[Legacy]

Originally Posted by painter4life05

I have .680 and .685 backs, not much else is needed now a days.

I for sure wouldn't rebuy any of those bigger backs, I bought those back 15 years ago and just hung onto them. I bought the .684 and .686 in the last couple years when I started playing again.

[UglyDuckGizmo]

I would love to have a .696 dye barrel.

[Mr. Charlie]

.696?!

That’s huge?

I’ve seen .695 UL backs...

[Pump Scout]

Originally Posted by Intern1

Interesting that the inserts are in increments of .002". I remember hearing backs and inserts had a greater tolerance than that.

It's always struck me as amusing that paintball players will buy things for the sole reason that the item(s) appear to be better. You're right, tolerances of .001 and .002 are pretty common. That means that a back or insert size claimed at .680 could be .681 to .683, and a .682 back/insert could be between .681 and .683. So even at the tightest tolerances, any two adjacent sized backs could be exactly the same bore, and that's assuming they're made well. Sloppy or out of tolerance manufacturing can be quite a bit more off.

That said, this looks to be a modern-looking barrel with the things a lot of players are looking for in a top level barrel. I'm sure HK will put many of these onto guns.

[Paul77]

Originally Posted by Pump Scout

You're right, tolerances of .001 and .002 are pretty common. That means that a back or insert size claimed at .680 could be .681 to .683, and a .682 back/insert could be between .681 and .683. So even at the tightest tolerances, any two adjacent sized backs could be exactly the same bore, and that's assuming they're made well. Sloppy or out of tolerance manufacturing can be quite a bit more off.

and to add to this, thats at 21 degrees c (all quality machine shops are kept at a stable temp for tolerances) any temp higher and the bore will start to grow 1-2 thou and the opposite for lower temps.

so an insert marked 680 thats on the high side of tolerance at 682 could become a 684 when the temps get into the 30's.

this is why i think all we need is 670,675,680,685,690,695 at the most. 5 thou is like 2 human hairs

[tweeter4]

Originally Posted by Paul77

and to add to this, thats at 21 degrees c (all quality machine shops are kept at a stable temp for tolerances) any temp higher and the bore will start to grow 1-2 thou and the opposite for lower temps.

so an insert marked 680 thats on the high side of tolerance at 682 could become a 684 when the temps get into the 30's.

this is why i think all we need is 670,675,680,685,690,695 at the most. 5 thou is like 2 human hairs

This is why these types of kits didnt make sense to me. Still the best size range for me is .675, .680, .685, .687 for the modern paint.

Aluminum inserts that are .675 in a 70* climate will shrink down to .671 in the winter when it is 35*. Same as it will expand up to .678 in temperatures in the low 100s.

This is why these kits being this tight in sizing are nonsense. (If made overseas) these likely have a tolerance of .002-.005 depending on the quality of the shop, meaning that your .685 can actually range from .680-.690 and still be sold to you. Then from summer to winter you will have roughly +/- .002 at a minimum in thermal expansion. So your .685 you started with can actually be getting used with .678 paint and still give a good match in certain conditions.

To be honest, this large range in insert size they offer actually may be beneficial, because you are all but guaranteeing you will at least have one insert that is a good match based on ****ed tolerances and current temperature regardless of what the printed on size actually is.

[tweeter4]

Originally Posted by Mr. Charlie

.696?!

That’s huge?

I’ve seen .695 UL backs...

lol. Honestly anything above .689 at this point is just silly wasted money. There isnt a paint on earth right now that is boring above that consistently.

[Legacy]

Originally Posted by Mr. Charlie

.696?!

That’s huge?

I’ve seen .695 UL backs...

It was custom bored out for one of the Aftershock guys back in like 2002 or so, at least that's what the guy I bought it off of told me. It started life as a standard .688 unmarked ultralight back and it was bored out and left raw aluminum in the bore. It came with a gun I bought. Sold the gun a long time ago but kept the back because it was kind of interesting. I've been thinking I should just send it out and have it freak bored since it'd worthless and I can't imagine it's all the collectable. I might as well get some use out of the thing.

[BMJoker]

Honestly, looks like something that checks a lot of marks if I was in the market for a new barrel system. Especially on length.

[Jordan Hart]

Looks like a nice kit. I'd like to see some readings on a sound meter to see if those slot ports make a sound difference. Quietest barrel I've ever shot is still a JR3 tip (ancient tech) on an ultralite back, and it has tons of porting. Either way it looks unique.

[RFP Professor]

Well, it looks cool, which is as good a reason as any to buy a barrel kit I suppose.

[BradJohnson]

I love how they are doing 15in!