300 yard ladder test 260 AI

[vervi1jw]

I completed a ladder test with my Criterion 28 inch 260AI barrel today. I started at 46 grains of H4831 SC and worked in .3 grain increments up to 48.1 grains with 140gr amax bullets.. The shots were all at 300 yards, shot from prone. I think I found an accuracy node. The small group is 0.5625 inches center to center. So roughly .187 MOA. I was using a pen to color in on an identical target where all the hits were, but I got confused with the tight cluster of 4. I pulled the last shot with 48.1 grains pretty bad, but it didn't matter. The vertical with the 46.3 and 46.6 was nice but the poi was so far from the others I am not going to try that charge at all. I am going to load up 47.5grs and play with seating depth.

The Rifle

The Target

 

[in2deep]

You gotta love that.
What kind of barrel and how long is it?

 

[vervi1jw]

Yea, I am super happy. The barrel is a 28 inch Criterion, Kreigers button rifling division. I can't wait to load up some at 47.5 and see how it does then.

 

[Plade]

Your 260AI looks to be shooting well with your initial load devt and nice looking rifle as well!! H4831 SC is a good stable powder with low ES which will all be contributing to accuracy also it's not temp sensitive. It's only downfall is that it can be a little slow and you can become quite limited with case volume. In my 260AI I have tried a range of powders all with the berger 140vld. At present I am using 45.5gn H4350 for about 2900 and good accuracy. I have used 49.2gn H4831 SC for an average velocity of 2866. VV n560 is also a good powder and 49.6gn gave me 2930fps ave. I am concentrating on hitting the accuracy node with ideally 2900 to 2950fps. To that end I know of 2 other shooters using H1000 with great success and low ES even with compressed loads. I plan to try this myself in the next 2 weeks. My rifle has a 26" trueflite barrel, with 1:8.5 twist. I have a long throat setup so I can maximise case capacity with those big bergers. I look forward to hearing how you progress with your load devt and new rifle.

 

[Rock Knocker]

These Criterion barrels seems to like this Amax H4831sc mix.

This is my best group with 140gr Amaxs in my last test at 300 yards.

At 46.5gr H4831sc im afraid to shoot through a crono but i will see what i can do to fit a little more into my cases, I like the results too much to see something like 2750fps. I will get out and do some 600yard Fclass and see how i like it.

 

[vervi1jw]

Wow! Looks like 140amax and 4831SC is definitely the way to go. I can't wait to get more of these barrels.

 

[Plade]

you are most likely going to need to chrony a load to be able to go to 600yds........in my 26" tube with the 140 VLD's 46.9gn 4831SC was giving me 2758; 48.4gn giving 2845 and 49.2 giving 2866 - all average speeds. Looks like your estimation of 2750 may not be far away.........

 

[Rock Knocker]

I am shooting through a 30" barrel and i was hoping that something as slow as H4831 could really come into its own element with this barrel.

I was shooting 47.4g R19 before with 140g Nosler Custom competition bullets with a .529 BC and getting 3000fps, at 300 yards i was getting a 3.4ish moa drop. These Amaxs have just less than a 3moa drop at 300. Amaxs have a better BC of .585 advertized (but ive heard thats a conservative number.) I know you cant gather much velocity info from 300 yards but the limited numbers i have point to a reasonable velocity.

Another bonus is that the barrel is much nicer to clean compared with the R19.

 

[vervi1jw]

I am a big fan of the 4831SC with this rifle. It is super consistent and like you mentioned, cleans up easily. It does however, smell god awful when fired.