One of the most fascinating things about the new 17 Hornady Rimfire
Magnum is the fact that the tiny cartridge can produce velocities of 2500
fps out of a 10" barrel. Now, that’s what I really call hauling the mail.
As a result, the little 17 shoots as flat as a pancake on a truck stop
griddle.
A cartridge that shoots that flat seems like a natural for Field
Pistol competition. After all, that’s most likely the main reason why the
22 Hornet is the number one cartridge of choice of Field Pistol shooters
today. It can shoot flat, there’s little recoil, and accuracy can be quite
respectable.
The Challenge
While marveling over the 17 Hornady, I began to wonder if the 22
Hornet could be loaded to match the little 17’s velocity. If it could, the
Hornet might be able to offer many of the advantages of the 17 Hornady as
well as provide all of the benefits of a heavier bullet and having a
reload-able case to boot. However, I had no idea whether it was possible
or not. I thought "You know this might be a fun challenge". Little did I
know what I was getting into.
Well the first stop would have to be at my firearms and
reloading library. A quick check of the various reloading manuals would be
a good start. The results of my research were kind of sparse, but I did
run across a genuine 2500 fps pistol load using a 40 grain bullet in the
4th edition of the Sierra manual. So now I knew that it could be done, at
least theoretically.
First Attempts
Next stop was my reloading supply cabinet. I used to shoot a
XP-100 in 223 in the unlimited half size category and a 22 Hornet for
Field Pistol and so had an extensive supply of 22 bullets on hand.
However, if I was going to meet the 2500 mark, I was sure it’d have to be
with a 40 grain bullet. Unfortunately, the lightest bullets I had on hand
were Nosler’s excellent 45 grain Hornet model. (By the way, these are
deadly on jackrabbits.) Well, I’d have to send off for some lighter
bullets, but while I was waiting, I’d see what I could do with the 45’s.
For powders, I used just about everything under the sun. They
included N110, H110, Scot 4100, AA #9, Little Gun, H108, N105, H4227,
AA1680, and Win 296. Almost all powders produced velocities ranging from
the 2000’s to the 2200’s - well short of the mark. Initially, Scot 4100
however came the closest to meeting my 2500 fps goal by churning out 2468
fps with one load. So close and yet so far. After trying several different
loads, it became very clear that I wasn’t going to get there from here.
Lessons
However, this first phase with the 45 Nosler's, while
unsuccessful, provided me with some very important lessons. The first
lesson was to remind me just how twitchy reloading for the Hornet can be.
This difficulty stems from the fact that the Hornet is a very small case,
and it’s also a very weak case - not a happy combination. Ordinarily with
other cases, if you found that velocities were limited by the amount of
powder you could stuff in, you always had the option of trying another
powder with a faster burning rate. If you do so with the Hornet, pressures
jump very quickly and case life becomes nonexistent. Abused Hornet cases
will usually separate about a half inch above the rim, so when you open
your TC, the rim will be extracted but the body of the case will be stuck
in the chamber. An oversize bore brush will usually be sufficient to
remove it however.
Another similar lesson, is that you have to be
extremely careful when loading the Hornet at the top end of its capacity.
A single tenth of a grain of powder can send velocities and pressures
through the roof. Indeed, there were several instances in which an
additional tenth of a grain of powder would deliver a 100 fps and even
more in velocities.
This initial period of experimentation also taught me that if I
were going to reach 2500 fps it would be with only four of the ten powders
that I had originally tried i.e. H110, WW296, Lil Gun, and Scott 4100. The
other powders were either too slow or too fast in their burning rates. Of
these four powders, Hodgdon’s LilGun and Scott 4100 were the most
flexible.
However, the most disconcerting thing that I observed during
this period was that the Hornet could have a mind of its own even with
careful attention to reloading technique. For example, I’d be shooting a
beautiful little group with one load or another, and then out of the blue,
one shot would fly off as much as an inch and half or even two inches
away. "Did I do that?" I would wonder. I’d then look at the chronograph
reading and the velocity would be as much as two hundred fps faster or
even slower than the other four shots in the group. "What the heck was
going on here" I wondered.
When I first observed this situation, one thought that occurred
to me was that I might simply be pushing the envelope way too far. Quite
often with other cartridges, when you slip over the ragged edge of sanity
into the realm of pressure madness, velocities will jump both up AND down
radically before the case blows. However that was not the case in this
situation. I’d find these variations with loads straight out of the
reloading manuals.
Then I thought variations in the thickness of the cases might be
the cause of the problem. (I used Winchester brass exclusively for this
little experiment.) Variations in such a small case could theoretically
affect velocities significantly. So I weighed the cases. I found that they
weighed between 53.0 and 53.9 grains. The cases were then separated into
identical lots and subsequent loads used only cases that weighed exactly
the same. Result? No change. I still got the occasional radical variations
in velocities. Nope. Can’t blame the brass.
I had a notion then to seat the bullets against the rifling on
the theory that it would cause the powder to burn more uniformly and
hopefully eliminate these strange swings in velocity. This turned out to
be impossible as my TC was cursed with a chamber that was more suited to
69 grain bullets rather than 45’s. It was another case of the bottomless
TC chamber, so no matter how far out I seated the bullets, there was no
way they would ever come close to touching the lands.
I then started weighing primers. I reasoned that the primer cups
and anvils were probably very consistent in their construction and if
there was any variation in weight, it’d be in the priming material itself.
I found CCI BR primers weighed either 3.2 grains or 3.3 grains. Again they
were separated into lots and were used with brass that weighed all the
same as well. Result? No change.
The last thing I thought that could be causing the problem was
variations in the powder charge. This seemed very unlikely for two
reasons. First, I use a Redding Bench Rest powder measure and it throws
consistent charges with boring regularity. Indeed if someone asks me what
powder measure that I recommend, this is the one. The other reason that I
didn’t think this was the problem was the fact that most of the powders
used were ball types which meter through most measures extremely well.
Never the less, I checked each powder charge on my RCBS electronic scale
and found that the powder charges thrown by the Redding were all
identical, and yet I still experienced the same goofy velocity variations
from time to time. I finally pretty much gave up and just accepted the
fact that this was a normal thing with the Hornet. However, loads with
these radical jumps or drops in pressures are not included in the table
below.
A Surprise from Winchester
While I was waiting for my bullet orders to come in I decided to
conduct another experiment. I happened to have on hand some Winchester
factory 22 Hornet ammo loaded with 34 grain moly coated hollow points.
These are dynamite on everything up to and including coyotes. I had never chronographed or grouped them on paper however. Five shots out of my 10"
TC totally flabbergasted me. 2625 fps!! Even better, the shots went into a
100 yard half inch group. I was intensely impressed with this level of
performance. Being instantly curious, I tore down one of the cases and
discovered it was loaded with 12.6 grains of what appeared to be WW296. I
vowed that if I was able to get some 35 grain bullets, I’d have to try a
similar amount of 296 with my own handloads.
Second Attempts
After a couple of weeks, I finally accumulated a supply of 40
grain Nosler Ballistic Tips, 40 grain Sierra plastic tips, 40 grain Speer
spitzer, and after some difficulty, Hornady 35 grain V-Max’s. Now I was
ready to begin in earnest.
You wouldn’t think that a mere 5 grains in weight would make a
huge difference in velocities, but with the tiny Hornet it does. I was
routinely meeting my 2500 fps goal and even exceeding it by significant
margins.
Impressive accuracy was often achieved at these high velocities
as well.
The 35 grain bullets gave even more velocity.
Will It Work on Steel?
Now that the intellectual goal had been achieved, the logical question
to be asked is whether a 2500 fps load with a 40 grain bullet would be
suitable to use in Field Pistol competition. I had been told been told
flat out that it wouldn’t take down the animals. Let’s see.
First, let’s examine the question as to whether there’s enough impact
momentum with these loads to reliably knock down the Field Pistol ram. In
order to begin to address that question, we need to know just how much is
enough. To the best of my knowledge, no one has ever examined this very
fundamental question in the 25 years of IHMSA’s existence. Our knowledge
of what’s required to knock down the big bore targets is better known, but
Field Pistol targets?
Anyway, I started weighing our club’s commercial made full size
T-1 steel rams. Interestingly they all weighed just about the same - 48
pounds. Good. While I was there, I also weighed our Field Pistol rams,
also commercially made. 10.35 lbs.
In my 20+ years of silhouette shooting, experimenting, and
writing about winning loads, I’ve found that 1 pound second of momentum is
the gold standard for reliably knocking down rams. It’s interesting to
note that with some very successful silhouette cartridges such as the 7
TCU, achieving 1 pound second is difficult to almost impossible. So how
can they be so successful if they can’t deliver that level of performance?
Actually, as little as .75 - .80 pound seconds works very well to kick
over the rams. It would take some unusual situations such as mud on the
rail etc. for .80 pound seconds not to work. So we don’t really need as
much momentum as one full pound second, but if we have it, we know with
certainty that the ram is going down - hard.
OK, so we know that 1 pound second will move the 48 pound ram
off the rail. That equates to .0208 pound seconds of momentum per pound of
steel ram. Therefore if a Field Pistol ram weighs 10.35 lbs, we multiply
that by .0208 to get our momentum requirement to reliably take it down.
Result? It will take .215 pound seconds to reliably knock down the Field
Pistol ram.
Now let’s look at our 2500 fps load with a 40 grain bullet. At
100 yards it’s still going approximately 2114 fps. It’s striking momentum
is then .375 pound seconds, well over what it takes to punch down the ram.
There should be no doubt then that our 2500 fps load will do the job.
Well what about that 35 grain bullet? Let’s
assume that our 35 is going 2600 fps. This is actually a very conservative
figure. When I duplicated the Winchester factory load I described earlier
with the 35 grain bullet and slightly less powder, I actually recorded a
velocity of over 2800 fps, which was absolutely incredible. But, let’s go
with 2600 fps just for the sake of the discussion. At 100 yards, the
bullet will have a retained velocity of 2165 fps. Striking momentum is
.336 pound seconds, still more than enough to take the ram every time.
The only question mark I had at that time about target
performance was bullet construction. Since there is little to no
experience using very fast, light bullets on steel Field Pistol targets it
was impossible to predict absolutely whether the jackets of these bullets
would hang together long enough for the momentum to be fully delivered on
the target. Only time and experience could completely answer that
question. One thing we do know for certain is that there’s plenty of raw
momentum available to do the job. More on this issue below.
Can I Take The Recoil?
The next issue of concern to a Field Pistol shooter is recoil.
Since most shooters who shoot Field Pistol with a scope use the taco hold,
the gun is being held fairly close to their face and obviously, no one
likes having a scope in their teeth when the gun goes off. There have been
various schools of thought when it comes to loading for minimal recoil and
adequate knockdown in Field Pistol. Some like fast middle weight 22
bullets, some like a slow heavy 22 bullet, and others like even slower
bullets in larger diameter calibers like the 270 Ren, or the 30 carbine.
No matter what school of thought they belong to, I’m sure there are folks
reading this that are thinking that a 2500 fps load in the Hornet is going
to generate way too much recoil to be practical for competition.
As you can see, the 2500 fps load, or in this
case 2498 fps, has less recoil than three out of the four loads examined
here and the difference between it and the lowest recoiling load is so
small I doubt if the average shooter would ever notice. Why is that?
Simple. Because when it comes to recoil, the weight of the bullet is the
most important factor in the calculation and not velocity. Conclusion? The
2500 fps Hornet load actually has less recoil than many standard loads
being currently used and is simply not going to rip off anyone’s face.
Now in all fairness there’s also the issue of muzzle blast which
is different than recoil. However the muzzle blast from the relatively
small amount of powder in even a full Hornet case could hardly be
characterized as being intimidating - just a brief orange flash and a puff
of air. But that’s just my very biased opinion. Some shooters are more
recoil tolerant than others. If this condition affects you to the point
that your performance suffers, obviously it’s not for you.
Range Results
Back to the issue of whether the 2500 fps load will take down
the targets reliably. While math calculations on paper are a good first
step, the rubber meets the road at the range. I borrowed a couple of the
club’s Field Pistol rams and put them out at 100 yards. The load used was
10.3 grains of Scott 4100 and the 40 grain Speer spire point.
All shooting was off the bench using sand bags for a rest. To
summarize, the little Speer slapped down the ram down hard every time.
Even when I slipped and punched the ram low in the center of the belly
line, it went over with only the briefest bit of hesitation.
In fact, the targets were going over so well I wondered if there
might be some damage on the targets. A quick check showed that the little
Speer bullets were making only a very bright, but tiny pencil like mark on
the steel. There was no absolutely no damage to the target.
I also found these little round lead "buttons" laying on the
ground right in front of the target. They were similar to the lead buttons
you sometimes find in front of the full size swinger targets when using
gas checked cast bullet. Obviously the base of the bullet was flattening
itself against the steel and then dropping to the ground.
The Good News
As we stated at the beginning of the article, this whole effort
was just an casual experiment to see if the Hornet could match the 17
Hornady Rimfire in velocity. We learned that yes it can, and it can even
exceed the Hornady by significant margins to boot. The other thing we’ve
learned from the experiment is that 2500 fps might be considered by some
to be serious overkill for Field Pistol competition. (It’d make a great
hunting load though.)
Indeed, at even 2300 fps, the Speer will still be going 1764 fps
at 100 yards and will generate .313 foot seconds of momentum. At 2200 fps,
it’ll be going 1683 fps and will deliver .298 pound seconds of momentum at
100 yards. Achieving these velocities is easy with the Hornet. When we
drop velocities, there’s also the added benefit of longer case life and
even less recoil than before.
One Last Mystery
The situation that I discussed previously concerning radical
jumps in Hornet velocities must have been gnawing at me because just
before I concluded the experiment, I did something truly desperate. I
decided to turn the necks on some brass to see if the uniforming process
would alleviate the situation.
This turned out to be more difficult than I thought it would be.
I’ve used a Sinclair neck turner for probably ten years and it works
great. However the 22 Hornet case is way to small to fit into the tool
that you use to hold the case while the trimming blade is rotated around
the neck. Consequently, I placed the Hornet’s rim in a padded vice and
held the case with one hand to keep it from moving from side to side while
I used the Sinclair turning tool with the other. Using just the right
amount of pressure with the vice was necessary to avoid distorting the
fragile rim. Here are the results.