chamber reamer for rimmed cartridge question.

[ammohead]

I am rechambering my H&R 17 hmr to 17 Hornet. I have a centerfire receiver and so far all is going well. I purchased a reamer from Midway and it should be here this week. The picture on their website is for a 17 hornady but the body looks a little long. This could be because it was photographed across the flutes making seem slim for length. This reamer should cut the rim area too correct? Am I correct in assuming that seeing rimmed cartridges head space on the rim that I can head space by using a straight edge across the head while in the chamber using Hornady factory ammo. I am thinking that the edge should barely contact the head with no space in between. Or do I allow the head to stand a bit proud and hand ream if closing the breech becomes a issue later?

I was a bit concerned with the cutout for the ejector (will mill cut ejector to fit new diameters) being an issue with starting the reamer where there is not full radius contact so I procured a 9/32 carbide end mill that I will make a starting cut till full radius and then start the reamer there. I also could make a false pilot from brass and slip it on the end of the reamer with the straight body diameter of the 17hmr for the first .200" or so. What are your recommendations?

[John Taylor]

I would dial the barrel in on a lathe and use a small boring bar to take the chamber out to the bottom of the extractor cut. You could take the spring out of the ejector, figure out a way to hold it in and cut it with the chamber as you cut the chamber. Do not try to cut the ejector his way if the chamber is already cut. Most rim thickness on the hornet run .062" but the book calls for .065". You can check the rim cut with a depth gauge. Might check the barrel to action fit, should not be able to get the barrel to lock up with a piece of paper between the barrel and breach (about .004")

[ammohead]

Thank you John, good advise as always. I will be using a 3 jaw chuck but it is 2 axis adjustable and I can indicate the bore in center, and I have made a bushing to center the muzzle in the spindle. Not sure that I have access to a boring tool that small. I will investigate and post results here. At least you didn't say that it could not be done and that is encouraging in itself.

[KCSO]

If you don't have a boring bar off set a milling cutter and use that for a boring bar.

[Rifle 57]

I am rechambering my H&R 17 hmr to 17 Hornet. I have a centerfire receiver and so far all is going well. I purchased a reamer from Midway and it should be here this week. The picture on their website is for a 17 hornady but the body looks a little long. This could be because it was photographed across the flutes making seem slim for length. This reamer should cut the rim area too correct? Am I correct in assuming that seeing rimmed cartridges head space on the rim that I can head space by using a straight edge across the head while in the chamber using Hornady factory ammo. I am thinking that the edge should barely contact the head with no space in between. Or do I allow the head to stand a bit proud and hand ream if closing the breech becomes a issue later?

I was a bit concerned with the cutout for the ejector (will mill cut ejector to fit new diameters) being an issue with starting the reamer where there is not full radius contact so I procured a 9/32 carbide end mill that I will make a starting cut till full radius and then start the reamer there. I also could make a false pilot from brass and slip it on the end of the reamer with the straight body diameter of the 17hmr for the first .200" or so. What are your recommendations?

Do not trust the pictures of the reamers on Midways web site they do not have the correct photo on some of there reamers.

[ammohead]

The reamer camen in the mail from Bwana Larry. All is good. Also got size dies and shellholder and from Black Hills Shooters Supply 250 pieces of Hornady 17 Hornet brass. I talked to the machinist at work and he fixed me up with a small boring bar. I think I still may make a small bushing to slide on the pilot for getting started. .245" od x .166" id just for the first 1/2" or so to keep the reamer centered. Here is the extractor after mods.

http://i574.photobucket.com/albums/ss189/brucerfrechette/elk/gunsmithing/DSCF3531_zpspy1h1ku4.jpg (http://s574.photobucket.com/user/brucerfrechette/media/elk/gunsmithing/DSCF3531_zpspy1h1ku4.jpg.html)
5/16" end mill for portion next to web and 3/8" for the rim.