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Here's
where I thought there would be a bunch of stuff
going bonkers a year or so later, but, guess what:
it's really not.
One
of the big "omissions" in the book was the
Sierra® 77gr MatchKing™ bullet. It wasn't
out when the book went to print. Here's the scoop:
it has a claimed BC of .380, which makes it about
the same, in that regard, as other bullets in its
class. Its class, by the way, is magazine fed
operation (2.260 oal) for 200/300 yard lines. It
works great: shoots easy. Get them and go on.
Lots
of rumblings about Redding bullet seaters stuffing
down overstuffed amounts of slower burning powders.
Right, it doesn't work too well when the bullet has
to crush gunpowder. Neither will a Jones, Wilson,
Bonanza, or most any other bullet seater. Something
will give when there's a long way to go and no room
to get there.
Suggestions
include having the rifle throated long so there
will be more room behind the base of the bullet.
Talk to your gunsmith but, chances are that he
won't be able to do a thing until you get a new
barrel. Other ways of getting more powder in the
case include really long drop tubes for powder
meters. Call Sinclair® about that set up. It
really makes a difference, but it may still not be
enough.
The
Sierra® 80gr MatchKing™ is the primary
culprit here since it will, relatively speaking,
protrude further into the case than will, say, a
Berger® vld bullet. Change bullets for one
"solution," but, jeez, that's harsh
reasoning...
Another
suggestion is going to a faster burning powder!
Obviously, if we can't get enough powder in the
case to get the needed speed, then the case is too
small for that powder. Live with it. Right, also,
that slower burning powders can sometimes (usually)
work really well with heavy bullets, but some
difference somewhere needs to be split, and the
powder burning rate is about the only variable. Try
H4895. It works, most always, and I don't think you
can get enough in a .223 case to hamper bullet
seating.
Lots
of "short stroke" complaints through e-mail. Most
are solved by gas port work. Some on Armalite®
rifles can be helped by shortening the recoil
spring about an inch (it's pretty stout) but I'd be
looking for gas port problems first. For example,
make sure the front sight base is okay and not
obscuring or misaligning the gas tube
opening.
I
had a few comments from AMU on my reference to
"...lathe turned bullets that AMU experimented
with..." which they denied ever having heard about.
Well, here's the hearing: several years ago a more
than reliable source there (which is what I have to
say since I don't want name dragging and pissing
contests to commence) said he had solicited for
some contractor (meaning, here, anyone outside
internal government channels) supplied milled
bronze bullets. I believe that the hands that be
changed before much, if anything, may have been
done, but that's the facts. No, the AMU doesn't
shoot lathe turned bullets. I don't care even if I
have to say what "experimented with" may mean
because the point is not not really an issue, but I
felt pretty well defenseless due, again, to
"protecting" my confidence in folks who like to
help me. The fellow who told me the story came and
went well before anyone who responded to my
comments came to their current posts of
responsibility. I have the tapes....
One
other note on bullets. There is no question in my
mind that the JLK bullets are the best .224s we
have. No question. More and more shooting with them
has convinced me of it. The best magazine bullet is
the JLK 77; the best 80 is the JLK; the best 70 and
75 are the JLK. Why do I say they're the best:
because they shoot better. They fly better too.
Jimmy Knox does a few things differently, and those
things evidently work. I've also NEVER had a speed
induced failure with a JLK. Others may have, but I
haven't (did have some Bergers come apart and
Hornady A-Max too). The JLK 75 vld is a really good
bullet to try if you want something better than an
80 Sierra that shoots dang near as "easy" -- it
doesn't take much fiddling to get the JLK 75
shooting well. It has a 12 ogive, which is not
quite as radical as a JLK 80 or the Bergers, which
all have a 15. Seat the bullet between touching the
lands and jumping 0.005 and stick around 23 grains
of H4895 behind it (WW case and primer). Just try
it.
New
cartridge: (well, not really new, but we got's a
name for it) 6mmX. It's a .243 short chambered or
"held back" 0.130. Take a .22-250 case, expand the
neck to 6mm, fire form, and now you have a 6X.
Works really, really well: less capacity than .243
so it doesn't scorch barrels as bad but still
plenty of speed to make those nice JLK 105s work.
(Matter of fact, that's more or less the idea: tune
bullet speed through case capacity.) .565 bc and an
easy 2850 feet per second, and you can shoot the
best bullets in the world (for bitty groups) at
short line: flat base 6s. I'm trying some Berger
88s but know beyond doubt that Walt's 68s perforate
as near together as other bullet on the planet at
200 yards. This cartridge works in AR10s and, of
course, bolt guns. The 6mm vld from JLK is the
slickest of the slick but Berger has something like
17 .243s to try.
Mostly,
though, folks are shooting their AR15s pretty much
like what went on in the book and are all doing
really, really well with them. It's a beautiful
rifle like that.
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