4140 for bushing firing pin hole?

i have a shilen dga that has been bushed with 4140, i run reasonably hot loads and it works fine

cheers
 
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Just go to a quality Hardware Store and get a Grade-8 bolt, or the junkyard and get a handfull of main cap bolts.

Often, when you have to have a piece of alloy steel at a pretty good RC hardness plus toughness, a grade 8 bolt will do just fine.

Keep in mind, "grade-8" is a strength specification, not an actual alloy designation. But, to meet those requirements, you can bet it is some type of Crome Moly, or even Chrome Moly Nickle steel.

Years ago, when I raced that High Gear Only Fuel Harley Motorcycle, (the one that almost killed me), I made the jackshaft out of a 1 1/2 inch grade-8 bolt, the head became the flange to bolt the sprocket too.

Sometimes the answer is easier than you think.........jackie
 
For the small diameter firing pins, .062 or .067, I use a socket hd cap screw by UN-BRAKO. That material is tougher than the bolt.
Turn the head dia. to match a .055 deep counterbore in bolt face. An interference fit of .0002-.0003 is good and you won't see
much of any line when its done. Start with a small endmill followed by a #21 drill and tap 10-32. When finished and faced off,
the length must be such that the pin never comes out of the bushing. When tightening and seating the socket hd cap screw,
I tap and turn the screw till its fully seated to the shoulder.
 
operator1 said:
Getting ready to bush the firing pin hole on my Rem. 700 and am wondering if 4140 be hard enough?
Click to expand...

4140 cut right off the bar will have about a 12Rc, but of course can be hardened to about 47Rc. I would use 4150 pretreat steel, and be done with it. It comes at 28-32Rc, and is very nice to work with. You can also buy 4350 Pretreat on occassion, but generic 4150 will do anything you want in spades and have better wear properties.
gary
 
Use the new style J-lock firing pins for material, thats the only thing they are good for after you convert to the original style.
 
I use pre hardened 4140, same material as most rifle bolts. I have used grade 8 bolts before, one target rifle I have with a grade 8 bolt material bushing has over 3000 very very hot rounds through it and the bushing is as new.
 
I took Jackie's advice to use a grade 8 bolt for turning new a firing pin for my Stevens 44 1/2 and it saved me allot of money! The prior recommendation was to use La Salle Fatigue Proof Steel and the minimum order was in the 69 dollar range from Brownell's and that grade 8 bolt cost me approx. 36 cents and I bought one long enough to turn 3 pins out of it. I was just to lazy to go to the junk yard to pickup some main cap bolts as the local hardware store was allot simpler approach and the price was right.

J.Louis
 
Thanks for all the input everybody. I ended up taking Jackie's advice and using a Grade 8 bolt. Cost me .48 cents, can't beat that.

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