Barrel band tightening?

Barrel band tightening?

Joined: August 24th, 2007, 2:49 am

August 20th, 2008, 9:04 pm #1

What is the proper way to tighten the barrel band? I would think it would be to tighten the bottom first and lightly snug the top one. Any thought on this?

Thanks,

Mike
Reply
Share

Joined: May 17th, 2008, 1:32 pm

August 20th, 2008, 9:26 pm #2


That is, tighten the barrel screw first,making sure the band is also centered around the air tube(even gap all around). Then tighten the bottom air tube screw.not every Disco barrel is perfectly centered over the tube and I believe the above method prevents any undue stress being placed on the barrel.

I have also had best luck overall with my band placed up front just behind the fill fitting.It's stronger and more resistant to bumps.

Harmonically, speaking, the barrel seems to shoot just as well when the band is placed there..
Reply
Share

Joined: August 24th, 2007, 2:49 am

August 20th, 2008, 9:36 pm #3

and he seemed to think it is better in the original position. I move mine up front and, like you find it more supportive. Tim thought the expansion of the air tube might cause enough movement to cause a POI issue with it up front.

I saw a pic of the prototype FT Discovery on the yellows and the band was up front on it. Just makes sense to me.

Thanks
Reply
Share

Joined: May 17th, 2008, 1:32 pm

August 20th, 2008, 10:13 pm #4

,so I really can't quite understand MAC1's position on that.

I thought at first the original placement was probably better ,but further testing has shown that the gun's grouping ability and POI are just as good when the band is placed at the muzzle- at least on my gun.

As to tube expansion, in terms of radial expansion, it should be LESS just behind the fill fitting as the fitting threads are just under that portion of the tube.

I guess I look at it this way, look at all the great shooting Falcons, Custom QBs and B-50/51 rifles (and others) that have barrel bands up at the front of the tube.

One thing is for sure... it sure is a cheap "mod". Just slide the band forward and try it out.If it does not work, then put it back..Simple and cheap.

A very cost effective learning experience for sure.
Last edited by jimairgun on August 20th, 2008, 10:26 pm, edited 1 time in total.
Reply
Share

Joined: May 3rd, 2002, 7:08 am

August 20th, 2008, 11:25 pm #5

They can be minimized if you take the "cup" off the tip of both set screws and polish the ends.
Reply
Share

Joined: November 17th, 2006, 3:51 am

August 21st, 2008, 1:35 am #6

What is the proper way to tighten the barrel band? I would think it would be to tighten the bottom first and lightly snug the top one. Any thought on this?

Thanks,

Mike
...barely "snug" to the barrel. Will keep the barrel from wandering around too much, but will allow any expasnion/contraction between the gas tube and the barrel to take place.

BTW: Look carefully at the Team Crosman custom guns shown in some posts...that sure looks like a barrel band inletted into the stock right ahead of the receiver (where it would do the most good for keeping the receiver stable)AND a second on out near the end of the gas tube.
Reply
Share

Joined: May 17th, 2008, 1:32 pm

August 21st, 2008, 1:57 am #7

I also see that they have put a SECOND stock screw just under that front band,most likely attached directly to it.

As to the barrel bands I am thinking of getting a custom Blue Fork designs barrel band for a more permanent installation for my front band.

The Blue fork bands are made to tight tolerances in terms of the hole sizes and have a solid web between the barrel and air tube.

I plan to JB weld "glass bed the air tube to the band and then allow the barrel to be a "slip fit" in the band.

Should allow for the tube to expand without affecting the POI much and be a very stout setup for hunting.

Maybe the best of all worlds??
Reply
Share

Joined: November 17th, 2006, 3:51 am

August 21st, 2008, 2:18 am #8

Just glass them to the gas tube (does require you to mark off the area on the gas tube and rough it up a bit to get a good epoxy "bite") and set the barrel as a snug, but slip fit. Haven't tried that on the Discovery (yet).

Will get around to reaming the upper part of the band, fitting eitehr a teflon bushing or going to old-school 'buttons" (like they once used on spring pistons) to make the barrel tight to the band, but free to expand or contract.

Doubt it will make much difference, not real sure there is much more accuracy to get out of my barrel...not complaining, any lightweight gun that can shoot to 1" at 50yards is OK by me.
Reply
Share

Joined: May 17th, 2008, 1:32 pm

August 21st, 2008, 11:58 am #9

ability .I will be doing it so I have some solid and protective barrel support that will allow it tube to move without bearing against the barrel and causing POI issues.

I am glad to hear it is an approach you have used before on your QBs ,Robert.. It makes me feel as though I am on the right track.
Last edited by jimairgun on August 21st, 2008, 11:59 am, edited 1 time in total.
Reply
Share

Joined: October 5th, 2006, 3:26 am

August 21st, 2008, 9:49 pm #10

Just glass them to the gas tube (does require you to mark off the area on the gas tube and rough it up a bit to get a good epoxy "bite") and set the barrel as a snug, but slip fit. Haven't tried that on the Discovery (yet).

Will get around to reaming the upper part of the band, fitting eitehr a teflon bushing or going to old-school 'buttons" (like they once used on spring pistons) to make the barrel tight to the band, but free to expand or contract.

Doubt it will make much difference, not real sure there is much more accuracy to get out of my barrel...not complaining, any lightweight gun that can shoot to 1" at 50yards is OK by me.
It's easier to bore a groove in the top hole of the band and put an o-ring there. It supports the barrel but lets it slide as the tube changes pressure.
Reply
Share