22BR Neck Split & Trim

[Accurifle]

Hi, I am at a case prep status for my new 22BR project.
After 100 run of 6BR cases through FL die, I found three of them had neck split. This is my first wildcat and don't know this is general or not. Of course I have read 22BR guide in 6BR.com and chamfer the outside of the neck and lubed in & outside before the squeeze. Oh, the cases are from Lapua.

In addition, I also found the case mouth seems like it has crashed, it is deformed slightly. The diagram says case length of 6BR is 1.55 and 22BR is 1.52. Should I trim them?

Please let me know what you know.

 

[Mikem]

You should trim them first, to make sure there short enough to allow them to grow a little when sized down to 22BR. Otherwise the necks may crush. And then you may need to trim them again to the correct length after sizing or fire forming.
Do you plan to full length size after every firing, or just neck size?
Normally neck splits happen on older harder brass, how many times has it been fired? If allot, you will either have to except a few splits, or anneal the brass first.
What are you lubing the case necks with? You might try a light cote of sizing wax, It might help.
Mike.

 

[Accurifle]

Mike, thank you for the info.
Believe or not, these cases are just out of the box of the manufacturer, unfired brand new.

I used common machine oil on inside with Qtips and imperial wax on outside with fingers.

I will trim them soon.

 

[anyrange]

Accurifle
I did 200 Lapua cases the same way you did couple of years ago. I did not have any problems, I think you just happen to get three bad cases that had neck issues before you resixed them. It happens.
What are specifications on your 22 BR reamer. I ordered mine with .248 neck, Zero Freebore, and 1.570 for 1.560 case length.
No trim length.
If you have to turn the necks, do it first. The 6BR neck shoulder will move up into the shoulder when necked down to 22BR.

 

[NorCalMikie]

Use the Imperial, inside and outside! Clean it off with brake parts cleaner, paint thinner, etc. Try sizing that way and see if it makes any difference in split necks. Never had one on new or fired brass while sizing to 22 BR.

You need to know your 'actual chamber length'. That will tell you when you cases need to be trimmed. Once you know that, you can set your case OAL to where 'you' want it.

 

[Accurifle]

The barrel is Border and the reamer is their own. I only checked their reamer is .254, no turn neck because 22BR info in the site did not mention the case length. I should have confirmed the diagrams first.
The form die is a Redding full length standard one. Don't know if it has a ceiling? to which the case crashes.

I will turn some cases and see what happens.
Thank you anyrange and NorCalMikie!

 

[NorCalMikie]

When I mentioned knowing your 'actual' chamber length, this is what I use.
When you know the measurements, you can set the OAL of your cases to the length you want and you'll know they are close to needing to be trimmed. If you set the headspace on the tight side, you will be able to go a long time before you need to trim.
Example: I've got 2 22BRs and a 6 BR. The chamber length,actual) on the 22 BR chambers is 1.584 and the 6 BR is 1.580 so if you're trimming to say 1.560 max, you've still got a way to go before you get neck interference. And that measurement won't change. And if you neck size only,,bushing) your brass won't grow like with full length sizing. Maybe 10 firings with no brass length change. A body die once in a while if the brass starts getting tight in the chamber.
And I use a Redding full length in 22 BR to neck down my brass.
Neck size with a Forster Bushing Bump Die and no shoulder bump. You don't need to know the reamer specs if you know the actual chamber length. Write it down so you won't forget, like me.

 

[Accurifle]

Great advice! Thank you Mikie

 

[Preacher]

Those necks look like they have been expanded to me...
No need to trim until they have been fired at least once...
Not so sure about using motor oil for a lube, when Imperial die wax works so good and sure is cheap enough...

 

[Accurifle]

Yeah, I thought the same. I have never imagined a case split happnes in necking down.

As to lube, wax is hard when it's cool and difficult to apply on inside the neck. So I used machine oil with Q-tips. Could you tell me how you do that?

 

[NorCalMikie]

Roll a Q Tip in the wax. Do the inside of 5 or 6 cases at a time.
Use some wax on your fingers to do the outside of the neck and upper body/shoulder area. Too much and you get dents in the shoulders but they'll blow out as they get fired. Doesn't take much on the outside. Trial and error.

 

[Accurifle]

Thanks a million! Will try. :thumb:

 

[jb]

having just done 3000 20vt from 223 lc. i learned a lot mainly what not to do. i found a small dent inword on the case mouth would some times cause an inward crease looking like a crack. any out of round mouths start over exspanding ball by hand to true up.

 

[NorCalMikie]

Might be that going from .223 down to 20 is a little tougher than from 6MM to .224. The smaller the caliber gets might have a bigger effect on the necks? Were you using new brass?
I might have split one neck out of 1000 or so.
After my brass is fire formed I only neck,bushing) size with very few problems. You could expect problems if the brass has been fired a bunch.

 

[Mikem]

One think that didn't get mentioned is, when making your 22br cases, its a good idea to chamfer the outside of the neck mouth, so it starts in the 22 cal neck bushing or die easily. This may reduce the number of cracked necks.
I also spin the case mouth down on a green 3-M scrub pad after chamfering, this smooths things out, and removes any burs.
I also use Imperial wax as the lube, both on the outside and inside the neck,if your die has a mandrel to size the neck.
If its just a outside bushing, there's no need to lube the inside of the neck.
Just a little wax on a Q-Tip, and its easy to remove with a 22 bore mop and a bit of lacquer thinner, or brake cleaner, as Mikie said.
And I have never split a case neck, knock on wood.
Mike.