How do you debur the inside of a barrel if you drill holes to port it? Or do you have to bore inside the barrel for the length of what you drilled. Maybe plane C, you install a ported section in a threaded barrel for a flash suppressor. I don't want to do it at this time but was wondering how they do it. I've seen barrel in pictures that were drilled right in them, no added section. Tks
Deburring a ported barrel
- Thread starter Black Jack
- Start date
trapandhunt
Regular
- Location
- the rock (nl)
yup edm is only real process that will not burr. in some cases an endmill in a mill will leave not much burr better then a drill but still not good enough in my thoughts anyway.
While EDM is common today thirty to forty years ago you could not find anyone in western Canada who would do it. Olympic rapid fire guns - especially a lot of hand built varieties - actually did have holes drilled into the barrel. This was usually done about two inches ahead of the chamber, three on each side angled up at 45 degrees. The technique involved drilling the holes, then casting a lead slug on a rod, notching the slug at a few points then using a very fine corundum slurry and working the slug back and forth until the flashing/burrs were polished off. Usually took three or four slugs to do the job as they wear fast. Since these were for rapid fire on the old oval target that is still used for PPC the spread of accuracy from half inch out to an inch or even inch and a quarter was tolerable. But then we were working 22shorts at 25 metres, five targets in 8,6, or 4 seconds. In anycase it is always the last couple do inches that are critical for accuracy. These days there is no need for this type of work at all.
Another way that barrels used to be ported was to fill the bore up with melted lead and then let it harden. Drill the holes and then melt the lead out of the bore.
I have ported several barrels and as long as you go slowly the bur is quite small and can be wiped out with a few passes of a bore brush. Shooting will remove any remaining burr. I try to make sure I drill into the grooves which isn't all that difficult to do on a decent mill with a rotary table.
I have ported several barrels and as long as you go slowly the bur is quite small and can be wiped out with a few passes of a bore brush. Shooting will remove any remaining burr. I try to make sure I drill into the grooves which isn't all that difficult to do on a decent mill with a rotary table.
Cool, tks a lot. I guess if I want to do that I will have to thread the barrel and screw it on. T&G mentionned that it's not needed but what about the guys who shoot handguns and have that ported section to reduce muzzle climb? AR15 are ported at the top of the flash suppressor. Always thought that it was for the same purpose--> muzzle control. Don't really know maybe totally wrong here. Tks
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I think what you are looking for is either the Magna-Port system which is a pair of large EDM cuts or the screwed on "compensator" form which do not have rifling but an expansion chamber and restriction baffles ahead of the exhaust ports. In either case the recoil reduction is very relative to the load. They work well with heavy to very heavy loads, but not at all with the light loads that bullseye shooters use.
As mentioned, porting isn't done with a drill. Can be done with ECM too. The holes need to be precisely made, of the correct size and at the correct angle to work properly. However, one shot will deburr with no ill effects.
"...thirty to forty years ago you could not..." I believe it's close to thirty years since Magna-port left Winnipeg.
"...thirty to forty years ago you could not..." I believe it's close to thirty years since Magna-port left Winnipeg.
