Next step for load development - .223 Ruger American Predator

[fattybinz]

I’m doing some load development for one of my new rifles, a Ruger American Predator in .223. Using once-fired norma brass, Benchmark powder, Hornady 50gr vmax, Winchester primers. CBTO 1.848. I’ve shot a number of 5 shot groups and these are the results I’ve gotten (I shot some at 200 and some at 100):



Wondering what my next step should be. I'm thinking maybe load up some more 24.4s (maybe 24.3 and 24.5) to see if those results are repeatable. Maybe also load up 5 each of 25.7, 25.8,25.9 since the 1 moa 25.7 and 25.8 suggests there may be a node in there. I started getting pressure signs around 25.2gr. By 25.4gr I had minor cratering. The bolt moved no problem until the very last part of the lift when it stuck a bit. Is that a problem? Does that mean I shouldn't go past that? I was getting some medium cratering around that 25.7-25.8gr zone. I want to keep experimenting in that area but I'm new to this so I'm not sure if it is a bad idea with the relatively minor pressure signs I'm getting there. Any feedback would be appreciated.

 

[VikingsGuy]

If 24.4 holds up, that is about as good as I would expect from that gun. How did it shoot with factory loads? Is it still in the factory stock? Did you make sure you can fit a couple of dollar bills along the barrel to ensure free floated and not touching stock? We have one of these and a .223 non-predator base model and both required sanding of factory stock out near muzzle end. Eventually moved to Boyd’s stocks. Sanding helped some, bedded Boyd helped more. Also, velocity sd data would be useful in assessment in you have it.

 

[Pelican]

If the bolt is getting a bit sticky, STOP, particularly if you are a new reloader. What is wrong with the 24.4 gr load? I would fine tune your load around that level. If that doesn’t work for you or is too slow, try a different powder. A sticky bolt combined with cratering should tell you not to proceed any farther. Other factors could be causing the high pressure signs you are seeing, but if you are new to reloading, do not continue to shoot loads that are showing 2 different high pressure signs. All rifle/load combinations are individuals. Ignoring pressure signs is what gets some people into a lot of trouble.

 

[Pelican]

I checked the Hornady 7th edition manual. It lists 25.8 grains of Benchmark as the max. load with the 50 gr. Vmax.

 

[jbowlin]

You may also want to look at your CBTO with some of your lower charges and see if that helps tighten groups.

 

[fattybinz]

I checked the Hornady 7th edition manual. It lists 25.8 grains of Benchmark as the max. load with the 50 gr. Vmax.

But pressure signs trump the manual right? A friend told me that this Norma brass is military grade and is a bit thicker, making the powder fill more. I did notice at the heavier of the charge weights the powder filled the whole cartridge (before some vibration and tapping packed it down)

To answer the question in your previous post, nothing is wrong with the 24.4gr load and I plan on exploring in that area more...but I'm tempted to keep looking at the 25.7-25.8 area since I have two good date points there. But your advice is not to do that because I'm in pressure sign territory, right?

 

[TheJason]

But pressure signs trump the manual right?

Absolutely.

 

[Fullquiver]

I've had much better luck shooting 748 than with Benchmark in lighter weight 223 bullets. I would also look into H335 as it shoots well out of a Savage bolt I have.. BTW cratering and stuck bolts mean that your pressure is already excessive..

 

[Pelican]

pressure signs trump the manual right?

Correct. Always work up. Don't assume the max. charge listed in a manual is safe in your rifle. I have not used Norma 223 brass, but heavier brass has less capacity which does increase pressure.

I'm tempted to keep looking at the 25.7-25.8 area since I have two good date points there. But your advice is not to do that because I'm in pressure sign territory, right?

Avoid the 25.7-25.8 gr area. If you are getting pressure signs, drop your charge down below where you get pressure signs. High pressure signs may not show up until you are well above safe pressure.

 

[fattybinz]

I've had much better luck shooting 748 than with Benchmark in lighter weight 223 bullets. I would also look into H335 as it shoots well out of a Savage bolt I have.. BTW cratering and stuck bolts mean that your pressure is already excessive..

Don't ask me why but I bought four pounds of Benchmark so I'm going to stick with it for now lol. I'll maybe try those other powders later on. Thanks!

 

[Fullquiver]

Yeah, I have quite a few partial pounds of powder I've tried in various cartridges and loads over the years.

When I get the idea just to blow through it. I go back to my load diary and find a halfway decent load and bulk load a bunch just to blow through my AR's. The neighborhood boys like it when I do this.. They love the trigger time on my range.. Usually bulk fmj bullets and primers I bought in bulk many years ago..

 

[Strutter]

Shoot the 24.4 again to verify your data. Forget the good node numbers you seen at the 25.7 the pressure is not going to work for you. There are many variables that could get you a good node around that 24.4 but only you can decide how far you want to take it. How far off the lands are you? What are you using for a front rest? bipod or bag? and is it the factory stock? Velocity and SD would help some no doubt but you can work a load without it easy enough. I would personally try a different powder. I understand you wanting to stick with Benchmark as you have plenty but if you do stay closer to published data. I would not be altering the distance your shooting at, your looking for consistency. You mention the brass is once fired, Was is it fired from your gun? Did you full length size the brass? The gun is new and your just starting your MOA are really pretty good, you will get there.

 

[fattybinz]

Shoot the 24.4 again to verify your data. Forget the good node numbers you seen at the 25.7 the pressure is not going to work for you. There are many variables that could get you a good node around that 24.4 but only you can decide how far you want to take it. How far off the lands are you? What are you using for a front rest? bipod or bag? and is it the factory stock? Velocity and SD would help some no doubt but you can work a load without it easy enough. I would personally try a different powder. I understand you wanting to stick with Benchmark as you have plenty but if you do stay closer to published data. I would not be altering the distance your shooting at, your looking for consistency. You mention the brass is once fired, Was is it fired from your gun? Did you full length size the brass? The gun is new and your just starting your MOA are really pretty good, you will get there.

Thanks for the encouragement! I'm .010 off the lands. Using a bipod and a rear bag rest. Factory stock, but I've free floated the barrel. Don't have a chrono to get velocity and SD. Brass is once fired, half from my rifle and half from another. Full length resized and trimmed.