Need help choosing a tightbore
 

Alright I'm actually look for something in a 6.04
My prometheus tightbore seems to have come fucked from factory, looks like someone pulled sandpaper through it. And it's not my BBs because my G3's prometheus tightbore is still good as new. As you can imagine I'm kinda pissed off that I received a dud.

So the options are KM, Systema or Guarder, 363mm. Any relevant input is appreciated :)

PDI 6.01 is the best. Aluminum construction, good QC, slightly better than my Prometheus 6.03.

My KM inners were okay when new, but after the teflon wore off from use, the accuracy went way down. It wasn't that noticeable to the naked eye, but when you use a scope and compare groupings when new versus after 20,000 rounds it was significantly worse even after cleaning.

Systema's are brass, stay away.

Guarder, no experience.

Where would you put the tanio koba's? I've been thinking about puttin on a grooved inner. On my GBB i notcied an incredible increase in acuracy

yea the twist is amazing for accuracy, but its only meant for sub 350 fps, if hes runnin anythin higher then that it wont do him any good

Through no fault of my own, the M4 shoots 396 fps. I put a prometheus hop up chamber on it and it gained 20fps, I'm eventually going to put a weaker spring in but I really don't want to take apart that mechbox until I get new screws...

i have a prometheus 6.03 in my tm m14, ive noticed such a difference from the stock barrel. the shots are extreamly consistant and accuracy is AMAZING but if i could do it over id get a 6.01 if i could do it againe :D
good luck

~Ghost~

So what's the downside to the brass systema barrel?
If I can't find a reputable 6.04 barrel I'll just buy a new 6.03 prometheus barrel.

Brass is a soft metal, prone to scratching. If you were firing steel BBs, this would be a problem. But, the polymer BBs are much softer than the barrel, so I wouldn't worry about it. Stock barrels in most guns are brass as well. They can hold up for many years and hundreds of thousands of rounds.

Stainless is harder, more brittle than brass, and is easily polished. So, it's fine for a barrel material as well.

As an aside, of all the common uncoated barrel materials brass is supposed to have the lowest coefficient of friction.

I'm getting good results with the Deep Fire stainless 6.04mm barrel I installed in my MP5A5, and for about half the cost of a Prometheus.............

None. The 7 year old Systema brass in my AK still shoots like new after I run a patch of Brasso through it and then clean it up with a quick rinse with hot water and a patch with Silli oil on it.

+1 on deepfire

I installed a 6.04 in my BA, and I noticed a great difference over the stock 6.08 brass barrel.

I think that under 6.03 you start to get random scater shots. I don't know by myself, but it seems to be a general opinion.

Ya that's pretty well what I figured, thanks :)
I'm really curious to try out the guarder barrel, but I think I'll go with good old fashioned brass systema.

http://cgi.ebay.com/Guarder-Airsoft-...QQcmdZViewItem
they say brass constructed, wouldn't be surprised if it was coated, but then again whens the last time ehobby made an accurate description? of anything?

Good point. A client of mine wh oI've had a hell of a time with his AEGs and his love of aftermarket parts (Systema and Guarder) is now sworn off those brands due to serious fuck ups and inconsistancies (more his lack of knowledge than anything else). But parts he'd send to to OK, didn't even say overbore or standard, and that was a big problem we dealt with regarding piston heads, cylinders, etc.

"Is this one ok?"

"Well, dunno, last time you bought from them it was overbore"

"How do you tell?"

"Umm, compare side by side is the only way. Cant' tell by pictures and the description is the same for all their parts"

"Shit"

omg love it, i get that a lot too when my friends come to me for upgrading help.

we should write a book :D

madbull v2 are amazing. version 1 where kinda lame as far as accuracy goes but some modification they did to there design now makes them incredible.

I have a KM 509mm (i think might be a different length) in my aug and a madbull v2 in my m4. (cant think of the length right now) even with the shorter barrel the m4 shoots more consistently then the aug. (was the exact opposite with stock barrels.)

Hmm, so those twisted barrels aren't any good for anything shooting hotter than 350? Dayum!

yea, but id pick it above any 400 fps w/ a tightbore anyday. it gives a nice stright flat trajectory, that is very predictable

Ahh, Ok.

How are the 6.01 tightbores, worth the money? Much better than a 6.03/6.04 or is it just a waste of the money?

they are good, but i recommend them for only M4 length AEG's, or spring/gas snipers.

in an AEG there isnt enough air volume for the barrel, so you loose some fps

Continuing the tightbore talk,

Has anyone experienced any problems with hopups not sealing properly (or working as effectively) after a tightbore upgrade.

The outer diameter of these tightbores are the same as stock but with a smaller inner diameter (obvously), thus the rubbers need to be thicker right to make a contact with the bb and seat the bb in place. Or is my assumption incorrect?

As for the FPS on a grooved Tightbore. Is <350fps a hard number or is that 350ish? what happens when you go beyond this 'limit'?. I guess i can shoot .30's or .28's for a FPS reduction.

yes, but we are talking about HUNDRETHS of MILLIMETERS difference, from 6.08 to 6.04-6.01, thats 4-7 HUNDRETHS of a MILLIMETER,

and its not specifically 350 fps, its 1 joule, which is the 350 fps range, it works best around 350, +-10 fps, but will still but is still an improvement within 20 fps

No you can't shoot heavier ammo.

The "Limit" is chronographed with .20g BB's.

Thanks for the clarification. was really helpful.

6.01's are not losing FPS because of airflow... what the heck are you talking about.

It should be the opposite., your have LESS internal volume, so you would need LESS air to push the bb.

Ir reduce FPS because the BB will bounce a LOT more on the inside of the barel, thus reduceing the speed.

It will however help stabilise the flight before exiting.

Best bore is 6.03 under that, you start to lose FPS, above that, the effect can be better.

I am using 6.04.

I just installed a Deep Fire 6.04 stainless steel in my M15 rifle. Works quite well at the short ranges I could try it at indoors. Can't wait to try it outdoors to see the results.

i was referring to the tighter seal that the bb has to the barrel, less air can flow past, so you need more air flow behind it, and with a longer barrel, thats harder to achieve

Referring to your other post, in any AEG you'd GAIN FPS, not lose it.

I've recently put a Prometheus 6.04 into my G3-SG1 and I must say that it is quite an improvement. The new metal body has helped to keep the barrel straight for the first time in a year, so the trajectory is quite predictable.

if you dont believe me, get a 24 inch front end, and put a 6.01 tightbore in it, and crono it.

Make sure you matched the proper cylinder to your barrel if you change barrel length. Other than that, it doesn't really matter what the bore is of your barrel is.

Also to reap the full benefits you need a good quality barrel. I would choose a KM out of the choices you gave. I have heard of people recoating these. Other people buy brass barrels and just use Brasso or some other brass polisher to "refinish" the barrel. Just get the promy barrel. Also did you order overseas or something? Have you tried contacting your retailer about your F'ed promy barrel that lead to this thread?

Just for reference I am using a DBC barrel. Haven't used it enough to see drastic benefits. But it is better than my other setup.

you cant just slap in a bigger cylinder though

You mentioned nothing about putting in a longer barrel. You just said putting it in anything longer than an M4 would degrade performance.

That isn't true.

If you put in a tightbore that's the same length as your stock barrel you'll gain FPS.

If you go too long, you will not have enough air to continue pushing the BB, so the barrel will create drag on it.

Same goes with a loose barrel...

Yea you can.. It's called a "Bore-up"

i ment the extreme cases of psg1 length barrels in a standard v2/v3 box

thats what ive been trying to say!!!!

and about the bore up, how can it be bigger if it fits into the same slot

Sounds like someone needs to quit giving advice on things they have no idea about.

There's lots of them out there for sale. Nearly every cylinder manufacturer makes a bore up cylinder for AEGs. They really do fit.

he said that the bore up is a bigger cylander, and i said how could it fit into the same slot as a stock one if its bigger

Length is the same, but bore is bigger. Usually, they are tapered as well.

Volume = pi x r(squared) x length

And thus the name "BORE - UP" :)

how much bigger are we talking here, a few mm?

we are talking a few 10th of milimeters, multiplied by the lenght of the cylinder, it adds enought air to clear the barrel.

And, reducing bore to 6.01 would need LESS air, as there is LESS leaking around the BB. No the opposite. LESS leak does not mean you need MORE air, quite the opposite.

And the reason why the 6.01 is dropping FPS is because the BB will bounce a lot more times for the same lenght of barrel, and thus will loose a bit of speed. It will however be a lot more stable when exiting the barrel.

The point is that the difference that a 6.01 will make is stability is compromised by the reduced FPS. So the best ratio stability/speed is achieved with a 6.03.

Bore-up kits are simply cylinders with thinner walls, and the corresponding piston head. Reducing the thickness of the walls while keeping the same external diameter causes the internal diameter to rise, thus creating a larger volume.

Most kits are made "taper", meaning the the internal diameter is reduced near the piston head. It helps creating a better airseal as the air pressure in the cylinder is rising.

LESS leak = more efficient = more FPS/longer barrel

i was always under the impression that it was also due that air couldn't slip past the bb as easily, so it needed more air/higher compression.

If your barrel is too long for your mechbox, a 6.01 will cause MORE friction than something like a 6.03 due to the tighness.

If your barrel is the proper length and a 6.01 you'll see vast improvements in range and grouping. (I'm talking about PDI barrels, I haven't dealt with any other 6.01)

The propulsive force on the BB is the air behind it as it tries to escape. That energy it gains from being compressed goes into it leaving the cylinder/barrel, anything blocking it's passage will be pushed out of it's way. If there is nothing blocking then it is free to move and that energy is dispersed into the open.

Try it with a garden hose with a marble and a golf ball. Plug up the hose with the marble (if you can) then turn it on. It'll spit it out at a decent speed but if you jam that golf ball in there you're gonna have either A) a massive structural failure in the hose if your water pressure is good enough or B) a hell of a hole in whatever object the golf ball hits.

i have a db custom one in my CA m15, and its worked out great

So... lemme get this straight, 6.03 is the best overall. I have a M4 that I am gonna probably convert into a DM rifle, so I need a M16 length barrel, will my mechbox be able to handle it or should I get a bore-up kit?

You'd just need a non-ported cylinder AKA an M16 cylinder in your case.

Ok, sweet, all I needed to know.