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EGW Comp Reamer Doesn't Fit Barrel


theWacoKid

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I have an EGW 9mm/38 alignment reamer and the pilot will not fit in a new 9x19 SVI barrel. The pilot is advertised as 0.3445" diameter and mine measures at 0.344". Does this happen to be a common issue or is my gun just plain cursed beyond belief?

The pilot fit fine when I tried reaming the comp on my old KKM, however, that barrel punched the prettiest keyholes you've ever seen.

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I don't think those kind of reamers work very well. If the comp is misaligned with the barrel to begin, the reamer is going to try to follow the original hole and the pilot will be putting a lot of side forces on the rifling as you try to true up the comp hole. YMMV. My method is to put the barrel in the lathe chuck and use a boring bar to bore the comp. Then the hole is srtaight with the barrel and no messed up rifling.

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Well, too late now, but lesson learned. I would try it on the lathe, but the only one working at the moment won't hold the barrel because the through bore isn't big enough to clear the lug.

It definitely was a fit issue. It was not from gross misalignment. It wouldn't even begin to fit in because of the OD/ID interference. I just knocked the OD of the pilot down to 0.341"-0.342" and it would slip all the way down the barrel and allowed me to ream. Bad news is this was after I gave it a good bit of frustrated effort while it was still too tight. I clearly gouged, scratched, and smeared the last half inch or so of the lands back from the muzzle. Any ideas if this thing has a chance of shooting? Right now if I can just get away from massive keyholing I'll be mildy satisfied.

Hint for anyone doing this in the future and something I wish I knew. It seems painfully obvious now. The pilot should not be so tight that you can't fit it all the way down the bore by hand until the reamer is against the first comp wall. Lots of oil is needed but if it won't fit all the way down by hand it's too tight. My assumption was that barrel tolerances and tolerances on a precision piloted reamer would no way have fit issues. Turns out that's a bad assumption. Still not sure how in the world it could drop in the old KKM and not even begin fitting in the SVI.

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The depth of rifling can run from .002 per side to .005 per side. The groove diameter must remain the same for a given caliber. That means the land diameter (the original hole drilled in the barrel) has to be the part that varies. This is the part that the reamer pilot rides on. Different barrel makers intentionally make the rifling a certain depth based on their philosophy of what makes a good barrel, as well as their method of forming the rifling.

Edited by Toolguy
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Hello WacoKid, I also have a small 7x12 lathe and we are certainly are restricted with some needed work. With comps I've installed I chuck the comp and then use drill bits to gradually open the bore, then the reamer for final sizing. My last build was my first Infinity barrel ( 38 super ) but I was lucky using that same reamer, it fit fine. Perhaps the 9 x 19 barrel bore you have is made a little tighter. Don't get to discouraged by learning curve mistakes, I' m self taught and don't like to think about the parts I've destroyed, including barrels.

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Digi,

I'm only discouraged by the possible loss of about $500. I've machined a lot of stuff in my day but I was royally ignorant on the possibility of the pilot on my dedicated reamer needing hand "fitting". Painful to say the least.

I'm sure the end of the lands are going to shave copper off bullets. I can only hope it'll smooth out enough with use to shoot consistent. I took a really bad gamble on this gun and am paying the price I guess.

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  • 1 month later...

It'd be pretty sweet if either EGW or vendors that sell SV and Nowlin barrels mentioned that in the product description. That way it makes sense when you run into this issue. It's a touch worrisome when you don't expect it.

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