Cartridge Base walks in Shellholder when seating

[DrSteve]

I checked 5 places and they were all sold out. They appear to currently have them on Amazon.

Actually, Amazon says they will have them in about a week so I placed the order.

 

[P7M13]

If you find you're SOL, I have three of them....

 

[LoneTraveler]

Does the Lee shell holder seat into the ram centered with the ram?
Have you had problems with RCBS shell holders in this press?
Check the diameter of the bottom rim and grove of the Lee shell holder against a RCBS shell holder, With a Mike or dial caliper.
If the diameter or the groove and bottom rim of the Lee is smaller, It is allowing the top of the shell holder to go back and out of center to the ram. This would make the shell case to slide forward so the shell case will stay centered in the seating die, If the case and bullet are in line when seating the bullet in the die the bullet should be seated straight.
Check the Sizing die closely. If it moves forward in the shell holder when using a Full length sizing die it could cause an OOH WHAT NOW, Tear the rim off the case where the shell holder is contacting the rim on both sides, And you will have a case stuck in the FL die.
Had a friend bring me an old turrent press this happened with. Had to remove a stuck case from the die.

 

[DrSteve]

Does the Lee shell holder seat into the ram centered with the ram?
Have you had problems with RCBS shell holders in this press?
Check the diameter of the bottom rim and grove of the Lee shell holder against a RCBS shell holder, With a Mike or dial caliper.
If the diameter or the groove and bottom rim of the Lee is smaller, It is allowing the top of the shell holder to go back and out of center to the ram. This would make the shell case to slide forward so the shell case will stay centered in the seating die, If the case and bullet are in line when seating the bullet in the die the bullet should be seated straight.
Check the Sizing die closely. If it moves forward in the shell holder when using a Full length sizing die it could cause an OOH WHAT NOW, Tear the rim off the case where the shell holder is contacting the rim on both sides, And you will have a case stuck in the FL die.
Had a friend bring me an old turrent press this happened with. Had to remove a stuck case from the die.

Thanks for your input. I don't think the shell holder is moving. The cartridge base is sliding partially out of the shell holder. I went with the Lee shell holder set since it was very affordable compared to the RCBS. I've ordered the RCBS shell holder and I should have it in a couple weeks. I'll do the measurements you recommend. The press only does this on about 1 in 10 cases. I'm busy holding the bullet in place and pulling the handle, or I would hold the base in place.

 

[longestrange]

Maybe a dumb question, but is the shellholder concentric?
You could try removing the shellholder from the ram, and pushing the shell all the way in. Then flip it upside down and look to see if the primer pocket lines up with the center of the hole in the shellholder.
If that checks out, it may be that the shellholder isn't concentric to the ram in the press. Typically the opening in the shellholder is somewhat towards the front of the press in order to load the shell. You might try rotating the shellholder 180 deg. in the press once the shell is in, then pushing it up into the die and note any movement.
It may also be that the die and ram are misaligned. You might be able to push the ram sans shellholder up against the die and have a look.
Another possibility is that the shell is tilted, maybe because the base of the shellholder isn't perpendicular to the ram.
Some precision measuring gear would be nice, but if you can see it move the error should show up visually.

 

[243winxb]

My RCBS rock chucker got worn . The hole the ram sits in got larger from loading many pistol rounds.
The ram would fall forward when seating a rifle bullet.
Rcbs replaced the RC with a RC ll press, free. Around late 80s.

 

[Chas1]

the case should be held firmly by the shellholder and walking prevented.

Agree. I'd get another shellholder.

 

[jerry moore]

I'm using a Forster seating die in my RCBS Rock Chucker Supreme with a Lee shellholder. Sometimes the base of the cartridge will walk out of vertical position when I'm seating. I haven't measured the runout, but it can't be good. I don't think there is anything wrong with using Lee shellholders. Wonder what I'm doing wrong or if anyone has had this problem?

there's a clip on the top of your ram that helps hold shell holder might check that

 

[baldhunter]

Thanks for your input. I don't think the shell holder is moving. The cartridge base is sliding partially out of the shell holder. I went with the Lee shell holder set since it was very affordable compared to the RCBS. I've ordered the RCBS shell holder and I should have it in a couple weeks. I'll do the measurements you recommend. The press only does this on about 1 in 10 cases. I'm busy holding the bullet in place and pulling the handle, or I would hold the base in place.

Are you using a #2 Lee shell holder?

 

[P7M13]

Wait - it walks while you're driving the ram up *before* you even reach the seater?
Do you feel it vibrate at all, or when the ram is up (no cartridge), can you move the tip where the shell holder should sit from side to side, or wobble it?

 

[Rebell]

I had a hard time finding an RCBS #3 also but found one at Black Sheep in Coeur d' Alene yesterday.

 

[Lenny Foffa]

I have had slight case movement with RCBS Shell Holders # 3 and #4 , with RCBS Dies in my RCBS Press. I use the RCBS Rock Crusher press for all Re Sizing and de priming . It does require me to keep re positioning the case to get it up into the die. Often I need to guide , by hand , the 270 Win cases up into the Re sizing die. BUT I use the RCBS Summit Press and the same RCBS shell Holders with Forester Micrometer Dies for all Bullet seating. Far less of a problem during bullet seating. I wish the RCBS shell holders had tighter tolerances .

 

[JD300WM]

I've been having a similar issue with Lee shell holders and RCBSII press. Not only that, but I use Lee shell holders on my RCBS hand priming tool and the primers get a "swirl" looking mark on them as if they're not being seated uniformly. Switched shell holders and the primer issue went away.

 

[JAYgs8163]

My RCBS rock chucker got worn . The hole the ram sits in got larger from loading many pistol rounds.
The ram would fall forward when seating a rifle bullet.
Rcbs replaced the RC with a RC ll press, free. Around late 80s.

I had the same happen with a Lee press. Junked it and bought a Summit for a clean seating press and use a RockChucker as my dirty sizing press.