MEC 600 JR Mark V Station 1 Adjustments

[Brett Farley]

Morning all, this may be a dumb question but here it goes. I have a post 1995 600 JR Mark V set up for 12 gauge shells. Station 1 (de-priming/case sizing) station does not properly resize brass on the shells. I have looked on line at MEC adjustments as well as following the limited directions in the manual for this station. However, when I check the brass sizing in a MEC Shell Checker the brass is still slightly to large to fit. At first I thought it may be the particular once fired hulls I was using (RST) but I also checked w/Remington STS once fired hulls and I get the same results.

To make sure I wasn’t losing my mind I resized them in a different 600 JR Mark V that I have and they resize properly. Any thing I’m missing or any suggestions would be appreciated. I may end up ordering new parts for this station but wanted to check before I did as this unit is in good condition and has seen little use. Thanks - Brett

[Brett Farley]

As a test I swapped out the collar on the reconditioning dies and the shells resized correctly so it leads me to assume I have a defective collar. I believe I can order that part instead of the whole reconditioning die.

[Double Lab]

Brett,

Give MEC a call. They are very helpful. 800-797-4632.

[edgarspencer]

Is the wire ring inside the collar? That ring is what actually sizes the brass on a 600Jr.

[Brett Farley]

Edgar, I looked at both the resize rings (part #20 on the diagram) and MEC Part #8465 and there is not wire ring inside either one of them. I’ll call MEC tomorrow and see what they say. Thanks!

[edgarspencer]

Originally Posted by Brett Farley

Edgar, I looked at both the resize rings (part #20 on the diagram) and MEC Part #8465 and there is not wire ring inside either one of them. I’ll call MEC tomorrow and see what they say. Thanks!

My mistake. That was only one the earliest version.

[J.B. Books]

Originally Posted by Brett Farley

Morning all, this may be a dumb question but here it goes. I have a post 1995 600 JR Mark V set up for 12 gauge shells. Station 1 (de-priming/case sizing) station does not properly resize brass on the shells. I have looked on line at MEC adjustments as well as following the limited directions in the manual for this station. However, when I check the brass sizing in a MEC Shell Checker the brass is still slightly to large to fit. At first I thought it may be the particular once fired hulls I was using (RST) but I also checked w/Remington STS once fired hulls and I get the same results.

To make sure I wasn’t losing my mind I resized them in a different 600 JR Mark V that I have and they resize properly. Any thing I’m missing or any suggestions would be appreciated. I may end up ordering new parts for this station but wanted to check before I did as this unit is in good condition and has seen little use. Thanks - Brett

The resizing ring on a MEC600 is a wear item. They wear faster when reloading hulls with steel heads rather than brass but they do last a long time.

They are gauge specific. It's 20A for 12ga. https://www.mecoutdoors.com/600-jr-mark-5-parts

[Brett Farley]

Thanks everyone for your feedback. I’ll order two to have an extra on hand. Brett

[Brett Farley]

Forgot to mention that I ordered new resizing rings. Before I left for Tulsa last week I loaded a box of shells and the new resizing ring worked great. All of the shells were in tolerance. Thanks for everyone’s help! Brett