Ladder Target Testing - How To

[RogueAussie]

In preperation for reloading .303 Brit, I was hoping someone could clarify the correct use of the Ladder Target.

As I understand it, I could be way off here, is that the target is set up at 25 yards and you aim at the black half circle, 6 o'clock hold, with the sights set at 200 yards. The point of impact should be around the 200 yard mark on the target. Sights are then set for 300, 400, 500 etc and the point of impact should correspond with the target marks on the ladder target sheet.

How far off am I?

Imgur: Ladder Target

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[CINDERS]

25 yards from the muzzle of the rifle not that I think a couple of feet would matter, I think 22 SqnRAE was going to do some testing on replicating the trajectory, I was going to try and replicate the ballistics with 174Gn SMK's I just got very badly side tracked with M/cycles though I have all the rounds loaded for it thing is with the SMK's Vel relates directly to B.C so the slower you go the less efficent the pill is.
As we would like the trajectory to line up with the ladder that may be good for shorts but the long ranges may find you wanting with the pill becoming unstable and losing the group, I would do the OCW ladder test to find out the best grouping load in the rifle then use that get to the range and shoot and log all the ranges your going to shoot as the projies today are far superior in flight than the MKVII pill.
Also our propellants are better so the harmonics may be different in the barrel thats the way I have done it loaded the rounds to 2440fps +- with the 174 SMK and recorded the DATA on all the ranges we shoot from 25 - 600M for all of my 4 shooters slow and painful yep it sure is but I have it on paper and easy peasy to dial it in and then just worry about kentucky windage.

You will always find with the SMK you're @ 150yds + higher on the ladder than you need to be if you were using MKVII ammunition, the only other pill that was close was the 174Gn Highland which is no longer produced but I managed to snaffle 580 + the 400 I had on hand so now have a good supply when I decide to go back to them.
Try the TAIPAN 174gn I used them years ago and they are fantastic cleaned the floor with them Malcolm Bone is not making them he sold out but the new ones I have look very good indeed they are 174Gn FBHP .312" and fly really well.
Heres the link to their web page https://jrbprecision.com.au/

Which ever way you decide to go have fun..........

[22SqnRAE]

I'll get off my arse and make an image of a .303 ladder for 25 Yards like Cinders suggests.

There is a world of variables that creep in when trying to compare commercial ammo, handloads and the venerable Mk VII ammo. Least of which is your rifle is not a 'standard' test bed that the legendary 2440 fps MV was recorded (?) from!

I'll see what I can do tonight for you.

[22SqnRAE]

RogueAussie,

OK, my mistake, I overlooked the image you've posted. Yep, that's a pretty much standard Mk VII .303 Ball ladder target for a 25 yard sighting in.

Here's a list of elevation changes per 100 yards, based on a 300 yard zero (full bore/target rifle in question) each raise is from zero, or total at that range, not from the previous distance.

300 yards zero
400 raise 3.5 MOA
500 raise 8 MOA
600 raise 13 MOA
700 raise 19 MOA
800 raise 25.5 MOA
900 raise 33 MOA
1000 raise 42 MOA

Now a word of caution, as Cinders mentions: This is all theoretical.

If you're handloading, even with a 174 grain projectile (recommended) then unless you really are sure you're getting 2440 fps at muzzle with both that handload and a genuine Mk VII ball round, then this is purely a guide. Nothing more.

Truth is that it is so hard to replicate the Mk VII ballistics for a variety of reasons:

1. Cordite and modern nitrocellulose powders burn at vastly different rates throughout ignition
2. the Mk VII bullet was rear heavy and non-uniform like modern commercial projectiles
3. your barrel wear affects actual velocity
4. The shape of your projectile is not consistent with a Mk VII bullet, hence will perform differently in your barrel and during flight

Now that is simply off the top of my head. 5 minutes cogitation would double the list.

In short (to relieve the pain of readers...) you've got a good ladder to begin with, trial it and see how your rifle shoots in comparison, make a range card when you test at actual differences and rely only on the range card form thereon.

Enjoy sending happiness pills downrange.

[CINDERS]

Correction the TAIPANS are a 170Gn FBHP .312" but still a bl**dy good pill reasonably priced at $76.00/100 AUD +10% GST & Postage, also one other thing I forgot to mention I make all my cartridges to the COAL of a MKVII round I used a 1967 P.O.F as a base. No use going all technical going from the ogive and fluffing with the jump as thats purely "F" class stuff and these Ol' Girls are not 1/2 minute tack drivers "Chaff Cutters" actually but still accurate enough.

[RogueAussie]

Correction the TAIPANS are a 170Gn FBHP .312" but still a bl**dy good pill reasonably priced at $76.00/100 AUD +10% GST & Postage, also one other thing I forgot to mention I make all my cartridges to the COAL of a MKVII round I used a 1967 P.O.F as a base. No use going all technical going from the ogive and fluffing with the jump as thats purely "F" class stuff and these Ol' Girls are not 1/2 minute tack drivers "Chaff Cutters" actually but still accurate enough.

The 174gn Highlands changed their branding to PPU. I have several boxes of the 174gn HPBT FMJ PPU stuff and that comes in at about $26/20. Not cheap but it's a starting point as it seems as close to the MkVII as I can find. Additionally, the PPU brass in .303 Brit is meant to be good reloading brass so I'll keep it to start load development.

Like you said, I'm not chasing thumb nail grouping but it would be nice to have something that shoots consistantly so I won't spend too much time or money finding THE load, just A load that is near enough. The curiosity around the ladder target is purely a matter of interest and something to play with at the range to see how close to MkVII i can get a load and how close the PPU factory ammo is.