Author Topic: Forend bedding and Lock-up  (Read 695 times)

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Offline aulrich

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Forend bedding and Lock-up
« on: December 04, 2004, 11:39:20 AM »
I tried an experiment today it has not be tested at the range yet but it looks like it might be a low tech solution to those of us who's handi seem to have a lock-up problem. It's a variant of the business card under the forearm mod.

In previous thread I have read about adding a business card either side of the forearm lug. This week I had talked with Fredm and asked about why he fully bedded the forend.  He said it aided in tighting up the action.  This stewed around for a while till this mourning I though that if I add some shims at the rear of the forend it might generate some upward force. My guess is I turned the forend into a sort of leaf spring, I think.

It seems to have worked, before the shims there was a visible gap when I held the action up to a light. Now it is gone or reduce to <.003 (I think that the limit to which you can see a gap). A the gun has a much more solid feel to it.

Again at this point it is untried but I though I'd throw it out for discussion.  With any luck I can get out in the next while to try it out, I'll report back when I do and let you know if it was an improvement.
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Offline MSP Ret

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Forend bedding and Lock-up
« Reply #1 on: December 04, 2004, 11:44:48 AM »
aulrich, very interesting approach, please let us know what happens....<><.... :grin:
"Giving up your gun to someone else on demand is called surrender. It means that you have given up your ability to protect yourself to a power that is greater than you." - David Yeagley

Offline fastvfr

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Forend bedding and Lock-up
« Reply #2 on: December 04, 2004, 11:50:13 AM »
That should help.

Personally, I had an old NEF shotgun for awhile, and after a year or two of slugs and buckshot it shot itself loose. I disliked the way it felt after that, so it was my version of WECSOG to the rescue!!

I used a bit of AcraGlas Gel to build the stock up, then sanded it down and reinstalled the lug.

That sure tightened things up!

Best part of this method is, if you add too much gel and it becomes too tight, a few passes with the 80 grit and it is perfectly hand-fitted. And if it shoots loose later on, then just add another layer of epoxy and repeat.

Let us know how much it helps!
Ambition:  The journey of a thousand miles sometimes ends very, very badly.

Offline Fred M

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Forend bedding and Lock-up
« Reply #3 on: December 04, 2004, 05:17:17 PM »
aulrich
Quote
I turned the forend into a sort of leaf spring, I think.


That is a pretty good analogy. That is what I did with the set up I described in my write up. It works fine as long as you do it in the proper sequence. I was not worried about a gap but to make sure that the barrel, hinge and the forearm is solidly conected when the action is in battery. This elliminates a lot of bad vibrations.

The 15lbs uplift on the forearm tip will create pressure against the hinge and the hinge pin via the forearm screw acting as as fulcrum and stiffen the whole system. The accuracy improvement together with the stronger latch spring was very substantial.

Rather than just glue the forearm plastic hinge guide to the stock I would bed it with steel bed to the forearm for perfect contact, driving a few thin wedges in between the forearm and the plastic hinge guide. The steel guide would perhaps do a better job of it. After everything is set up you put the screws in and the bed the hinge guide to the barrel.
Fred M.
From Alberta Canada.

Offline Donaldo

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Forend bedding and Lock-up
« Reply #4 on: December 04, 2004, 05:33:06 PM »
aulrich
This is an interesting approach.  This in effect applies upward pressure on the barrel.  Keep us posted on the results.  Be sure and only change one thing at a time, otherwise, you will not know which caused the change, if any.
Luke 11:21

Offline aulrich

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Forend bedding and Lock-up
« Reply #5 on: December 06, 2004, 05:07:30 AM »
When I go to the range I am thinking of bringing two types of shim material. The rigid material that is in there now. and as an option I have some bycicle innner tube. I was thinking a springy material  might have a dampening effect.  Do you think that this has any potential?
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Offline PA-Joe

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Forend bedding and Lock-up
« Reply #6 on: December 06, 2004, 05:20:32 AM »
How does this relate to the rubber O ring under the forend screws to improve accuracy? One goup of guys are freefloating the forend with the O rings, while in this case you are adding pressure points.

Offline aulrich

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Forend bedding and Lock-up
« Reply #7 on: December 06, 2004, 07:41:14 AM »
I think the two fixes are valid my guess is that they are fixing different things. The o-ring is used isolate the forearm. I my case I think I am fighting a in-tolerance but loose action. So the pressure points add some rigidity.


I wonder what is normal forend bedding on other split stock guns is, like ruger No1's, leverguns or contenders. I wonder if they are "free floated" or tight.
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Offline Fred M

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Forend bedding and Lock-up
« Reply #8 on: December 06, 2004, 08:43:53 AM »
With the system I have used for both the Ruger#1 and the 25-06 Ultra which are quite simular in concept, I have extracted all available accuracy that these two rifle offer. That is not to say other systems will not work.

The Ruger #1 shoots less than a 1/4" 3 shot groups at 100m and the the Ultra an honest 1-1/4" with my hand loads and Rem factory 100 gr loads.

I have never found that free floating a light factory barrel will provide the best accuracy and I am not alone with that accessment. You can find both tune ups for the above mentioned rifles on my web site.

On a Handi the barrel forearm treatments are only one part that is  intrincic to accuray and we have mulled about that endlessly.

A quote from my friend Dan.

It all comes back to the rifle and how well it's tuned. Nothing you can do with the ammo will make up for a bad barrel, poor bedding, or other gun problem. The best you can hope for is to bring out whatever the rifle has to offer
Fred M.
From Alberta Canada.