1903 bolt

[milboltnut]

what do you all make of this... at first I thought, at the range, it was a crack but with a magnifying glass, it revealed it was not. The light impression beneath the dark gouge is double along side each other. My take is somewhere in the raceway it was/is rubbing?

I'm assuming waaaay back when.. dirt in the race way gouged it.



IMG_1221.jpg

[cplnorton]

I've seen that area polished on bolts before to make the bolt just slide easier. I wonder if they polished it and when they did, whatever tool they were using to polish it, made a rub mark on the bolt from trying to polish that one face? Especially since this bolt was jeweled and all the finish has been removed.

Or even when you take the bolt in and out of the receiver, the inside of the receiver where the bolt cutoff is, I wonder if it rubs there when you remove and reinstall them? I pulled out a few bolts I had laying around and a couple have a mark in this location. And sliding them in and out of a receiver a couple times, I could see it possibly causing a rub mark in that spot.

Either way I have several bolts in the pile that look exaclty like this. So I don't think it's anything to be worried about.

[milboltnut]

I hear ya... it's actually a gouge not a rub mark...

[cplnorton]

Well this is what I was sort of imagining in my head. I've seen that surface of the lug polished on many bolts, and I can imagine if you took a stone or a fine file, it you were polishing that surface, it would be easy to cut into the bolt in that spot.

I don't know what honestly they used to polish them. That would be more a question for the gunsmith guys than me. I collect them, and not so much work on them.

But I just sort of had this image in my head. I just grabbed a small file I had layin in my box. I don't know what they would have used, but it just sort of made sense in my head what could have made a mark like that.

[milboltnut]

as long as it's not a crack... I'm satisfied.

[cplnorton]

I think you can test for a crack with lighter fluid. At least that is what I've always read.

[milboltnut]

I just threw some out... I had a notion to hold on to it. How do you do that?

[p246]

From hanging around a gun shop bolt lugs were stoned. A file is too abrasive and aggressive IMO and experience. I don't see how stoning the bolt lug would cause that fine wear pattern. I stand to be corrected but don't see it.

We use a pen (dispenses pigment) to paint steel then look at it under black light to check for cracks on the tails of our AR bolts. I use the same method to check all my old suspect rifle parts. If it is cracked it glows along the crack line under black light. The bolt or part being inspected has to be magnetized before painting it. It works very well and is inexpensive. It's a form of magnetic partial inspection. I believe harbor freight sells the pens along with other distributors. There is also a dye method that is inexpensive but prep is more intensive hence why I don't use it. I've heard of the lighter fluid technique but have never tried it.

Your photo looks like a wear pattern not a crack. Obviously one picture is not a basis for a sound decision on that though.

[cplnorton]

If you google the lighter fluid technique they will have more. I've never tried it, but they say you just squirt it on, and then dab it with like papertowel. If it's cracked, it will stay wet in that spot. At least that is what I remember off memory.

[milboltnut]

oh I remember that...