Chamber reamer extension?

[Willys]

I did the shot case trick but used a piece of 320 grit cut from a peel and stick sanding disk. I think a strip stick through a slotted wood dowel may be best. You can by chamber hones on amazon too.

 

[11A-18A Vet.]

Lots of good advice. I will chew on this and decide how to go forward. Thanks!

 

[Blaster 1]

Lots of good advice. I will chew on this and decide how to go forward. Thanks!

If your just neck sizing that might be your problem

 

[Coyote Shadow Tracker]

I have bought a PTG chamber reamer to open up the chamber (a tiny bit) in a custom-barreled 300WM which is a bit tight. I want to use the reamer without having to take off the action. What can I use to extend the reamer so I can turn it from behind the action? Thanks.

Is the Case tight in length? Can't you size the Case with your FL Dies to match the chamber? Or are you looking to extend the Throat for a longer Bullet? If looking for a longer Throat use a Uni Throat Reamer. If your Neck is tight you can use a Uni Neck Reamer or Turn the Necks.

Uni-Throater, HSS with T-handle & Extension-119377

www.pacifictoolandgauge.com

 

[Rflshootr]

Is the Case tight in length? Can't you size the Case with your FL Dies to match the chamber? Or are you looking to extend the Throat for a longer Bullet? If looking for a longer Throat use a Uni Throat Reamer. If your Neck is tight you can use a Uni Neck Reamer or Turn the Necks.

Uni-Throater, HSS with T-handle & Extension-119377

www.pacifictoolandgauge.com

What I'm getting out of it is the body diameter of the chamber up close to the body shoulder junction is tighter on one chamber than the other. It is causing the fired case to not headspace by approximately 1/2" in the chamber before it binds because of neck sizing only. So, depending on the reamer ( I'll wild guess he bought a SAAMI reamer), the thought is to enlarge the tight part of the chamber up to the shoulder.
It can be done, but there is a high risk of the reamer cocking ever so slightly that it will dig in. If that happens, you're pretty much screwed. At that point, the barrel will have to be taken off, put in a lathe, and set back to get rid of the marks. I've done similar to this to lengthen headspace a couple of thousandths, but I made a bushing that slipped in the action to align and support the reamer shank. I would suggest to take it to someone that knows how to install barrels and have it done in the lathe,......OR just full length size instead of neck sizing.....problem solved.

 

[Rodbolt]

I have bought a PTG chamber reamer to open up the chamber (a tiny bit) in a custom-barreled 300WM which is a bit tight. I want to use the reamer without having to take off the action. What can I use to extend the reamer so I can turn it from behind the action? Thanks.

Open up the chamber in what dimension? Headspace? Bullet to barrel land distance? Diameter of the cartridge taper - where along the datum? If you haven't done a chamber cast with micrometer measurements to compare to your PTG reamer you'll have no idea as to what/where the cut metal is coming from. A lot of custom chambers are oversized at the rear/base of the chamber for various reasons such poor lathe bearings, poor set up, poor reamer pushers, chamber cutting oil/coolant etc.

Blindly running a reamer into a cut chamber is a recipe for disaster, you have to know exactly what you have as size of current chamber and what the new reamer will cut. I've have new reamers that only cut on one flute, so even with a precise and rigid lathe setup the ream cut oversized. If you are just extending the thoat or adding free bore it's easier. Any accuracy smith would remove the action for this as a perfectly centered and consistent throat is huge for accuracy. If you must use an extension turn a bushing to fit the throater extension and rear of receiver.

So simple to do a chamber cast and see what you've got. Might be worthwhile to cast your sizing die and see if it's compatible with your chamber before reaming out your barrel. HTH's.