Really Tight Bore?

[Papabois]

I was messing with my older KSC (Taiwan) USP .45 today, and I noticed it just didn't seam accurate. I've been wanting a tight-bore barrel for it anyways, so I figured a purchase like that, would improve it's precision.

Then I felt like going inside the gun to look about. I discovered that the crappy accuacy; as of lately, was due to a ripped hop-up rubber. I'll get some soon.

Then I felt like measuring my barrel, just to see how much tighter, a tight-bore barrel is compared to stock. To my supprise, the stock barrel ID is 5.95 (average). After seeing these after-market, tight-bores @ ID's of 6.04, 6.03, 6.01, It just doesn't seem right?.....

Is my stock barrel really that tight?.. I measured a ksc BB...it's 5.89.

Does any of this sound right; cause if so, I don't think I need to buy and aftermarket tight-bore.

[pusangani]

buy some heavier bb's and try that first, cheaper and easier than ordering a new inner barrel, you won't lose much fps going to a heavier weight as you are using a gbb.

[hattrick]

None of that sounds right....


I think the smallest bb's get is 5.93......(made my ksc)
Stock ksc barrles are 6.05 and up IRRC.

[Papabois]

There is a posibility, that the calipers might be off. I'm going to get another pair now.
I will post my findings with the other one soon.

[Papabois]

It's the calipers. Their the cheap Mastercraft, battery version. I remembered that my buddie's is here in the basement, so I switched batteries to his, and this time the barrel reads 6.03. Glad I did not shop for an 6.03 tight-bore... This caliper could be off as well.

I'll try a 6.01 in the future; but before that, hop-up rubbers, and a much more precise caliper set.

[Thenooblord]

6.03 is more accurate than a 6.01

[Dynamo]

Originally Posted by Papabois

There is a posibility, that the calipers might be off. I'm going to get another pair now.
I will post my findings with the other one soon.

basic calipers are not accurate for measuring small inside diameters. the points of contact on the caliper are 4, as the edge is flat. on either side is a surface of about 0.3 to 0.5 mm, so the contact points on either side makes your measurement seems smaller then it is.

[Papabois]

Yes. I see now. The corners touching, giving false info.

To the Dremel...(key oldschool batman tunes).

[Stealthee]

Originally Posted by Thenooblord

6.03 is more accurate than a 6.01

So the higher the better? I've got a KSC USP Compact with stock inner barrel and may change it. Should I get a Nine Ball 6.03mm 77mm Precision Barrel or a KM 6.04mm TN Inner Barrel?


Or is the stock better? (Which I doubt).

[hattrick]

Originally Posted by Thenooblord

6.03 is more accurate than a 6.01

Ummmm I was under a different impression.

Tighter barrels provide better compression which in turn gives you a more accurate shot...


Correct me if im wrong - alex

[Thenooblord]

6.03-6.04 are the best, 6.10 are about the biggest they get, those are stock barrels, they are NOT as accurate, and 6.01 will give better accuracy and more velocity, but not as much accuracy as a 6.04, dont know exactly why, but 6.04-03 is the sweet spot for accuracy

[Kokanee]

Originally Posted by Thenooblord

6.03 is more accurate than a 6.01

When you make statements like that, is would be very helpful to back them up with facts. Otherwise users here will read your post, look left to your join date, and laugh. Not trying to be rude, it's just the way things work around here.

[m102404]

not sure for pistols (i.e. expanding liquid gas systems) vs. AEGs but there was a write up a while ago about optimum accuracy vs. velocity gains with barrel diameters ranging from 6.08 to 6.01 (maybe 6.00).

IRRC 6.04 did result in the most consistent accuracy while tighter did seem to increase velocity.

I'll see if I can dig it up.

This isn't it...but here's some stuff from Redwolf
http://www.redwolfairsoft.com/redwol...il?bulletID=58

Here's another one I read a while ago
http://infectedairsoft.wordpress.com...-inner-barrel/

blow up of pic


Again, IRRC (it was a long time ago), the article I read noted that while "really" tight inners resulted in less blow-by (good for velocity and if everything is working right good for accuracy)...the consistency and "perfectness" of each and every BB was critical and became more so as the inner diameter decreased. Slight out of round and BB diameter variations would cause as much inaccuracy as having a bigger bore...and the upside of a bigger bore is the tolerance to jams. That trade off seemed to favour 6.04mm as a good safe tightbore compromise.

Wish I could find that article again (even though it was posted by just some dude on a forum it was a well thought out piece).

Personally...I just use 6.03 or 6.04...whatever's Jugglez has in stock when I'm buying a barrel . Oh...that's for AEGs. When I'm buying an inner for a race gun GBB pistol...I get a PDI 6.01mm. With good BBs they're soooooo nice. For a 5.1 or 6" custom...hard to beat. Never a problem with BB bastards or Madbulls...but I don't go to the extreme and have the individually foam packed boxes of 100 BBs like Illusion.

And for the last couple of months my field gun as been my go-to gun for CAPS...so the 6.01mm inner works just fine for field use too.

[Twin#1[Op-for]]

Originally Posted by Thenooblord

6.03-6.04 are the best, 6.10 are about the biggest they get, those are stock barrels, they are NOT as accurate, and 6.01 will give better accuracy and more velocity, but not as much accuracy as a 6.04, dont know exactly why, but 6.04-03 is the sweet spot for accuracy

That's probably because 6.03 gives more space for imperfections, since no BB is perfect.

[hattrick]

So I'm not just crazy tired, he really doensn't know what hes talking about.....