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Extrusion hone

When I worked on race cars years ago a process was being used to polish ports and passages by forcing a gel like media with gritt in it through at high pressure. The passage was deburreded and polished with minimal metal removal depending on gritt and other factors. Has anyone ever seen this used on a barrel to deburr and pollish rifling. Just wondering??
 
If I'm not mistaken, that process was/is used on racing engines because actual port blending and polishing is not allowed in some classes. It was a way of cheating, just a little bit but not all the way. Lol!

Kinda like acid porting in the stock classes with iron heads & intakes?...or so I'm told :). Although I personally never used Extrude Hone, I have seen the results inside an aluminum intake (Victor Jr.). It was impressive.
 
Kinda like acid porting in the stock classes with iron heads & intakes?...or so I'm told :). Although I personally never used Extrude Hone, I have seen the results inside an aluminum intake (Victor Jr.). It was impressive.
Yes. I spent a few years in an automotive machine shop. We didn't have that machine and sent those out, so I never actually saw it done in person, but we had a good shop and built some motors for some pretty well known racing teams. Extrusion honing was popular in the stock and super stock drag racing circuit where rules were very strictly enforced. One of the racers was Dickie Ogles. He had a 427 Camaro Super stock stick car that was a bad dude. Not much can compare to a big block chevy, dumping the clutch at 9,600rpm. That's been years ago, so that might seem like child's play today but it was pretty much unheard of at the time.
 
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When I worked for a Diesel Engine Manufacturer I took a few cylinder heads to Extrude Hone. Great people to work with, like most of the folks I worked with in Western PA.. Not sure it would work in a rifle barrel, it removes all material, not just burrs. Small displacement engines saw the biggest gains.

Great thought, if you don't ask you won't know.
 
The extrude honing I saw was very obvious. If it was illegal in your class and you had to do a tear down, you would get caught.

A friend of mine burns the cotton off a bore mop, uses what is left to cast a lead bore lap, then he laps his bore with diamond paste.

You could do that or a barrel break-in procedure to smooth out your rifling.
 
A good barrel is obviously the place to start, just curious if it had ever been tried. Let's face it, people bitten by the accuracy bug have gone to some extremes. Just a random thought that went through my head
 
They were always vague on the treatment, but Blackstar used to advertise something like this. There were some seriously conflicting reports as to their product quality.
 
Blackstar used an electro-chemical process. They put a taper in the bore. There are companies using the extrusion hone on barrels. None that would be considered top shelf match grade barrels.
You don't want a barrel to smooth. More friction and fouling. When I'm polishing a barrel to a bright finish I can feel a difference in resistance between the highly polished areas and the areas that need more polishing. I don't have to stop the lathe for inspection.
 

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