Min or Max Saami Spec Reamers

[J E Custom]

This has been an interesting debate and the main reason that I posted was to prevent the original
poster from getting a reamer that "could" cause problems if he did not know the effects of subtle
changes in the SAMMI dimensions.

I hear horror stories all the time about a chamber reamer that has been modified without the
owner understanding what the change may cause if not dealt with.

An experienced shooter/re loader may have a specific reason to change the SAMMI dimensions
and knows how to deal with the change.

As a smith I do not recomend any thing other than a SAMMI spec reamer unless the person
understands exactly what he is doing (Cause and effect) and the pluses and minuses that come
with changes to the standard and knows how to deal with them.

It does not take a special reamer to build an accurate rifle.

J E CUSTOM

[EddieHarren]

"It does not take a special reamer to build an accurate rifle" True.

[gunaddict]

Any other thoughts on how much freebore for the ultramags when ordering a reamer?

[ken snyder]

minnimum and maximum dimensions exist for both chamber and cartridges they are maximum manufactureing deviation tolerances. anything within those tolerances is a standardized cartridge or chamber In my earlier threads my objection was and still is the use of the words min spec. or max spec. when we are actually refering to modified cartridges. I am certain most are aware of the difficulties Smitty's have with the general public and not at all interested in explaining poor nomenclature. For many of us it is a liability issue or at the very least a reputation issue as well.

[milanuk]

Just to clarify... because this subject is of considerable interest to me on another front....

There is a SAAMI spec for the chamber dimensions, with a plus tolerance.

There is a SAAMI spec for cartridge dimensions, with a minus tolerance.

The idea is that (factory) ammunition that is at or below the maximum SAAMI cartridge dimensions should still pass into and out of any chamber that is at or above the minimum SAAMI chamber dimensions.

Yes/No/Maybe?

As a result, these 'minimum SAAMI spec' reamers are not truly 'SAAMI spec', but custom ground reamers that are at exactly the minimum chamber dimensions plus/minus nothing, correct? Or are they cut to maximum SAAMI cartridge spec? As an example, .308 Win min SAAMI chamber spec is listed as .344-346 at the neck (tapered), +0.002, but the cartridge spec is listed as a *maximum* of .343 (no taper)... which is a lot closer to what I see in some 'match' chambers - they pretty much start at .343 and go on down - .342, .341, etc.

[azgutpile]

Where does a"Match Grade" reamer fall into all of this?

[ken snyder]

This is a very interesting thread and perhaps one that we are shareing the same general thought. It is not possible to manufacture anything exact. all reams have unimportant differences. Unless specified, a tool grinder will not manufacture a ream that will cause him headache because it is too small. A Resizeing die manufacturer will not make dies that do not re-size far enough, because neither receive complaints about a cartridge that will chamber. any thing other than that is a custom modification available only by request. How ever military and police have strange requirements including fluted chambers. ( I leave their strange world totally alone). Even at that, the small differences in same designation dimensions is tremendously out weighed by the accuracy of the lathe being used to do the chambering and the skill of the operator. A poor set-up will never make a chamber smaller than the ream it will always make a hole larger than it. Shoddy examples can make massively oversized chambers with the best ream that any man can make.