Modifying rcbs pistol seating stems.

Status
Not open for further replies.
AJC1

AJC1

Member
Joined
Jan 14, 2020
Messages
12,371
Location
St Marys Georgia
Is the black seating stem hardened, and does it cut ok with high speed steel or is a carbide cutter required. Is cutting the flat point seater completely flat a bad idea or should I try and keep a little of the shoulder as a guide. My issue is with a lee cast bullet and a standard flat nose die both in 38.
 
Dont believe they are hardened steel. I did modify several of my RCBS seater plugs to fit specific bullets. Also messed up a few seaters too and ended up buying replacements from RCBS too.
 
bummer7 said:
Dont believe they are hardened steel. I did modify several of my RCBS seater plugs to fit specific bullets. Also messed up a few seaters too and ended up buying replacements from RCBS too.
Click to expand...
Did you use a collet or thread some material and make a holder
 
You aren’t taking much off so you can probably hold on the threads without distorting them.
 
can't you just thread the stem upside down on the die then put the die in the press? put a rag around the die to keep the slag away from the press?

luck,

murf
 
The seater plugs are easy to modify and make fit any bullet nicely. As far as the shoulder of the flat seater, yes you can remove it without issue, but I found it's better to leave it and just polish the sharp corner so if you have a bullet too crooked it won't dig in before straightening it out. If you ever mess up a plug they're easy to fix and make a custom seater while you're at it. I've made several custom seaters by enlarging the end, filling halfway with epoxy and setting a bullet into it. Here's one I recently did for my Lee 401-175TC bullets. It does a much better job when seating bullets than the flat plug did because the tip of the bullet looks flat but it's actually not.

plug1.jpg plug4.jpg
 
AJC1 said:
Did you use a collet or thread some material and make a holder
Click to expand...

Wish i can tell you how i did it. But i dont remember the details. I just jerry-rigged a way to hold it in a drill press vise and in the chuck. Then hollowed out the seating stem enough to seat bullets on the shoulder instead of the bullet nose.

Note. I did screw up the first one i tried making as the seating plug collapsed the first time i tried it. Overall, modified seateing plugs work fine. Have one each for the H&G 68 bullet and the second custom plug for 158 gr LSWC bullet for a 38/357 cartridge.

Still have to make a custom seating plug for the 148 gr LWC bullet tho. Will try using epoxy for this one project.
 
You can also send them 2 samples of your bullet and they'll mill a new stem to fit exactly. The price was reasonable...under thirty bucks if I recall.
 
I used a file to flatten a rcbs seating plug for .38 wadcutters. The file cut the plug with some quickness. I am practiced with a file and was able to get it very flat and perpendicular to the threads of the plug. The black finish wearing off of the part tells you a lot about how true you are cutting it. A file in IMHO is the single most underrated tool in the shop.
 
Last edited:
BC17A said:
The seater plugs are easy to modify and make fit any bullet nicely. As far as the shoulder of the flat seater, yes you can remove it without issue, but I found it's better to leave it and just polish the sharp corner so if you have a bullet too crooked it won't dig in before straightening it out. If you ever mess up a plug they're easy to fix and make a custom seater while you're at it. I've made several custom seaters by enlarging the end, filling halfway with epoxy and setting a bullet into it. Here's one I recently did for my Lee 401-175TC bullets. It does a much better job when seating bullets than the flat plug did because the tip of the bullet looks flat but it's actually not.

View attachment 928121 View attachment 928124
Click to expand...
These look interchangeable. Did you make plugs you can swap out
 
Otto said:
You can also send them 2 samples of your bullet and they'll mill a new stem to fit exactly. The price was reasonable...under thirty bucks if I recall.
Click to expand...
For a competition bullet this just makes sense. If I did not have a lathe at my parents I would just do it.
 
If the non-threaded part of the seating stem is long enough, you can tighten a lathe chuck on it also, with the threaded portion behind the chuck. You can use a boring bar or end mill to deepen and flatten the inner portion of the stem. You could also turn the stem flat.
 
garandsrus said:
If the non-threaded part of the seating stem is long enough, you can tighten a lathe chuck on it also, with the threaded portion behind the chuck. You can use a boring bar or end mill to deepen and flatten the inner portion of the stem. You could also turn the stem flat.
Click to expand...
My initial idea was to make the seating section shallower and try and match the angle of the bullet ojive. It's a cone point so I hope it's just a continuous angle. Indicating will let me know.
 
AJC1 said:
My initial idea was to make the seating section shallower and try and match the angle of the bullet ojive. It's a cone point so I hope it's just a continuous angle. Indicating will let me know.
Click to expand...

Now you have me thinking. If you customize the seater plug on the ogive; does this only fit that particular bullet?

I have thought of tryjng this for a specific rifle bullet but would use epoxy to create a custom fit.
 
AJC1 said:
These look interchangeable. Did you make plugs you can swap out
Click to expand...

No, just two pics of the same stem. First was taken after it was hollowed out, second is completed after epoxy.
 
bummer7 said:
Now you have me thinking. If you customize the seater plug on the ogive; does this only fit that particular bullet?

I have thought of tryjng this for a specific rifle bullet but would use epoxy to create a custom fit.
Click to expand...
Yes if you try for an ojive fit it will limit your fit possibility. When working with flat nose bullets it should not be so limiting.
 
Guys, here's the link to PSA's clearance. Looks like they still have several 97¢ RCBS seater plugs left. I bought fifteen of them and with shipping was under $25. Ignore the pictures as some show die bodies but they are actually just the plugs.

PSA Die Clearance
 
Some photos of the RCBS seater plug I modified for seating the H&G #68 as well as the H&H 130 bullet. One is black and the other is grey. The walls of both plugs is thin but thick enough to seat bullets by pushing the shoulder instead of by the nose.
DSC00614.JPG DSC00613.JPG DSC00615.JPG
 
Status
Not open for further replies.

Similar threads

PO2Hammer
  • Locked
.38/.357 seating die with flat stem?
Replies
18
Views
4K
theReloadist
T
AJC1
  • Locked
Seating lead bullets and seating stems.
2
Replies
32
Views
1K
AJC1
AJC1
D
  • Locked
How do I make a bullet seating stem?
Replies
9
Views
1K
jeepmor
J
S
  • Locked
Problem with RCBS .380 seating die cutting into bullets.
Replies
10
Views
1K
ssyoumans
ssyoumans
N
  • Locked
RCBS rifle die - "plain" seating stem?
Replies
1
Views
314
fguffey
F
Back
Top