Partial Neck Resizing Question

[texas270]

I've been resizing about half the length of my necks and acuracy has been great; however, after a couple firings, it seems that the case is not chambering well, I think due to expansion of the portion of the neck which is not resized?

Would appreciate thoughts on this and others experience pro/con with partial neck resizing. Thanks in advance.

 

[Gene]

What caliber? Factory or custom chamber? Tight or no turn neck? Most likely answer is that its time to bump the shoulders back a tad.

 

[boomtube]

Normal. Either get a body die to push the shoulder back or FL size them.

 

[texas270]

thanks for the feedback.

I do bump the shoulder every time the neck is partially resized, so it is not an issue with the shoulder.

guess I need to either, (1) quit partially resizing the neck and go to full neck resizing, or (2) after partially resizing the neck a couple times, need to then full resize the neck or full body resize???

does that seem to make sense?

and yes it is a fairly tight fit in the Shillen match grade barrel for my custom 270.

thanks for your feedback!

 

[Gene]

Tex - Your #2 is correct. But I have another concern: Do you know the neck diameter of the reamer used to chamber the barrel? If not, your gunsmith should know this diameter. Or, you could measure it using a micrometer on a fired round.

Next, take a loaded round and measure its neck diameter with a micrometer. How much difference between the loaded round diameter and the fired neck diameter? Your loaded cartridge neck should measure about .002 - .004" (or even more) less. If it does not, that could cause a tight loading sequence, and very high pressures. To correct it, you will need to turn the case necks down until you have enough clearance.

 

[Mikecr]

+1 Gene's checks
Also, you mention chambering 'not well', but how is the extraction?
Stiff bolt lift? Popping free(bolt click)?
Do you have body expansion near the webs?
You might check this also.

You implied that your die bumps while neck sizing. Is this a custom die?
And finally, would you say your loads are stiff?

 

[texas270]

Thank you much for the input Gene and Mikecr.

I'm guessing that I need to look at a few of the issues you point out, such as checking the neck diameters before and after firing.

Often when extracting, it is easy until the bolt is fully raised and then I have to slightly "pop" the bolt upwards for the cartridge to dislodge---is this what Mikecr is referring to?? What would that imply?

I started using the Forster die which decaps, bumps the shoulder and allows a predetermined resizing length for the neck. Have really liked it.

thanks again and hope to hear back from you......

 

[woods]

I believe the Forster bushing/bump die does allow you to set the amount of neck you want to and bump the shoulder back. But from a previous discussion on another thread it was determined that the die does not size the case body at all.

Sounds like you are having a problem from no sizing of the case body. This will cause the bolt catch at the top of the lift. I know because I have a tight chambered 280AI that the Redding Body Die will not size the case body and I have the same problem after several firings on the case.

Get a Redding Body Die and use it to bump the shoulder and size the case body and that will solve your problem.

 

[texas270]

thanks Woods...very much.

I've been trying to decide whether to have a custom resizing die made and think I will since this is my primary rifle.

Happy shooting...

 

[Gene]

That implies that the lower part of the brass case is not being sized small enough. You may need to buy a Redding body die or a small base die.