers in other countries have assembled the kit smoothly.
As I indicated in the “Tutorial assembly”; you use “liquid Teflon” or “liquid sealant”. And let dry +/- 24 hours.

Kits customers




Kind regards,

Rapid-70

I brought my res with gauge block to a plumbing store and found a metal plug. Worked fine till I got the tapered riser.

Nnnooooo… That would never work… wood to plug a 3k psi tube? 😯

One possible way to go about my build: Custom tube w/no gauge hole. This way gets me a tiny bit more room for air. Then plug the hole in the stock w/the dowel.

The other way to go: Use that adapter from ebay… Would you happen to have a link? 😀

im not talking about the hole in the stock… I’m talking about the hole left in the air tube if you don’t have a gauge in your gun..

Also there’s a seller on eBay who sells a stainless 6kpsi rated NPT adaptor for $9.50 shipped. It looks exactly the same as the one pictured above, but it’s a hair shorter so it makes the gauge perfectly flush with the stock. It’s length is between Javier’s gauge and the other one pictured. It’s the one I bought and used on mine, it also sealed no problem with some Teflon tape.. Hasn’t leaked a wink since.
I can dig up the exact web link if needed.

1″ dowel, maybe a bit larger for a tight fit, glued in, and smoothed… I’m planning on having mine dipped anyway.

Yea, no gauge would be no problem.. Just curios how you plan on plugging up that gauge hole though without one..?

Here’s a weird question- would the trigger linkage be okay w/o a gauge there?

I sent a fitting to a GTA member, but only $8 for part and shipping. I got a few from a Marauder forum member 4$ each who specialized in high pressure systems. 1 wrap of tape and it sealed perfectly. I had to file down the 2 sides that the linkage ran past, it was a little thicker. Wingman you are on point with your review. $360 to my door, so for $700 you can get a SWEET compact pester.

I was also having problems with sealing the gauge adapter. Could not get tape or sealant to work. A GTA forum member was able to find this stainless 1/8″ M&F NPT extension. After shipping total came to about 20 bucks, pricy, but look at the finishing – nice quality part. And it holds air! 😆 It’s a little bit longer than the adapter supplied in the kit so the gauge sticks out a little from the stock, but the fit with the original adapter left the gauge sitting too far down into the stock IMO.

quote Wingman NZ:

For your reference, Crosman use 6061 T6-51 alloy on their guns. It is a slightly lower tensile alloy to your “tooling grade” 7000 series alloy but it has a different mix of alloys so is much easier to anodise and leaves a better matt finish when bead blasted first.

In regards,to your the brass gauge extension, would suggest you look outside of the hydraulic suppliers you have because the bsp to bsp adaptors do exist.. here’s a few I found with a quick search..

http://www.kiowa.co.uk/products/2525-Camozzi-18-x-18-BSP-Male-Female-16mm-Extension-Adaptor-OA-22mm/P00002948/1205

http://www.bestfittings.co.uk/shopdisplayproducts.asp?id=139&cat=1%2F4+BSP+Fittings

There are several ways you could drop the gauge down lower into the stock that would also give the required room for the trigger linkage…
Another way is to use an 1/8″bsp to 1/8″bspT (tapered) coupling into an 1/8″bsp barrel nut:

Either way I think you should be supplying the correct part with the correct threads for the job with your kit to save other customers with less of an engineering background the headache of ongoing leaks. (mine has started leaking again)
You could even supply the same brass extension but with the 1/8″bsp-t male and suggest to your customers they need to buy a new 1/8″NPT gauge.. they are very inexpensive.

As for the finishing work, I totally understand and appreciate the time it takes to have a perfect product, and I think your compromise to keep the customer cost down is very acceptable, however as with all my reviews “I tell it as I see it” so others can judge for themselves if they can live with a few imperfections or attempt slight improvements themselves etc.
Your price and product is good and of above average standards, most of the imperfections would not even be noticed by the untrained eye and in general the fit and finish on my compact pup is very good, again I commend you on this. :thumb:

I have spent the last two days shooting it and Im enjoying it a lot! Its is certainly more fun than a std P-rod in pistol or carbine format and the rearward centre of gravity seems to aid in a steady hold..
The H&N FTT’s at 18ftlbs have proven plenty for smacking the starlings that loiter around my property..

Buy with confidence guys.. right out of the box or with a few small improvements this little pup is a gem.
Rapids service is great and his product is solid.. go buy one..
I know you want one Hoot: :hoot: :mrgreen:

Hi Wingman:
Thank you very much for the info, the aluminum used by Crosman.
And thanks for the information from the two websites hydraulic / pneumatic.
A greeting and a hug,

Rapid-70

quote charlie101:

Hi WingM,
I always read your review carefully and learned a lot from them. Thanks.
I see that Prod only has about 16 good shots.
Do you have any good idea to make the rapid mini to close to Lelya? e.g.
regulated and close to 35 shots? Disco’s double kit and Making mini bullpup for it?

Forgot to ask if SPA will make mini bullpup less than 20″?

Thanks Charlie,
The P-rod is what it is.. it is a cheap but reasonably good quality pistol/carbine and now thanks to Rapid a compact bullpup too.
sure you can mod the crap out of it with a reg, twin cyls and cyl extensions etc but it will never be a Lelya. Enjoy it for what it is.. it will never have the power v/s shot count the Lelya has as the air cyl is smaller, nore will it ever look as cool.. (IMO) if it is the Lelya that steals your heart then put your name on the list…

The factory tuned out of the box .22 P-rod gets 45-50 shots from 3000psi to 1400psi with an av velocity of 640fps (13ftlbs) with 14.3gr pellets, I get about 22 shots with the 14.6gr FTTs at 18ftlbs so to me that’s pretty darn acceptable 😉

Here’s Ted’s take on the little pistol..

http://tedsholdover.com/video/reviews/benjamin-marauder-pistol-22/

As for SPA’s future model plans… your guess is as good as mine. :whistle:

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