6ppc small base reamer??

[DngBat7]

This may be a very stupid question, so I pre-apologize for asking. But last year at a benchrest class I took, one of the instructors mentioned he is toying with a 6ppc small base reamer. He is a notable shooter, so I am wondering what the purpose of this type of reamer would have in a benchrest rifle. Please don’t shoot the messenger. Just curious.

 

[Dusty Stevens]

In conjunction with dies made from the sizing reamer that matches it will give you better primer pocket life

 

[BartsBullets]

Or he could have been talking about using it to make a small base die. If you shoot your brass long enough you’ll need a small base die to keep your brass running smooth.

Bart

 

[butchlambert]

Well not hearing exactly what your shooter had to say, but I spec my resize die reamer .003" smaller at the diameter above the extractor groove and .002" at the shoulder. These specs are from my chamber reamer dimensions. I would never chamber my barrels with a reamer that would make it difficult to resize brass.

 

[BoydAllen]

Years ago, I knew a shooter who did his own work and told me that he had tried a reamer that was just a little smaller than those that were common at the time. He quickly abandoned the project because it caused him to have click at the top of bolt lift problems. If your FL die is a good fit for your chamber, the only time that a case will fit loosely is before it is fire formed.
When a case is repeatedly fired using warm to hot loads. the diameter of the solid case head gradually increases in very small increments. If a chamber starts out too small in relation to new brass this will lead to an interference fit (the aforementioned click) that is partially because of the difference in coverage of sizing dies and chambers. This is one of the reasons that you hear of people resorting to ring dies that are used with pushers instead of shell holders. Some of this can be dealt with by clever chambering and die and shell holder modification, but many do not completely understand the problem.