RCBS Bench Primer Modification

[A-10driver]

I wanted an easier way to prime 200 cases than my RCBS universal hand held priming tool. I liked the 21 century click to change the seating depth but I did not think it would solve the problem of my hands getting tired after the first 100 primers. I wanted something that would not require inserting a primer by hand each time and that left me with the RCBS and a $600 model that was very nice but a bit of over kill for me.

I ordered the RCBS and the auto prime function worked out of the box perfectly. The only problem was getting a consistent seating depth. At first I was seeing anywhere from .002 to .006 below flush. I was considering buying the Holland’s perfect primer seating modification for $140 that would definitely solve the problem. His modification is way more elegant than what I came up with.

I looked around to see what would allow me to get a consistent seating depth and I came up with an old feeler gage that was in my tool box. I took it apart and found a stack of sufficient height to give me the exact seating depth I was looking for. Now that was great but I did not want to have to move a stack of feeler gages in and out each time I needed to have the auto primer place a new primer into place. I had mounted the primer tool to a RCBS mounting plate so I drilled and taped a hole off to the side so I could swing the feeler gages out of the way and then swing it right back into place. The result was a very consistent seating depth (within .0005 ) and keeping the auto prime function.

If you need to change the seating depth on a regular basis then this would not be a good solution. It was just what I needed because I only shoot one caliber and use the same primers and brass.

 

[nmkid]

I wanted an easier way to prime 200 cases than my RCBS universal hand held priming tool. I liked the 21 century click to change the seating depth but I did not think it would solve the problem of my hands getting tired after the first 100 primers. I wanted something that would not require inserting a primer by hand each time and that left me with the RCBS and a $600 model that was very nice but a bit of over kill for me.

I ordered the RCBS and the auto prime function worked out of the box perfectly. The only problem was getting a consistent seating depth. At first I was seeing anywhere from .002 to .006 below flush. I was considering buying the Holland’s perfect primer seating modification for $140 that would definitely solve the problem. His modification is way more elegant than what I came up with.

I looked around to see what would allow me to get a consistent seating depth and I came up with an old feeler gage that was in my tool box. I took it apart and found a stack of sufficient height to give me the exact seating depth I was looking for. Now that was great but I did not want to have to move a stack of feeler gages in and out each time I needed to have the auto primer place a new primer into place. I had mounted the primer tool to a RCBS mounting plate so I drilled and taped a hole off to the side so I could swing the feeler gages out of the way and then swing it right back into place. The result was a very consistent seating depth (within .0005 ) and keeping the auto prime function.

If you need to change the seating depth on a regular basis then this would not be a good solution. It was just what I needed because I only shoot one caliber and use the same primers and brass.

View attachment 1187618 View attachment 1187619 View attachment 1187620 View attachment 1187621

What is that little tool you are using to check primer depth?

 

[A-10driver]

I made it out of parts sitting around. I used a starrett indicator with a part from a Hornady case gauge tool. If I had a lathe I would have made one that was perfect, but I don’t so I just grabbed what I had and made it work. It is very repeatable.

 

[TrapperBR549]

Thanks for sharing. I have the same tool, although much older, and will be giving this a try.

 

[Shooter13]

Question, before the mod did it seat the primers to deep or not enough? Or was it just inconsistent?

 

[A-10driver]

It was just inconsistent for me. It has pretty good feel but has way more leverage than my old hand held seater. I had very tight primer pockets that would only seat to.002 below flush and looser pockets that would seat fully bottomed out at .006 or more. I was trying to get to .004 below flush which would give me about a 50% anvil compression.

 

[Mad_Charlie]

Just curious, did you try uniforming your primer pockets before you went through all that?

 

[Cryhavoc]

"where there's a will, there's a way"....pretty ingenious! Thanks for sharing!

 

[clowdis]

I have to agree with Mad Charlie. Primers need to be seated to the bottom of the pocket. The way to get consistent seating depth is to uniform the primer pockets, not leave the primer sitting off the bottom of the pocket just to make the depth the same.

 

[A-10driver]

I looked at uniforming the pockets but the Brass I have is all within .001. I might try it in the future.

 

[chop house]

clever