I have a problem, help me figure it out.

[Doghunter23]

Let us know how it turns out, I also shoot 7mm SAUM, with 180 hybrids, and use the Redding bushing die. I am also using Norma brass. My rifle loves 2 tho of neck tension, but I was told the reamer was a minimum SAMI speck reamer, so maybe I have a tighter throat area. I have not bumped shoulders back yet as I have only had 4 reloads on my brass and bolt still closes with no effort, I am waiting to get some resistance when closing then bump back 2 tho from there.
I tried those BR2 primers, I found cheap winchester WLR gave me the lowest SD, seemed like it just needed a little more fire.

 

[L.Sherm]

You can try the smaller bushings all you want until you reduce the size of the expander you will have the same tension. As long as the bushing is smaller than your loaded round. I have ran into expanders that were oversized and turned them down. I would do as suggested above go with a .281 expander with spring back it still probably will only be .2815. Inside dia. controls neck tension not outside.

 

[Crowe284]

I'm not using the expander in the Redding bushing die...never have with any rifle. New bushings come in today but will be guiding a hunt till Sunday. Will try it out then and report back.

 

[L.Sherm]

Anneal your cases and see if that helps. I would measure at the shoulder and .200 line after sizing and compare to reamer print could be oversize chamber or die undersizing. Daves reamers are usually good but stuff happens.

 

[Crowe284]

Anneal your cases and see if that helps. I would measure at the shoulder and .200 line after sizing and compare to reamer print could be oversize chamber or die undersizing. Daves reamers are usually good but stuff happens.

.200 line should measure .550, correct? See print.

 

[L.Sherm]

That .550 measurement he hasn't got drawn isn't right on the .200 line of his print I would call Dave and ask him sometimes he's busy but he will get back to you if he can't take your call normally his wife answers.

 

[TwoMore]

my RSAUM reamer is .551 at .200, I have two a-bolts , one a 7 wsm and the other a .223 wssm , both have huge factory chambers, they shoot fine, but I had to match dies for both of them to get any type of life out of cases. I still have to keep necks annealed to keep them from cracking that is the main problem is the necks on both rifles open up a bunch over loaded rounds. so the necks get worked pretty hard

 

[J E Custom]

You can try the smaller bushings all you want until you reduce the size of the expander you will have the same tension. As long as the bushing is smaller than your loaded round. I have ran into expanders that were oversized and turned them down. I would do as suggested above go with a .281 expander with spring back it still probably will only be .2815. Inside dia. controls neck tension not outside.

+1
When using a bushing die, you need to remove the expander ball for a better sizing, plus it just works the brass twice instead of once and defeats the purpose of the bushing in the first place.

The neck is already larger because it was fired and now fits the neck chamber. All you want to do with the bushing is size the neck down to grip the bullet.

If you don't turn the necks then an expander may be the best way if the neck thickness is not uniform, but as said, the expander then controls the neck size.

If you want to use an expander ball to set bullet tension a standard set of dies are all you need.

J E CUSTOM

 

[Crowe284]

I'm not using the expander in the Redding bushing die...never have with any rifle. New bushings come in today but will be guiding a hunt till Sunday. Will try it out then and report back.

+1
When using a bushing die, you need to remove the expander ball for a better sizing, plus it just works the brass twice instead of once and defeats the purpose of the bushing in the first place.

The neck is already larger because it was fired and now fits the neck chamber. All you want to do with the bushing is size the neck down to grip the bullet.

If you don't turn the necks then an expander may be the best way if the neck thickness is not uniform, but as said, the expander then controls the neck size.

If you want to use an expander ball to set bullet tension a standard set of dies are all you need.

J E CUSTOM

 

[Crowe284]

Reporting back. So as mentioned, I started out with a .313 bushing. I bought a .312 and a .311 bushing to try. The .311 bushing, which is what the virgin brass measures, got me to .311 with a .281 inside neck diameter. I sized 3 pieces of once fired brass with a Redding neck sizer die and shot. The problem is gone and accuracy is even better with 4 of the 6 groups shot measuring .2 or less (one holers). I fired a total of 18 rounds and all of them were with the same 3 pieces of brass, so they now have 7 firings on them. The 7th firing was pretty tight to chamber but now I know three things. First, the neck tension solved the problem with powder on shoulder. Second, I can get at least 6 firings out of them before having to bump and third the Norma brass is good stuff. The primer pockets feel as tight as when I started with them as virgin brass. The load I'm using is not a light one as I am shooting 63.8 gr of H1k, 215 fgmm primer and 180 hybrid .025 off. I did measure my throat today before starting and I have had .006" of erosion in 180 rounds. I want to thank all of you that offered up suggestions to help me out with my problem.
Very best to all,
Dusty Crowe

 

[dok7mm]

Two things. First, your brass may not have fully formed on first firing. Would once fired brass chamber? Capacity of case changes.
Second and most likely, you had more neck tension on fireforming rounds, if you just loaded and fired new brass without any sizing. That would explain why case necks are not sealing. Try a smaller bushing.

Glad to hear your problem is solved.