Sounds rather pornographic but actualy I'm after a brief description of the technique of mixed reamer chambering, ie acheiving a chambering by using 2 different reamers.

No doubt it is possible to for example make a 6mm international from a 22-250 reamer for the body and finishing with a 6mm rem reamer for the neck (if the 6mm rem shoulder and body are narrower - this is an example only) I have been told by my smith that it is very difficult to prevent the neck reaming going off centre and that a proper reamer is allways best. Is this correct? Here wildcat reamers are very very rare and certainly not for rent.

But how about the other way around to try and acheive a 22 chambering from a 6mm reamer. Unless the neck part of the reamer is removable surely it is impossible.

I am interested in obtaining a standard thickness necked 5.6x57 utilising a thick necked 5.6x57 reamer and another centrefire 22 reamer.

Hola 1894
you can made a proper reamer , try www.reamerrental.com or clymertools.com , I never work with the 5.6x57 with the thick neck what's the main problem ?

Regards

Daniel

1894,
With a proper setup there is no problem with alignment. In the case of the 5.6x57 though you cannot make a reamer cut a smaller hole than it is designed to do. So to make the neck smaller it will be necessary to reduce the size of the neck portion of the reamer. Regards, Bill

Bill is Ok that not possible to cut smaller than the reamer dim

a reamer from Pacific Precision ( DAVE KIFF ) cost no more as custom than a reguler one so you can order a 5.6x57 with reguler 0.260 neck dia and a REAL THROAT 5.6x57 original throat is very deeeeeeeep and very broaaaaaaaaad the best respice to make NOaccurate round .

why not work on 22/6 REM reamer is available from midaway ( PPG with solid pilot ) and dies from RCBS .brass is cheap not like the 5.6x57 from RWS.
and velocity is the same range .

Note cut a chamber in 5.6x57 with thin neck is dangerous if any people try to shoot a regular thick factory round in your rifle .

good shooting

DAN TEC

I once chambered a prototype test barrel using 3 separate reamers, body dia, neck dia, throat. But that was a straight wall bottleneck (no body taper). Still had concentricity issues. There are a LOT of machine shops with grinding capabilities that can grind a reamer of your design. Some of the smaller bodied calibers can be ground using $15-$30 chucking reamers as a "blank". I have even been advised (in the case of a truely unique application) that the chamber can be single pointed, IE cut with a boring bar instead of a reamer. Of coourse if you already have a reamer for the larger caliber, it can be reshaped/reground to that of the smaller caliber.

If you have a Lathe with a rear headstock spider and you indicate the bore exactly to NMT .0001 runout and you allign your tailstock perfectly to the center of the bore ( easier said then done ), then I believe that you MIGHT have a good chance of making a chamber using two or more reamers assuming the second reamer is used only for the neck/throat and that the rest of the dimensions are such that the reamer will not touch the chamber anywhere else. Using this method you will have to be extremely carefull to locate the neck/shoulder position exactly
correctly or you will have produced a CUSTOM chamber that may no longer work with your dies.
Frankly, I really can't reccomend this approach any more than I can reccomend chambering with a boring bar and taper attachment. Sure It can be done ( yes I have done it this way), but why? for a $30 dollar reamer rental or a $120 reamer you risk wrecking the barrel. Unless your gunsmith is a certified machinist don't even think of having him try this. -Rob

take the risk to ruin a barrel or get something never accurate is for me not interesting if you compare to the $137 of a true custom reamer from PPG .

making chamber reamer is not so easy and only few company in USA sucess to produce very good reamer I work with JGS , Dave MANSON , and most PPG it is just when you have finish the rifle that you can check the quality of th eparts you have purchase and if they are bad it's to late .

if you shoot a lot with 22 cal big case barrel life is just 1000 shots of barrel life and when you need to change barrel you get the same chamber and the same result .

I do some chambering ( for my own use ) by using several reamer , generaly that to get neck up cartridge as 8.06 or 338.06 or 6/22.250 I get good accuracy ( prefect machine tool and live pilot reamer ) but I use these chambering for hunting or case forming wilcat developement .

good shooting

DAN TEC

I have fitted and chambered literally hundreds of barrels and many have been done with seperate reamers for the neck and throat. As I said previously, with a good setup and good pilots there is no problem with concentricty. I throat seperately as a matter of routine in some calibers since throat length requirements can vary widely.
The caution by Dantec on tight necks makes sense but I will recount an experience in this regard.
The other day I was out with another shooter while he sighted in a rifle with a chamber I had done for him. The chamber was a 6.5x55 with a .290" neck. The load was the same as I was using in my long range "F" class rifle. I noticed he was having a hard time closing his bolt and in fact some cartridges he was unable to chamber. Those he did chamber after considerable effort shot fine and produced velocities about the same as my rifle. Finally after watching him pounding the bolt closed on another I stopped hin and extracted the cartridge. It turned out his necks had been turned insufficiently and were about .002" oversized. My cartridges fit fine and the chamber dimension were exactly the same as mine. The interesting thing was that pressures didn't seem to be excessive from those tight cartridges. Nonetheless I think it is safe to say that oversized necks are bad!
A couple of other observations. That shooter is a powerful man. RPA actions have good, strong bolt handles. Regards, Bill

This is very common in Australia.

Just recently a mate of mine got a JGS reamer for the gunsmith to use and with removable pilot in 25/300 Win and that was to do 25, 270 and 7mm on 300 Winchester case.

Last time I had contact with Dave Manson he recommed one reamer for 416 Rigby based calibers.

Another mate of mine is getting a Manson reamer in 25 Ultra with removable pilot, but he actually will be doing 7mm Ultra to start with and that way he can do every Ultra except the 338 Ultra.

Mike

This is the added benefit of having a removable pilot on a reamer.