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Sholo · Veteran Member

Hi guys,

I posted this on a couple of other forums, thought you might be interested as well.
This is my first review of...well...anything, so I will apologize in advance for any/all short-comings or missed information! Embarassed

Let me start by saying that as much as I would like to take credit for machine work, ALL custom fab work was done by Leonardj/Suprmatic (Airguning Canada). My only part in this so far was to supply base gun, new barrel, a multitude of questions/suggestions, and paint, re-seal, re-assemble once I got it back.

I had originally purchased this MK as a parts gun. Mechanically, it was fine (just needed seals), but from a cosmetic POV - it was a wreck! It had been modified by the previous owner with extra holes drilled/tapped for wire stock, scope/red dot(?), plus a couple more that to this day, I have no clue what they were for...Rear sights were missing, the "wings" that locate the windage screws was ground off, a bolt of sorts was threaded into cocking knob, and the "piece' de resistance'" - a hokey looking 2-barrels-made-into-1 setup using a coupler to attach 2nd barrel.IMO, it was FUGLY as hell!

I thought about it for awhile, and seeing as it was already modified/chopped up, decided that rather than use it for parts, it would be a good candidate for an "LD" clone project I had been pondering, and get her back shooting again.

After gun was stripped, the extra, un-needed holes were plugged with aluminum threaded rod (with a bit of epoxy resin applied to the threads to keep them tight), then peened to fill the voids around threads, and finally filed flush with frame.
(photos courtesy of Leonardj/Suprmatic)

The barrel used is just your ordinary, run-of-the-mill Crosman 14" (ScopesAndAmmo), cut down to 12" and threaded accordingly. I would have liked to have supplied a LW barrel, but my wallet said "No can do!" ($15 vs $100+).
Shroud is 7/8" O.D. x 9" long.

I wanted to be able to shoot this all year long regardless of temp, and Co2 just wasn't going to cut it. So...I decided to go the HPA route. Now, having said that, I didn't go HPA for max power/fps (I have other guns better suited for that, plus I don't have an R-PAL), but more for reliably consistant fps (as close to 499.999 as I can get) in all temps. I will be using a 13 ci bottle regulated @ 750 - 800 psi, attached to gun via a remote coil hose.

NOTE: MK I/II frames are made from a zinc alloy. Maximum pressure to be used is 800 - 850 psi. Failure to stay at or below this point may result in serious damage to your gun, as well as a prosthetic hand being fitted where your real hand used to reside! Make sure you have a low pressure burst disc on the downstream side of your reg in case of regulator failure.

In order to attach coil hose, I needed a custom end cap. This was made from an old push button cap, fitted with a mini Foster fitting. Knurling was damaged, so it was turned down and milled to what you see here. I think it looks sweet!

The valve is stock, except for this TP o-ring mod. It effectively eliminates any air leakage that the MK's are known to have between valve and frame. It does make installing the valve a little more tricky, but with a bit of care and some lube, not too bad at all.

Now that I have gun back in my hands, all I have to do is clean/paint, install new seals, re-assemble, and get this puppy shooting again! Cool

Hopefully next post I will have some #'s to show you, along with more pics.

Better get busy...

Thanks for looking, hope you enjoy!
Todd

radar · Silver Status Member

Cool!

SMP · Silver Status Member

Still very very nice

Is that barrel system going to be a tensioned barrel when it gets assembled

Sholo · Veteran Member

Thanks for the compliments.

Yes, it will be the tensioned barrel system. Stock barrel nut and breech retaining nut are used, just longer barrel/shroud.

I'm not exactly sure how the muzzle piece is secured. As best as I can tell, it looks like there is a shoulder milled into the shroud at a depth equal to the length of "bushing" (for lack of a better word), then either pressed in, or epoxied, or maybe both...Same goes for the breech end. Whatever he did, I can assure you that it will NOT budge!!! Makes for a very rigid, one piece unit.

Not sure if it helps, but here is a few pics of the muzzle end (sorry for the poor quality of pics)

^And no... I haven't done the crown yet!

Todd

SMP · Silver Status Member

Perfect

Excellent set up. That should work extremely well.

Thanks

Sholo · Veteran Member

Well...after some quality time with the dremel, and a bunch of sanding/buffing, I finally got all the casting marks and imperfections in frame smoothed out. I then went to see a buddy who had a bead blaster, only to find out he's in Flroida 'till the end of Feb!... Mad

. So much for bead blasting... Rolling Eyes

Took it back home and went over the whole gun with 800 grit wet/dry sandpaper, then washed everything off with Varsol. Each piece was blow dried and painted immediately, before oxidation could start. I ended up putting on 4 coats of Krylon Camo Flat Black. Looks good, but I'm not sure how durable it is. Guess I'll find out soon enough!

The cocking knob, bolt knob, and safety were all given the wire wheel treatment, polished and clear coated for a bit of contrast.

Ready for assembly (and - NO, the barrel isn't bent! Wonky camera angle, or something)

I know I should have let the paint cure for 5 - 7 days rather than 36 hrs, but...well...you know how things go! Gingerly got everything back together without marring the paint, and except for the scope (which I haven't purchased yet), she's pretty much done - for the moment, anyways. I'm using the factory grips for now, but plan on getting a custom set later on.

Ready to test fire.

Comparison of my new MK vs stock. Don't mind the condition of bottom gun, it's my next 'refurbish' project!

I haven't scraped up enough cash yet to place my next order (pump, scope, light kit for chrony, among other things), so for now I am limited to Co2 (12 gr). Good enough for a baseline, plus, I did say that I would show you some #'s.

So with daylight fading, I took a Co2 end cap from one of my other MK's, set the chrony up on its stand (roof of car), and grabbed some CPHP (14.3 gr). Not sure how accurate the numbers are, as it was only +2*C outside. I would take 2 - 3 shots, go inside for 10 min or so, back out for 2 - 3 more, and so on - so take it for what it is. I really need to set up some chrony lights in the basement... Laughing

!

Anyways, here is some #'s from her maiden voyage:
1 - 497.2
2 - 510.4
3 - 519.7
4 - 531.4
5 - 530.1
6 - 538.1
7 - 537.8
8 - 539.6
9 - 539.1
10-536.7

Cool

I am quite happy with the results so far, to say the least. Obviously I'm going to have to "de-tune" it to keep it legal - either by lowering reg pressure, or hammer spring, or both - but not before I try it on HPA in its current configuration (stock hammer/valve springs, reg pressure, etc...) and see what it is capable of...

HPS is less dense than Co2 (therefore flows more easily), so if these numbers are even half-arsed accurate, then... Shocked

Once I get my pump and can actually do HPA, I will do a proper set of shot strings on both Co2 and HPA, as well as some accuracy tests.

'Till then, cheers!
Todd

Sholo · Veteran Member

Well...it's taken forever, but I finally have it scoped and running on HPA! Clap Clap

First thing I noticed was how shaky I am with a pistol! Thought I was having a siezure at first! Her bark is a little more substantial too, compared to Co2.

With the regulator set @ 850 psi, and stock hammer spring, I got 120 shots @ 553.5 fps (avg). Highest=555.9, lowest=551.1. Just for giggles, I tried 5 shots with 16 gr Polymags (heaviest pellet I have at the moment) and averaged 529.1 fps. I'm really happy with how consistent the fps #'s are - max 4.8 fps differential over 120 shots!!!

In order to get to the required sub-500 fps mark, I have a few options to explore:
1) Keep shooting past the 850 psi set point until I reach my goal (495-499 fps), then measure pressure and adjust reg accordingly, or
2) keep reg @ 850 psi, and clip hammer spring 1/2 - 1 coil at a time until goal is reached, or
3) just use a pellet that is heavy enough to get me under 500 fps.

The gun is going to be used primarily for target shooting, so I don't think I will persue option 3. Having said that though, I will try some heavier pellets just to settle my curiousity. If I stay in the 13.5 - 14.5 gr range, and stay under 500 fps, I should be able to add to my shot count.

I think that seeing as I have a couple of stock MK I hammer springs, I may do option 1 first, then do option 2 and compare shot counts to see which one is more efficient - if in fact there is any difference at all. Better stock up on pellets! Smile

As for accuracy, I was pleasantly surprised at how accurate it is, considering it's a pistol (and more importantly - me squeezing the trigger...). Scope I'm using is an NcStar 2-7x32 (10.5" eye relief) sitting in CenterPoint medium height Weaver rings, which, to be honest, is not too bad at all for a $70 scope. I just wish it had a Mil Dot reticle and AO...Scope rail is from a Thompsom Centre Contender (fits shroud perfectly)

Was rainy/drizzling out today, so I was confined to the basement for some sighting in/target practice (10 yards). After practicing different holds, controlling my breathing (which helped considerably) etc, this was my best grouping so far:

Not world class by any means, and granted, it's not at 30-40 yards, but still pretty gratifying for me, who has never been very good with a pistol to begin with!

Out of the 4 pellets I had to choose from (CPHP, CPUM, Benjamin Discovery HP, and Predator Polymags), the Benjamin's were the best, with the Polymags a close second. Can't wait to try some JSB Exacts...

toadmyster223 · Senior Member

Is there a law that limits how fast a pellet pistol can shoot, or are you referring to some competition regulation?

Sholo · Veteran Member

toadmyster223 · Senior Member

Ooooooh, silly Canadians! I was worried my dreams of a high velocity pistol were ruined :P I did see a movie about that hardcore crazy jail back in the 80s or 90s where they just threw you in a cement room and hit you with a fire hose...... I'd want to avoid that too!

Sholo · Veteran Member

Got the day off work yesterday and thought I could get some more testing done, but the dreaded "Honey Do" list kept getting in the way. (Damn list is longer than I thought!)

Anyways, it was after supper when I finally got to work on it Rolling Eyes

. With the regulator set @ 850 psi (all disc springs in place, no shims), it was over the 500 fps limit...avg 553.5, with 14.3 gr CPHP. So I drained bottle, took regulator apart, and removed 1 disc spring, and added 1 thick shim (.020"), which gave me 448-450 fps. Pressure with this set up was 425psi.

Sooo...took reg apart again, added 1 thin shim (.005") to the thick shim already in place, and it shot @ 481 fps, pressure was 525 psi. Roughly a 30 fps gain.

Took reg apart once again (getting pretty good at this now!), added one more thin shim, and shot 506 fps (10 shot avg, 3 fps deviation). Pressure now was 625 psi. Oh, so close!

I want to be as close to 500 fps - but not over - using 14.3 gr ammo so that if I decide to use heavier pellets, i.e: 15.9 gr JSB Exacts, I won't be too far from the 500 fps mark (475?). I think I may leave regulator set at this point (625 psi), and turn my attention to the hammer spring for the final tweaking. I think that I would only need to clip 1/2 - 1 coil in order to reach my goal. That will be tonight's chore after work, then hopefully do a shot string...

Todd

broommaster2000 · Moderator

I like this project. It has my approval and it is relevant to my interests. Mr. Green

Sholo · Veteran Member

Thanks, Broom! Glad you like it...

First off, regulator set point pressures in my previous post should have read 450, 550, and 650 psi - not 425, 525, and 625 psi. Sorry 'bout that...

I decided to stay at 650 psi as this was the pressure closest to 500 FPS (506). I then clipped 1/4 - 1/2 a coil from hammer spring, and landed right where I wanted to be: 492 - 497 fps. Sweet!!!

So...I went for a full 3000 psi fill and subsequent shot string, but had a wee problem when I got to 2500 - 2700 psi:`

DAMN!!!

By the time I got pump disconnected, and bottle attached to gun again, I was down to 2100 psi. Oh well, enough pressure left to compare with the 850 psi set point I originally started with.

Shot#-----High-----Low-----Avg
1 - 40------498.0----492.2---495.1
41 - 80-----494.7----488.7---491.7
81 - 120----491.1----486.2---488.7 *reached regulator set point of 650 psi*
121-132 dropped about 2-3 fps per shot (484.6 - 459.8)

Shocked

I got 120 shots within 12 fps of peak fps (498 - 486, 492.1 avg) using 14.3 gr CPHP as my test ammo.

The same # of shots as a 3000 psi fill @ 850 psi output, but with 900-1000 psi less fill! If my math is right (?) this should equate to roughly 170 - 180 shots in the 492 - 495 (avg) fps range! Cool

I contacted Eric Thursday night regarding fill hose, and had a new S/S braided fill hose in my hands by Friday noon! How do you beat service like that? Thanks Eric, top notch as usual! Thumb Up!

Now to do a full 3000 psi fill shot string and accuracy test @ 25 yards!

Todd

ZipSnipe · Veteran Member

Great job looks good and I like it !!!!!

robert w · Senior Member

i like it kool