Tuning a nelson for efficiency

[Drcemento]

Now that my comp is pumping nice and smooth, i took it out and ran a couple 12 grams through it - its cold and wet here ( cali cold anyway )it chrono'd at about 290 -300. i'm getting about 28 shots a twelvy then it drops off dramatically. not bad - I've never gotten either of my phantoms to get more than 30 - but they do drop off slower after 30. my velocity screw is all the way flush with the face of the bolt.

got me wondering about tuning nelson based guns like these - with all the tweeking you can do with say - an autococker and all thats been written about them I don't see much about tuning a nelson, and I've never given it much thought

I have springs - is the principle the same as with a cocker - finding an optimal balance between the valve spring and main spring? anything else that can effect efficiency? is there just not allot of room to move with this platform?

[iamthelazerviking]

There really isn't much to tune on a Nelson. So simple already. Underbore helps. Sadly there aren't really any Nelson spring kits out there anymore aside from what CCI sells for the Phantom. I guess a different kind of power tube can make a difference. Maybe.

[Nish]

https://www.mcarterbrown.com/forum/paintball-news-aa/the-armory/pump-guns-aa/2720-old-nelson-owners-group-info

Start here. About 2/3 of the way down. Lots you can play with when it comes to springs, hammer weight, and valve volume.

One old member here use it use a spent shell. I think from a 45, to make a sleeve in the valve to prevent liquid from getting out. The idea being that since the inlet is so close to the front of the valve the sleeve would block that direct path of the gas and give it more time to expand.

[Chuck E Ducky]

12-14” barrel good fitting paint to bore match. Make sure your bolt tip oring is sealing properly on the barrel you are using. Insure your spring combo is well balanced and the proper stiffness for 12g efficiency. Buy quality brand 12g this makes a difference when it comes to shot count. (I like food grade no oil) Speaking of oil don’t use to much use something thin. I really like outlast. Keep the marker clean this is important for performance and efficiency. Nelson’s will always shoot but they shoot better clean.

After that it comes down to technique, temperature, and elevation. The warmer the weather the faster the 12g will “cook” the deeper you can shoot into it. The slower you shoot the more time allows the co2 to expand fully. This lets you shoot more. Higher your playing elevation is to sea level the less shots you will get out of a 12g.

Co2 is slow to expand. Even slower at cold temperatures. You need to adjust your play style to the type of day you plan on playing in. The colder it is the slower you will want to shoot to hit your numbers. I counter this by chrono down to 280fps. I find it gives me a lil wiggle room if I fire a few quick shots back to back in a gunfight but still allows for a good chance of breaking at range. I prefer to get close with my stock class markers ware I can make my shots count so I’m not taking long range arc shots often so the 20fps hit I take by running at 280 isn’t a big disadvantage and a well placed shot at 280 will still break. I also find the paint flys a lil more true at lower velocity. Maybe it’s just what I’m use to but I hit more of my shots this way. It’s also worth the 3-5 extra shots and helps with those less then ideal conditions.

[Drcemento]

Thanks nish - that’s a good resource.

• one thing he did not describe well is the nylon valve spacer he wants you use - where does it go and what’s the idea behind it? are you just sleeving that over the power tube to shorten he travel of the hammer? 3/8” of an inch is a huge amount? Wondering if that’s more related to the older Nelson’s?

i’ve checked most of your boxes chucky. Got 450 of the good Leland 12 grams from redrock at a great price on someone’s advice here. Outlast is really great lube. Working to get the velocity down a little to the 265 -70 range - that might take springs. Think that will put me in the 30 shot range where I’ll be stoked - its close already. In the heat of battle i rarely get a full 30 out of it - I always get paranoid and change it before a game.

[Chuck E Ducky]

If you are having trouble getting it down around 280 your probably close to your max efficiency. For the particular velocity. That valve is closing as fast as you can get it to. I would look at the bolt tip oring. Is it sealing on the barrel well when the handle is fully forward. On a Phantom you can adjust the pump rod in or out. With the Comp it’s fixed right?

[Nish]

Thanks nish - that’s a good resource.

• one thing he did not describe well is the nylon valve spacer he wants you use - where does it go and what’s the idea behind it? are you just sleeving that over the power tube to shorten he travel of the hammer? 3/8” of an inch is a huge amount? Wondering if that’s more related to the older Nelson’s?

i’ve checked most of your boxes chucky. Got 450 of the good Leland 12 grams from redrock at a great price on someone’s advice here. Outlast is really great lube. Working to get the velocity down a little to the 265 -70 range - that might take springs. Think that will put me in the 30 shot range where I’ll be stoked - its close already. In the heat of battle i rarely get a full 30 out of it - I always get paranoid and change it before a game.

The ones I use are straight out of the local hardware store. Put them in the back of the valve behind the spring to decrease the volum eof air in the valve.

I don't remember the exact size I use but here is a link to examples on Home Depot's site https://www.homedepot.com/b/Hardware...s/N-5yc1vZc2fd

[coyote]

I have owned a few Nelsons in my time.

I had 1 Dye era buzzard that got 47 shots above 245 on a July afternoon with a 30 second wait between shots. This was shooting over a Chrono in my backyard in South Napa.
I can assure you the paint I used was exceptional.

The same marker was good for about 30-32 shots under game conditions.

The moral of the story; potential does not equal real world performance. If you are chasing performance you the player are easier to improve than your marker. The Nelson paint you are planning on ordering will probably be a more practical upgrade than chasing a few extra shots. The inconsistency of 12 grams and playing conditions doesn't make for repeatable results.

[Drcemento]

I agree - but I’ve got time on my hands, a pile of 12 grams and lots of paint and no games to go to, so geeking out is the menu.

[Drcemento]

The gift that keeps on giving - took it out to do some tuning and play with spring and i discovered a very small leak in the valve body where someone had Helicoiled the rear frame screw at some point. Measuring down I think they got a little to close to the center tube and there is a small leak.

How the hell do you fix that one? Anyone ever successfully fill the hole with weld bead and re- tap? - whomever helicoiled it did not do that great a job and the top of the helicoil is loose. Might have punctured it with the tip of the tap when they should have used a bottoming tap.

[Chuck E Ducky]

You my friend need a thread insert. Carter’s are notorious for striped threads. Because your stainless screws thread directly into soft aluminum. It’s an easy fix if you have a drill press and or steady hand. You will drill out the old hole re tap to larger size of the insert and red lock tight a new stainless threaded insert in its place. I have done a few Carter’s and it’s the only way to properly fix them for good. Basically what Mike did with the phantom. You can order various sizes from Mc Master Carr depending on what you need it’s possible you can use a Phantom one as well. The Helicoil is a Kind of a half ass way of fixing the true issue. Get a thread insert lock it down with some good thread locker and you will fix it forever.

For reference these are what you are looking for.
https://airsoldier.com/product/cci-s...hread-inserts/

[Drcemento]

thanks chuck - i came across them on mcmaster and was going to ask if that was the key. looking at my phantoms, mike had the right idea!

the catch here is the leak from the bottom of the tapped hole. taking some quick measurements the insert has 5/16" length, which is almost exactly the hole depth. hoping what I can do is drill and tap the insert, then loctite a 10-32 plug in the bottom, and still have the thread i need to hold the grip frame to the marker. certainly worth a shot!

the only other option would be a stainless plug made from threaded rod, then drill and tap that.... have a feeling that wont be as easy as it sounds.