358 Norma Confusion

Takujualuk

Takujualuk

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Whitehorse, Yukon
I have a very light synthetic stocked 358 Norma that is driving me crazy. It will shoot very nice groups for a short while. After a bit of shooting the zero will shift..usually up and accuracy go to crap.

At this point the guard screws will have worked loose and after tightening I'll get a few more good groups.

The action is an old tang safety Ruger

I have steel bedded the stock and added steel bed pillars. I have tried several different scopes.

I am unsure what to do next but I am convinced this rifle can shoot when it isn't working itself loose. Any ideas?
 
Forgot to mention that I had used medium strength lock tite this time and let it cure a full week. It lasted a full 40 rounds before the 1.25-1.75" groups turned into a 7" group and I could easily turn the screw a 1/4 turn with an ordinary screw driver.

I just don't get it.
 
Is the action bedded?

If not, then it may be time, including adding pillars, then torqueing the action to 65in lbs.

You shouldn't need LocTite on action screws.

RePete.
 
Perhaps the bedding is collapsing slightly... Rugers have an unususual canted front action screw - any movement of the action to the rear of the rifle would cause the loosening you describe... (Couple this with a light rifle, heavy calibre....!)
Try indexing the screws with "whiteout" to see if they repeat between trials, using the same torque.

Edit (with more coffee in me) If you installed a pillar at the front action screw, this could cause you problems. This would prevent the tang and action from seating against the stock, and prevent the pre-torque against recoil. I believe this was the original purpose of the canted action screw.
With the pillar taking the recoil load, you can envision the problems that would ensue...
 
Takujualuk said:
........At this point the guard screws will have worked loose and after tightening I'll get a few more good groups.

I have steel bedded the stock and added steel bed pillars. I have tried several different scopes.

I am unsure what to do next but I am convinced this rifle can shoot when it isn't working itself loose. Any ideas?
Click to expand...

It sounds like all your attempts have failed :(
This is what I would do: 1. remove the action from the stock and clean and degrease the threads where the screws thread into, since any old crud will prevent the Loctite from working properly. I have in the past sacrificed a guard screw by cutting a groove into it thus turning it into a type of tap that I used to clean action threads. If the threads are clean and dry the Loctite(even the blue type) will be quite difficult to remove, alittle dab on screw and reciever is all you need when all is dry. Thread fit is very important with Loctite too loose of a screw fit will greatly reduce the Loctites effectiveness. With proper fit it will be quite difficult to turn after only a couple of minutes. Loctite cures when air is not present this is why a drop on a table will remain there for a long time without hardening, a drop is all you need so don't over do it!
2. You say you pillar bedded the action, do you have a positive stop on your screw tightening when installing the guard screws? If not then the pillars are not properly installed! Did you do the pillar/bedding yourself?Finally is this a wood stocked rifle or synthetic?
bigbull
 
Yes I did the pillars myself out of Brownells steel bed. This was after I couldn't solve the problem with regular steel bedding.

The stock is synthetic...looks like fiberglass skin over a foam core. It is very light and there is no manufacturer written anywhere though it has a pachmeyer decelerator pad.

I plan to:

1) Reinforce the recoiul area further..perhaps with a through bolt and a load of steel bed?
2) Install the Brownell aluminum pillars to front and back
3) Play with lock tite if that doesn't work
4) See if I can pick up an old wood stock

OR

5) Admit defeat and sell the son of a ##### .

As a concept gun it has been helpful in teaching me the following :
1) A lightweight 358 Norma is my cup of tea (I love the power and ballistics in a short barrel).
2) Rugers bedding system sucks
3) A wood stock is easier to work with than a 16 oz foam thing.
 
Can you post some picturs of the rifel and bedding? We might be able to recognize the stock and see something in the bedding. If your screws are loosing tension, somehing is moving.

Is the barrel free floated?

Is there any movement in the action when the screw loosens?

Barrel clearance before and after accuracy problems?

What mounts are you using out of curiousity?

Joe
 
Takujualuk, don't sell it yet! :)

I am wondering if you have you bedded the action at all, or just done the pillars for the action screws? I have bedded the model 77 before and never had any trouble like you describe.

My advice would be to fully bed the action area, and then install a steel crossbolt behind the recoil lug like you are planning to do. Drill a hole completely through the stock and bond the crossbolt in with the same bedding compound. After it cures you can cut it off, file it down flush with the stock and finish it with some fine emery paper. You can touch it up with matching paint or cold blue when done.

I would then carefully remove a little of the Steel Bed that you used on the front guard screw so the screw can actually pull everything down and back a bit tighter.

The idea would be to pull the recoil lug, which is quite small on the model 77, tight against the crossbolt-reinforced bedding, rather than against the pillar. I did this recently on a 375 and it has not budged since.

Ted
 
Ted :oops: - read the opening post :lol: :lol: :lol:
 
Unfortunately I have already begin modifying the bedding for the fifth time. I am enlarging the screw holes for installation of the aluminum pillars. It is a bit sloppy but I'll forgo the embarrasment and show anyway. The barrel sits on a little band of material in this version I have tried the two inch chamber pad and also forend pressure with even worse results.

329928.JPG
 
Can you show a few general photos of the stock (side view left/right) with plan view of complete bedding? This is a great photo but a couple abit further away would be nice.

Are you doing a two point bedding - front receiver ring and tang area?

Is the barrel contacted by the bedding at all?

On an ultra light stock you need to make certain the front receiver ring area is well supported by bedding and tied into the side rails very well. Normal practice would be to have some relief (no contact) in the rear tang area, however as a last resort you could bed this area as well to help transfer the recoil directly into the pistol grip area.
 
Its a bit premature, but I'm guessing that the stock structure is the problem. It may take the 40 rnds to start breaking the bedding up if it isn't tied into the side rails sufficiently. If the barrel also sees some contact with bedding that would help explain why you see the accuracy go to hell. The barrel area remains rigid while the receiver area is floating. Just some thoughts. Look for fractures or flexing in the recoil lug area.
 
If you say so Ted. Seemed pretty clear to me.... :roll:

Quote: I have steel bedded the stock and added steel bed pillars. End Quote. :!: :wink:

Easy there partner didn't mean to bump into your corn flakes :lol: :lol:
 
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