size does matter

[chicago]

I need some help. Not trying to stir up controversy here but I'd like people's opinions, input, and observations on "bore size." I'm specifically think of the riffled barrel size as it relates to First Strikes.

This all came out the other day when I said to VooDooAddict, "I should have known that HammerHead was going to be more accurate. They have a bigger bore and I've seen charts and graphs showing that over boring makes a barrel more accurate." To which he responded, he thought it was just the opposite, "under boring" (making the barrel bore size smaller than the round) makes it more accurate. I believe Wolfen believes in under boring as well; but, I'm not trying to put words in his muzzle.

Your opinions please. To me, logically, deforming a round before it even has a chance to escape the barrel tip is just asking for trouble. Anyway, if anyone knows about those bore tests, could you please provide us a link!

My posse says its a myth, "size doesn't matter...it is knowing how to use it, that's what important!" MajorGhost, what's your opinion? "Does size matter?"

[Allu]

well I dont have any hard facts, but when it comes to normal paintballs I get the feeling that its like applying ballistics to a water balloon, sure it will affect it in different ways, but predicting it can be tricky, for example i have gotten the feeling that a progressive spiral porting seems to infuse some kind of stabilization to the trajectory, and a good fit without under or overbore will result in more consistent fps, and thus accuracy, since accuracy is about repeat-ability in a predicted manner.

When we move over to the first strikes, we enter a realm of slightly less deformation, and a lot of "real bullet" effects
(and yes, for all intents and purposes I am aware of that real bullets are a different zipcode, but we'r starting to enter the same country)

Therefore i tend to lean towards the under boring theory, for without it, the spin of the first strike is induced in the air (I'v heard that it would be the first 10 or so meters) as opposed to already having spin when exiting the barrel.
This in turn translates to a more stable trajectory in the beginning, witch in turn translates to less spread the further out you go(small deviation in beginning= large deviation in the end)

This does however demand consistency... Each round should be the same, and the under-bore should not be s big a to slow down the round in a random manner(under-boring will slow the projectile down(so you crank up the pressure to achieve desired fps) but it will do so in a consistent manner). Over boring again defeats the purpose of rifling. Unless the air escaping along the rifling will induce a spin to the projectile, but then we enter a realm of the effect of how the air escapes in porting, and how different lengths of porting affects the projectile, this is unfortunately out of my comfort zone, and my opinions on the matter are iffy.

Just my two cents

[Wolfen]

Underboring normal paintballs or first strikes will be more accurate because you get a a consistant push from the air and the trajectory gets lined up in the barrel as opposed to once the round stabilizes in flight. When overboring the round will bounce from side to side which can give it a odd spin. also the air flow pushing the ball forward will leak inconsistantly past the ball thus giving it "pushes" from all sides. Also unlike common belief overboring will actually make your fps less consistant and your marker will need more air/co2 for the fps then if you underbore (unless you overdo underboring ofcourse.) Now is it a huge difference? depends on the size of the rounds as well as the bore itself.

Now if you want to be specific about the lapco rifled barrel it's fairly extreme underboring, BUT i have yet to see a single barrel outperform it. imo the biggest problem (though i understand why they did it) is that the lapco/tib rifled barrel is a bit too long, which leads to alot of drag, thus in turn means pretty damn poor efficiency (i do get around 120 shots out of my 13CI though so for me that ain't an issue). I think the optimal rifled barrel for shooting first strikes would be one build like the lapco/tib but be either .684 or .685 and be only 10", why not 8" you might ask? well i believe (after doing alot of tests) that you will need atleast 10" for the rifling to get a good enough spin on the round.

Since i've never shot a Hammerhead barrel i can't really comment on it. From what i've read and seen though it does seem to almost match the lapco in accuracy, but will far outperform it in efficiency. I did read a very very thorough testing of the HH vs Lapco and the milsig rifled. All his tests show that at 40m the lapco and HH is almost identical (only a 4% difference in pattern spread) while the milsig was slightly more inaccurate. However what his test also showed was that the lapco barrel will keep almost same pattern spread when moving to 50,60,70,80m (something i know for a fact that's true, i only have about a inch difference between 40m pattern and 60m pattern). The HH however started losing more and more towards the lapco the further away you get (you guys that have both have you tested it? would really like to know if it's true since im still fairly interested in picking up a HH). at 70m the pattern spread was over 50% bigger then with the lapco. Now if this is true i dunno. BUT if it is true then im fairly certain it has to do with the fact that the HH is slightly overbored and the rifling might to engage fully.

Bottom line is YES bore size does matter and WILL affect accuracy. But going really extreme underboring is still a really bad idea (im talking about shooting .685 paint through a .679 bore) since at some point the drag will be so great that accuracy will fail (or you'll chop more then a woodcutter)

[chicago]

Soldier of Fortune over on Tiberius forum provided the first link from Punkworks over on TechPB. Appears they have have done extensive testing. This is their conclusionary video on barrel accuracy/ consistency.

www.youtube.com/watch?v=197yZ859h74[/QUOTE]

I watched it all the way thru as well as this one:

www.youtube.com/watch?v=mpUTWDY5NFE&feature=related

And, this one"
www.youtube.com/watch?v=NwN03gMASew&feature=related

My problem with any of them is they are talking about round paintballs. And just as I'd agree that a bullet is not a paintball; I'd like to say that a first strike is not a paintball either! Not not really. They do not "deform" the same and they have fins and spin. So, from my observations/testing, I believe larger riffled bores are more "consistent" than underbored riffled barrels when comparing them with first strikes only. Strangely what I got out of the videos is - that it is the same/true for paintballs.

Let me summarize what I got our of the vids here: Actually matching the bore size to a paintball is the worst thing you can do. You should be overbored or underbored. Which was surprising to me (let's say it was counter intuitive).