300 win mag brass differences

[mrb1982]

I know a lot of people use bushings these days, but I was told that it isn't bad at all to go from a 30 cal to 7mm in one step with just a neck sizer also. I haven't decided what route I am going to go yet.

I was thinking about when I do my 7/300 brass the first time through, just taking the expander ball out of my full length 300 win die, so that when it takes down the neck, it won't re-expand it on the up stroke. Then when I go to the 7mm neck sizer, it wouldn't be as big of a step. Do my theories on this have any truth????? Be a little less work on the necks maybe? From what I understand, the dies compress the necks down smaller than needed, then the expander ball expands them to size. I am wondering how much a 300 win full length die will compress the neck I guess. MIght not be as good of idea as I thought.

 

[Broz]

I know a lot of people use bushings these days, but I was told that it isn't bad at all to go from a 30 cal to 7mm in one step with just a neck sizer also. I haven't decided what route I am going to go yet.

I was thinking about when I do my 7/300 brass the first time through, just taking the expander ball out of my full length 300 win die, so that when it takes down the neck, it won't re-expand it on the up stroke. Then when I go to the 7mm neck sizer, it wouldn't be as big of a step. Do my theories on this have any truth????? Be a little less work on the necks maybe? From what I understand, the dies compress the necks down smaller than needed, then the expander ball expands them to size. I am wondering how much a 300 win full length die will compress the neck I guess. MIght not be as good of idea as I thought.

I think this will work too. But when you go to the 7 rem die remember the 300 case is a lot longer. Care will need to be taken in die set up so you don't crush the shoulder and push it back.

Then after initial sizing you will need to run the brass through the 7 rem die to do the neck, then a 300 win die to do the web area. Could get interesting bumping shoulders back to the proper spec as the trip through the 300 win die could move the shoulder headspace out again. ahhhh, yeah, I like my bushing dies.

 

[Pdvdh]

Sizing brass necks down one caliber from .308 to .284 in one step is fine.

I would remove the expander ball from the 300 WM resizing die also, as you suggest. No need for it in what you're doing. The necks will end up smaller than final dimension for accepting .308" bullets. How much smaller in diameter varies from FL sizing brand/die to FL sizing brand/die, but probabaly in the 0.008" to 0.012" range.

I would anneal the case necks after sizing them down from 30 to 7mm diameter.

I'm using Hornady .375 Ruger brass in a 30/375 improved and it's decent brass. I size the necks from .375 to .338 in the first step. Then from 338 to 308 in the second step down.

Only time I ever collapsed the shoulder on a casing while sizing a neck down was when I tried to step a 300 RUM down to 25 RUM in a single resizing step. Stepping down one caliber is generally never a problem. However stepping down two calibers in one resizing step is generally not good.

 

[mrb1982]

Is annealing hard to do? Anybody have any videos or links that give info on it? Seems like I saw somewhere where someone was doing it as a business or something.

 

[Pdvdh]

There's a lot of information available on annealing case necks on the internet. Some good and some bad. Even on this Forum. Some good, some bad.

Here's a link to a recent Thread to get you started in your research.

http://www.longrangehunting.com/forums/f28/i-would-like-suggestions-using-tempil-158626/

Too high of a temperature or too long and the brass case necks will become too soft and loose almost all tensile strength. Too low of a temperature or too short in the flame will not produce annealed case necks.

When I anneal case necks on 300 Win Mag and 7mm Rem Mag cases, approximately 5 1/2 to 6 seconds in my propane flame is the correct amount of time. I set the deep blue portion of the flame to a length of about 5/8" and rotate the case shoulder/neck junction just barely off the tip of the darker blue flame. Cases are secured in a Lee case holder w/adapter which is chucked into a battery operated drill. When I remove them from the flame I then rotate the case shoulder area on top of a wet sponge for a few seconds. The wet sponge brings the case temperature down quickly enough that I can handle/remove them from the Lee case holder without burning my fingers, and then move on to anneal the next casing.

 

[mrb1982]

Very interesting. I have never done it before, but usually with good explanation I can handle doing quite a bit of stuff.

From what I gather, the Tempil is just to gauge how long you heat it?

The heating to specific temperature is the functional part of the process that is what you are actually trying to accomplish?

Do you have to constantly rotate it while heating it?

Should I anneal before I even use the brass one time? Or could I size them the first time, then before their second sizing do the annealing?

Sorry for all the questions, but better to ask the questions and get it right the first time. Thanks.

 

[Pdvdh]

Very interesting. I have never done it before, but usually with good explanation I can handle doing quite a bit of stuff.

From what I gather, the Tempil is just to gauge how long you heat it? Correct

The heating to specific temperature is the functional part of the process that is what you are actually trying to accomplish? Annealing is a combination of temperature and time. We heat case necks quickly with a high temperature flame so the case necks come up to temperature without raising the temperature of the case head. Anneal the case heads and the case heads will let go under pressure and injure the shooter.

Do you have to constantly rotate it while heating it? Yes, to ensure the heat is evenly applied around the circumference of the case shoulder/neck junction.

Should I anneal before I even use the brass one time? Or could I size them the first time, then before their second sizing do the annealing? My advice: I would anneal them after you've sized them down and prior to the first reloading for firing in the 7mm/300 Win Mag rifle - ideally. You could shoot them without annealing also, but the case necks will be on the brittle side after swaging them down from 30 cal to 7mm. They will be a little more prone to case necks splitting. And case neck tension will be less consistent.

Sorry for all the questions, but better to ask the questions and get it right the first time. Thanks.

See responses in bold text above.

 

[mrb1982]

Very interesting. I will have to do some investigation. To be honest, it seems crazy simple, but yet at the same time, kind of easy to mess up. Do you know if there is anybody out there who maybe does this as a business that I could send them to when I am ready? Not that I couldn't do it, but if it was reasonable enough and they are all set up for it, it would be worth it to me I guess. Seems like I saw someplace where somebody was advertising this sort of service.

It appears these guys do it. I don't know how much work it is though, not sure if $25/100 is good or not. Doesn't seem that hard though I guess.

http://coppercreekammo.com/index.php?main_page=product_info&cPath=33&products_id=96

 

[Pdvdh]

Sorry,
I don't know anything about commercial case annealing services available for the home handloader. If you are much into handloading, load for a number of cartridges, and are quite particular or have any obsessive/compulsive disorder when going about your reloading and shooting... ... you might seriously consider learning the process and doing your own. It's easy to get it right. But easier to do it wrong if you blunder into it without the proper knowledge/understanding.

Good advice would be to practice your annealing procedures and time exposure to the flame on some low quality field pick-up cases before annealing your precious ones.

 

[mrb1982]

Probably a good idea. So how do you know if it is too much or too little before you load it?


I know there is the tempil for setting temperature, but is there other signs that you have done it too much or too little without shooting it?



As far as rotating it in the flame, do you have to do it with something like a drill or can you hold it with a tool and rotate it by hand? How do you experts do it?

 

[Broz]

I did try the one step sizing from .308 to .284. It works with care taken. I did shove some necks back on WW brass doing it and ruined those cases. Other than that it also induces more runout for the first firing. But that goes away after the fire form.

Jeff

 

[mrb1982]

I keep talking myself in circles as to which brass to settle on. It is probably going to come down to whatever I can get my hands on hahaha I usually try to keep 200 pieces around, but if I could get some good RWS stuff I could probably get away with only have 120-150 due to it being so much heavier stuff. Pretty tough to find that stuff though.

 

[BigSwede]

Not to derail the thread ... But the quick n dirty on how I ANNEAL is as follows: disclaimer ..I'm not an engineer..I did teach science for 6 years before joining the state police... That said, I get a hand drill and fit a deep socket (heat sink for case body) that fits the choice case so that the case fits with only a bit of case shoulder and neck are exposed. I spin the case slowly for 6-12 seconds in the flame of a torch. When I see the case shoulder and neck turn slightly bluish I douse it in a cup of water or soaked rag to fast cool it. That's it. That my procedure that works for me. I'm getting ready to do a bunch of winchester 7mm-300's tmrw. If you get a bluish line and it's still shiny then it should be good to go.

 

[Pdvdh]

7-12 seconds would be way too long in my propane flame. But like I stated earlier, annealing can be accomplished at many different combinations of temperature & time. A lower flame temperature would require a longer exposure time.

The approach for annealing brass cartridge case necks is a high temperature for a short period of time so the case neck/shoulder reaches the annealing temperature quickly - before the heat travels down and affects the case head area. If I held my cartridge necks in my propane flame for 12 seconds the brass case necks would lose all tensile strength. Their tensile strength would be comparable to case necks composed of a thin layer of soft lead.

I've seen video on this Forum of guys hitting the case necks until they glow red and sparks fly off the case necks, as a demonstration of how to anneal case necks. They don't know what they don't know.

6-12 seconds could be a correct time duration in a lower flame temperature, but that seems like an excessively broad range of exposure time in the flame. Once the flame is adjusted to its set point, the case neck exposure time in the flame should be very similar. Less than one second variation, in my opinion.