300 rum Reloading Bolt Won't close sometimes

[CogburnR]

Nothing wrong with RCBS. I have RCBS and Redding for the RUM based chamberings I load for and shoot.I have a 650 and would not resize RUMs on it. Too much flex in the base plate. IMO You will break it before you can bump the shoulder.

What I believe after reading this far is that:

You have a wide, short chamber. Not a bad thing but...
When you resize you are reducing the diameter of the case but the shoulder is "moving" up. Think squeezing a balloon. Which is a great metaphor for cases anyway. In many ways then are balloons with a cork in them......

so You are not bumping the shoulder back far enough. IMO you will break your Dillon if you try.

IIWM:

• Get a single state press to resize the RUM brass in. Something fairly strong. Get the Recommended RCBS shell holder, it's on the box and I think its a #38 but could be a #4.
• Get a Hornady headspace comparator. Measure a fired case that will rechamber nicely, on the shoulder per the instructions, then measure a sized case. Adjust your die until the sized case is .001 to .003 shorter.

You can keep using the Dillon for the remainder of the reloading process just without the sizing die.


When I use my Dillon for rifle reloading, I do this or similar:

• Clean the brass.
• Resize without the expander ball.
• Clean off lube.
• Use the Dillon to complete the reloading process. Instead of a resize die in the first position, a neck expander die. The rest is the same.

I agree.


In addition to the above:

A 40 cal pistol case can be used for a comparator until you get a real one. Aim for .002-.003" shoulder bump for reliable feeding. Compare your resized case length to the shoulder with the comparator( or a 40 case) to a fired case.

 

[el matador]

I would do the sharpie test to see where the brass is binding up. Take a cartridge that is hard to chamber and cover it completely with black marker. Chamber it, tap it out, inspect. This will tell you exactly where it is binding.

 

[Deleted member 46119]

I would do the sharpie test to see where the brass is binding up. Take a cartridge that is hard to chamber and cover it completely with black marker. Chamber it, tap it out, inspect. This will tell you exactly where it is binding.

I get so embarrassed when I miss the easy because of focusing on a high tech solution. IE comparator (tech and tools) vs. sharpie solution (cheap, fast, easy).

Yes, by all means, sharpie method.

 

[ehryk]

I am going to have to second the insufficient shoulder bump here as you have just described what happens to me when my cases after 3 or 4 firings. I also partially full length size my brass for my .300 WSM when it has grown too long from neck sizing only. I smoked the neck and shoulder to see how close I was as I very slowly turned down the die. I also have an RCBS case micrometer that I use for setting the die to exactly .002" shoulder bump. The partial body resize coupled with the shoulder bump makes for very easy chambering when hunting.

 

[baydog]

Hi
Just wanted to thank everybody for your time and helping me figure out the problem that was causing the cambering problem or the bolt not closing with some of, well most of my reloads. The ole sharpy test put me on the trail until I figured out that the problem showed up around the bottom of the shoulder. I just wasn't resizing or shorting the shoulder up enough. I ended up screwing the die down so much that it does actually cam over. I kept screwing the die down and expecting a mushroom to pop out but nope! The bolt shuts like a champ now! Slick as butter!! Besides this website the sharpy is a great tool to have in your reloading tool box!!
Thanks everybody!!

Scotty

 

[baydog]

I get so embarrassed when I miss the easy because of focusing on a high tech solution. IE comparator (tech and tools) vs. sharpie solution (cheap, fast, easy).

Yes, by all means, sharpie method.

Me to jfseaman..And it worked !!..LOL

Thanks

 

[baydog]

I would do the sharpie test to see where the brass is binding up. Take a cartridge that is hard to chamber and cover it completely with black marker. Chamber it, tap it out, inspect. This will tell you exactly where it is binding.

Thanks el matador!! The sharpy did it.. It showed me that the problem was around the bottom of the shoulder. I kept screwing the resizing down until it does cam over but the bolt shuts like butter now!
Thanks again

Scotty