Will a MAX SAAMI spec cartridge, reach or be short of the lands in a MIN SAAMI chamber?

Searched the forum and couldn't tell.

By the time you're done pounding it in, it'll be close.

Fish30114,

A max SAAMI spec cartridge will not touch the lands of a min SAAMI chamber. There will always be a little clearence. This is done by design to prevent pressure spikes.

Headache

Cheechako,

SAAMI and CIP chamber specs do include the freebore and throat dimensions. Also the cartridge specs for both include the min and max cartridge length. The actual seating depth for a specific bullet is usually specified by the bullet manufacturer as an OAL for that specific bullet.

Headache

quote:

By the time you're done pounding it in, it'll be close.

Especially in A Mauser 98! The bolt has enough caming leverage to get the bolt closed.

Sometimes the max cartridge and min chamber overlap.

There is plenty flex in the cartridge and action to accept this.

The cheapest way to get the SAAMI drawings with tolerances is to buy a used copy of the book
http://www.amazon.com/Handload...9/ref=cm_cr-mr-title



It does not have the cartridges registered since 1981, like the 40S&W.


The more expensive way is to buy the drawings from SAAMI.

SAAMI max. CASES are spec'd to fit SAAMI min
CHAMBERS. Throat configurations are selected to allow chambering and acceptable-pressure
performance with the bullet weights & profiles used in developing pressure data during the standardization process.

What is NOT specified in SAAMI standards is the bullet profile. Every factory loading for every SAAMI cartridge I've ever measured would fit in a SAAMI-std chamber without contacting the lands. It is, however, conceiveable that a bullet profile (long, round-nose)could be chosen by the handloader that would be hard into the rifling when loaded to max. allowable cartridge length.

Hope this helps.

Dave Manson

Dave Manson not only makes the best reamers at the best price, but when I call in a custom, his persona on the phone is intelligent and business like.
Compare that to the "Who's on first?" phone calls over at brand X.

The SAMMI drawings typically have the same dimensions on the case and chamber or a few thousands clearance*. The tolerance on the chamber is typically +.006" and the tolerance on the cartridge is typically -.006".
Measuring chambers and reamers, they are at the bottom of the chamber range.
Measuring ammo and sizing dies, it is aimed at the bottom of the cartridge range.

The bulk of the clearance between the chamber and the ammo is then not the difference between the listed dimensions, but rather the SAMMI tolerance on the ammo.

The fix for this huge tolerance is:
a) Order a tighter tolerance reamer. In .223 I ordered from Dave one with .250" neck and .030" shorter throat.
b) Order a larger necked die. In 223 I found that the .245" bushing die is best, so I ordered a .244" honed neck sizer die from Forster.

*One exception is the 308 headspace on the SAAMI drawings shows the chamber headspace at 1.630 to 1.640" and the ammo at 1.634" -.007". This makes a possible interference of .004".