Flaring problems

[Alberta woodsman]

Hey I searched Google with no luck but I need help. I have a swedish rolling block in 12.7x44r that I Started reloading for this spring. I just noticed recently that when i flare the cases they only flare on one side of the case mouth instead of an even flare all the way around? I am using Bertram brass and lyman 50-70 dies and a buffalo arms .513-.517 flaring plug. I should say it does this with the original flaring plug and other brass too. Any solutions to this problem?

thanks in advance

Woodsman

[herbert buckland]

Have you trimmed and squared the cases all to the same length

[MT Chambers]

Are you using a press? With proper alignment? Is there an alignment problem with your shellholder?

[25ring]

Sounds like an alignment problem.I would either leave the die loose in the press or put an O ring under the lockring.FWIW---Mike.

[Alberta woodsman]

Herbert- I have made sure they are all squared up.
MT- I am using a older RCBS Rockchucker, might be a problem with the shell holder but I have tried with a 50-70 shell holder and a 8mm lebel shell holder and both gave me the same results.
25ring- I shall try what you have suggested

thanks for the imput. I will let you know this evening how it turns out.

[fouronesix]

It is fairly common when expanding necks with M type expanders in similar type cartridges.

I think it is caused by uneven neck wall thickness and/or uneven temper around the neck circumference. VERY LITTLE differences of either around the circumference will show those symptoms.

Not much can be done for 100% cure. You can try truing up the mouths by lightly trimming and chamfering. Outside neck turning of this type case is a real pain. Annealing may help but it's almost impossible to achieve a 100% evenness of anneal- it only takes the slightest difference to start the offset during expansion.

I think I would try truing and chamfering the mouths. Anneal the necks. Then use the MINIMUM amount of both resizing and expanding that will both chamber easily and hold the bullet. Depending on the match or mismatch between the sizing die and the chamber, you can try backing out the sizing die a little at a time and checking the chamber fit and bullet fit. With brass springback the expander only needs to be bullet diameter to maybe .001" less than bullet diameter. Bullet neck tension only needs to be minimal in singles shots.

[country gent]

Neck thickness, Hardness, alighnment of press, squareness of die, all affect this. A die body with the thread out of square or not concentric can have this effect. A press with ram to die thread not true. a press with a die thread or top not square or true. A bent expander or not true with threads. The o-ring allows the die to "float" some and stay in position. Make sure cases are burr free on the case mouths and edges are properly chamfered. You also might try a light polish on the expander itself with flitz or jewlers rouge, work slow and polish the stem and taper keeping the polish lines parrell to center line of expander. Also make sure there is no Build up of hard fouling in cases or on expander. Some press have play in the ram allowing for it to float to center with tooling. Keep in mind when the ram is extended 4" play and or run out is mutiplied. A .001 run out at bottom of stroke is .005 at top of stroke. Also lightly dry lube the case necks with ica and a bore mop to aid even expansion

[montana_charlie]

Herbert- I have made sure they are all squared up.
MT- I am using a older RCBS Rockchucker, might be a problem with the shell holder but I have tried with a 50-70 shell holder and a 8mm lebel shell holder and both gave me the same results.
25ring- I shall try what you have suggested

thanks for the imput. I will let you know this evening how it turns out.

I agree with those who think you have an alignment problem in your press/shellholder/expander die.
Run a case up and back while noting where the off center error is.

In other words, does it look like the case is too far back (away from you), too far forward (close to you), or to one side or the other.

Then, do another case and see if the error is always to the same side of the case.

Once you establish which way the off center error lies, it should be easier to detect what is causing it.

In any event, once you see which side the expander goes to, turn the shellholder a half turn to see if it changes.
Then, turn the expander die a half turn. If that cures it, turn the expander plug a half turn to figure out if it's the die or the plug that is crooked.
(It MIGHT be that the expander plug was crooked when mounted in the lathe to be turned.)

CM

[hiram]

Is a friend available with a press to try your die, brass, shellholder on?

If not, you could try running the brass in without the shellholder engaged(frefloating), then slide the shellholder on and tap down with a small hammer or weight.

[fouronesix]

I doubt it's a shell holder/die/press alignment problem. Most cartridges are not held rigidly in the shell holder and have quite a bit of "play" in all directions. As the expander enters the case mouth it will "find" center and alignment as the case has freedom to follow same.

By all means test it with someone else's press and shell holder but keep all other variables of the test the same.

[Alberta woodsman]

Well I tried letting the die sit loose with no luck. I might just have to deal with it as it has never happened to me before as I reload for many pistol cartridges and a couple rifle cartridges that need to be flared.

[fouronesix]

I've seen this many times. It's especially noticeable when expanding a case mouth by more than a few thous. That's why I suggested minimal resizing and minimal expanding.

If there is a large mis-match between your chamber and the 50-70 sizer, the case mouth might be getting sized down quite a bit thus requiring a bunch of expansion. If that difference is large, the condition you're describing is common.

I would try to find a way to reduce that difference.

[hiram]

Check the expander button......see if it was machined out of round.

[Alberta woodsman]

I think the problem I was having was the shell holder not holding it aligned. If I leave a gap between the shell and the back of the shell holder it usually flares evenly but I not have another problem. I was using a lee 450gr .515 mold but the bullets come out at .517. Once loaded they will not fully chamber without problems. I guess I'll have to get a sizing die from Buffalo arms.

[fouronesix]

Glad you got that working right! A trick to try is to raise the ram slowly until you can just feel contact, stop and back it down a little, then go back up to finish the sizing or expanding. Many times that will allow the cartridge to find center. Also, sounds like the shell holder you're using isn't correct for the cartridge head. Of course that is understandable with old type or odd cartridges like the 12.7x44.

A way to check correct alignment between shell holder and cartridge is to remove shell holder and slip it over the cartridge, then turn it over and see if the primer is centered in the hole in the shell holder.

[Alberta woodsman]

Thanks fouronesix I'll try that.

[MT Chambers]

That mold sounds way too big, all the .50 Sharps rifles that I make bullets for want .512" bullets.