Running a Reamer in deep

[xswanted]

So I’ve heard about gunsmiths “running a reamer in deep”

I have a few questions pertaining to this.

How far can you run a reamer in deeper than it’s supposed to go before you can’t use the same brass? For example I have a 22BR reamer, how deep could this be run into the new blank before I couldn’t use regular 6 Br brass necked down?

Is this a legitimate way to gain case capacity or would I be better off just purchasing a 22BRA or 22 Dasher reamer and go with that?

What do you do for dies on a cartridge that the reamer has been run in deep?

Thanks in advance.

 

[varget204]

you can face off the barrel to shorten,as long as you have enough barrel threads left

 

[Dusty Stevens]

The deeper you go the bigger the base gets. Get a 22brx

 

[boltfluter]

As Dusty said, the back end will get bigger and bigger. Cases would not last long as primers pockets will loosen fast. Get the correct reamer for the job. Carry on.

Paul

 

[gunsandgunsmithing]

These guys are right but don't let them scare ya. If the case has .010 taper per inch and you run it .100 deep, it'll be
.001 bigger in the butt end. Different reamer designs vary that much and more. A bigger issue is that the neck will be way short if you run it in that deep.

 

[swd]

Don't forget if your using the parent case the amount you run the reamer in adds that much free bore to the throat. And the back part of the free bore will be unsupported neck diameter also that length. Running a reamer in that deep might work but it has a few big drawbacks depending on your needs. Draw it all out on paper and it will make more sense. More often than not the correct reamer is the better decision.

 

[holstil]

I've had success running a reamer in .010-.020" to better match the die I had.
Most of my reamers are short to no throat.
I like options that a throat reamer give me.

 

[linebaugh]

As stated above the real problem is going to be excessive neck length in the chamber and a seating depth increase. I actually did this in a test barrel and had an excess in the neck cut of about .050 and it seemed to work just fine. Probably not the best plan however.
In the case of the 22BR you did not specify what version you have. If you have a 22 BR remington reamer you can go in .050 and use lapua brass to satisfy the neck issue. Otherwise you will need a 22 BR improved reamer of some type with corrected throat and neck length.

 

[DaveTooley]

Years ago I ran a 6BR reamer in deeper to make a 6X47 case just to see what if anything was to be gained. I still have that rifle with the fat ass end. Really zings 66 gr. Br bullets. I made cases to fit the new case length so the FB length is what I wanted. Then I had a new reamer made. Don't worry about getting bigger on the back end. The primer pockets are unsupported and tight chambers have never proven to extend the life of primer pockets around here. I have many reamers that are too tight on the back end and I have to polish out chambers to make them work. You need a minimum .003" over brass diameter to get things in and out. If the primer pockets move half of that they're toast. I'd suggest just get a new reamer made the way you want it. Always works out better in the long run.

 

[Dusty Stevens]

Don't forget if your using the parent case the amount you run the reamer in adds that much free bore to the throat. And the back part of the free bore will be unsupported neck diameter also that length. Running a reamer in that deep might work but it has a few big drawbacks depending on your needs. Draw it all out on paper and it will make more sense. More often than not the correct reamer is the better decision.

Wont the neck, shoulder, leade, everything move forward? How does the neck get longer with a shoulder following it?

 

[swd]

Wont the neck, shoulder, leade, everything move forward? How does the neck get longer with a shoulder following it?

The case doesn’t get any longer but the chamber does when you run the reamer farther in.

 

[swd]

If you have a .104” FB 6BR reamer and you run it in another .100” to make a 6BRX you now have a .204” FB chamber.

 

[Dusty Stevens]

If you have a .104” FB 6BR reamer and you run it in another .100” to make a 6BRX you now have a .204” FB chamber.

No. You have a .104 fb. It traveled forward with the neck and shoulder. If what you said is right you ran the neck of the reamer in .100 but not the shoulder

 

[gunsandgunsmithing]

No. You have a .104 fb. It traveled forward with the neck and shoulder. If what you said is right you ran the neck of the reamer in .100 but not the shoulder

That's incorrect. The chamber neck length remains the same but the case would have the shoulder blown forward, hence a shorter neck. IOW, lets say the chamber neck is .250 long as well as the reamer. We run that in deep and of course, the shoulder follows it into the barrel. Now we have a chamber that is nominally .100 longer than the parent case and as you know, the neck of the brass would become part of the shoulder. I know it's confusing but suffice it to say, if you have a 1.500 parent cartridge and you run the parent reamer in +.100, you now have a 1.600 long chamber...any way ya shake it.

 

[Dusty Stevens]

The fb, neck, shoulder etc is still hooked to the reamer and moves with it forward. You get a longer case but everything else stays hooked to the reamer. If the neck is .250 long on the reamer its going to be .250 long if you run it in 2 foot

 

[gunsandgunsmithing]

The fb, neck, shoulder etc is still hooked to the reamer and moves with it forward. You get a longer case but everything else stays hooked to the reamer. If the neck is .250 long on the reamer its going to be .250 long if you run it in 2 foot

Exactly, but think about bolt face to end of chamber.

 

[Dusty Stevens]

Exactly, but think about bolt face to end of chamber.

Bolt face to shoulder is longer, shoulder forward is exactly the same no matter how deep it goes. Necks cant shorten, freebore cant get longer. If you run it in 3 inches farther your neck, shoulder and freebore is exactly the same.

 

[DaveTooley]

Bolt face to shoulder is longer, shoulder forward is exactly the same no matter how deep it goes. Necks cant shorten, freebore cant get longer. If you run it in 3 inches farther your neck, shoulder and freebore is exactly the same.

Dusty
It's the same but the basic BR case length doesn't get longer so the case neck gets shorter and the FB gets longer by the amount the reamer is run in deep. You have a longer gap from the end of the neck to the start of the FB.

 

[swd]

No. You have a .104 fb. It traveled forward with the neck and shoulder. If what you said is right you ran the neck of the reamer in .100 but not the shoulder

The OP wants to use a 22BR reamer to make a 22BRX. If he runs the reamer .100” deeper you get an additional .100” free bore ahead of the end of the case. Unless you’ve found a way to stretch the OAL length of a 6BR case that’s how it works out.

 

[Dusty Stevens]

Dusty
It's the same but the basic BR case length doesn't get longer so the case neck gets shorter and the FB gets longer by the amount the reamer is run in deep. You have a longer gap from the end of the neck to the start of the FB.

you know I respect you about as much as anybody but im having a hard time seeing what yall are seeing here. if what you say is true then that means the case mouth stops moving forward, the fb does keep moving forward along with the body and shoulder. so everybody that has posted here has reamers stopping certain points but other points moving forward. ive drawn a diagram and everything and I just cant see how a case mouth stops but the shoulder keeps going.