Bullet dip coatings and barrel pressure

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Bullet dip coatings and barrel pressure

Post by mikor » 08 Jul 2014, 9:17 am

Clear something up for me if we can :D

On one hand... Before shooting a cleaned rifle we're told to patch out the oil so we don't create pressure, bulge the barrel, etc etc. Makes sense.

On the other hand I see guys dipping their bullets in a Moly coating and hand feeding them. That's gotta be thicker on a bullet than how thin a patch will apply a layer of oil in the barrel?

A contradiction obviously... What do we think?
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Re: Bullet dip coatings and barrel pressure

Post by Chronos » 08 Jul 2014, 9:40 am

Moly coating is a bit more involved than dipping a bullet and hand feeding them, unless there's a dark art the rest if us aren't in on yet :lol:

Moly coating (and boron coating ) reduces friction therefor it reduces chamber pressures and velocity. I couldn't say what leaving oil in the bore would do and wouldn't like to try. I have had oil left in the chamber when a round was fired. It allows the case to slide rearward during firing, putting more load on the bolt. Not good.

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Re: Bullet dip coatings and barrel pressure

Post by mikor » 10 Jul 2014, 11:36 am

Hi Chronos,

I have seen (with my eyes, not on the internet) a bloke just straight up dipping the bullet in a bottle of something before hand feeding it.

I shouldn't have said "I've seen guys dipping their bullets in a moly coating", that's wrong. I've seen a guy dipping them in something at the range.

I know you can moly coat bullets "properly" before loading so they're like powder coated? That's probably the wrong word but I'm sure you know what I mean.

For this question I do mean "dipping" them in a solution.
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Re: Bullet dip coatings and barrel pressure

Post by whert » 10 Jul 2014, 11:40 am

I've seen an old guy at Little River doing this too.

He had a bottle of white liquid that he dipped the case in, covering the whole bullet up to the neck. The little hand written label on the bottle said 'boron'.

Quite a bit of stuff on the bullet too. You know when you microwave milk for too long and it gets the skin on top? It looked like he dipped the bullet in milk and the skin stuck.
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Re: Bullet dip coatings and barrel pressure

Post by Seconds » 10 Jul 2014, 11:41 am

If there is a visibly thick 'skin' on the ammo he's loading, I'd be moving to a bench further down the firing line...
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Re: Bullet dip coatings and barrel pressure

Post by Shotfox » 10 Jul 2014, 12:05 pm

Sounds like an old bloke myth, something out of a 1950s popular mechanics mag. Bet these guys still use solouble oil in the radiator of their cars.
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Re: Bullet dip coatings and barrel pressure

Post by mikor » 10 Jul 2014, 12:15 pm

Whert - I didn't see a label but it was at Little River. Maybe we saw the same guy.

Shotfox - He was an older guy in his 60's or something, maybe he's just been doing it for ever and it's since fallen out of practice. I guess no one told him.
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Re: Bullet dip coatings and barrel pressure

Post by Chronos » 10 Jul 2014, 12:30 pm

Boron would be referring to hexagonal boron nitride.

If you're interested in bullet coatings have a read here

http://www.6mmbr.com/bulletcoating.html

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