Tuning HW90 barrel droop

[Hateful McNasty]

Hi, I know what you mean about balancing the straight edge. That's why I finally got that Wixey electronic level. It's got a magnet which just snaps on the barrel and cylinder.

I was looking at Hateful McNasty's post above. He used a pair of levels. Good idea! So I tried an old line level.
First level it on the cylinder, then move to the barrel block, and then the end of the barrel.

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Holy Moly!

Two key observations.

• The bubble is the same on the barrel and barrel block. Therefore the barrel is straight.
• All the droop is between the cylinder and the barrel.

But how much is it actually drooping? For fun I tried my old torpedo level. It has a magnets on the bottom, and a set of graduated divisions.

Empire 8 in. True Blue Magnetic Billet Torpedo Level EM71.8 - The Home Depot

The Empire 8 in. True Blue Magnetic Billet torpedo level features True Blue vials that deliver best-in-class accuracy. Coupled with anodized aluminum, allowing this billet to deliver unparalleled strength

www.homedepot.com

The divisions are equal to 1/8" rise per foot. One division is therefore equal to ASIN( (1/8) * (1/12) ) = 0.6 degrees.

So this HW90 barrel droops about 0.6 degrees with respect to the middle of the cylinder. That's about the same as the UTG drooper mount, which gives you 10 inches rise per 30 yards.

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My levels match.. i test them to be sure they read the same .. if one shows level and the other dont on the same test piece it's a no go... ( Same with tape measures) they all read the same...lol

 

[Slingworks]

So I have a 90 for all of a couple days...I see all kind of thoughts on the mounts here. Mine has the .5 degree droop I see mentioned as standard here for iron sighted guns. That is 30 moa, so many Leupolds are about maxed out on install. I am thinking to order a rws lockdown mount w droop comp rather than a dampa mount that wouldn't correct anything.

Does it sound like a decent plan?

 

[Tuacati]

So I have a 90 for all of a couple days...I see all kind of thoughts on the mounts here. Mine has the .5 degree droop I see mentioned as standard here for iron sighted guns. That is 30 moa, so many Leupolds are about maxed out on install. I am thinking to order a rws lockdown mount w droop comp rather than a dampa mount that wouldn't correct anything.

Does it sound like a decent plan?

I have no experience with dampa mount. But my HW90 works great with the RWS lockdown droop compensated, and the Bkl one piece mount droop comp. Note, the RWS mount will not fit an Airmax scope.

 

[JayJay]

Another way to look at this is...why is it that the barrels generally droop if not perfectly straight, that is to say droop seems to be primarily the only way they are untrue as far as straightness is concerned, at least I haven't seen any discussion about barrels being out of alignment any other way than 'down' other than the occasional 'up' pointing barrels, which seems attributed to the barrel slipping from the hand before fully cocked and snapping back to closed via the spring. Once in a blue moon it's been mentioned a barrel being bent other than down..or up. So much so there are scope mounts manufactured to compensate for barrel droop

Good question.

Sideways bend is different because the barrel is positively located between the yokes, which are machined parallel to the cylinder OD. Therefore I believe that sideways bend will usually be caused by a bent barrel.

However, it's not a bad idea to check for sideways bend. I had a gun that shot consistently to the right. I pulled the barrel and checked. It was dead straight. Finally I realized that it happened with a particular pellet.

 

[JayJay]

I believe if your barrel is true the droop is at the breech. Them old rws / diana used the ball instead of the chisel . ( A few others as well ). Today even if you look at the diana 34 ems breech block it looks almost like a hw with the chisel ..

Also if the angles of the breech block is off or of the chisel point angle is in correct.. i seen some guns that looked hunchbacked..lol the droop showed bad at the breech.

Thing about the breech is you really cant take off the block to make it come down cause you loose clearance ( tightness) at the detant chisel..

Now you think is the chisel angle cuts wrong ? Will a new one cut " better ' lock up straight ? Cant say this go round in air guns my latest been stright even the poor ol'gamo..
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That looks pretty good. Can't get any better than that.

True, too much droop makes guns look like they're hunchbacked.

By the way, Is that a BSA GRT Lightning?

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[Hateful McNasty]

That looks pretty good. Can't get any better than that.

True, too much droop makes guns look like they're hunchbacked.

By the way, Is that a BSA GRT Lightning?

​

Gamo .. i was reading one deal , maybe pa blog on droop and the guy said it eas made to help the loopy trajectory of the pellet.

Then i got to wonder how do you have any Q.C and let this go. Then if so how loose is there tolerance on whats accepted... Ship it.