Ballistics For Canada's Connaught Range

[IanP]

I have been asked by a few shooters interested in trying out for the Aus F-Class Team and as individual shooters what the spreadsheet means and how do you use it. The spreadsheet I'm discussing is available at the link below.

https://dl.dropboxusercontent.com/u/297 ... ksheet.xls

Its a template for shooters to use to check to see if their load complies with the range restrictions in place at Connaught. Its a simple matter of inputting your muzzle velocity and bullet BC into the yellow input boxes. If you are new to spreadsheets, just click on one of the yellow boxes with the BC and velocity showing and just type in the data over the top of the existing entry. Check the plot that will appear on the graph and if its on or below the line it complies. Its probably better to have the plotted data appear just below the line to play it safe.

I have been asked if the sheet calculates muzzle energy but it does not. It has on its two axis, x = BC and y = muzzle velocity. Basically it calculates the trajectory of the bullet and the drawn line denotes the template limit. This calculation does not require the bullet weight to calc the trajectory just the bullet's BC. Its using the wrong drag model for long range bullets but I'm guessing G1 is used over G7 because more manufacturers have G1 on their boxes? The spreadsheet tells us simply how far the bullet will travel and if it meets with the Connaught restriction.

What effect does the restriction have on loads to take over there?

Lets look at bullets people will use first to maximise ballistic advantage.

F-Open

7mm 180gr Hybrid BC = 0.674
7mm 195gr Hybrid BC = 0.743+ New Berger bullet should be available for Connaught

30 cal 215gr Hybrid BC = 0.696
30 cal 230gr Hybrid BC = 0.743

F T/R (in addition to the 30 cals listed above)

30 cal 185gr Hybrid BC = 0.569
30 cal 200gr Hybrid BC = 0.624
223R 90gr Vld BC = 0.551

Thats enough to get us started, when I get a chance I'll come back with the velocity limits for the bullets to meet the template and discuss cartridges.

Ian

[DaveMc]

Of course the future named Captain may well want to stick with one caliber and a set speed (as many teams do). Personally I would be holding off developing anything at all for this intent and purpose until the Captain is named and some direction given.

If I was a betting man I would say 7mm (180 grain at 2800-3000) fps would be the most likely and quite possibly some 30 cal with "equivalent" 1000 yard wind drift but who knows? There are equally good reasons for opening it up as well as shooting one caliber.

With or without Connaughts restrictions this is a likely scenario anyway.

CAPTAINS CALL!!!

[IanP]

Of course the future named Captain may well want to stick with one caliber and a set speed (as many teams do). Personally I would be holding off developing anything at all for this intent and purpose until the Captain is named and some direction given.

If I was a betting man I would say 7mm (180 grain at 2800-3000) fps would be the most likely and quite possibly some 30 cal with "equivalent" 1000 yard wind drift but who knows? There are equally good reasons for opening it up as well as shooting one caliber.

With or without Connaughts restrictions this is a likely scenario anyway.

CAPTAINS CALL!!!

Chill Dave

This is not about anything except ballistics and how the restrictions will effect the loads. Anything more read into this is the product of an over active imagination!!!!

As I understand it individuals as well as teams may want to enter and that is their call as to what calibre etc, they chose, not some future captains!

This info is for the many who are interested in what the Connaught Range restrictions may involve, and if you give me half a chance, I will get back to it and it will become clear.

Now if you want to add your wise words to this thread you are most welcome as is every other forum member.

Ian

[IanP]

Lets look at bullets people will use to maximise ballistic advantage.

F-Open

7mm 180gr Hybrid BC = 0.674 Velocity on template line = 3025fps
7mm 195gr Hybrid BC = 0.743+ Velocity on template line = approx 2840fps

30 cal 215gr Hybrid BC = 0.696 Velocity on template line = 2970fps
30 cal 230gr Hybrid BC = 0.743 Velocity on template line = 2840fps
30 cal 240gr MatchKing BC = 0.700 Velocity on template line = 2960fps

F T/R (in addition to the 30 cals listed above)

30 cal 185gr Hybrid BC = 0.569 Velocity on template line = 3260fps
30 cal 200gr Hybrid BC = 0.624 Velocity on template line = 3100fps
223R 90gr Vld BC = 0.551 Velocity on template line = 3350fps

As you can see from the velocities shown, the Connaught range restriction is not a big handicap. Its worth noting that these are the velocities which take you to maximum allowable within the template.

7mm

The 180gr hybrid is good but bettered by the new to be released 195gr hybrid. The higher BC 195gr bullet even travelling substantially slower than the 180gr bullet at 2840fps provides a little less wind drift at 1000 yards. The 180gr bullet would need to launch at 3180fps to equal the 195gr for wind drift at 1000 yards. Using the standard comparison of a cross wind of 10 mph at 1000 yards.

The allowable limit for the 180gr at 3025fps makes the SAUM look very attractive as it could also launch the heavier 195gr bullets easily if needed.

30 cal

It seems team USA like the 300WSM and the 215gr hybrid combination. They also make claim to the fact that the 300WSM can launch the 230gr hybrids at 2850 fps. The 215gr bullet has a little higher BC than the 180gr hybrid and has a max launch constraint of 2970fps at Connaught.

I have had personal experience shooting the 300WM with the 230gr hybrids and have been amazed by their accuracy and low wind deflection. The 230gr hybrid bullet is the highest BC bullet available at the moment for F-Class and it compares well to the 7mm 195gr bullet. the 195gr bullet is about to be released when Berger find a a gap in their current bullet production. Could be quite a long wait!

The downside for the heavy 30 cals is recoil, some can tolerate it and some cant. It took me some time to start shooting 60s with it and it demands the same hold every shot. The 7mm's are a lot more forgiving.

F T/R

The Connought restriction will not effect the 308W load and bullet you are using in Australia now. Have a look at the velocities that are allowable and wish you could just get close to some of them!

Comparing the Connaught Restrictions to the Qld Range Restrictions.

Qld ranges currently have a range restriction in the form of a muzzle energy limit of 3500 ft/lbs.

Lets look at how it compares with Connaught.

Qld 180gr (7mm) limited to 2960fps - Connaught limited to 3025fps

Qld 195gr (7mm) limited to 2850fps - Connaught limited to 2840fps

Qld 230gr (30 cal) limited to 2625fps - Connaught limited to 2840fps

Qld 215gr (30 cal) limited to 2710fps - Connaught limited to 2970fps

Qld 200gr (30 cal) limited to 2810fps - Connaught limited to 3100fps

Whereas Connaught is based on trajectory and factors in BC the Qld restriction is solely based on muzzle energy. This severly limits the 30 cal bullets that carry a higher weight for a lower BC.

If you find mistakes (no doubt someone will) please correct them so we all know what it should be.

This info is not intended for the Dave Mac's among us who are experts in ballistics but for those shooters thinking about what the restrictions mean in simple terms. Its good for our sport to have lots of shooters interested in trying out for the F-Class team or even going over to Canada as an individual to compete. More power to you all!

Ian

[DaveMc]

I am chilled Ian but your first line is indirectly addressed to "shooters interested in trying out for the Australian F class team".

It needs clarification purely because the team management may in the end decide to run with a single caliber (for the good reason that you cannot swap/change calibers) - once you have fired a shot with a 30 cal you cannot pick up a 7mm - if your rifle/scope has a breakdown mid competition you need to have another rifle sitting there that you can shoot well. Last year we had one shooter with a 30 cal and team management decided to leave it out and shoot all 7mm in the actual comp.

Indeed they can enter any caliber and rifle that fits within the Connaught template if they enter as individuals but for "team" advice it is wise to wait for the guidance of the next Captain.

[IanP]

I am chilled Ian but your first line is indirectly addressed to "shooters interested in trying out for the Australian F class team".

It needs clarification.

Indeed they can enter any caliber and rifle that fits within the Connaught template if they enter as individuals but for "team" advice it is wise to wait for the guidance of the next Captain.

Ok fair point Dave! My intentions are simply to discuss the ballistics involved and how to use the spreadsheet which is also stated clearly in that first sentance! Communication is a tricky thing to master and for me its a work in progress.

Ian

[Range Rector]

Hi Ian,
Great info, where do you reckon the 30 cal / 240 gr SMK figures into the templates?

[DaveMc]

No worries Ian.
And it is good information!
This topic has been raised a few times before. I just think it is very important that all those with ambitions to represent the Australian team at the next championships (and are watching these posts) understand a little about the process. Every time discussions like this come up they should be balanced with the "teams best interest" viewpoint rather than the individual. I know a lot of people are itching at the bit to develop the gear for Connaught and it would be nice to be aiming at the highest ballistic edge possible but for team shooting it could possibly work against you. I think our Captains (Rod and Linda) did a great job last year by not being too restrictive on choice. They allowed some room so that rifles that were working well could make the team rather than forcing people to develop new rifles (e.g. all short 7mm magnums between 3000 and 3050). BUT the next Captain/management may be more specific??? Who knows. They may want all 300WSM, or all 7mm magnums or all 284's??? or allow all of the above plus more.

Some of the considerations are 1) Matching similar ballistic performance so coaches can communicate effectively and use each others shots for wind gauging. 2) ensuring each shooter has backup rifles on the mound. It is no use having 1 30 cal if there is no backup rifle (They cannot pickup a 7mm after firing the 30 cal - I couldn't shoot Marks that well but loved his 7mmSAUM) and the added issue with 30 cal is recoil management. It is not easy to pick up someone elses 300 magnum and shoot it well (as you would well know). So for 30 cals to be considered in a team there needs to be a few people shooting them well and they need to be able to shoot each others - or take a spare. Having the SA boys that could all shoot each others rifles last year was a godsend. As was having Rod Davies who can pick up any rifle and make it work - We had to use both these options. When working away from home you must build a team that can all work off (and back up) each other.

If anyone is really itching to get going on a new build and can't wait for Captain to be announced (and give directions) then just be aware that the Captain could ask for specific requirements (as the US team did).

[IanP]

Hi Ian,
Great info, where do you reckon the 30 cal / 240 gr SMK figures into the templates?

Ok Range Rector, I have averaged the G1, BC's given by Sierra to be BC = 0.700. Given that average BC, then the allowable max template limit at Connoaght for the big 240gr bullets is 2960fps. I have added it to the list with the others in my previous post as well.

Ian

[AlanF]

Dave,

Hopefully the Captain will be appointed soon, and make decisions like that very soon. That will allow shooters several years to get their gear well sorted, and equipment accuracy is critical I'm sure you'll agree. I think one of the key strengths of our F-Open team in Raton was the high standard of accuracy of the rifles that were used. Centre count is an indicator to equipment accuracy and ours was relatively high. But I'm not for a moment taking anything away from the coaching - it was an outstanding effort and the primary key to our success.

Alan