Powder charge test with new brass Q’s?

[RyeGuy]

Is it possible to do an initial powder charge test with brand new brass/ non fire formed?
I just tried it and I had 30-40 fps ES’s with same charge. (Shooting 3 rounds per charge, .5 gn increments).
I was kind of frustrated thinking something was wrong but after thinking about it I’m wondering if the inconsistencies in shoulder bump was the issue? Most measure -4.5 thou to -2thou from my fired case. Would that cause 30-40fps spread? I’m hand throwing and measuring on a Hornady scale $250. After using mandrel. 6.5 Saum, ADG brass. Berger Elite hunters 140. H1000
thanks for any feedback

 

[Chubbs]

The problem using unfired brass is that your using some of the pressure to form your case to the Chambers dimensions. The case has to expand and lengthen. This coupled with different internal volume will cause a larger spread of FPS.

 

[quest450]

Increased ES with increased velocity

I’m wondering if there is a simple explanation as to why my ES/SD increases as my velocities increase. Loading for a 7PRC with h1000. I should mention this is virgin ADG brass. I would stick with the lower velocities but it’s a little slow. Factory ammo runs about 2750 in my gun and these are...

forum.accurateshooter.com

 

[RyeGuy]

The problem using unfired brass is that your using some of the pressure to form your case to the Chambers dimensions. The case has to expand and lengthen. This coupled with different internal volume will cause a larger spread of FPS.

I figured so just thought I’d ask to confirm. Off to load up a bunch to fire form before I continue with my load testing.

 

[CharlieNC]

Three per charge for Chrono es? A ladder test on the target for point of impact ( not group size ) will get you close with virgin brass.

 

[Doom]

Three per charge for Chrono es? A ladder test on the target for point of impact ( not group size ) will get you close with virgin brass.

The OCW method (a three shot ladder shot at 100 yds) that Dan Newberry formulated does this and works pretty well in defining a charge range that will handle new and resized brass as well as minor changes in powder charge. As @CharlieNC noted 3 shots on a chronograph is not worth the effort unless you are just curious about the velocity. New brass will usually be a little slower than fired.

When you boil it down to basics, load development is about two things. One is finding a load where the rifle system puts rounds on target consistently (primarily about powder charge followed by seating depth) around a point of impact (not group size). The other is about loading ammunition that is consistent so that velocity deviations have minimal affect on the POI at longer ranges. This is where a chronograph and statistical analysis can be helpful in determining what changes can be helpful in the reloading process. Just shooting shots and measuring SD and ES is not statistical analysis.

 

[D-4297]

Regardless what Brass you are using ; It should have at least three firings on it before trying to do any Load testing , simply because it should be fully formed to the chamber by the third firing , if you are using a "Reasonable" starting load . Bullet , powder , primer , and neck tension ( Interference fit ) all play into this or developing a good load . This is one of the reasons why so many keep such OCD-based records . All data is relevant at some point .

 

[JFrank]

I’ve used virgin brass for basic load work ( a 308 not a comp rifle ) without issues. Don’t read too much into the chronograph information though.

 

[Webster]

Is it possible to do an initial powder charge test with brand new brass/ non fire formed?
I just tried it and I had 30-40 fps ES’s with same charge. (Shooting 3 rounds per charge, .5 gn increments).
I was kind of frustrated thinking something was wrong but after thinking about it I’m wondering if the inconsistencies in shoulder bump was the issue? Most measure -4.5 thou to -2thou from my fired case. Would that cause 30-40fps spread? I’m hand throwing and measuring on a Hornady scale $250. After using mandrel. 6.5 Saum, ADG brass. Berger Elite hunters 140. H1000
thanks for any feedback

What's the caliber. What wt. bullets do you shot. On the main page there is a list of calibers that lead to load maps for various calibers. See what others are using for powder. Don't try to force one powder to work. I think Erik Cortina said on a video ES is related to type of powder and powder charge???

 

[Webster]

Regardless what Brass you are using ; It should have at least three firings on it before trying to do any Load testing , simply because it should be fully formed to the chamber by the third firing , if you are using a "Reasonable" starting load . Bullet , powder , primer , and neck tension ( Interference fit ) all play into this or developing a good load . This is one of the reasons why so many keep such OCD-based records . All data is relevant at some point .

I FF 6BR to 6BRX. The brass is moved a lot. 100" longer and a new shoulder. The brass looks good to me. 55,000 PSI moves the brass pretty good. The gun shoots small groups when FF. If it's isn't a competition rifle I wouldn't get to OCD about it.

 

[mgunderson]

Remember you aren't shooting a 6mm br. 30 to 40 es in a larger case isn't horrible. Is this a new barrel too? Next trip to the range. Reload 5 to 10 of the once fired and shoot them after some new cases. Prove this to yourself. Measure the case volume differences and plug it into quickload.

Single digit sds will win lots of matches. You are in the ballpark. How did it shoot? That is the real measurement.

 

[243winxb]

New vs full BR prep, about 1/4" difference in group size @ 100 yards. 243Win cartridge.