Questions on how to spec a reamer ?

[Hal]

I have a few questions about ordering a reamer that will work with factory dies.
How much sizing is required at the base of the case,or .200 above the back of the case,.
How much does the shoulder needs to be resized ?
What clearance works best in the freebore diameter and leade length ?
Some of this info has been posted but I can,t seem to find it in my searches.

Thanks for any help.

Hal

 

[Shawnba67]

I dont have good answers, but if you make a cerrosafe cast you could send it to the reamer maker. They should know how to spec reamer to the die.
Also I like your idea, probly better outcome for cheaper than custom dies!

 

[spclark]

You want a custom reamer to cut a custom chamber just so you can use factory dies for sizing brass?

For what cartridge?

Seems kinda backwards-thinking to me, but whatever floats your boat.

My suggestion would be to 1) pick a reamer-maker then 2) send them the dies you want them to make you a reamer to work with.

Be a lot shorter path to success than getting (well-qualified? Yes, but still...) various opinions here, then trying to come to a decision on your own, without regard to what the folks you want doing your bidding might have to say.

 

[spclark]

I dont have good answers, but if you make a cerrosafe cast you could send it to the reamer maker. They should know how to spec reamer to the die.

i agree with your last sentence, but the first one? Why bother casting a die, when you can send the die itself? Cerrocast is dimensionally accurate for a very small window of time after pulling from mold. Two or three days later? Not worth the trouble.

 

[gunsandgunsmithing]

I have a few questions about ordering a reamer that will work with factory dies.
How much sizing is required at the base of the case,or .200 above the back of the case,.
How much does the shoulder needs to be resized ?
What clearance works best in the freebore diameter and leade length ?
Some of this info has been posted but I can,t seem to find it in my searches.

Thanks for any help.

Hal

I've done it this way for a long time with zero problems. On ppc and br size cases, I have the chamber reamer made .003" larger than the die. With springback, this yields a sized case that is about .0015" smaller at the shoulder and about .0005-.0006" smaller at the web.

Works great and I've never seen a down side. It makes perfect sense to me.

 

[DaveTooley]

I don't think you're building a target rifle since you'll be using factory dies.

1. Leave the body at SAAMI specs. There is absolutely no reason to go smaller unless you'll get custom dies made.
2. If you have the brass already spec the neck diameter .006" larger than a loaded round.
3. Freebore doesn't have to be as tight as most think. In fact a freebore .0005" over nominal bullet diameter will from time to time cause problems. Spec it at .0012" over bullet diameter. I can't help with length as I don't have enough information. Caliber and rifle specs.
4. 1'-30" lead angle

 

[geraldgee]

I don't think you're building a target rifle since you'll be using factory dies.

1. Leave the body at SAAMI specs. There is absolutely no reason to go smaller unless you'll get custom dies made.
2. If you have the brass already spec the neck diameter .006" larger than a loaded round.
3. Freebore doesn't have to be as tight as most think. In fact a freebore .0005" over nominal bullet diameter will from time to time cause problems. Spec it at .0012" over bullet diameter. I can't help with length as I don't have enough information. Caliber and rifle specs.
4. 1'-30" lead angle

Good advice here

 

[Hal]

My son wants a .17 Remington for a calling rifle and I have a lot of brass and several sets of dies. Loaded ammo neck diameter is .196 - .197 , I thought I would go .200 - .201 on the reapers neck. The .17 bullets measure .172 with a pressure ring measuring .1721 on the small amount of bullets I measured.
That was the reason for wanting a reamer that would work with factory dies.
The chamber size (reamer size),brass and dies all have to work with each other to get the best accuracy and brass life.
Thanks for the replies.

Hal

 

[hogpatrol]

My son wants a .17 Remington for a calling rifle and I have a lot of brass and several sets of dies. Loaded ammo neck diameter is .196 - .197 , I thought I would go .200 - .201 on the reapers neck. The .17 bullets measure .172 with a pressure ring measuring .1721 on the small amount of bullets I measured.
That was the reason for wanting a reamer that would work with factory dies.
The chamber size (reamer size),brass and dies all have to work with each other to get the best accuracy and brass life.
Thanks for the replies.

Hal

SAAMI spec is .200. You may have better brass life with .199.

 

[Dusty Stevens]

Id call jgs and tell them what youre doing and they will get you what you need or let the gunsmith handle it

 

[gunsandgunsmithing]

Id call jgs and tell them what youre doing and they will get you what you need or let the gunsmith handle it

That's what got me started doing it this way. I spoke with Dave Kiff, found out that he makes a lot of the resize(die) reamers for the die makers and he clued me in to how much smaller the die reamer should be. I then started checking things, and he was right. So, I started spec'ing chamber reamers accordingly.

I know that Dave has been a controversial name to mention of late. Whether or not you agree, he was the MAN for many years. I still think he knows now, what he knew then, and very likely, more. I started doing business with him a long time ago....when we all knew, he was the MAN.

Most people that run him down wouldn't know how to turn a T&C grinder on.

 

[Dusty Stevens]

I dealt with dave when he was at jgs. Thatll blow some minds. He is the depository of reamer knowledge for sure but i never have much luck talking to him and cary at jgs hasnt let me down yet

 

[Hal]

SAAMI spec is .200. You may have better brass life with .199.

 

[Hal]

.002 total clearance or .001 per side is a little tight for a hunting rifle.

Hal

 

[BoydAllen]

I have spec'ed out a few reamers for factory dies. IMO the best way to do this is to get a hold of some well used, (fully work hardened) fired cases and size them with the die, and then measure the sized case. With those measurements in hand you can add the clearances that you want at various locations in the chamber. This is a bit trickier when doing it for a one piece die, which will of course require a tight neck chamber. for a FL bushing die you need only concern yourself with the body diameters, principally at the shoulder and .200 up from the head. You may also want to consider how different die companies dimension their dies, and how that relates to unfired cases. For instance, in the past, RCBS used SAAMI minimums for loaded ammunition while Lee used SAAMI max. Years ago I helped a friend order a reamer for a tight neck .223 based on cases sized by a RCBS one piece die. With necks turned to the proper thickness we had the exact amount of neck tension and chamber clearance that we wanted. The loaded rounds were extraordinarily straight and since everything else in the rifle was correct, it literally shot like a competition rifle. For the doubters....I suggest that you not discount what you have not experienced. For a hunting rifle I would not make the clearance at the back too small. .002-.003 from very work hardened brass would be my suggestion. You can always polish out the die or the chamber to make a slight adjustment. If you feel the need later. This can be a very good method to come up with reamer dimensions. I have done it...several times.

 

[hogpatrol]

.002 total clearance or .001 per side is a little tight for a hunting rifle.

Hal

My .17FB reamer is .2012 and load rounds are .199. Have used it on four barrels, no issues.

 

[butchlambert]

Hal,
I spec my sizing reamer at .003 smaller at the base above the extractor groove and .002 smaller at the shoulder. This is from my chambering reamer specs.