Preparing 30BR brass

[mk_gram]

I have recently had my Benchrest Rifle re-barreled from 6mm PPC to 30BR. I have expanded 100 rounds of Lapua 6BR brass to 30 cal. I am having an issue when trying to turn the necks to remove the donut (created after expanding) at the base of the neck. The neck will not fit onto the neck guide (pilot). Can I shoot each case once with the donut still there in order to expand the neck or is there some type of reamer I should purchase?

 

[yat3b35]

When necking up your 6br brass to .308 you should use a good expanding mandrel ( not an expander button that is in a sizing die ) that is .001" smaller than the bullet diamenter. When you then turn your necks use a turning mandrel .002" smaller than the bullet diamenter. I use a Sinclair NT-1000 neck turning kit and it works just fine for me , http://www.sinclairintl.com/.aspx/pid=38664/Product/NT_1000_Neck_Turning_Kit

I'm not sure that you could even close the bolt on an unturned neck with the bulge on them , especially if you have a good tight neck chamber ' and if you could and then fire them , where is the bulge going then ? The're plenty of time before the season starts so I'd purchase a good expander die and the correct size expander and turning mandrel , run the cases thru the expander and then turn them. Don't forget to lightly lube the inside of the necks before necking up and or turning.
Hope this helps you. John

 

[artbosco]

I have recently had my Benchrest Rifle re-barreled from 6mm PPC to 30BR. I have expanded 100 rounds of Lapua 6BR brass to 30 cal. I am having an issue when trying to turn the necks to remove the donut (created after expanding) at the base of the neck. The neck will not fit onto the neck guide (pilot). Can I shoot each case once with the donut still there in order to expand the neck or is there some type of reamer I should purchase?

First, make sure the neck turning pilot and the neck expander are made by the same manufacturer. If not, most of the time your going to have problems with the fit.

In short range benchrest we don't worry about the donut. However, if you don't want them, go here for a carbide cutting pilot: http://www.kmshooting.com/catalog/neck-turner-tools/carbide-cutting-pilot.html

When using one, make sure you lube it sufficiently and slide it on slowly so you don't scratch the inside of the neck where the bullet will eventually reside. It's easy to do because the cutter is very sharp.

If you use the K&M cutting pilot make sure you use the K&M expander too.

 

[82boy]

I have found that I don’t like expanding up brass. I found for me the best way to do it is to just fire form the brass, and forget necking it up.

But since you have necked up your brass you need to fix what you got. The brass with a donut more than likely will not fit into the chamber and allow the bolt to close. If your neck trimming pilot doesn’t fit the brass after being sized up, then you need to fit it to fit. I chuck my pilot into a drill and sand it down with sand paper staring with 120grit and working my way up to 2000 grit. It will be highly polished. I prefer a tight fit, I sand my pilot to where it will not go in dry, but will slide in with a drop of oil on it. You may have to go back and forth between the sandpaper, and brass to get a proper fit.

If you have a chamber gauge, you can measure the cut. My finding is that you will have to trim the donut off flush with the neck to get the case to chamber.

 

[mk_gram]

Thanks for all the tips!

I have ordered the K&M 30 Cal. Expandiron Mandrel and a K&M Neck Trimmer. The other thing I am attempting to do is make a tool from one of the cases to measure the over-all-length (OAL) in order to know how deep to seat the bullets. I put a piece of pencil with 350 grit sandpaper wrapped around it in my drill press and I was able to sand the inside of the neck to where the guide fits the inside of the neck and will drill & tap this to fit the Stoney Point O.A.L. tool. After sanding, I was able to use my neck trimmer and remove the outside donut. I am going to wait until I have the K&M components before working the rest of the brass (I have goofed up enough stuff to know that proper tools are necessary).

I read an article to trim the brass to 1.500. My new barrel is a Hart but they could not tell me what the chamber depth is and I am assuming it is around 1.520 which would give .020 of free bore. Their chamber neck diameter is .333. They told me to contact the chamber reamer manufacturer as they had no way to measure it. Hart did the barrel with what they call "Skip Flat" fluting and did a really nice job.

 

[82boy]

I read an article to trim the brass to 1.500. My new barrel is a Hart but they could not tell me what the chamber depth is and I am assuming it is around 1.520 which would give .020 of free bore. Their chamber neck diameter is .333. They told me to contact the chamber reamer manufacturer as they had no way to measure it.

I have talked to Randy Robinett about this and well, it gets more confusing. Randy told me that his original 30BR reamer has a 330 neck diameter, and he likes to see a case cut 10 thousands short. With the original design it should have a neck length of 1.510, and he cuts his necks to 1.500. The original design has 0 free bore. Now this is where it gets complicated there are many reamers out there that are called 30 BR Robinette, but they have been change slightly and they are all different. With that said, what works for some people may be different for others.

 

[P1ZombieKiller]

I have pics of how I do my brass on my website. The pics are not great as I was using my phone to take the pictures when I did it. Go to the benchrest shooting page. Stay with the K&M tools and you'll be happy.

www.p1huntclub.com

 

[Steve Blair]

I read an article to trim the brass to 1.500. My new barrel is a Hart but they could not tell me what the chamber depth is and I am assuming it is around 1.520 which would give .020 of free bore. Their chamber neck diameter is .333. They told me to contact the chamber reamer manufacturer as they had no way to measure it. Hart did the barrel with what they call "Skip Flat" fluting and did a really nice job.

The Sinclair Chamber Length Gauge is what you need. I have these for all calibers that I shoot. It removes all the guessing and gives you a true "trim to" length. Most chambers are longer than SAAMI specs.

http://www.sinclairintl.com/.aspx/pid=32925/Product/Sinclair_Chamber_Length_Gage

 

[25AI260]

mk_gram
i ran it to the exact problem as you... i rig'd up a drill bit just to make 5 round for a test... i was gona go thru for the next 95 cases.. anways i started with a 7m br fl die an then went to .30 cal tapered sizer... the cases would not fit on K&M's mandrel.. curses !.. i solved that problem with a [midway has them] 511497 $8.49 Forster Oversize Expander Ball that fits on the redding's decap rod .. mine is a fl bushing die

 

[mk_gram]

Thanks ... I will order one!

 

[artbosco]

I have ordered the K&M 30 Cal. Expandiron Mandrel and a K&M Neck Trimmer.

Did you order the "Special" 6mm to .30 Caliber expandiron mandrel http://www.kmshooting.com/catalog/case-neck-expanding-tools/special-6mm-.30-expand-mandrels_for-expand-iron-assembly.html and not just a .30 Caliber expandiron mandrel?

Also, did you mean you ordered the K&M Neck TURNER vice the trimmer? You said trimmer above. There's a big difference.

 

[artbosco]

I was able to use my neck trimmer and remove the outside donut.

I hope you mean neck TURNER and not a trimmer. A turner reduces the thickness of the brass in the neck. A trimmer reduces the overall length of the brass.

 

[mk_gram]

I meant a neck turner!!! I also ordered their neck expander.

 

[artbosco]

... anways i started with a 7m br fl die an then went to .30 cal tapered sizer... the cases would not fit on K&M's mandrel.. curses !.. i solved that problem with a [midway has them] 511497 $8.49 Forster Oversize Expander Ball that fits on the redding's decap rod .. mine is a fl bushing die.

Question. After you introduced the Forster Over Sized Expander Ball into the expanding and turning process, how much of a gap was there between the turning mandrel and the inside diameter (ID) of the unturned neck? Was the gap .002", .003", .004" etc.?

Or, was it the .001" that you would expect to see when using the same manufacturer's expanding and turning tools?

This is really a simple process. If you find that once you do get matched up tools, that it's a little tight when trying to slide on and turn a neck on the matched mandrel, then run the neck through the expander a few times.

As a habit, I expand the neck once, then turn the case about 120 degrees, expand it again, turn it another 120 degrees and expand it the third time. I've never experienced a problem with a tight neck once doing that. At one time I made 90 degree turns and expanded four times but found that I was overdoing it.

I've found over time, that the metallurgical properties of brass vary just a little in each case, and that complete dimensional expansion is a little harder to achieve in some than others.

You might give the multiple expansions a try first before using a die's expander ball [which may not give you the ideal neck ID prior to turning] as a substitute, for a matched expander and turning mandrel.

 

[mkihne]

Outdoorsman is correct. With new Lapua brass, some cases will not slide onto your turning mandrel without unusual effort. By going back to the expander mandrel(matched to that turning tool) and running the case up one or two times more, you will find the fit easier. Be sure to use enough lube in the case neck and on the turning mandrel. Assuming you are shooting score with the 30br, the donut is not significant. If you turn your necks to the proper level on new brass, you can do so and have them chamber ok. A friend of mine over sizes his cases to about 20 thou too short to leave the donut below neck level. He also anneals after sizing to get a better fireform and uniform headspace measurements, even on the first fireforming. Even if you do not do this, the bullets used will seat well above the donut even with no free bore. Fireform with a jam(with or without a little machine oil on case as TB and my friend does). After firing the cases first time, return to your expander mandrel and re expand. This will transfer the donut from inside to outside of case. Then turn again with final cutter setting unchanged to remove donut, again taking care not to cut into the shoulder. You can use pin gauges after first firing to check your neck inside diameter. You will likely find some cases have a donut and some don't.

This works with K&M, Sinclair and Nielson turning tools and I suspect others as well.

mike

 

[P1ZombieKiller]

I have recently had my Benchrest Rifle re-barreled from 6mm PPC to 30BR.

MK... maybe I missed it, but I want to make sure that you changed bolts out, or at least had a bolt that would work with both the PPC and the BR cases. Don't want you doing all that work, and then not being able to shoot it. ;D

 

[25AI260]

Outdoorsman..
sorry i didn't get a reply option to the thread..

the oversized ball left the ID very still tight..

i have two neck turners, one is Hornady the other is k&M... i use the k&M to finish

after i size from 6mm to .30 i use the Hornady to skin the neck.... then i run the case thru the oversized expander ball.. with the neck now more willing to stay expanded it will then slip on the oiled k&M mandrel.. no space if.. if there was it would be like .0001

Mk... the old brass didn't go either which i have cardboard gold an black box

[i checked the notify button this time]

 

[artbosco]

Outdoorsman..
sorry i didn't get a reply option to the thread..

the oversized ball left the ID very still tight..

i have two neck turners, one is Hornady the other is k&M... i use the k&M to finish

after i size from 6mm to .30 i use the Hornady to skin the neck.... then i run the case thru the oversized expander ball.. with the neck now more willing to stay expanded it will then slip on the oiled k&M mandrel.. no space if.. if there was it would be like .0001

Mk... the old brass didn't go either which i have cardboard gold an black box

[i checked the notify button this time]

Rich,

The use of an expander ball is not part of the turning process and introducing the Hornady turner along with the K&M turner is complicating matters.

My recommendation:

1. Use the Special 6mm-30 caliber K&M Mandrel on the Expand Iron.

2. Obtain one or two K&M Turners. You really only need one. [I only use one for the 30BR and two for the 6PPC because I turn very thin for the PPC.]

3. Make sure you also use the K&M 30 Caliber Mandrel on the one or both of the K&M Turners. Matching up all tools by the same manufacturer is VERY IMPORTANT and will eliminate all the problems you've been encountering. Turning will be a snap and will proceed much easier.

4. Read this as a supplement: http://www.accurateshooter.com/technical-articles/neck-turning-basics/ There are no expander balls used here. Forget that it's written for High Power Shooters and uses the 30-06 as the sample cartridge. The BASICS are all the same. He's covering two topics: Why to turn necks and how to turn necks. German Salazar provides great pictures and good advice.

If your 30BR has a .330" neck chamber, you'll be turning brass so that the OD measures .328" with a seated bullet, measured on the pressure ring. Your total diametrical clearance will be .002" or .001" on each side.

Since I use Ronnie Cheeks .308 caliber bullets, with a .3084" pressure ring diameter, my calculations are: .3084" + [brass turned to] .0098" + .0098" = .3280"

Good Shooting!

 

[25AI260]

thanks outdoors...
looks like a good read

i'll tell ya what i'm having trouble with is logging on here every darn time kinda get'n ti B a pita...

 

[mk_gram]

I did not use the oversized expander because I used the K&M "6mm-.30 Special Expand Mandrel" and the neck then fit the pilot perfectly.

I measured the chamber length of my rifle and it is 1.567 and the brass length after expanding is 1.525 (+/- .001). This means the freebore is .042 but I still have to trim the case length to have them all uniform. If I trimmed them all to 1.520 I would have .047 freebore (I assume "freebore" is the difference between case length and chamber length).

1) Should I shoot them once without trimming the length and then trim?
2) Will the brass length get longer after I shoot them the first time?
3) What should the maximum freebore be?