.300 win mag ladder test

[Joefrazell]

This is my second ladder test I've ever done. I'm thinking of loading up 5 rnds of 72.5, 73 and 73.5 and see how things group. This is my first time shooting this perticular load. I was shooting 210 vlds with 76gr of h1000 and it shot about 1-1/2" groups at 100 yrds but held moa all the way to 700 which was the furthest I shot for groups. These custom competition bullets cost 1/3 of the bergers. How would you guys read this test? All info of test is on pic attached. Thanks all

 

[jimbires]

looking at the picture , I'd be working in the 72 , 72.5 , 73 , 73.5 . the vertical spread is not much on these shots . with 72.5 , 73.0 looking like the sweet spot .

 

[Bbear]

I'd agree with jimbires. Might try loading 72-73.2 (or so) in .3 increments. I think you'll find your sweet spot somewhere between the 72.5-73 range

 

[L.Sherm]

I would try a ladder with 74.5 -76.0 and see the results of that to and watch for pressure and a plateu with your velocity. Alot of times there is a lower node and a higher one. The middle of a velocity plateau can be a good node.

 

[Joefrazell]

Yeah I didn't see any pressure signs at all. I dont have a chrono but figure I'm right around 3000 fps with the 26" at around 73 gr. Was thinking of going higher but don't know if I need any more speed then this

 

[Mike 338]

I would say inconclusive. IMO, a ladder test works best with charge weights in about 1% increments or maybe .7 or .8 grains difference per charge. With highly ballistically efficient bullets in your particular caliber (300 WM), you may even go .9 or 1.0 grains between charge weights so your shots don't jumble. Also, if you can, stretch it out to at least 600 yards (more is better) with 6 shots at each charge weight. You should see some pretty obvious separation between different charge weights. The more powder, the higher the bullet should impact. When you find two adjacent charge weights (and in some cases, three) that sorta jumble and don't separate, that's the band of powder charge to work within. The idea being, within a certain pressure range that powder is responsible for, the bullets act the same. When you find that optimal charge weight, you can go back and fine tune the charge weight within the range of that sweet spot and shoot for accuracy and then mess with seating depth to further fine tune it. Forget the wind for now. Your looking for two adjacent charge weights that hit more or less in the same horizontal plane. If you moved back further, you'd see different charge weights separate but at that range, it's just a big jumble of holes that are more or less hitting within the shooters range of error. Good shooting by the way but for me, there is no way to interpret the data. What you have there is not a ladder test because it doesn't ladder.

 

[Joefrazell]

I would say inconclusive. IMO, a ladder test works best with charge weights in about 1% increments or maybe .7 or .8 grains difference per charge. Also, if you can, stretch it out to at least 600 yards (more is better) with 6 shots at each charge weight. You should see some pretty obvious separation in like-charge weights. The more powder, the higher the bullet should impact. When you find two adjacent charge weights (and in some cases, three) that sorta jumble and don't separate, that's the band of powder charge to work within. The idea being, within a certain pressure range that powder is responsible for, the bullets act the same. When you find that optimal charge weight, you can go back and fine tune the charge weight within the range of that sweet spot and shoot for accuracy and then mess with seating depth to further fine tune it. Forget the wind for now. Your looking for two adjacent charge weights that hit more or less in the same horizontal plane. If you moved back further, you'd see different charge weights separate but at that range, it's just a big jumble of holes that are more or less hitting within the shooters range of error. Good shooting by the way but for me, there is no way to interpret the data. What you have there is not a ladder test because it doesn't ladder.

I really appreciatethe feedback and will do another test at longer range. What's the desired range as I can shoot as far as I need?

 

[Schnyd112]

As he said, the longer the better because the differences will be magnified. You look to be a competent shooter so if ou can do 600 without the wind pushing you off the paper it provides easier to interpret data. I have never done 6 per charge weight, but usually sling 3 at 5-6 different charges. I stay with .5 grain increments and shoot at 600 yards. The problem comes trying to find time to shoot 15-18 rounds in similiar conditions on the same day with a sporter barrel. Wait time for barrel cooling can keep you at the range and allow the atmosphere to vary significantly. I started taking multiple trips, early morning, and marking the bullet holes on a big piece of paper. I do pretty much exactly what you did here but repeat once a day over three days. It takes more time but it is easier to keep track of impacts (which charges hit where) and keeps you from waiting for conditions to even out.

If you can do it early, before the wind and heat become a factor, it can be a very data rich process. I like ladders for sporter barrels for this reason. For heavy barrels I prefer a full ocw test, with 5 shot groups, round robin, at separate targets for each charge.

 

[jimbires]

when I do ladders I start out at 300 yards and find the node . then I'll work around that node at 400 yards , and find that smaller node . then I'll work around this node at 500 yards . by now I usually have something decent figured out . you started at 450 yards , so I would add 100 yards to your next ladder test . just going by the target you have posted , next time out I would shoot from 550yards with loads from 71.7 gr - 73.8 gr in 0.3 gr increments . add distance and cut the powder charge increment amount is how I fine tune using ladders .

 

[lancetkenyon]

What bullet?
What Powder?
What case?

In MY opinion, a ladder test is not shooting 3-6 rounds of each charge weight at a single target. It is exacy how you are doing it. 1 round at each charge weight, from minimum to 3 grains ABOVE published max load as long as you know how to look for any sign of pressure and stop when you see the first one. I do my ladder tests at 300-600 depending on conditions.
How are you going to go mark 40+ impacts after each shot at 400-600 yards?
Also, I shoot over a chronograph to help identify flat spots in velocity across consecutive shots.

Higher charge weight at 400 yards will not necessarily equate to higher bullet impacts. It Has more to do with barrel harmonics and when a bullet is leaving the barrel.

 

[Mike 338]

I really appreciatethe feedback and will do another test at longer range. What's the desired range as I can shoot as far as I need?

That's a thing you can figure out pretty easily.

• Go to an online ballistic calculator. Plug in your bullet data.
• You'll have to estimate your bullet speed for each charge weight. IMO, you'll want about 40ish fps between charges. Keep in mind that it is very common within each charge weight to have an extreme spread (ES) of 30 fps so it tells you nothing if your charge weights are so close together that normal ES is overlapping above or below where your next adjacent charge weight will likely be performing. That's why you go in about 1% charge weight increments in a ladder test.
• When you plug in your estimated bullet speed for each charge weight/yardage into the calculator, you should see about a 2 or 3 inch difference in bullet drop between charge weights. Whatever yardage that gives you a 3" difference in impact is a good place to start.
• 5 or 6 different charge weights. Preferably 6.
  
• 6 shots per charge weight, not 3. There will be some ES variance and shooter error. Shoot enough shots to give you enough data.
• Bench Rest type shooting. Don't waste your time if your not solid and repeatable. Try to shoot when there's not much wind so the shooter doesn't get blown around.
• Hopefully, you'll find two adjacent charge weights that more or less don't separate. That's the pressure band where the bullet flies about the same despite minor variances in pressure. An extra kernel of powder or a slightly funky ES is less apt to throw a shot. Work up some loads within that band and test for accuracy.

Note: Ladder testing doesn't always give you itty bitty holes at 100 yards. The theory and goal is to develop a load that performs consistently with very little vertical dispersion at long range. It can be a lot of work and unless the gun and the shooter are borderline awesome, definitive test results can vary.

 

[Joefrazell]

This is all great info here guys. What I've done is load up 4 rounds of each of these charge weights 72.5, 73 and 73.5. I will shoot them around 600 yards tomorrow or the next day depending on wind conditions. I will shoot fist batch and then mark the shots of the group and measure then shoot the next group at the same target and mark then do the same with the last group. This should give me a better idea of vertical seperation while seeing how it groups. We will see how it goes. I noticed that my lee scale is giving me doffered readings each time I hang the dish with the charge. Varies by .2 of a grain either way! Looks like it's time for a new scale.

 

[Canhunter35]

I highly recommend load development over a chrony. You will find a charge where you up the powder and the velocity stays very similar. That's likely close to a node.

 

[Joefrazell]

I highly recommend load development over a chrony. You will find a charge where you up the powder and the velocity stays very similar. That's likely close to a node.

I would love to but money doesn't allow it now. You know how this hobby is on our pocket book! I've got 3 hunts starting this weekend and through the next 2 months. By next year I should be set up with one.