Capture Screws, why didn't they catch on?

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Dr.Zubrato

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The mauser 98k pattern of rifles used capture screws with moon cuts, and they're pretty effective at retaining screws as the recoil would cause regular screws to back out during firing, however a lot got lost over time and they've been difficult to replace for many folks.

I love the design and ingenuity, so I'm wondering why they didn't catch on?
Too difficult to manufacture? Loctite sealed it's fate?
 
And once the wood stock shrinks or swells over time?

They are never again in the right place to torque the action screws to the proper tightness

Besides that, action screws just don't loosen themselves due to recoil when properly tightened in the first place.

rc
 
Besides that, action screws just don't loosen themselves due to recoil when properly tightened in the first place.
Click to expand...

There are exceptions to this. It doesn't happen on many rifles but the Savage MkII rimfire rifles will only accept 15 inch/pounds of torque. If you go higher you are in danger of crushing the wood at the bottom of the stock. It's very thin there and as little as 18 inch/lbs. can start to crush it. I pilllar bedded mine to allow me to keep more torque on the screws because they would back off in a short time if I went with the factory spec 15 in./lbs.. I have no idea if this would apply to the Mausers though.
 
RC that's more of a slam on wooden stocks, moreso than the design of the screws. I don't see why you wouldnt be able to torque down the main screw to spec, and install the capture screw afterwards, not to mention it would provide a convenient placeholder for the correct torque spec, without the use of a special tool like the torque wrench.

Having said that, I'd prefer having capture screws on my weapons, rather than having to loctite everything. Do it right at the factory once, for life.

Seems more convenient for field and heavy use as well, knowing it will not back out, as the russian capture mausers do not use the capture screws, and many people complain of this problem, after-all there is no factory torque spec for something the Ivans lost and jury rigged.
 
The Vltor upper rails for M1As come with capture screws. It definitely stays securely in place.

Geno
 
Just like how they milled in the little hole in the trigger guard so they could pass a steel rod through all the little holes to lock the rifles into a rifle rack. While they could have skipped that machining step and simply ran the rod through all the trigger guards. A larger hole that was already there and much easier to run a rod through.

But as with many German developments, why use 20 parts when you could use 40....??
 
bravo company's new KMR rail for AR15s uses them
STCK5891-1200-Stick.jpg

DSC00319_zpsdb8650a2.gif
 
rcmodel said:
And once the wood stock shrinks or swells over time?

They are never again in the right place to torque the action screws to the proper tightness

Besides that, action screws just don't loosen themselves due to recoil when properly tightened in the first place.

rc
Click to expand...

The only two weapons I have with "capture screws" is a Browning B-92 (copy of Winchester 1892) and they are in the lever assembly. Which means they're in steal.
The other is a 12 gauge Auto-5 Shotgun, also in steel.
I think modern tech has developed better methods for keping screws tight.
 
I encountered my first such screw last week when I disassembled the bolt on my No.4 Enfield. The firing pin screws into the cocking piece, and is kept from turning by a capture screw instead of the usual cross-pin.
 
RC that's more of a slam on wooden stocks, moreso than the design of the screws. I don't see why you wouldnt be able to torque down the main screw to spec, and install the capture screw afterwards, not to mention it would provide a convenient placeholder for the correct torque spec, without the use of a special tool like the torque wrench.
Click to expand...
When you get the main screw torqued to spec, you usually find the capture screw is out of time. Remember, the main screw has to make a full turn before the capture screw will go in.
 
Thanks guys!
Didn't realize the KMR handguard had capture screws, and I've been thinking about getting a new KMR upper, that is once I've got the funds (not anytime soon :( )

Joshua, that's a pretty awesome home job! Doesn't look all that easy either
 
Most nations figured out you could upset some metal into the screwslot with a punch and achieve the same effect.
 
No need for them to catch on with civilian guns. That's more parts that increases expenses and reduce profits. As for military arms, Legos rule the day (everything snaps together, or is held by spring & plunger, or interlocking parts).
 
1) It's more parts for soldiers to mess with and lose.
2) It's more expensive to manufacture.
3) Requires more metal to make all those screw holes. For example: I've got a Steyr AUG, which has three screws in the stock. Each of those screws is surrounded by plastic and screws into a nut and is locked with adhesive. There literally isn't any metal there to add a capture screw.

BSW
 
I suspect it is hard to find the torque you want with only 1 (or 4) notches per rotation. Some times I have enough trouble finding the torque I want with 20!
Barrel_Nut.jpg

Mike
 
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