One BAD 13xx - My 13xx BLACKOUT is now finished!!!

[jonnnyboy]

That's a very well-thought out and attractive package, Josh.  It's obvious that you put a lot of time and planning into the project.  I think everyone agrees, YOU SUCCEEDED!!!  What a beautiful gun.

joe

[Joshua A.]

Thanks again everyone. I did put a lot of time and money into this project. Its hard to ballpark the price that i paid, because many of the items were items acquired in grip trades, namely the custom shroud, power adjuster, and shoulderstock..

The modified reduced volume valve would consist of the following:
1. boring out the transfer port to the maximum outer diameter while still allowing a .22 pellet to pass by without falling into the valve.
2. Adding an extra item into the valve to take up some volume.
3. A shorter lighter valve spring would be in order due to the extra piece added to the inside of the valve.
4. Re-shaping the valve stem to allow maximum airflow.
5. Fitting a transfer port seal that matches the inner diameter of the valve and barrel port EXACTLY.. This is very important.
6. Polishing the inside of the valve in any area that air will be traveling through.
7. There's no indication that Viton 90 durometer o-rings seal tighter, or add to performance, but what they DO do - is last a *(&^ of a lot longer! You can now pump 15 - 20 - or even 30 times if you want... regular o-rings wont last long if you do this, but if you use the viton 90's they can handle the heat and pressure with flying colors.. Its not reccomended to pump like that on a stock or even modified set-up, but if your valve is pinned like mine, and you have these o-rings, little can really go wrong.

Some of these procedures may seem picky and a waste of time, but if you want to get up over 700fps with a 14.3 grain pellet with the fewest amount of pumps - literally EVERY single bit helps.. procedures like drilling out the flow-thru bolt to match the ID of your transfer port.


drill it so to make it all line up exactly! it really makes a bigger difference than you might think... when you do this. And when you have your top end off of the gun, and the flow-thru bolt foreward and locked down - you should be able to look through the transfer port tube and see straight into the top of the barrel with not even the tiniest obstruction.




Same thing with the valve. If you put the seal onto the valve you should be able to see directly down into the valve - no obstruction. Another very important procedure is to pin your valve... I found that at the higher pressures with the reduced volume valve that the front gripframe screw actually bent a tiny bit allowing the valve to move rearward - therefore pinching the transfer port tube and restricting airflow... No good.. That valve needs to be in there completely solid with no rearward movement. there is a picture of the valve pinning in the photos I originally posted.

Below is a picture of how my valve is set-up for reduced volume. You can see how the valve stem is re-shaped and polished here too. This is a trick i learned from roy at mountain air... every lil bit counts when you're going for full power!! Drill and countersink your valve and barrel with an 11/64 drill bit and countersing with a 1/4" endmill.. this way your transfer port seal will sit completely flat.




Testing by members over at the CAPOF have found that a reduced volume valve can be used to get som nice numbers! The Idea is: that with less volume, the pressure is higher, and with a large enough transfer port and seal, that pressure can send the pellet with some force! I've talked to sever guys that have gotten up over 700fps with a 14.3 gr pellet @ 15 pumps with this set-up and at least a 14" barrel. Even less pumps with a 24" barrel. The main problem I've had is making/cutting/acquiring the right valve spring... I need to learn ow to make the darn things LOL.

Here is what the nylon tubes look like that I use for my transfer port seal. 59 cents at most hardware stores. These are less flexible/more sturdy, and easier to make flat on the ends. The sealing ends of the tube absolutely need to be flat so to make an airtight seal at the valve and barrel ends... This is easily accomplished by cutting them off with a razor blade and rubbing them on a nice new file. you cant do that with the poly-refrigerator tubes.


Some of these mods can also be applied to a discovery, 2240, 2250, 2260or others like them.

ALSO - This information, is all obviously JUST MY OPINION, and is all the results of my observation, and tests. I'm merely sharing it here, I'm not trying to start a debate or arguement. Others may have different opinions or findings, and thats fine. Its all good stuff to me. If there are any other questions please just ask.

Thanks,
J.Austin

[bart the fart]

not sure how i missed this thread? BUT AWESOME work there Joshua! What a sweet looking carbine

[Toolmaker]

 That's a great looking 13xx Josh! Really nice work inside and out. Thanks for sharing all the details with us.

[woogie_man]

Now that is a sick looking set up!!!


What a great source of inspiration!!

[MountainMan126]

Thanks, pics and write up of the valve are excellent.  I have a rifle I need to get a little more out of and this may be worth considering.

[Chortdraw]

Thank you for all the photos and information Josh. This helps more than you can imagine.

[LAalex]

Too cool.

Scotty

[bushbandit]

Too cool! Do you sell grips?

[Izztyrr]

Nice job. Hope that you get many years of safe and happy shooting with it.

[BigErn]

Very very nice.

Ernesto

[Muppit]

up nice airgun and just one more reason why i can't make up my mind on my next project it would be a 13xx or a 22xx but what to start with they are all good and all mod able choices choices choices

[MountainMan126]

I couldn't help myself. I had the stock valve from my pc77 sitting around and a bunch of other spare parts from it too. I think I will take all the internals as far as I can with your photos handy. Add some of my own ideas, when it is done if I like the results, so far so good by the way, I think I will buy a used/refurb. pc77 to put it all in.

Thanks ,
Ethan

[Joshua A.]

Great Idea. A few of us have gotten very very good results with the valve/gun set-up like i've described, the small details really count. I do sell grips and stocks. If you run a search here and on other forums, you'll find hundreds of examples of my work. Especially grips for crosman pistols like 2240, and 13xx. I've made and sold over 100 sets of grips in about a years time. I will have a website up soon hopefully lol, I keep saying that, but I continue to be flooded with grip orders, and haven't needed to make a site yet because once I do that, I can only imagine that i will get that much more business lol.. Anyhow THANKS everyone for all of the great comments, and if anyone has any questions please let me know. I consider it my duty to share my knowledge about these guns, as a lot of it was shared with me in the past. I wasn't born with the ability to build a 1377 lol!
Thanks,
J.Austin

[Millipede]

hey josh, you could try selling on Etsy.com, it's easy to get started and i hear the fee's are cheaper than ebay. its mainly for handcrafted stuff like scarfs and jewelry so youre stuff wouldn't exactly fit in but your grips ARE handmade and it IS a craft, soo... im not sure if they have any policies against "gun parts" either but it could be worth a shot. people sell handforged knives on there so i dont see how they could make a fuss about a couple pieces of wood

[poomwah]

up nice airgun and just one more reason why i can't make up my mind on my next project it would be a 13xx or a 22xx but what to start with they are all good and all mod able choices choices choices

I know what you mean, this one really complicates what I THOUGHT I was going to build, LOL
I am inspired by this one, but don't want to copy it too much, and at the same time, after seeing one this nice, I'm afraid to share mine

[Joshua A.]

Copy it all you want bro lol. thats what the info is there for I've found that you can get a 13xx gun to shoot just as powerful, if not more so than a co2 platform 22xx. Now if you are talking about a 22xx on hpa?? that changes the game altogether. Not to mention all the pumping that is involved with a 13xx.. Thats not for everyone. Doesn't bother me any, but My dad hate it. He won't even consider building or owning a pumper. Either gun is a heck of a lot of fun, but with winter coming up, a co2 gun is not the best idea, unless you live where its warm all year round. If you don't, consider building the 13xx this winter, and save building the co2 gun for spring/summer.
J.Austin

[poomwah]

I think the short  pump on the 1377 is what bothers me. if it had a longer tube and pump, I'd probably like it a lot more.  Not looks wise, but function wise.

[Scooter B]

That thing is sweet!  I haven't been around much, but that thing makes me want to get to work on mine...(it's been in the closet since spring)

[0351_Vet]

Joshua,

Looking good my brotha.......Great post, great pics, great guns.

I would have posted sooner, but.......I dropped my computer

(Now you know, I'm just going to have to have a pair of those fine grips for my 13xx)
You knew that already though.