How longer and tight bore effects shooting?

[ThunderCactus]

Well seeing as the only difference between your setup now and before is the hop rubber, I would say it's either the hop rubber, or you installed it incorrectly & it's got an air leak between the hop rubber and air nozzle

[m102404]

Shame to take this off track...it was turning into quite a good discussion.

@ problem P90 guy
- you answered it yourself...you've swapped things around to pin it down to your hopup rubber. I'd say that you either have a bad setup of the rubber/barrel in the hopup unit...or a mis-match between your nozzle and rubber. Have you reverted back to a "known-good" setup to reconfirm nothing else has changed? Have you tried this new hopup rubber with your old barrel/hopup unit? Change one thing at a time...observe...repeat if necessary.

Re. BB Weights and speed
I've never really needed to use weights beyond .30's for my setups. For most of the guns I've worked on I've found that 360-375fps with 0.20's seems to be a really good sweet spot for accuracy/consistency...but my two go-to setups happen to be 399fps and 430fps rifles (chronied with 0.20s...but they prefer 0.28's and 0.30's respectively). While there's plenty of generalized guidelines out there...when you get down to searching out that last bit of accuracy and range it really comes down to testing each factor that affects BB flight, and it all comes after a solid compression system. To me that means hopup rubber, hopup setting, inner barrel, BB weight. Those are the three factors that are most easily and repeatably changed for most setups. And the settings are obviously different for one FPS vs another...or one BB weight vs. another.....when one part changes the others have to adjust in some way.

For example. My CQBR PTW shoots a very consistent 397-399fps. I've modded the hopup rubber/cage. At that power level it prefers 0.28's...difference between BBBastards and Madbulls is negligible but I go with BBB since they're local guys. 20's...25's...just horrible flight paths. I can adjust the hopup until it's acceptable, but it's never stellar. 0.30's...it's acceptable but accuracy/consistent shot placement at range almost doubles with 0.28's. A minute change to be sure...but it's there. I can adjust it for 0.30's to be really close to the performance with 0.28's...but I can't be bothered. Setup as it is...side by side it'll hold it's own or outright smoke most bolt guns out there for range and accuracy if I do my part.

If I swapped a m90 spring into the cylinder it all changes...BB weights (usually 0.20's at that power level for CQB...but 0.25's for some places), hopup settings all have to change. I can still get a very good setup out of it...way more accuracy and range than is needed for CQB. But since it's one of my field guns I just leave it setup for 0.28's.

How easy it is to change parts...how consistently they remain as you've set them...how long they last....those are some of the key points to having a good setup. So far as length of barrel...to quite a bit of a reach I'd say that once you're into MP5/M4 length range it doesn't really matter...and past a certain point and it simply adds additional considerations to your build.

[highny]

So in conclusion:
BB has a ideal FPS. The higher FPS the heavier BB you should use. Therefore, high FPS doesn't determine better range and consistency.

So if I did find the idea weight vs FPS with a 650mm inner barrel, the difference would so small it's not even worth it compare to a 510mm inner barrel. When I started airsoft my buddy told me 'Just go the longest inner barrel and highest FPS and you'll snipe like a real sniper!'. Definitely smacking him across the face.

Thanks for all the input. I'll use my bolt action to test out the topic mention here and hopefully come up with a reasonable report before I perform any purchase for my GBBR.

[Styrak]

Originally Posted by highny

Thanks for all the input. I'll use my bolt action to test out the topic mention here and hopefully come up with a reasonable report before I perform any purchase for my GBBR.

If you're using a GBBR the physics of a longer or shorter inner barrel are completely different...

[ThunderCactus]

With a GBBR, using a longer barrel also increases your FPS lol
Remember AEG's and GBBR's are totally different animals. The same physics apply in much different ways.

And to sum up your friend, the typical noob response to range and accuracy is tighter, longer inner barrel and more FPS.
Whereas you can, in fact, get more range and accuracy gains from an $8 higher quality hop rubber and heavier BBs.

[Kimbo]

My VSR, MK23, and PTW all have barrels that are ridiculously short (all under 305mm or 12") for how long they all shoot. In fact, my most accurate guns have the shortest barrels.

I'm firmly in the camp that says the quality and consistancy of the inner barrel as well as the quality and consistancy of the hop up make the the most difference in accuracy.

Typically a good tightbore will be manufactured to higher tolerances which I believe accounts for it's increase accuracy over a stock barrel.

[Warlock]

Originally Posted by Blackthorne

In every other application on earth (rifles, blow guns) longer gives more time under pressure and more stability. I have seen nothing convincing other than the PR on their website to convince me otherwise.

Airsoft is a completely different world and no comparison between airsoft technology and Real firearms can be made.

For an efficient backspin, the BB doesn't touch the inside of the barrel and is floating on an air cushion that is surrounding the BB inside the barrel.

The BB diameter is 5.95 mm and if the inside bore of the inner barrel is 6.03mm we have a air cushion thickness of .08mm wich is the minimum recommended for a good accuracy.

Barrel lenght is matched with the cylinder volume and has no effect on accuracy or range in an airsoft gun.

It is way more important to carrefully match the correct inner barrel lenght and inner diameter with the correct cylinder.

[MaciekA]

Barrel length and bore diameter affect the volume of the barrel's interior, which is supposed to be ideally matched to the volume of the cylinder. That's it.

As Thundercactus mentions the biggest thing here is bore quality (affects laminar flow and turbulence and such) and hopup quality. Once you've got the BB spinning at the speed you need for proper hop, you want to accelerate it to the correct exit velocity depending on the form factor of your gun.

These aren't rifled barrels with spinning bullets travelling through them, they don't operate on the same principles.

This is all pointless chit chat anyway. Once you've got volume matching and compression figured out, you've got one remaining step to ascend to level 12 onion knight: Install r-hop and a super high quality barrel (eg: prometheus).

You won't experimentally achieve anything better, and nobody (to my knowledge) really has. The rest is speculation.

edit: Oh -- and if you're not using heavy and high quality BBs, there's not much point in discussing this kind of stuff. Any comparison testing (and play, really) should be done on quality 0.28g or 0.3g BBs.

[Warlock]

Originally Posted by MaciekA

Barrel length and bore diameter affect the volume of the barrel's interior, which is supposed to be ideally matched to the volume of the cylinder. That's it.

As Thundercactus mentions the biggest thing here is bore quality (affects laminar flow and turbulence and such) and hopup quality. Once you've got the BB spinning at the speed you need for proper hop, you want to accelerate it to the correct exit velocity depending on the form factor of your gun.

These aren't rifled barrels with spinning bullets travelling through them, they don't operate on the same principles.

This is all pointless chit chat anyway. Once you've got volume matching and compression figured out, you've got one remaining step to ascend to level 12 onion knight: Install r-hop and a super high quality barrel (eg: prometheus).

You won't experimentally achieve anything better, and nobody (to my knowledge) really has. The rest is speculation.

edit: Oh -- and if you're not using heavy and high quality BBs, there's not much point in discussing this kind of stuff. Any comparison testing (and play, really) should be done on quality 0.28g or 0.3g BBs.

+1