Long range load development at 100 yards.

[Erik Cortina]

Here are mine ! please comment on what you think is the sweet spot....

and for comparison and to see that if it shoots at 100, it will most likely do good further out. Here is an 800 yard target. C1-C5 = 54.5 and D1-D5 = 55

At 800 I was holding center of X and not compensating for wind. The wind was blowing at 10-12mph from left to right as seen on target.

I like 54.8 gr.

 

[jsthntn247]

Here is an interesting one...load development on 6.5-284...140gr Berger VLDs jammed .010"...4831SC in 1/2gr. increments starting from top left at 47.5 and going in order to 51gr. Very little vertical difference between charges at 100. Any thoughts?

That's one fine shooting rifle riht there. In between your last two groups should be good but I would work up a little higher

 

[lawrence97]

Finally cleaned the barrel after 100 rounds and decided to shoot my last 8 pieces of brass to fire form. I used 54.8 of H4831sc which shot a tight group on a dirty barrel and did just as well on a clean one.
Next step is to play with seating depths using once fired brass.

 

[lawrence97]

Erik, as per your advice I performed seating depth testing with a 54.8g powder charge of H4831SC. I started of with 3 rds at a soft seat to warm up and from there I went from soft seat with .001 neck tension out to .030 from that dimension.

Here are my results, what is your opinion? to me it looks like soft seat is still good but maybe you think otherwise!

Thanks for the help.

 

[barnesuser28]

I like .012 off, because .009 and .015 and (.012) off both shoot well and they all have similar POI

 

[savageshooter86]

12 off looks very good. Good shooting there

 

[lawrence97]

Thanks for the comments. I do like .012 but soft seat is promising and has performed the same on my previous targets..... choices, choices ! Any benefit from one or the other given that the groups look to be very close?

Thanks.

 

[barnesuser28]

ES might be the determining factor.

 

[Erik Cortina]

I like .012 off, because .009 and .015 and (.012) off both shoot well and they all have similar POI

.012" is exactly what I would pick and for the same reasons. Load -.012" and go to town. It offers you room for error on both sides of seating depth.

 

[Nomad47]

But .009 off lets the throat erode .006 before any re-seating needs to be done.

 

[Erik Cortina]

But .009 off lets the throat erode .006 before any re-seating needs to be done.

But it leaves almost no room for error. Look at -.006"!

-.012" still leaves .003" erosion, wich is plenty and all he needs to so is keep a close eye on it after every match and re-adjust seating depth as necessary.

 

[lawrence97]

I will test tomorrow from 800-1000 at - .012. What is the average erosion for a given amount of rounds ? will I erode more than .003 at the 500 round mark?

 

[Erik Cortina]

I will test tomorrow from 800-1000 at - .012. What is the average erosion for a given amount of rounds ? will I erode more than .003 at the 500 round mark?

Yes, average erosion is about .003" per 100, so check periodically.

 

[savageshooter86]

so about every 100 rounds you have to adjust your seating depth to keep up with the same amount of jump?

 

[Ed333]

I will test tomorrow from 800-1000 at - .012. What is the average erosion for a given amount of rounds ? will I erode more than .003 at the 500 round mark?

Yes, average erosion is about .003" per 100, so check periodically.

Erik, is that rate of erosion with reference to the .284 only?

 

[Steve Blair]

Erik, is that rate of erosion with reference to the .284 only?

[br]
Obviously, it varies with cartridge, pressure and powder. My last .284 Shehane barrel, shooting full pressure loads of H4831SC, moved .034" in 1436 rounds. I suspect H4350 is a little harder on the barrel. N160 or N165 is probably easier. Lower pressures produce better barrel life as do cooler burning powders.

 

[TZaun]

My first time posting a picture, hope this worked. Erik, would you mind throwing in your opinion on this one?

 

[Erik Cortina]

My first time posting a picture, hope this worked. Erik, would you mind throwing in your opinion on this one?

Do you have any chronograph numbers?
On your last group, did you see any pressure signs or could you go hotter?

 

[TZaun]

No chronograph numbers. Pierced two out of the three primers on that last one and the bolt started to lift harder.

 

[Steve Blair]

Pierced two out of the three primers on that last one and the bolt started to lift harder.

[br]
Those could be interpreted as pressure signs.