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 Post subject: Stabilizers on FP60
PostPosted: Fri Jun 23, 2017 1:11 pm 
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Joined: Tue May 09, 2017 3:19 pm
Posts: 6
Location: Long Island, East End, South Fork
I recently got a new Hammerli FP60. I'm real happy with the gun, but I am having an issue with the stabilizer set. The stabilizers are almost infinitely adjustable, and I can find no information as to where to start, the effects of incremental changes, etc. The best I have come up with is that it is a "trial and error" thing and that I should just keep experimenting and re-adjusting. No starting point? No approximation of the effects of changing the angle(s) or distance of the weights? Seems wasteful. There is not a word in the owner's manual, I can't find a youtube on it, and I'm still waiting for a reply from WaltherUSA.
Does anyone have experience with these and can give an idea as to where to start and what effect each angle and length change might produce? It could save me a lot of ammo and time if I could be pointed in the right direction.
Thanks in advance,
Maier


Last edited by Maierar on Fri Jun 23, 2017 2:17 pm, edited 1 time in total.

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 Post subject: Re: Stabilizers on SP60
PostPosted: Fri Jun 23, 2017 1:20 pm 
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Joined: Sat Nov 15, 2008 4:20 pm
Posts: 4918
Location: Scottsdale AZ
Start with NONE. We've been playing with this at my club for a while and find no REAL effect one way or the other. If the muzzle is really twitchy, put some weight out there.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Fri Jun 23, 2017 4:51 pm 
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Joined: Sat Sep 04, 2004 6:04 pm
Posts: 1400
Location: Massachusetts
Basically, the more mass you can use, and the farther forward it is located, the more it increases the moment of inertia. This will tend to reduce wobble for a given amount of twitching on your part.

The catch is that more mass further forward makes the pistol muzzle heavy, which is tiring.

To see what effect it has, put all of the weight as far forward as it will go, and try a few shots. That may already be too much to hold steady. Once you have found a weight configuration you can live with for ONE shot, you can see how much it helps. Then, you have to back off to something you can live with for 70 or more shots. As you build up your strength, you can add more weight, or move it further forward.

Here's the way the physics works:

The pivot point for supporting the pistol is roughly at the wrist joint.

The "moment" of a small weight (mass "M") at a radius "R" from the pivot is just MxR. Gravity pulling the mass down will produce a torque that's going to add to the muzzle heaviness. Doubling the weight has the same effect as doubling the radius.

The "moment of inertia" is a measure of how much the pistol will resist forces that want to make it wobble around. This is equal to MxR^2 (squared).

If you double the mass, the moment of inertia doubles. HOWEVER, if instead you double the radius, the moment of inertia goes up by a factor of FOUR!

Basically, you can double the moment of inertia while keeping the moment the same by cutting the weight in half and doubling the radius. This means that if the pistol is too muzzle heavy for you, it's better to keep the weight as far forward as possible, and reduce the weight until the balance is manageable.

The limit to how much benefit the weights can produce for you is really set by how muzzle heavy the pistol can be without wearing you out over a match. That is why nobody can tell you how to set them up. It's a VERY individual matter, and will also vary with time as your fitness level fluctuates.

YMMV (your moment may vary)


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 7:06 am 
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Joined: Tue May 09, 2017 3:19 pm
Posts: 6
Location: Long Island, East End, South Fork
Thank you for sharing your information. Your insights are much appreciated.
M


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 7:12 am 
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Joined: Sat Nov 15, 2008 4:20 pm
Posts: 4918
Location: Scottsdale AZ
Go have a beer at the Shagwong.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 7:17 am 
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Joined: Tue May 09, 2017 3:19 pm
Posts: 6
Location: Long Island, East End, South Fork
Sorry, Rover, I miss your point.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 8:59 am 
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Joined: Sat Sep 04, 2004 6:04 pm
Posts: 1400
Location: Massachusetts
Don't worry about it. Over time, you will discover that many of Rover's posts have no point...


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 9:12 am 
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Joined: Tue May 09, 2017 3:19 pm
Posts: 6
Location: Long Island, East End, South Fork
I wasn't worried, I just didn't want to miss a valuable gem from an experience sage, my being a neophyte and all.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 12:47 pm 
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Joined: Sat Nov 15, 2008 4:20 pm
Posts: 4918
Location: Scottsdale AZ
You say you're from the East End, South Shore and don't know The Shagwong? You HAVE been leading a sheltered existence!

Go forth and conquer your pathetic ignorance and the nay-sayers on TT.

http://shagwongtavern.com/

http://easthamptonstar.com/Business/201 ... ong-Tavern


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 1:20 pm 
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Joined: Tue May 09, 2017 3:19 pm
Posts: 6
Location: Long Island, East End, South Fork
Pretty much a tourist place for weekenders and renters (not that there is anything wrong with people paying taxes and not using the services). Montauk is just about inaccessible this time of year, and not really worth the trip from Southampton.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 2:17 pm 
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Joined: Sat Nov 15, 2008 4:20 pm
Posts: 4918
Location: Scottsdale AZ
Too true! It really is only suitable for winter patronage. Last time I was there it was December.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 4:02 pm 
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Joined: Fri Oct 09, 2009 6:13 pm
Posts: 149
Location: Dallas, Texas
...Anyhoo, back to the topic: Thanks, GWhite for pointing out the difference between changing mass and changing radius. I, for one, am glad to know the difference. Go MIT!
And one question: Would this account for part of the alleged preference for a long sight radius by those who can keep the sights steady? Could some of the benefit be due to increased moment of inertia and not just the optical benefit of sight radius?


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 4:33 pm 
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Joined: Sat Sep 04, 2004 6:04 pm
Posts: 1400
Location: Massachusetts
Certainly the mass of the front sight assembly will add to the moment of inertia, right where it matters most. Some pistols allow some leeway, like the Morini CM84E), where you can move the sight block back & forth AND move the sight blade itself back & forth somewhat independently. Other pistols have front sight extensions that can increase the radius without adding a lot of weight far forward.

One of the things I don't like about the Morini is that the barrel is tapered. The best place to put added weight would be clamped right behind the sight mount, but with the taper, it's hard to get something to stay put (I've tried). The factory barrel weight clamps near the action, where the barrel is cylindrical and it will stay put. However, that puts a lot of mass from the rod and the mounting block back where it doesn't do much except make the pistol heavier.

You could attach weights directly to the Morini sight block, but the added mass could slowly damage the mounting screw for the sight block.


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 Post subject: Re: Stabilizers on FP60
PostPosted: Sat Jun 24, 2017 8:01 pm 
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Joined: Wed Dec 09, 2015 11:54 am
Posts: 2
I too own a FP60 and had and have the same questions about the stabilizers. This is what I tried. The rods in the lowest position provide an excellent way to set the gun on the bench. The rods at the highest position do the opposite. To be more serious I have tried them all over the place and noticed they will make small changes when the gun recoils but you almost have to be looking at the rear sight sometimes to see any change. So far I have always had the weights at the outer most point. The rod and weight under the barrel is a little on the heavy side unless you shoot it a lot. With all the weights on and rods in the highest position I have noticed the rear of mine will recoil up but front sight tends to stay put. I have tried the rods only on one side or the other and it seems to make a small difference.I have not done much with this gun lately as I am now focusing on International Black Powder Matches. This is my suggestion. Shoot at a blank target. Watch the front and rear sights then make a big change and watch again. Try to get the sights to be stable during recoil. I would stay away from an actual target until you are happy with sight movement during recoil. Talking about this makes me want to work with mine again. This is just my 2 cents handle with care I am far from an expert
Thanks Bob L.


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