Stripped Action Screw Hole - Help!

Hello all,

I'm finding myself in a bit of an unfortunate situation here...

I removed my barreled action (110 Hunter model in 300WM) from the Accustock for the first time today to sand down a part of the stock that contacted the barrel. I started to put it back together, working incrementally toward 40 in./lb. of torque. It felt just fine threading in, but upon removal, the front action screw hole is buggered up.

This is where I am at now. The screw will screw into this hole directly (albeit with some resistance due to messed up threads), however, doesn't seem "long" enough or have thread to grip onto when I add the stock into the equation and try to put it back together.

What are my options here? As of now, I have a buggered front action screw hole and I can't put the rifle back together.

Thank you all in advance.

Go to the closest open hardware store and buy a 1/4- 28 tap ( if you don't already have one). Tap out the action screw hole that is damaged.( you might get by without doing this).

Also purchase a few 1/4 28 socket head cap screws longer than the original action screw and cut the new one to fit the length you need. (probably 1/8" to 3/16" longer than old one).

Then check to make sure the new screw is not protruding above the inside of the action when everything is put together and torqued..
I hope this helps.
Jack

I am pretty sure the front action screw would be a blind hole in the bottom of the action, so make sure you get the bottom tap.
https://www.mcmaster.com/26955a88

^^ No, the hole goes all the way through, as does the rear one. If the action bolts are too long they will interfere with the bolt operation.

The hole is not blind as stated by GreGuy. It is as mentioned by JW a 1/4-28 screw.

The original screw is probably damaged on the starter thread. Replace it. Make sure it is the correct length.

If you tap the action be very careful. Us a small file or hone to remove the buggers around the hole first, then tap.

If you have to go up to a 5/16-24 NF or a 5/16-32 NEF Make sure you can get the screws in the length you need first.

As GrenGuy said, too long of a screw will interfere with the bolt rotation.

Next time, take a wood working clamp and squeeze the action into the stock before you install the screw.

Not surprising to me at all. My 2018 Model 10 FCP-SR with Accustock had a too short front action screw from day one. Fortunately I was paying very close attention and realized that screw was only engaging for 1 1/2 turns. I found a cap head bolt (different size hex) and cut it to what I believed to be the correct length 3/4". Since the bolt/screw hole passes through the action's barrel threads I was afraid to let the bolt extend into the bolt chamber (for lack of a better description) and interfere with bolt head rotation. I currently have my barrel off and have a clear view and realize I could have been a bit longer and able to engage two more threads. So I wonder if a 1" screw would have been fine or not.

So as others said, chase those threads with a tap and then get a longer screw/bolt (1") and shorten as needed.

Quote:

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Originally Posted by Robinhood

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Next time, take a wood working clamp and squeeze the action into the stock before you install the screw.

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Sound advice. I use a welders type squeeze clamp with nylon blocks.
One of my other smith buddies prefers a ratchet strap when pulling
screws.

Please do not tap the hole to a larger size bolt. They make heli-coils for this type repair. You can buy a Helicoil tap and insert with installer as a kit, if you don't have one. If it were me, I'd install a self locking Helicoil so the the action screw would be less likely to back out. https://www.amazon.com/Helicoil-5528...6610855&sr=8-3

Some things to look out for: Make sure the helicoil is the correct length for the depth of hole. You can cut off excess coils if necessary. Don't try to back out the coil if you don't like how it seats. Just run it all the way through. Backing out requires a removal tool.

Quote:

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Originally Posted by Texas10

Please do not tap the hole to a larger size bolt. They make heli-coils for this type repair. You can buy a Helicoil tap and insert with installer as a kit, if you don't have one. If it were me, I'd install a self locking Helicoil so the the action screw would be less likely to back out. https://www.amazon.com/Helicoil-5528...6610855&sr=8-3

Some things to look out for: Make sure the helicoil is the correct length for the depth of hole. You can cut off excess coils if necessary. Don't try to back out the coil if you don't like how it seats. Just run it all the way through. Backing out requires a removal tool.

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Interesting. As a machinist, and I have lots of experience with thread repair on larger stuff, that would not be my inclination. Have you done this before Tex? :p I mean if you do a helicolil you must drill oversize and tap anyway.

For others having the "short screw" problem with the accustock.
The bedding block in the accustock will hold the receiver from dropping all the way in. It actually is a tight "spring" fit in most accustocks. It was designed that way. A couple of threads should be enough to start "pulling" it in. If the action is not level front to back, the start of a crossthread could easily bugger up the first thread. If started correctly 4 to 5 turns will be sufficient to hold torque. More is always better.
If you decide on a longer screw double check with blueing or a "sharpie" on the bolt lug to assure it is not too long. Also use an empty or dummy round during the blueing check to make sure bolt head assumes battery position.

Quote:

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Originally Posted by Robinhood

Interesting. As a machinist, and I have lots of experience with thread repair on larger stuff, that would not be my inclination. Have you done this before Tex? :p I mean if you do a helicolil you must drill oversize and tap anyway.

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I don’t have close the skill set as Robin, he’s a professional & I’m a hobbyist, but I agree with his statement.

I’ve never been a fan of helicoil. Unless it’s a must. Either drill & tap to to the next size, or if the smaller size must be preserved there are steel screw sleeves, like the EZ lock. Of course there is always doing a fill weld & re-drilling/tapping to 1/4-28.

Quote:

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Originally Posted by Robinhood

Interesting. As a machinist, and I have lots of experience with thread repair on larger stuff, that would not be my inclination. Have you done this before Tex? :p I mean if you do a helicolil you must drill oversize and tap anyway.

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Yes, I have. And yes you do drill and tap it slightly oversize but the you retain the original hardware, often very important. I have about a thousand dollars worth of tangless helicoil insertion tools, removal tools, and tanged insertion tools, std and metric. Many times an aluminum part will have helicoils in place to give greater clamping power than aluminum alone can provide. Recently did some work for a Space-X subcontractor installing these inserts on flight hardware.

A helicoiled hole, done properly is actually stronger than a bare metal one because the thread material is often harder than the parent metal. Another recent example of a part I worked was a stainless steel part with helicoils installed in the holes. Stainless bolts will not gall and lock up when pulling tight.

I agree with everything you said. Most important is how much I respect your opinion.

That is thin walled in that spot. I am guessing .175 thick. That equates to 3.5 threads at the most....?

The caveat for the OP is that you have the experience and the tools, he may not. And whatever way he goes, it is a one shot deal.

Savagesmithing can be expensive.

I'm going to set this right here so the OP knows his options. If I were to drill and tap oversize on the front, I would do it in the rear action screw hole also.

Thanks, I appreciate your compliment, RH. I think your suggestion to install inserts in both action holes is a very good one. Especially the rear screw that tends to loosen. I may make this mod to my actions that seem to like a particular torque but tend to loosen.

I'd suggest he get this kit: https://www.amazon.com/Helicoil-5528...6867496&sr=8-3 and use a dremel tool to cut off part or all of one coil, even more if necessary, then insert it so it's the correct length. If necessary a small amount of locktite can be applied to the action threads to lock the insert in place if it tends to back out. Install, check and recheck before breaking off the tang.

I'd have to see the severity of the thread damage. But, If it were me
I'd use a thread chaser, then screw in and under sized 1/4 28 bolt.
By under size, I mean take a bolt and chuck it up. Take some fine
grit, and knock the edges off. You can do this with just a simple drill
motor. Thread in the under size bolt, then displace the metal into the
bolt by peening. It's an action so leave the sledge in the garage.
Remove bolt, and see if a new action bolt will thread in. If it starts
hard, that's a good thing. You can now use tap.

Quote:

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Originally Posted by Texas10

Thanks, I appreciate your compliment, RH. I think your suggestion to install inserts in both action holes is a very good one. Especially the rear screw that tends to loosen. I may make this mod to my actions that seem to like a particular torque but tend to loosen.

I'd suggest he get this kit: https://www.amazon.com/Helicoil-5528...6867496&sr=8-3 and use a dremel tool to cut off part or all of one coil, even more if necessary, then insert it so it's the correct length. If necessary a small amount of locktite can be applied to the action threads to lock the insert in place if it tends to back out. Install, check and recheck before breaking off the tang.

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I actually meant to go to 5/16 -32 . Mcmaster carr has them. :)

I also agree with Fuj. I don't know if I would be that elaborate but peening around the edges and running a tap through would not do any further damage.

I would do 1 of 4 things. If I had already just tried to clean the holes with a chaser and that didnt work I would
1. Go get some liquid metal and fill the hole, drill it and tap it to correct size or
2. Just run a 7mm×1.0mm tap through it and buy a 7mm bolt
3. Take a center punch and stake the hole and retap it to the original size
4. Break out the tig and fix it
(Before you go to beating up your action with a punch to stake it here's how to stake a hole.) Take a 1/4 -28 tap and screw in the hole. Tap will have 4 flutes on it so punch beside each flute. Back tap out until cutting edge of tap lines up with the stakes you just made and now make 4 more stakes lined up with the flutes. Now ryn the tap through it, should be good to go