Pressure issues

[Topwater]

Recently I bought a couple hundred high end 243 brass. I loaded 50 with my normal load. Upon testing, these exhibited signs of excessive pressure, flattened primers and extremely difficult bolt lift. My question is: could there be that much difference in case capacity between different brands of brass? I have already pulled Bullets and reduced loads twice and am still having pressure issues. Any suggestions? Thanks in advance.

 

[old_heli_logger]

Norma brass is soft. What's your load?

 

[dminn1]

Your new brass likely has significantly less internal case volume than your old brass. I would start over with load development working with a starting charge from a good reloading manual. There can be, and usually is a significant difference in case capacity between different brands of brass. Lot to lot variations within the same brand of brass sometimes require tweaking of a previously good shooting load.

 

[6MMsteve]

cut a winchester 308 brass case and then cut a lapua 308 case see how thick the walls are, but lapua brass is thicker walled and the lake city military brass is super thick walled

 

[grovey]

Compare the h20 capacity of fired cases yourself. That's the first place I'd look.

 

[ShootDots]

I bought some Peterson brass awhile back. I had pressure issues too. I called them and spoke to ??? (I can't remember who) but the person stated that their cases have an internal capacity approximately 2 grains less than Lapua. He was correct..

 

[Ggmac]

All reloading books suggest any time you hange a component or lot #s (powder) ,you reduce your load and start over .

 

[JFrank]

Recently I bought a couple hundred high end 243 brass. I loaded 50 with my normal load. Upon testing, these exhibited signs of excessive pressure, flattened primers and extremely difficult bolt lift. My question is: could there be that much difference in case capacity between different brands of brass? I have already pulled Bullets and reduced loads twice and am still having pressure issues. Any suggestions? Thanks in advance.

Yes
I would run a short ladder test to confirm node.

 

[jepp2]

My question is: could there be that much difference in case capacity between different brands of brass?

I've seen that much difference in cases with the same headstamp.

I use a good bit of Hornady brass in my 204 Ruger. Had already recorded water capacity on the cases. Then I bought some once fired Hornady 204 Ruger brass on this forum. As I was working up loads and nearing max, I blew a primer. Never had done that before. Velocity was over 200 fps faster. After it happened a couple of weeks later with a different load, I checked the water capacity of several cases. Some cases weighed significantly more (107.8 vs 96.4 gr) and had much less water capacity (32.3 vs 33.4 gr). I had experienced minor differences between the same headstamps, but never this much.

 

[boltfluter]

I've seen that much difference in cases with the same headstamp.

I use a good bit of Hornady brass in my 204 Ruger. Had already recorded water capacity on the cases. Then I bought some once fired Hornady 204 Ruger brass on this forum. As I was working up loads and nearing max, I blew a primer. Never had done that before. Velocity was over 200 fps faster. After it happened a couple of weeks later with a different load, I checked the water capacity of several cases. Some cases weighed significantly more (107.8 vs 96.4 gr) and had much less water capacity (32.3 vs 33.4 gr). I had experienced minor differences between the same headstamps, but never this much.

jepp2,

That sounds like some quality brass right there!! Not!!

Paul

 

[Jackal2016]

All reloading books suggest any time you change a component or lot #s (powder) ,you reduce your load and start over .

I do believe that is considered the Golden Rule.

 

[GWY]

What was the velocities with the new brass? A chronograph can be one of your best friends when changing components or developing a new load. And to specifically answer your question, yes in 243, there can be significant differences between brands

 

[jlow]

The best way to rule out significant volume difference is to determine internal volume using rubbing alcohol, but a much faster/easier way is to just weight 5 pieces of each and see if there is significant difference.

Of course, we are assuming it is volume difference, but it could be other things – for example, did you check their neck lengths. If they are significantly over SAAMI, the second shoulder in the chamber will push the neck into the bullet causing a crimp and significantly elevate chamber pressure.

 

[Topwater]

I think I’ll start with weighing averages between the Winchester and Lapua brass. Then I’ll check liquid volume. Is there a particular reason for using alcohol for this process?

 

[Ccrider]

The way the brass was sized or how it fits your chamber could be the cause.

 

[jlow]

Do some research on this as it is not a straight forward thing and there is like ream of stuff written on it.

We use alcohol because it has less surface tension than water so you can get a flat surface when you fill the case to the neck. This does involve dealing with very small volume of liquid so you have to be good with dealing with uL volume of liquid.

A couple of things.

One is if your technique is not good, you will be chasing your tail. You verify your skill by being able to reproducibly measure the volume of a number of cases. If you cannot reproducibly measure the same case and get the same number, you can imagine why it is a waste of time trying to determine differences between cases.

Second, case weight and volume has an absolute correlation, BUT this is only true for new unfired brass because if you use fired brass, they have expanded differently if you have shot them with different charges. This is something most people most people have not take into account and make them come to the erroneous conclusion that there is no correlation between weigh and volume.

 

[Webster]

Compare the h20 capacity of fired cases yourself. That's the first place I'd look.

A quick check. Use isopropyl alcohol it has a very low surface tension and less likely than water to trap air bubbles. Fill one case with alcohol and dump it into the other brand. Is it lower in the neck or does it overflow.

 

[jlow]

I don't believe in dumbing down when talking to a new reloader. What I do think is important is explaining the rationale for any suggestion which I always try to do.

 

[Zero333]

243 Win. brass H20 Capacity....

Lapua = 54.3 gr.

Winchester = 55.6 gr.

And I can't for the life of me get my Lapua 243win brass to shoot half as good as my loads in Winchester brass.

I started with new 243win Lapua brass and worked up loads from scratch with a few different powders, and couldn't get it to shoot.

So I fireformed all the Lapua brass and still no cigar.

Winchester brass on the other hand shoots like a laser for me. New Win. brass and fireformed Win brass shot the same bugholes.

 

[dminn1]

243 Win. brass H20 Capacity....

Lapua = 54.3 gr.

Winchester = 55.6 gr.

And I can't for the life of me get my Lapua 243win brass to shoot half as good as my loads in Winchester brass.

I started with new 243win Lapua brass and worked up loads from scratch with a few different powders, and couldn't get it to shoot.

So I fireformed all the Lapua brass and still no cigar.

Winchester brass on the other hand shoots like a laser for me. New Win. brass and fireformed Win brass shot the same bugholes.

I have had similar experiences with a .308 and one of my .243 barrels .When working up specific loads for each type of brass, both had a distinct preference for Winchester brass over Lapua when it came to their most accurate loads. I have another .243 and 6.5 barrel that prefer Lapua.