Finish Reamer Question

[duurmeehr]

Can I please get an education on finish reamers.

I am re barreling my daughters Remington 700 from .243 to 260 Remington.

I pulled the barrel and have a new short chambered one on order.

I see there are pull through and regular.

I see there are fixed and live pilots.

Why can you buy different size pilots for some reamers?

Can you use the same reamer on all .308 based calibers by just changing the bearing?

Does the reamer cut the throat some or is that done during the rough reaming?

Barrel is still 4 months out so I have plenty of time to learn.

 

[mao0720]

You can get different pilots for reamer so that the pilot can more closely match the bore of your individual barrel and therefore guide the reamer better. You can only use a 260 reamer to ream a 260 chamber, and a 308 reamer to chamber in 308 win, etc. The biggest reason being neck diameter. If you used a 308 reamer in a .264 Dia bore, you would have a perfect 308 chamber and massive neck clearance between the loaded round and the neck are of the chamber. Upon firing the case neck would most likely split and the bullet would not travel down the bore perfectly straight ruling in poor accuracy, no brass life, and possibly a dangerous situation. As far as freebore and throat angle, that will be determined by the finish reamer as well although you can use a uni throater to lengthen the throat after finish reaming the chamber. Hope that helps.
Mason

 

[duurmeehr]

Thanks, that makes a lot of sense. I couldn't understand why for instance PTG offered a solid or interchangeable pilot reamer. I am thinking that the solid pilot would be for the more "noncritical" applications because they would have to leave it at minimum to make sure it fit all bores within the tolerance.

Now my anal self is thinking I need to buy an interchangeable reamer with an assortment of bushings while my practical self is thinking a 300 yard deer rifle will work fine with the solid reamer!

Can you offer some advice on that?

 

[EWaugh]

I think for a 100-300 yd hunting rifle, a solid reamer would work. Having said that I would spend a little more and purchase the piloted reamer. It will come with a bushing at least mine have been supplied with them. And you could always sell the piloted reamer, while IMO selling a solid reamer would be difficult.

 

[liseo]

You can get different pilots for reamer so that the pilot can more closely match the bore of your individual barrel and therefore guide the reamer better. You can only use a 260 reamer to ream a 260 chamber, and a 308 reamer to chamber in 308 win, etc. The biggest reason being neck diameter. If you used a 308 reamer in a .264 Dia bore, you would have a perfect 308 chamber and massive neck clearance between the loaded round and the neck are of the chamber. Upon firing the case neck would most likely split and the bullet would not travel down the bore perfectly straight ruling in poor accuracy, no brass life, and possibly a dangerous situation. As far as freebore and throat angle, that will be determined by the finish reamer as well although you can use a uni throater to lengthen the throat after finish reaming the chamber. Hope that helps.
Mason

I dont understand how you can drive the 308 size pilot in the .264 bore...Is this correct? :-\

 

[liseo]

Ok, got it.

Removable pilots :-[

 

[X Ring Accuracy]

Above said is true. A floating piloted reamer is better. Different pilots for differing bore diameters. Not picking on you but it seems your'e new to this. I suggest you do a few trial runs on set up, threading, chambering on a scrap barrel. I may have some rem take offs Ill send you for cost of shipping. Better to learn on that then the match grade barrel.

 

[338 Mollett]

What a nice offer,a very refreshing attitude X Ring!

 

[duurmeehr]

Hey, thanks for the offer X Ring. A lot of nice people on here.

This is just a Shaw $200 barrel that will already be short chambered just needs finishing.

It's a tinkering project to spend time with my daughter and build memories more than anything.

I feel like when you teach them how a firearm functions rather than just how to shoot it it's better.

If I ruin it running a finish reamer in it I will either pay my smith to set it back and fix it or throw it away.

 

[spclark]

I am re barreling my daughters Remington 700 from .243 to 260 Remington.

I pulled the (.243) barrel and have a new short chambered one (in .260) on order.

I see there are pull through and regular.

I see there are fixed and live pilots.

Why can you buy different size pilots for some reamers?

Barrels differ very slightly in bore diameter. Using a reamer with a removable pilot allows the fitter to best match the pilot to the bore diameter of the barrel being fitted. You can't do this with a solid piloted reamer, you have to use it as it comes.

Can you use the same reamer on all .308 based calibers by just changing the bearing?

Does the reamer cut the throat some or is that done during the rough reaming?

No to the first question and yes to the second, usually.

Roughing reamers are just that; they remove the bulk of the metal when a chamber's being cut in a new barrel blank. It's not absolutely necessary to use one unless you plan on chambering a bunch of barrels with a finish reamer, but it does extend finish reamer life before they need resharpening.

Pull-thru reamers are for finishing chambers in short-chambered barrels that are already mounted on actions. If you can get a given barrel and action separated, then get the barrel centered up in a suitable lathe, there's no reason to use a pull-thru reamer... unless it's the only reamer you have available.

All 'flavors' of reamers will cut both the chamber body as well as the neck profile. You don't chamber a "308-size" case body then cut a "243-size" neck with a different reamer. Now that's not to say one couldn't use a .243 rougher to start a chamber that's going to end up as a .308! I'm sure that's been done fairly often.

Then there are 'specialty' reamers called "throaters" that are specifically designed just to cut the area ahead of the chamber neck to lengthen the distance from the neck end to where the bore's lands begin. Frequently done to allow using bullets that are on the longer side of those available for a particular cartridge, like using 220 grain bullets in a 308WIN that's been cut with a typical 308 reamer designed for bullets up to, say 165 - 185 grains.

It's good there's time between now and your barrel's expected delivery. You do have time to learn more about what you want to undertake. You might want to read up on what GO and NO-GO gauges are to be used for between now and then.