Forster Products Match Headspace
R.H. VanDenburg, Jr.
One of the older companies
manufacturing equipment for the handloader and gunsmith is Forster Products of Lanark,
Illinois. It is difficult to imagine anyone who has been at the game for any length of
time not having several items on his bench with this venerable companys mark on
This is in mind when I make up my
short list of companies I must visit at each years SHOT Show. It was no different
this year, and as I made my way to the Forster booth, there was Bob Ruch, Forsters
vice president of finance and point man for shows like this. Bob was quick to point out a
few new items the company was introducing this year. I was equally as quick to request a
sample for review.
One of the items that struck my
fancy was its new Match Headspace Gauge Set. Normally, when we think of headspace gauges,
we think of instruments or tools that measure the limits of cartridge case movement in a
chamber once the action is closed. Each gauge is a piece of hardened steel shaped much
like a cartridge case and turned to very precise dimensions. Each gauge is inserted into
the chamber as measurements are determined.
In a rimless (or rebated rim)
bottlenecked cartridge, this measurement is taken from the bolt (or breech) face to a
datum line on the chamber shoulder. In a rimmed (or semi-rimmed) cartridge, its from
the bolt (or breech) face to a shoulder cut into the chamber to stop the front of the rim
from moving forward. Likewise, in a belted cartridge, the measurement is from the bolt (or
breech) face to a shoulder cut into the chamber to stop the front of the belt. All
specific headspace dimensions, and gauge dimensions, for factory cartridges are industry
standards set by SAAMI.
Also, normally, headspace gauges
come in sets of three: A GO gauge is the shortest. If the action will not close on this
gauge when it is inserted into the chamber, the chamber is too short to reliably accept
standardized factory ammunition. If the action will close, the chamber should accept all
industry standard ammunition.
A NOGO gauge is the middle length.
In theory, an action should not close on the gauge. If an action will close on the GO
gauge and not on the NOGO gauge, the chamber is within ideal specs and should accept all
factory ammunition. Some actions, however, will close on a NOGO gauge and further checking
must be done.
A FIELD gauge is the longest. No
action should ever close on a FIELD gauge. If one does the gun should not be fired until
checked by a competent gunsmith. The theory here is simple. If the chamber is too long,
the firing pin may slam the case forward resulting in no ignition, or poor or erratic
ignition. The former means the gun wont fire, the latter two will guarantee poor accuracy when the gun
does fire. Perhaps worse, the extractor may hold the case back against or near the bolt
face, ensuring ignition, but the case will expand to fill a chamber that is too long,
stretching and weakening the case. At best case life will be reduced. At worst, a case
separation may occur at firing. The hot, pressurized gases will always follow the path of
least resistance, and with a separated case that path may be back into the action, or the
shooter. Serious damage to the gun or injury to the shooter or a bystander could result.
One of the things that attracted me
to the Match Headspace Gauge Set is that each set consists of 11 different gauges. Being a
match set, cartridge selection is limited to three choices: the .223 Remington (5.56
NATO), the .308 Winchester (7.62 NATO) and the .30-06. The .308 set is also correct for
derivative cartridges such as the .243 Winchester, the 7mm-08 Remington and .358
Winchester. The .30-06 set will handle other cartridges as well: the .25-06 Remington, the
.270 Winchester, the .35 Whelen and also the 6.5-06 and 8mm-06, according to Forster
literature. I selected the .308 set for review.
Each of the 11 gauges was clearly
marked and housed in a separate tube. The tubes, and an instruction sheet, resided in a
well-made plastic container. The top was hinged and had two locking points. The
instruction sheet was written for the three-gauge set and should be rewritten, but anyone
getting this far would have no trouble understanding how to use the larger set.
For the .308 set, the minimum gauge,
the GO gauge, measures 1.630 inches. Each gauge increases in length by .001 inch with the
11th measuring 1.640 inches. The NOGO gauge measures 1.634 inches; the FIELD gauge, 1.638
When I checked a .308 Winchester, I
got exactly what one should. The action closed on the GO (1.630) gauge with no resistance.
The action would not close on the NOGO (1.634) gauge. There was no need to go further for
the chamber was cut as it should have been. Further review did determine that the action
would close on a 1.633 gauge. I should have no problems with factory ammunition or
handloads, assuming I do my part, nor have I.
A .243 Winchester, however, was
another matter. This rifle was the real reason I chose this set as Ive always felt
there were things going on I didnt quite understand. No problems, really, its
just that this rifle has always behaved differently than others of the same make.
When the GO gauge was tried, the
action closed without a hitch. It also did the same thing with the NOGO gauge (1.634) in
place. Hmmm. Fortunately, the action would not close on the FIELD gauge (1.638). As I
worked backward through the gauges, I was able to determine the action would close on the
1.635 gauge but not on the 1.636. If we assume the maximum desirable length is .001 inch
less than the NOGO gauge, or 1.633 inches, then this chamber is between .002 and .003 inch
too long. Or to put it another way, the rifles headspace is excessive by the same
amount. Not bad, not dangerous, certainly, but well worth knowing.
As I thought back over the rifles
history, I recalled that when I got it, 20 years or so earlier, only one locking lug mated
with its recess in the receiver. It took quite a bit of lapping to get both lugs to seat
evenly. Accuracy improved immediately. It may well be that the lapping is the cause for
the now slightly excessive headspace. However, several thousand rounds have been sent down
this barrel, and normal wear may have contributed. Anyway, the rifle is still accurate,
and Id just as soon leave it alone. Also, in all those rounds, almost exclusively
handloads, Ive never had a case failure. Ive retired a few with loosening
primer pockets and the odd split neck, but no separations of any kind. I attribute this
good case life to being careful never to set the case shoulder back unless I mean to, and
then only enough to ensure easy chambering.
In summing up, I learned something about two
of my rifles. I wish I had a set for each rifle in the house, but I wont, at least
not a match set. Availability aside, the match sets come pretty dear. A standard Forster
three-gauge set is quite reasonable at under $60. The 11-gauge set, on the other hand,
will set you back a suggested retail price of $175. All is not lost, though. Gunsmiths
need headspace gauges and builders of match rifles in the above calibers need these match
sets. An enterprising shooter should be able to locate
a gunsmith with the appropriate gauges, or,
barring that, might persuade his gunsmith to lay out the cash for a match set and help pay
for it too by having his guns checked. Cant hurt, and knowledge is a good thing.