Hunting Washington Forum

Equipment & Gear => Guns and Ammo => Topic started by: 87Ford on June 28, 2016, 12:34:05 PM

Title: reloading question - shoulder bump
Post by: 87Ford on June 28, 2016, 12:34:05 PM: Just started reloading last summer. I began with new Nosler 280AI brass so there was minimal case prep involved at first. Now, I'm preparing to load the once-fired brass and have a question regarding headspace and bumping the shoulder back a couple thou. Using the Hornady headspace comparator I measured a bunch of once-fired cases and compared those measurements to what new Nosler brass measures. I was surprised that it was the same or very close. Essentially, the brass didn't "grow" after being fired once. So, if I adjust the die to bump the shoulder back .002, it will create more headspace than the new brass had out of the box. What to do?
Title: Re: reloading question - shoulder bump
Post by: AWS on June 28, 2016, 05:47:24 PM: Try chamberring your brass without bumping it back. If it chambers easily you don't need to bump it, wait until it is snug to chamber and them bump it just enough to chamber easily.
Title: Re: reloading question - shoulder bump
Post by: 87Ford on June 29, 2016, 09:44:37 AM: Quote from: AWS on June 28, 2016, 05:47:24 PM
Try chamberring your brass without bumping it back. If it chambers easily you don't need to bump it, wait until it is snug to chamber and them bump it just enough to chamber easily.

Thanks for the reply to my question. The brass does chamber easily, so I'm gonna do as you suggest and not worry about bumping the shoulder. I guess it threw me off a bit when I was expecting the cases to have grown, but they hadn't at all.
Title: Re: reloading question - shoulder bump
Post by: Emptyhanded on June 29, 2016, 10:59:06 AM: As AWS said, you'll know when it's time to bump the shoulders back. I had some short mag brass a friend gave me that would barely chamber in my rifle. I don't know how many firings he had on them but after trimming, annealing and bumping the shoulders back they chamber fine.

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Title: Re: reloading question - shoulder bump
Post by: Bill W on June 29, 2016, 11:05:48 AM: one thing I learned about hard chambering rounds is that if you are group shooting with rounds mixed, meaning some hard chambering and some not, the group will be larger than all easy chambering rounds.

just a heads up.
Title: Re: reloading question - shoulder bump
Post by: CaNINE on June 30, 2016, 11:51:54 AM: It sounds like you have a a chamber with tight tolerances, which is good as you won't be overworking your brass when you resize. If you are loading for a hunting rifle I would recommend that you do a full length resize after each firing. Set the die up per the mfg instructions and size away...in my experience this gives 2 to 3 thou set back. In reloading consistency is king.
Title: Re: reloading question - shoulder bump
Post by: 87Ford on June 30, 2016, 02:03:13 PM: Quote from: CaNINE on June 30, 2016, 11:51:54 AM
It sounds like you have a a chamber with tight tolerances, which is good as you won't be overworking your brass when you resize. If you are loading for a hunting rifle I would recommend that you do a full length resize after each firing. Set the die up per the mfg instructions and size away...in my experience this gives 2 to 3 thou set back. In reloading consistency is king.
This is just what I did.. After adjusting the die to make firm contact with the shellholder as per instructions, then FL sizing and measuring again, the shoulder wasn't touched just as I expected. This brings up another question though. What about trimming the cases? After FL resizing the necks didn't grow at all or very little, maybe 1 or 2 thou. Should I trim the cases or skip that step this time around?
Title: Re: reloading question - shoulder bump
Post by: washingtonhunter121 on June 30, 2016, 02:15:41 PM: Trimming is really about how uniform you want to make ever batch of reloads. If you are within spec of the manual trim max length you will be fine for safety reasons but if your looking for ultimate consistency say every 2 reloads you trim to shortest case length granted as long as that length is writhing the max trim to length you can in your mind say that group wasn't affected by my trim to length. I would say it's all about what you as a reloader are trying to accomplish. Some guys want to know every thing is consistent from every reload every time to cut down on those groups they are shooting. We are talking .1 of an inch maybe smaller. It's hard to say what you personally are trying to get done. I know in my 300 wm I have to prep the cases and spend more time on that process because it seems that if I slack on that groups open up. On my 6.5x47 lapua I can get away with only making sure everything is within the book specs and not worry about it. That gun will shoot with a rock as a bullet it seems. But to better answer your question after all that nonsense in my opinion I would trim to the shortest case length when you trim provided it is within spec and not all the way to the book minimum to cut down on trimming the case more then I have to but ymmv
Title: Re: reloading question - shoulder bump
Post by: 87Ford on July 04, 2016, 06:41:43 PM: Quote from: washingtonhunter121 on June 30, 2016, 02:15:41 PM
Trimming is really about how uniform you want to make ever batch of reloads. If you are within spec of the manual trim max length you will be fine for safety reasons but if your looking for ultimate consistency say every 2 reloads you trim to shortest case length granted as long as that length is writhing the max trim to length you can in your mind say that group wasn't affected by my trim to length. I would say it's all about what you as a reloader are trying to accomplish. Some guys want to know every thing is consistent from every reload every time to cut down on those groups they are shooting. We are talking .1 of an inch maybe smaller. It's hard to say what you personally are trying to get done. I know in my 300 wm I have to prep the cases and spend more time on that process because it seems that if I slack on that groups open up. On my 6.5x47 lapua I can get away with only making sure everything is within the book specs and not worry about it. That gun will shoot with a rock as a bullet it seems. But to better answer your question after all that nonsense in my opinion I would trim to the shortest case length when you trim provided it is within spec and not all the way to the book minimum to cut down on trimming the case more then I have to but ymmv
Thanks for the info, it was helpful..

After FL resizing and measuring the cases I decided not to trim this go 'round. Very little growth, if any in the necks. They are well within the max trim to length. Also, I have the Sinclair chamber length gauge, so I know the actual chamber length of my rifle and can let the necks grow a bit if I want.

As an aside, I'm using the Redding competition bullet seating die and that thing works great! Very precise on seating depth and I'm getting bullet runout of less than a thou :)
Title: Re: reloading question - shoulder bump
Post by: Bill W on July 04, 2016, 07:36:35 PM: I like the Redding competition dies with neck bushings. Definitely extends case life and reduces trimmings.
Title: Re: reloading question - shoulder bump
Post by: 87Ford on July 04, 2016, 08:29:00 PM: Redding dies are all I've used so far, so they're all I know.. I did go from standard Redding dies to the competition FL sizing die with the bushings and the competition seater. I was getting 3-4 thou runout with the standard dies and now less than 1 thou with the competition micrometer seating die. Concentricity is awesome with this die.
Title: Re: reloading question - shoulder bump
Post by: rudysts on July 08, 2016, 06:58:15 AM: My experience with Nosler 280AI brass is i usually don't have to trim till over 12 firings on them I full length resize every time and bump the shoulders 1.5 to 2 thou every time. I use Whidden bushing dies they come with a shoulder bump gauge in the die set. I full length resize for every rifle I have with a custom barrel or factory barrel.