Articles | Documents | Equipment | Events | Links | Membership | Miscellaneous | Scrapbook | Targets | What's New |
The Mild Bunch Part 1: 7mm | September 2007 | |||||||
Dan Martinez
| ||||||||
Several years back, I picked up a Sako Hunter in 7mm Rem. Mag. for a decent price.
It features a 25½” barrel, a wonderfully ergonomic stock made out of a really nice
piece of walnut, and it has a truly angelic trigger pull. The Sako got to go on
two deer hunts with me, but without getting the opportunity to take game.
But I was never really happy with the rifle. On good days, it would group five
shots under an inch, but on another day, same load, nothing else changed, it would
shoot a two-inch-plus group. That’s the kind of performance that can really sour
the trust you have in a gun at the moment you need it to shoot right.
There were other things too, primarily the length and weight of the piece. Like I
said above, the stock is an ergonomic masterpiece. It has a very comfortable palm
swell which aids your hold when squeezing the trigger, and the comb of the stock
meets your cheek perfectly as you hold to make the shot. But the rifle is long and
it carries a slightly heavier than standard contour barrel. The rifle gets really
heavy after a day of humping the deer hills.
I tend to carry a heavy daypack filled with lots of water and other fluids, an MRE
for lunch, raingear, various electronic gadgets for navigation, rangefinding, and
communication, and other whatnots. I’m constantly trying to figure out how to pare
the weight in my pack. Usually when I find a better, lighter solution to something
I’ve been carrying, I find something else to add that I just HAVE to take with me.
The upshot is that it I never seem to be able to lose weight in my daypack. Add
this big rifle to my heavy daypack and you can see how my field mobility might be
seriously impaired.
That’s the main reason that the 7mm Mag hasn’t seen that many days in the field with
me. I usually prefer to carry a lighter standard- or short-action sporter.
On one scouting trip, I got to carry a Browning Micro Hunter in .260 Rem. I’ve
written about this rifle before. It’s the one my youngest son Sam usually hunts with.
It’s really a compact rifle, not exactly a youth rifle. Most so-called youth rifles
are made rather cheaply with a shortened birch or plastic stock and an 18” barrel.
The Micro Hunter does have a shortened length of pull, but not so much that a big guy
like me feels crowded. The barrel is shorter than standard at 20”, but does not give
up the velocity that an 18” barrel does. And the stock is made out of a nice piece of
genuine walnut, not birch or plastic. The forend of the stock is slightly abbreviated
and the stock is turned to overall slimmer proportions.
Because the Micro Hunter is so trim and light, and is easily one-handed, it is a real
joy to carry in the field. Yet, because it can be had chambered for some pretty serious
cartridges, you never have to feel under-ranged with this little carbine. This year the
Micro Hunter is chambered for .22 Hornet, .22-250, .243 Win., 7mm-08, .308 Win., .270
WSM, 7mm WSM, .300 WSM, and .325 WSM.
But alas, because we usually have our .260 Micro Hunter zeroed-in for some Sammy load,
rather than for a load that I would hunt with given my druthers, I never really get a
chance to use this gun. So I started thinking that I might like to have my very own
Micro Hunter, one I wouldn’t have to share with the kid. I was thinking one in .308
might be nice.
So one evening, I was sort of absent-mindedly browsing the internet gun auction sites,
AuctionArms.com and Gunbroker.com, as is my occasional habit. There was no extra wad
of cash in my bank account that I could use to buy a gun anyway, let alone any more
room in the abode to store it. I typed in the search term, “Micro Hunter” to see what
was out there. One offering caught my eye.
Someone was selling a new-in-box Micro Hunter in 7mm-08. OK, seven-O-eight is cool.
But the important thing about this listing was that they said they were willing to
entertain trades. I shot off a very short email offering up the Sako. I told them
that it had been hunted with, so it did have a few scuffs and bruises, but I said
that it was still in about 90% condition. Any interest?
They said yeah, maybe, send some pictures. So after a number of emails back-and-forth,
offers and counter-offers, the deal was sealed. The Sako 7mm Mag was on its way to
Texas, and a 7mm-08 Micro Hunter was on its way to Arizona (following all federal and
local laws, of course). From wild to mild, I downsized my only 7mm just like that.
Shortly after receiving the new Micro7, the thought occurred to me that somehow over
the years I had now accumulated a number of rifles chambered for middle-sized,
mid-power cartridges that could be characterized as “The Mild Bunch,” and the
idea for this series of articles was born.
What is The Mild Bunch?
This time around we’ll be exploring the 7mm bore size. Future installments will
key-in on the 6.5mm and 6mm calibers. But first, what are the general boundaries
which for me, define The Mild Bunch?
While its certainly true that the various .22 caliber centerfires can be considered
mild in recoil and a hoot to shoot, I’m focusing on cartridges which are at least
deer-capable. Yes I know that the more powerful .22s are used by some on deer, but
I share the general opinion of most hunters that the .22 calibers are too small for
deer.
So that sets the minimum caliber boundary for The Mild Bunch at .243 or 6mm. Now
what about case size? I think a deer-capable case in 6mm starts with a case based
on the standard set by the 7mm or 8mm Mauser head size. Of course to you Americans,
that’s the same as the .308 or .30-06. With a heavy enough bullet, wildcat 6mms
based on a .223-class case size are probably powerful enough for deer at short range,
and definitely enough for smaller big game like javelina. But practically speaking,
if we limit ourselves to factory cartridges, that means that The Mild Bunch starts
with the .243 Winchester.
At the upper end of caliber size, I am excluding .30 cal. This sets the upper limit
at 7mm bullets. As for case size, I would exclude cartridges based on the .30-06
length case and any case of similar powder capacity. This effectively limits The
Mild Bunch at the upper end to the “x57” case size, such as the 6mm Remington, the
.257 Roberts, and the 7mm Mauser (7x57). The new Winchester Super Shorts (WSSM) fit
into The Mild Bunch club because their case capacity is just about identical to the
x57 case. The WSSMs are lesser in case capacity than .30-06 class cartridges such
as the .270 Win. and the .280 Rem. These longer, more powerful cartridges are
excluded from The Mild Bunch, even though their caliber is under .30.
So what is it exactly, that makes The Mild Bunch worthy of defining as a group and
talking about? In one word, fun — fun to shoot. More to the point, comfortable to
shoot. Yet, they crank out enough velocity, and carry enough bullet weight that you
are definitely commanding serious power when you trip the sear on a Mild Bunch rifle.
That’s the key. Power, accuracy, reasonably flat trajectory, but with the comfort
that allows you to shoot all day without hurting yourself.
Getting back to the point that started me down this path, rifles chambered for Mild
Bunch cartridges can be made smaller and lighter, thus easy-carrying in the field.
Since the cases are smaller in capacity than standard sized cartridges (read “.30-06
length”), the ballistic penalty for a shorter, handier barrel is less. Plus Mild
Bunch cartridges based on the .308 case size are made on short actions, which also
contributes to rifle downsizing.
The 7mm-08 Micro Hunter
OK? Now that you understand the general idea behind The Mild Bunch, it’s time to
get into specifics. I don’t own or have access to any .25 caliber Mild Bunch guns,
so I’m going to have to skip discussion of them in this series. I also don’t have
a 6.8 SPC, the only .270 caliber Mild Bunch cartridge I can think of, so I can’t
talk much about that either. I do have 6mms, 6.5mms, and now a 7mm Mild Bunch rifle
that I can discuss though.
I’m going to start with my newest rifle, the 7mm-08 Micro Hunter, since that’s the
one I’ve been playing with the most lately. The fall draw results for deer recently
came out, and when the news is positive, as it was for me this year, my focus shifts
away from summer activities and naturally turns to ballistics and rifle practice.
With the arrival of the Micro7, plans were immediately made to use this as the
primary rifle for my hunt.
Now that it had arrived, the first decision was how to scope it. We scoped Sam’s
.260 Micro with a Weaver K6 fixed 6x38mm scope. The thinking was that small, light,
and simple is best for what is supposed to be a light and handy carbine. That’s
certainly the path I was heading down when I started shopping for a scope for the
Micro7.
But before ordering the Weaver, I decided to see what Leupold had to offer in the
way of fixed-sixes. (We may be having a talk about fixed-sixes some time in the
future, too.) In the FX-II series, Leupold offers a 6x36, but new for this year,
the scope is available with their Long Range Duplex ballistic reticle.
The LRD reticle features two extra dots below the central crosshair at specifically
defined MOA values to give you additional aim points for longer range shots. After
discovering this scope, there was simply no other choice!
Looking over my small assortment of leftover bullets from the days of loading
7mm Mag, I found 140 grain Nosler Ballistic Tips, 120 grain Barnes Triple-Shock
X Bullets, and 140 grain Sierra Gameking boat-tail softpoints. To that selection,
I threw in a fresh box of 130 grain Speer Hot-Cor softpoints.
Upon perusing the loading manuals for recommended loads, I found that IMR 4064 is
an almost ideal powder for the seven-O-eight in typical deer hunting bullet weights
(120 grain to 140 grain). This is great since I buy IMR 4064 in the 8 pound jugs.
I use this powder almost exclusively for all the different old military calibers
that I load for.
I ended up assembling ten different loads using the bullets I had, all loaded with
IMR 4064, 5 rounds of each load. The plan was to fire them for velocity and group
size. I wanted to find out how the gun shot in general, and to see which of the
loads might be the golden load for hunting purposes.
One note about the overall loaded cartridge length for my handloads: I measured
the factory rounds and found that they just fit in the Micro Hunter’s magazine.
That length was 2.745”. It has been my experience with other Browning A-Bolts,
that the limiting factor for overall cartridge length is magazine space, not
throat depth. So when assembling my loads I just went with the 2.745” length
for everything.
The chart below lists the results. For the Nosler 140, the Barnes 120, and the
Sierra 140, I loaded 40, 41, and 42 grain charges of IMR 4064 to plot the velocity
change with charge increases. I didn’t have enough leftover Nosler 140’s for this
test, so I disassembled some of my leftover 7mm Mag rounds to recycle the bullets
and the powder. This resulted in some tip damage to some of the Nosler bullets.
So it’s possible that the Noslers would have grouped a little better if I used all
fresh bullets.
An unexpected result concerning the Noslers is an increase in velocity from 40 to
41 grains of powder, but a velocity decrease from 41 to 42 grains! Huh?
The bullet that shot the best overall is the 140 grain Sierra Gameking BTSP. The
velocity standard deviation started small, and as powder charge increased, it kept
decreasing. The Sierra book says that I’m still a couple tenths of a grain under
the max load at 42.0 grains. The Speer bullet load also looks like a winner.
Each of these is a sample of one – one group of five rounds per load. So really,
any of the loads could show better for the next five-round group fired – or not.
One could spend a lot of time shooting, verifying, and adjusting the loads to the
Nth degree – or they could just pick a good one and get on with it! That’s what
I’m doing. The Sierra 140 grain bullet flying at 2735 fps into a group less than
an inch is fine with me. Grouping with this load was the most satisfactory of
all the loads tested. I did suffer a bad primer that didn’t go off in this batch,
so my final group size for the 42 grain charge is only for a four-round, instead
of a five-round group. Still, the results look darn good.
So what’s next? Ballistic Reticle Analysis and sight-in of course! I went into
all the gory details of ballistic reticle analysis in my February 2006 article,
“Understanding the Ballistic Reticle”, so I’m
not going to dive deeply here. Check out the story on the website if you need a
refresher.
The short version that I’ll give you here, is that with the chosen Sierra Gameking
load, when the center crosshair is zeroed at 215 yards, the bullet should strike
the first dot down at 300 yards, the second dot down at 390 yards, and the top of
the 6 o’clock picket-post is the 485 yard hold point.
Do I really expect to be shooting out at 485 yards with a 6x scope? No. On the
other hand, I have made first-shot e-Deer kills at over 400 yards with a 6x scope
at our Buckhunter’s Challenge shoots – and no, it wasn’t mere luck.
You might be surprised at what you can do with a 6x scope if you’ve never tried one.
This load is fully capable of delivering more than adequate power for deer all
the way out to 500 yards. It has 2300 ft-lbs. KE at the muzzle, and still over
1200 ft-lbs at 500 yards. As long as the load is accurate and velocity consistent,
a ballistic reticle makes it possible. With a heavier bullet, from 150 to 160
grains, even elk (at more reasonable ranges) can be on the menu for the 7mm-08.
The 7x57 Mauser is very similar ballistically to the 7mm-08. These two are the
strongest members of the Mild Bunch. Factory loads for the 7x57 are actually a
little weaker than the 7-08 due to the many old military surplus rifles chambered
for it. But handloaded for a modern bolt action, it will do anything that the
7mm-08 can do, maybe a little more. The advantage that the 7mm-08 holds is that
it is usually seen in true short-action rifles, thus trim and light rifles like
the Micro Hunter can be built around it.
Other members of the 7mm Mild Bunch are the 7mmBR and the 7-30 Waters. These
7mms are specialty cartridges. They are often seen in single-shot handguns,
less often in rifles. If you want to know more about these, one of you guys
will have to write the story, as I have no experience with either of them.
Well that wraps up my look at the mild 7mm rifle rounds. The next time around
we’ll take a look at the 6.5 millimeters. That may or may not be in the next
newsletter, but we’ll get there.
|
If you enjoyed this story, or found it useful, please consider clicking here to join the NRA at a discount of $15 off the normal membership cost. You will be supporting both this website and adding your voice in support of the Second Amendment. Thank you very much. |
|
|