Headspace Of Reloading Brass - Part 3
In parts one and two of our fundamental skills series we
looked at the tools used to measure head space and why we do so on reloading
brass. If you haven’t read those yet, we recommend you do so now before reading
this one. Today, we will look at a couple of ways headspace of the reloading
brass is measured.
So, for optimum accuracy and case life,
the goal is to set the shoulder back the minimal amount while still enjoying
reliable feeding. But if you own several rifles of the same caliber, and you
want your reloads to function flawlessly in all your rifles, then you will need
to set the shoulder back from the shortest chamber. This way it will cycle in
There are a number of options for
measuring headspace and shoulder set-back.
One of the more common methods, and
least expensive, is a collet or bump gauge that fits in a standard set of dial
or digital calibers. Hornady and Sinclair are popular and the collets are quite
affordable. The most expensive part is an accurate set of calipers, which every
conscientious reloader should own.
Another option is the RCBC Precision
Mic set specific to each common caliber. These are very handy but a little
slower than using calipers. Cost is around $50 depending on caliber.
The top shelf option is a Cartridge
Comparator from Dave Manson Precision Reamers. This system consists of an
indicator stand with a base, datum blocks, and plunger-type dial indicator.
Once set-up it is very accurate and efficient to use.
These three systems
are not only used to measure headspace and shoulder set-back on reloading brass,
but they are also to be used when measuring the overall length and seating
depth for bullets. For more consistent accuracy from your reloading brass, you
will generally want to load your bullets longer and closer to the lands than
most factory ammunition. You will often hear shooters talking about 0.015” off the lands or a jump of twenty thou – meaning that the ogive of
the bullet is 0.020” back from the lands. However, if you are feeding rounds
from the magazine for hunting or competition, then you will be limited to an
overall length (OAL) that still fits in the magazine.
Finally, as you get into reloading, and
in particular reloading for precision rifle shooting, the more you need to
quantify actual measurements and tolerances. Don’t think of this as a painful
chore. Instead, treat it as a science that you are attempting to perfect. Once
you really understand the advantages of reloading and see the proof on the
target, in your scores, and the tight groups, you will find precision reloading
to be as enjoyable as the shooting itself (well, almost). There is something
very satisfying about producing high quality rifle ammunition
on Old Military rifles
An old military surplus rifle like a Mauser, Mosin Nagant,
'03 Springfield, Enfield, Arisaka, and others may close on a NO-GO gauge. If it
does, check it with a FIELD gauge. A FIELD gauge measures the absolute maximum
allowable, safe headspace. If the bolt does not close on
a FIELD gauge, and the gun is in good condition, it is generally safe to
However, the strength of these old guns can vary
a lot depending on when and where they were manufactured. Headspace is not the
only factor in deciding whether one of these guns - or any gun for that matter
- is safe to shoot. When in doubt, take it to a qualified gunsmith to have it