Belmont Range Report - Watch for the Drop Offs!

As I have previously noted, all rifle ranges have their quirks, so it's always a good idea to go and have a bit of a pop before you go and do anything serious on a particular range. As it had been nearly six years since I'd last had a crack at Belmont during the 2011 World Long Range Championships, I decided that it would be worthwhile to pop over with the NZ Commonwealth Games squad and have a shoot there to get my eye in. It proved a worthwhile venture.

Belmont Range, Brisbane. The terminal on the right connects to the HEXTA electronic target system.

After a bit of a logistical cockup with the course of fire to be shot alongside the Aussies, I was going to be a Queen's I short of a full HMQPCOF. Fortunately I was able to enter the short range of the Natives' Rifle Club Championships on the Saturday. Shot on the superb HEXTA electronic targets* in fairly benign conditions, it was a nicely gentle reintroduction to the range. I was pleased to slot them all in, even if the conditions weren't massively challenging, mostly requiring only a bit of centering and the occasional change.

300x - Not a bad start. The HEXTA electronics worked well also.

500x - Keeping it together well, and still sheltered from the wind.

600x - Ignore shots 8, 9 & 10 as they were tacked on the end using CWG ammunition.

After my arrival, I'd found out that the Commonwealth Games ammunition was available in the Q Store; albeit at a rather steep AUD47 per 20 rounds. I picked up a box so I could see how it would go and was able to tack a few rounds on the end of my shoot at 600 yards. It seemed to group OK, although about 1/2 minute lower than my Optimus 155 handloads**.

With the third round of the Australia Cup not taking place until the Monday, I'd get to have a day off with the family; we had rented a place down in Broadbeach on the Gold Coast which backed on to the beautiful golden sandy beach. In addition to being a shooting holiday and a chance to refresh my memory of the conditions on the range, it was a treat for Katrina who would be celebrating her birthday on the Tuesday. We spent the Sunday morning on the beach, before heading over to one of the many amusement parks clustered around the area.

Heading up to the range on the Monday morning for an 08:30 start, it was clear that the conditions were going to be a bit tougher; I could see the flags standing proud from their poles as I drove along Old Cleveland Road, although they were mostly coming from between 1 and 2 o'clock. It was looking like angle could be more important than strength if it started to mix it up.

300x went well.

500x continued in much the same vein.

600x finished well, but no idea what happened to that second sighter.

In the event, we were tucked over on the right hand side of the range. Coupled with the dip in the range and some tree cover, this minimised the effect of changes at 300x and 500x; however back at 600x a careful eye was needed to avoid the occasional wind change which could have taken a shot out of the very tight bullseye. I was delighted to put them all in with solid vee counts at all three ranges to take the highest score on the range by a couple of vee bulls.

While the shorts had gone well, it was obvious that the long ranges in the afternoon were going to be a bit trickier. The wind didn't look like it was dying down and the bullet would be much more exposed to the wind with the additional elevation from both the range to target and the rising backslope in the back half of the range.

900x sensible group, just losing a couple out the sides to small wind errors.

1000x acceptable group, but one poor shot and a major wind error.

In the event, 900x went reasonably well and I lost only a couple of points to minor wind errors; it was nowhere near as difficult as I had feared might be the case; however 1000x would be much more taxing. Even though the angle of the wind kept the numbers relatively low, angle and strength changes produced a couple of big dropoffs during the shoot and several of us got caught for magpies and outers. Having dropped 6 points in aggregate by shot #5 I needed to go clean for my remaining ten shots to achieve an MCS. I successfully navigated a second big drop off but I let a slightly slack shot go, possibly as a result of my trying to get them away quickly to avoid another change in the aim and picked up a 4 for my 12th to count, taking an MCS with it. I stuck the final three shots in the bull to end up on 398.47, a single point short of the magical 399 score.

While I didn't quite achieve my goal, I did shoot well; particularly well at short range; and there is much for me to be pleased with. I've also now got some of the CWG ammunition back in NZ to make a few measurements, establish some zeroes and check that my rifle will group at 1000x when using it. Massive thanks must go to Malcolm Dodson, Brian Carter, John Snowden, Rob Johansen and Bevan Mehrtens from the NZ CWG Squad, but most particularly to Kim Ologhlen from the Natives Rifle Club for sorting me out secure storage for my rifle and gear, and allowing me to go slightly off-piste with my course of fire during the Natives RC short range.

Kim Ologhlen from the Natives Rifle Club. A top bloke.

Well, in conclusion I've left myself some work still to do; however I've got further opportunities to shoot minimum consideration scores between now and November, and my preparations for the 2017 Imperial Meeting are looking solid. If you're going to be around on Bisley Camp for the TR meeting, I'll see you then.

 * Yes, I was nice about electronic targets. I'll cover this off in a future article.
 ** RWS Cases, Fed 210 Match Primer, 155 grain HBC Optimus bullet loaded 40 thou off the lands, with 46.5grains ADI AR2008.

Shooting Jackets III, The Saga Continues

In previous posts I have shared my view on shooting jackets - What Have Shooting Jackets Ever Done for Us, and The Trouble With Jackets - I've dealt with some of the issues that I have endured over the past decade during which I have shot moderately well; however by way of a stunning irony my lovely new Kurt Thune jacket has arrived and doesn't fit.

The quality of the workmanship was otherwise superb and the materials suitably durable but however comfortable it failed in the very essence of being a shooting jacket in that it did not provide support in the right places and to the appropriate degree. After some head scratching from the folks who fitted the jacket, it looked like a manufacturing error had left the jacket with too much material in one shoulder, allowing the jacket to slide round when in the aim. It has gone back to the manufacturer; full review to follow when it returns.

In the meantime, let us step forward in time to shortly before the second of the two trials described in Trials and Tribulations. After the first set of long range shoots, it became clear that I was going to have issues at the longer ranges, where errors get magnified exponentially.

Just about held it together at 900x. A good score if not a great group.

I'd love to claim those as wind shots at 1000x but really it's mostly just a big group. Things fell apart, I didn't hold the centre.

After some thought, and a bit of a run around the block I decided extreme measures were required. I stopped in at a sewing shop in Upper Hutt and bought myself some needles and thread, and did the needful. I had heard say about running a line of stitches up the back of a jacket to take up some of the slack before, but had never tried it myself...

Stitch line running up the back of the jacket.

Close up view of my crap seamstressing, seamstressness... sewing.

Now I'm not going to claim that everything is now perfect; however pre-modifications I was just about able to touch my elbows together wearing the jacket* and this was not possible after; it also feels suitable snug, without the uncomfortable feeling of tightness. It is no coincidence also that I shot just as tight at short range, but considerably tighter at the longs.

After a bit more playing back at home on the SCATT, I put a line of stitches in the left shoulder to close things up a bit further.

Butchery. But functional butchery.

Where I am now is that I have a jacket that I would be confident with in going out and shooting SCATT; a high-level competition; a trial. With an extended trip to Belmont Range Complex next weekend** watch this space.


* This is a rough test for the fit of a jacket. Stand up, bend your elbows at 90 degrees and hold your arms in front of you so your upper arm is parallel to the ground. Squeeze your elbows together. If you can get closer than about 10cm / 4 inches of touching then the jacket is too big.

** This is, of course, assuming that the Queensland firearms licensing team and/or NZ Postal Service get me the documentation back in time.

Wind - Near or Far?

One of the questions which comes up occasionally on internet boards and which can cause a bit of consternation is whether greater allowance should be made for wind conditions nearer the shooter or nearer the target. A surprising number of people believe that the wind nearer the target will have a greater effect, after all the bullet is going much more slowly when it gets to the other end.

Let's look the ballistics of a shot fired by a target rifle shooter on a flat, open range with a 10 mile per hour crosswind from 3 o'clock. (S)he is using ammunition with an old-style Sierra 155 HPBT bullet (part number 2155) with an average real-world BC of 0.417 (vid. Brian Litz's superb experimental data) which achieves a muzzle velocity of 2925fps*. Using the JBM Ballistics page, we get the following results:

Range	Muzzle	100x	200x	300x	400x	500x	600x	700x	800x	900x	1000x
Velocity / fps	2925	2711	2505	2306	2117	1937	1764	1596	1443	1307	1193
Wind Drift / Inches	0	0.7	2.9	6.8	12.7	20.7	31.2	44.6	61.4	81.8	106.1
Time Elapsed / s	0	0.107	0.222	0.347	0.482	0.630	0.793	0.972	1.169	1.388	1.629

EDIT: The tables in the figures are now correct! I transposed the times of flight from the 1307fps muzzle velocity calculation onto the data for the 2925fps calculation.

We see that the last 300 yards account for more than 50% of the wind difference. Clearly the wind closer to the target is more important, right?

Not so fast!

I was taught that the wind closer to the shooter has a greater importance, and the various books I've read tend to agree on this point. My experience on most rifle ranges tends to agree; although there are notable exceptions. Let's perform a thought experiment:

Scenario 1 - The same shooter fires a shot on the same flat, open range at a target 1000 yards away. For the first 900 yards, the air is perfectly still. In the final 100 yards, there is a 10mph/16kph wind running at 90 degrees to the line of flight. We know that the wind drift will be zero for the first 900 yards; however we need to calculate what the drift will be in the final 100 yards, which we can do using the ballistic calculator. Using the results from the JBM ballistics page the bullet will be going about 1307fps at 900 yards. Re-entering this value as the muzzle velocity allows us to calculate what the wind will be over the final 100 yards of the range.

Range	Muzzle	100x
Velocity	1307	1193
Wind Drift / Inches	0	1.9

This gives us a total effect of about 1.9 inch or 0.2MOA from the perspective of the shooter 1000 yards away, which is roughly equivalent to the contribution of the final 100 yards to our hypothetical shooter's first shot; therefore the wind in the last 100 yards accounts for only 2% of the total deviation.

It would be interesting to know, by way of contrast, how much wind the first 100 yards would account for. To understand this, let us return to our hypothetical shooter:

Scenario 2 - Our shooter fires another shot at a target 1000 yards away; however this time for the first 100 yards, there is a 10mph/16kph wind running at 90 degrees to the line of flight. In the remaining 900 yards, the air is perfectly still. What will the deflection of the bullet be? We know from our original calculation that the bullet will have drifted about 0.7 inches in the first hundred yards.

This is where is gets interesting. Even though there is no longer any wind, the bullet will continue to move sideways even as it flies downrange because of Newton's 1st Law of Motion**. Thanks once again to Sir Isaac, we can estimate the sideways velocity of the bullet as it transitions from the windy 100 yards into the remaining, still 900 yards; and therefore the total deviation.

If we calculate the acceleration on the bullet over the first 100 yards given the known displacement and time of flight, we can then calculate its sideways velocity at the end of the 100 yards. The bullet will continue to travel sideways at this velocity as it flies down the range, but no faster because there is no more wind.

Following a series of calculations, I make this about 20.6 inches*** however because of errors in assumptions this could be as much as twice the actual contribution. Even so, it is between 5 and 10 times the effect of the wind nearest the target.

Conclusion
Hopefully I've provided a reasonable argument that as a general rule, the wind nearer the muzzle has a greater effect than the wind nearer the target on a flat, open range; however ranges are not always (often?) flat or open in the real world!

Clevedon rifle range is situated just outside Auckland, lies between a series of low hills, and points towards a ridge with several deep ravines leading down to the butts. Particularly at 600 yards, the flags closer to the butts appear to have a greater effect than the ones closest to the firing point. While it is entirely possible that we are mistaken in this; I and other club members think that the funneling effect from the ravines coupled with the shelter of the hills alongside the range leads to this rather odd observation.

The 500x point on Clevedon rifle range near Auckland. Not flat or open!

Indeed, most ranges have their own quirks which must be learned: it is for this reason that top-level teams frequently send advance parties to recce ranges the year before major championships, the Palma Match in particular. I have no doubt that GB, the US and other teams will be sending shooters and coaches to New Zealand to learn the inimitable character of the mighty, frustrating and rewarding Trentham Rifle range.

* This is roughly equivalent to RUAG or GGG.
** A body will remain in constant motion unless an unbalanced force acts on that body.
*** Actually, it will be a bit less because of wind resistance but this is going to be reasonably close.

Addendum - Scenario 2 Calculations
To calculate the acceleration due to the wind on the bullet, let's use one of Newton's equations of motion...

s = ut + 1/2 at^2

Where:

• s = sideways displacement of 0.7 inches
• u = initial sideways velocity of 0 (the bullet isn't moving sideways when it exits the bore)
• a = acceleration that we want to calculate
• t = time elapsed of 0.107s

s = 1/2 a t^2

2s = at^2

a = 2s / t^2

a = 2 * 0.7 / 0.107^2

a =  122.1 inches per second ^ 2

Using this acceleration and the time of flight for the first 100 yards, we can calculate the sideways velocity of the bullet at the end of the 100 yards.

v = at

Where:

• a = Acceleration of 122.1 inches per second ^ 2
•  t = 0.107 seconds

v = 13.1 inches per second

We can calculate the total wind drift by adding to the 0.7 inches of drift in the first hundred yards the sideways drift over the next 900 resulting from this velocity.

s = 0.7 + 5.8 x (3.158 - 0.241)

s = 20.6 inches

NB - There are two limitations that I can think of to this: Firstly, this discounts wind resistance; and secondly, the acceleration on the bullet will reduce as it approaches the wind velocity. Both of these will tend to over-estimate the effect. By applying a similar calculation to the whole 1000 yard range it is possible to see that the over-estimate is at worst 100%.