Unconventional sizing of base !

[Okumacaptain]

So bought a new rifle (6br) and factory barrel has smaller chamber than my Shilen and Criterion. I don’t have any new brass so had to size base down about .0015 and I don’t have a small base die and I want to shoot tomorrow . So I put the base of the case in a collet and adjusted collet so on closing it crimped base down about .0015. I know this isn’t normal but I’m not normal . I see only having to do this once as long as I keep this brass for this gun . Any issues with way I did it ?

Thx

Mark

 

[SSL]

If your current die doesn't size the bases, when you get to the point where you have to bump the shoulder, it will be interesting to see how much the base expands as the shoulder is set back. Maybe not at all, but I wouldn't be surprised to find that it does.

 

[Okumacaptain]

If your current die doesn't size the bases, when you get to the point where you have to bump the shoulder, it will be interesting to see how much the base expands as the shoulder is set back. Maybe not at all, but I wouldn't be surprised to find that it does.

After I crimped the bases down .0015 I had to bump shoulder back because bolt still didn’t want to close easy. After bumping shoulder case chambers fine and I just measured base and it did not grow .

 

[RegionRat]

Not that unusual. Collet sizing the case just above a belt is even more widespread, but folks collet size or push cases through a ring die now and then, that is, if they have the tools and resources.

Do watch your primer pocket diameter.

 

[SSL]

After I crimped the bases down .0015 I had to bump shoulder back because bolt still didn’t want to close easy. After bumping shoulder case chambers fine and I just measured base and it did not grow .

Good. Glad you seem to have solved the problem.

 

[D-4297]

You may also want to check case over-all length , as brass can "migrate" when this is done , Similar to having cases expand in length when fired . Brass flows to the neck . Annealing and trimming will be helpful to maintain your newly "re-formed" cases .

 

[bainp]

I think using a collet die to size the base of the case is a great idea but have never heard of it before. Can you actually buy a sizing die to do this - for rimless cases?

 

[Okumacaptain]

I think using a collet die to size the base of the case is a great idea but have never heard of it before. Can you actually buy a sizing die to do this - for rimless cases?

This was definitely unconventional. I used a 5c collet in a manual lathe to do this . I don’t think they sell a collet to fit a press to do it this method . I work in a machine shop so I can come up with different ways to do things . Not always the right way , but hey , if it works !

 

[Fast14riot]

I use an old RCBS 45acp die gutted as a ring/base sizer for my 260AI cases. I can try it on a 6br case and take some measurements, if you want.

 

[Okumacaptain]

I use an old RCBS 45acp die gutted as a ring/base sizer for my 260AI cases. I can try it on a 6br case and take some measurements, if you want.

Sure ! Would appreciate it .

 

[Fast14riot]

Sure ! Would appreciate it .

I took 6 cases, all fired from 1x-3x times. Measured fired base diameter in a CBI 6br Norma no-turn neck chamber (off the shelf, prefit barrel, PTG reamer). These cases have been annealed after every firing, but I did not anneal them before this sizing. I pause for a count of 5 at the top of the stroke during sizing, no matter which die I use.

Here is a pic of the data and the RCBS 45ACP die I use. These old style dies, when you gut them, are the same diameter all the way through. I can and have run 30-06, 270, and 260AI brass through this die and it only sizes the base, how much depends on case taper. Each line across represents the same case.





Hope this helps. I think I paid like $15-$20 bucks for this die on ebay. Works well. I also have a custom made ring die that does not size as far down as this die does, I did not include it in this sample.

 

[Fast14riot]

As you can see, the amount of sizing down from the fired dimension is from .0021" at the least to .0026" at the most. Final size range of .0005" isn't bad in my book, especially for mixed firing brass. If you also notice the trend, the largest base diameter fired, regular sized and ring die sized all stayed the same. This speaks to brass memory, and how over pressured cases may not always be salvageable, which may not be your case as you're trying to fit a different chamber.

 

[Intheshop]

I've tried the 5C collet idea in the past for other handloading chores.... works OK. Have also used the 45 acp "gutted" die. Also can use altered "cheap" dies,usually a larger bodied/bore and peeling off the needed few .001's from the bttm. Another is roll sizing,I use it on cast bullets. Need to make a video on it because I can't properly put into words how it functions. But there are "roll sizers" on the market. Not that hard to reverse engineer.

But thanks for the headsup/sharing in anycase.

 

[Coyotefurharvester]

When you use the die for the 30/06 brass, do you just lube the .200 line or the whole body?

 

[boltfluter]

Great tip with the 45 die. I use an old .243 die that has a smaller diameter than my regular 6 Dasher die. Works great sizing just the base. I have several. 243 dies of different manufacturer's and they all vary a little at the back. One of them is always right for the job at hand. Many ways to skin this cat.

Paul

 

[Okumacaptain]

I took 6 cases, all fired from 1x-3x times. Measured fired base diameter in a CBI 6br Norma no-turn neck chamber (off the shelf, prefit barrel, PTG reamer). These cases have been annealed after every firing, but I did not anneal them before this sizing. I pause for a count of 5 at the top of the stroke during sizing, no matter which die I use.

Here is a pic of the data and the RCBS 45ACP die I use. These old style dies, when you gut them, are the same diameter all the way through. I can and have run 30-06, 270, and 260AI brass through this die and it only sizes the base, how much depends on case taper. Each line across represents the same case.

View attachment 1291073

View attachment 1291074

Hope this helps. I think I paid like $15-$20 bucks for this die on ebay. Works well. I also have a custom made ring die that does not size as far down as this die does, I did not include it in this sample.

Thank you .

 

[Fast14riot]

When you use the die for the 30/06 brass, do you just lube the .200 line or the whole body?

Out of habit, I typically lube most of the case body. I use Imperial wax, its not like I'm saving anything lubing only 25% of the case.