Insert Sizes and Reballs

[Lord Odin]

I was curious about which insert size would be best for testing using Reballs. For those that aren't familiar with Reballs, they are much smaller than a standard paintball (closer to .679). I have the Freak system with stainless steel inserts, that are exactly the bore size as labeled. Smart Parts also made a Reball insert, which is bore size .670 and supposed the same size as the Reball size.

However, when trying to do the "blow through" test, the Reballs are a VERY tight fit inside of the Reball insert and actually match the .682 insert that I have perfectly. Not knowing which is best to use, I decided to do a test. I took my Reball insert and inserts .682, .684, .687, .689, .691, and .693 to look for a trend in performance. That should range everything from underboring to drastically overboring the Reballs.

For the test, I used my ION, which has a TechT L7 v2 bolt, AKA 2 Liter Plus Dual (not fully broken in), SP 360 QEV, and All-American Apex-ready front and aluminum Freak back. Those are the only relevent mods for consistency for this test that I thought I should mention. I also used the F1 Chrony, which is accurate within 0.5% (or approx 1.4 fps). I used the ION to get the best possible consistency for this test.

Here is the data that I obatined:
Google Docs - Inserts and Reballs

As you can see, the Reball insert outperformed all the other inserts by quite a margin. I used sample standard deviation because 20 shots is too small of a sample to confidently portray as all possible combinations of the performance of the gun and inserts. Using the Reball insert yielded the best standard deviation, range, and experienced the smallest average velocity drop.

The reason I think it does so much better is because Reballs tend to slide easier than paintballs due to less friction. So when given a tighter insert to fit into, it seals up the gap for any gas to escape around the ball without having to worry about getting a barrel break. Even though Reballs are made much better than paintballs and tend to be closer to a perfect sphere, they still have imperfections in them. A perfect ball to barrel match still allows fluctations in the amount of gas to escape around the ball. The Reball insert actually squeezes the ball and ensures no gas escapes every shot. The larger the bore size gets, the worse the consistency it gets.

So those of you using your standard insert, you may want to reconsider and use the Reball insert for testing purposes. I would highly recommend either getting the Reball insert or the smallest bored barrel you can get that is close to a .670.

[scoreshot]

Excellent job Odin.
I'd say that settles the question of ball/bore match relative to consistency.
my friend!

[simmy952]

I use a Python compression system and they make a .670 insert for the reballs. As with paint also, ball/bore match is very important. Nice job!

[Lord Odin]

Originally Posted by scoreshot

Excellent job Odin.
I'd say that settles the question of ball/bore match relative to consistency.
my friend!

For Reballs, I would say that's true. I'd like to repeat a similar test using regular paintballs to confirm CockerPunk's results.

You should try using the Reball insert on your A5, SS, and see if your consistency improves any once you're done with your other tests.

Thanks guys.

[scoreshot]

Originally Posted by Lord Odin

For Reballs, I would say that's true. I'd like to repeat a similar test using regular paintballs to confirm CockerPunk's results.

You should try using the Reball insert on your A5, SS, and see if your consistency improves any once you're done with your other tests.

Thanks guys.

Well, the reballs may be more consistent in size from one to another then paintballs, but unless you used the same reball for every test shot, I believe your data is applicable to paintballs as well.

By using the same reball and same insert for every shot in my tests, I tried to remove the ball/bore match from having any influence on shot to shot and test to test consistency. Cockerpunks consistency data may not apply when using the exact same reball for every test shot. As you know, his recommendations as far as consistency is concerned, was for either an under bore or 1 or 2 steps up from a "blow test" ball/bore match. That recommendation was based on the fact that paintballs vary in size. Therefore the bore needs to be either small enough to disallow "blow by" or large enough to compensate for the size variance of the paintballs to achieve the best consistency. Even tho the .679 insert I used was a considerable "over bore" with my reballs, (more than just a 1 or 2 step up from a "perfect match blow test") it was the same identical over bore for every test shot. As I mentioned earlier, my reballs were a very tight fit in the reball insert. In fact, and as I remember now, so tight that after several shots I could see "scuff marks" inside the reball insert. I thought that the friction and scuff marks may have an inconsistent influence on shot to shot consistency so I used the next larger closest insert, the .679. Theoretically, using the same reball on every shot should produce similar shot to shot consistency regardless of the insert used. (At least as far as ball/bore match is concerned)

I guess my point is that I don't think using the reball insert instead of the .679 will net an improvement in consistency in the context of my tests because there was no variance in the size of the reball from shot to shot.
However, I can see how an under bore, be it paintball or reball, will obviously be more air efficient. My testing however leads me to believe that a tight fitting, dull surface, rubber reball produces a considerable amount of friction inside the insert, possibly more than that of a glossy shell paintball in the same environment.

That said, I believe your tests were very comprehensive and probably conclusive relative to paintballs/bore match/consistency, (not withstanding possible friction/drag issues). It would be interesting to see how using the same reball for your tests would effect the data.

Once again Odin, excellent work.

[Lord Odin]

I'm wondering which really has more or less friction: reballs or paintballs. Under ideal conditions, paintballs seem pretty hard and slick but get them outside and they change. The shells are made of a gelatin, which is a type of food product. Heat and humidity start to get to them and they get softer, which increases the friction coefficient and, IMHO, is the main cause for barrel breaks when bore sizes are too tight. I also think that paintball shells have a tendency to stretch and tear more than reballs. So I'm thinking of doing his tests twice. Once with room temp balls and the other with softer balls that have been outside and in the shade (just like at a field) for a while. Also, I don't know which has more friction against aluminum and steel. Perhaps the materials of the reballs and the paintballs have different amounts of friction. There's a lot of different things to consider between the two and I think the best way to find out is to put them to the test.

Using the same reball is kind of interesting but I'm also worried about wear and tear on the ball. Like you mentioned before, the reball insert you used received scuff marks because of the tight fit. That means the ball left mass on the inside insert. The same thing may be happening with my balls and insert as well but I didn't think to look inside it. If the same ball were used repeatedly with the same tightness, the diameter and shape of the ball may change when shot many times. If that occurred, the performance would change as time went on. I'd have to take a caliper to it before and after testing to see if that is what is really happening.

Great, I got 2 more ideas to test out. LOL.

[scoreshot]

Originally Posted by Lord Odin

I'm wondering which really has more or less friction: reballs or paintballs. Under ideal conditions, paintballs seem pretty hard and slick but get them outside and they change. The shells are made of a gelatin, which is a type of food product. Heat and humidity start to get to them and they get softer, which increases the friction coefficient and, IMHO, is the main cause for barrel breaks when bore sizes are too tight. I also think that paintball shells have a tendency to stretch and tear more than reballs. So I'm thinking of doing his tests twice. Once with room temp balls and the other with softer balls that have been outside and in the shade (just like at a field) for a while. Also, I don't know which has more friction against aluminum and steel. Perhaps the materials of the reballs and the paintballs have different amounts of friction. There's a lot of different things to consider between the two and I think the best way to find out is to put them to the test.

Using the same reball is kind of interesting but I'm also worried about wear and tear on the ball. Like you mentioned before, the reball insert you used received scuff marks because of the tight fit. That means the ball left mass on the inside insert. The same thing may be happening with my balls and insert as well but I didn't think to look inside it. If the same ball were used repeatedly with the same tightness, the diameter and shape of the ball may change when shot many times. If that occurred, the performance would change as time went on. I'd have to take a caliper to it before and after testing to see if that is what is really happening.

Great, I got 2 more ideas to test out. LOL.

LOL,LOL
Just what you needed Odin...more things to do in the limited time you have.
Sorry bout that LOL.
Even with the .679, I was constantly using a barrel swab to be sure the insert stayed clean.

Just received my 2 new Palmers...sweet!