Shoulder bump questions

[Benjerman08]

On my last 100 reloads for my .243 Ackley I had quite a few noticeable hard bolt closures. Some did not though. I would say about half. This is the 4th loading for the Lapua brass. Apparently, I need to bump my shoulders. I have the Redding s type competion dies with the shoulder bump die. This is the first time I have done this and have a few questions. First, on the cases that do not have a hard bolt close, should I go ahead and bump them with the others anyways? I have also read that if you over bump the shoulder much past .002, you can ruin the brass. I ran the die down until one of the shells would go in the chamber with just a small amount of pressure at the bottom of closing. Is this correct or should I go a little further and feel zero resistance on closing? At the point that it seemed it was bumping most of the shells fine, I had a few (out of the 20 I tried so far) that seemed to not size down as good and still had a hard close when tried in the rifle. I just want to keep from ruining any brass and thought I would see if any of you good people had advise on this process. Also, how would I know if I over did it and ruined the brass? Thanks.

TF

 

[NorCalMikie]

Shoulder bump is the "norm" for all my brass. Havn't ruined any brass yet.
You'll only need about .001 or .002 bump. Might need a body die somewhere in the process if your die won't full length size.
Resize and see if the bolts closes. If it's snug, run the die in about 1/16 to 1/8 turn. Measuring the bump would be the best way to go. That way you'll know exactily how far you've pushed the shoulder back. Size to where it feels good to you. A slight resistance tells you you'll need to bump the next time for sure. Set your die so it bumps all the time and you won't have to think about it.
The less you move the brass around by resizing, the longer it will last.

 

[tenring]

Excessively bumping shoulders, say below about .006, can be dangerous, because you are creating excess headspace. Best method is to remove the firing pin and spring from the bolt to get a good feel. Size a case down, try it. If the bolt is hard to close, turn the sizer die down about 1/8th of a turn. Keep doing this until the bolt handle goes down most of the way easily, then requires just a bit of light presure to fully close it. Your shoulder bump should be correct.

I use a Redding Instant Indicator with dial indicator to check shoulder bump. It is so quick and easy that I run all my cases thru it. I can easily bump shoulders .001".

 

[drano38]

Benjerman08,

Yes, we want to push the shoulder back just enough for re-chamber.
I set up my Hornady full length bushing die to push the shoulder back .001-.002.
I use the Hornady headspace gauge.
http://www.hornady.com/store/Headspace-Gauge-Kits/
Measure fired brass, then adjust die to set shoulder back desired amount.
I now use Redding competition shell holders. I use a holder that causes the die to bottom out on the shell holder which stresses the press (all presses flex, including my Redding Big Boss). This setup allows more uniform shoulder setback control because the shell holder/die stress is higher than the resizing stress. As you noted, some casings are longer at the shoulder than others. If the shell holder does not touch the die base, varying case lengths will flex the press more or less during resizing, resulting in varying shoulder lengths, giving you your current situation of differing bolt closing pressures.
Ken Markle from K&M told me in a phone call a few years ago that this is how he does it. Been doing it ever since w/ better set-back results.
good luck
drano

 

[boogershooter]

German Salazar wrote an informative article on the subject,not sure were to find it....do a search in indicated bar at top.

 

[Benjerman08]

Thanks for the information. I guess I am a little confused about the different dies. My reddings came with the neck sizer (bushing type), seater and bump die. Do I need a full length sizer to bump the shoulder? Thanks.
TF

 

[jr600yd]

Use one of the cases that had hard extraction. Turn your body sizing die down 1/16 turn and run the case thru it. Now place in the rifle and see if the bolt will close without resistance. If it does your good to go. If not turn the body die down another 1/16 turn, use another case and repeate the process. Do this until you get to where you want to be.

A lot of rifle dies come in a two die set. The first full length sizes the case, removes the fired primer and expands the neck. The second die is a bullet seater. Your dies split the body sizing snd neck sizing into two seperate dies. This gives you more control in sizing different parts of the case. NO, you don't need to buy a FL die. Lapua makes good brass but remember each case is just a little different. If your using the rifle for hunting I would suggest sizing till no resistance is felt on closing the bolt.

Good shooting, Jim

 

[BoydAllen]

Typical threaded dies are 7/8"- 14. 1" divided by 14 is .0714 per full turn. One sixteenth of a turn is about four and a half thousandths. Don't use your rifle as a gage. If your die is a little too large for your chamber, you could end up with excessive shoulder bump. Get the correct tools, and measure shoulder bump. If the bolt does not close easily enough on a case that has been FL sized, with a .002 bump from a tight case, you need another die...period. Also, case to case variation in factory annealing can lead to major differences in how much cases' shoulders are bumped with the same die setting. A friend ran into this with his 7mm WSM. A rotary annealer fixed the problem. His bump is now very uniform.

 

[Winchester69]

Advance the die 1/32 of a turn to reduce the shoulder height by 0.002". Might take practice, huh?

The simpler way is to use shims under the die or the aforementioned shell holder set. Another way is to measure the gap between the die and shell holder with a feeler gauge and then adjust.

 

[Innovative]

This shows the method that I use to measure the clearance (at the shoulder) that YOUR handloads have in YOUR particular chamber.

http://www.larrywillis.com/headspace_separation.html

It's the quickest and easiest method I've ever tried.

- Innovative

 

[groupshooter22]

If you have a set of calipers use the Hornady bushing or the Sinclair bump gauge before and after sizing to measure how much you are setting back your brass. The best and most consistant way to adjust is the aforementioned shims or Redding comp shellholder set.

 

[Benjerman08]

Thanks for all the replies. I have a few other q's. My bump die has a hole in the top to allow the bullet to stick out when loaded. Does this mean that I could bump shells that are already loaded? Otherwise, is bumping usually done before or after sizing? My runout has been great so far. Can bumping distort that? It is probably time to anneal the brass also. Is bumping the shoulder easier directly after annealing? The rifle is used almost exclusively long range shooting 115 dtacs. Shoots great, just hit this shoulder bump dilemma and it is new to me. Always wanting to learn.

 

[Benjerman08]

Dumb question #68. When you guys are talking about shims and competition shellholders, are you talking about for/under the bump die, my neck size die or a full length die. Thanks for your patience.

 

[groupshooter22]

The shims would go between the f/l or bump die and press. You would set your die up with a midrange shim and check setback and depending on your measurement add or subtract from that thickness to get desired amount of sizing. The shellholders are in .002 increments and you set your die with the one that is + .010 measure and go down until desired setback. Hope I explained it clearly.

 

[Laurie]

Thanks for all the replies. I have a few other q's. My bump die has a hole in the top to allow the bullet to stick out when loaded. Does this mean that I could bump shells that are already loaded?

The die manufacturers always say to never, ever do this to a live round! Basically, it's a bad idea to monkey around with a live cartridge in any way. Although, the likelihood of ignition would be very small, if it did happen, the bump die would act as a rifle chamber supporting the case body, so the bullet would be ejected with lethal force at one end, while the case-head which is poorly supported by the press ram and shellholder and not enclosed would rupture violently at the other. The primer wouuld be ejected down the press ram at high velocity, and even if you, your house, your marriage etc survived the detonations(s) unscathed, your ears might be permanently damaged.

(I know this because I once foolishly decided to pop a live primer in an old Berdan primed Mauser case where I'd pulled the bullet and dumped the powder using a Lee Loader body to hold the case and belting the primer with the Lee decapping rod and a hammer as a 'firing pin'. The unsupported primer came out of the case and disappeared luckily without hitting my face just above the action, and my ears rang and whistled for hours afterwards just from the primer explosion!)

Most people body size first before using the neck die, but I cannot see any issue about the order, unless there's something I'm missing.

Hope this helps!

Laurie,
York, England

 

[garyw]

LAURIE.im trying to get to grips with this shoulder bumping-i have dies for.22br -6br cant seem to master it-peter walker tried talking me through it and still cant get it,if theres a slight chance of you showing me i would appreciate it-i am not far away in leeds ,thanks gary

 

[Laurie]

Hi Gary,

yes, I can probably help. I may have some stuff that I've written for Target Sports plus pics that may help you. I'll have a look tomorrow and send you a pm. If not, I'll pm my phone number across and you can give me a bell next week.

Regards,

Laurie

 

[garyw]

laurie you are a gent-thank you.im in WIGGINGTON tommorow on our game shoot not far from you?
gary

 

[Benjerman08]

I think I am understanding the whole process much better now. I believe I have two issues here and most of you probably already duducted that. I need to anneal as soon as possible as that is why I have a few of the rounds that don't seem to want to bump down as easy as the others. That is where most of my confusion came from and it now makes sense. TF

 

[garyw]

just a thank you to LAURIE for helping me with my "bump" problem, his advice and e-mails with pictures made it easy even for a newbie like myself.
merry xmas to all-gary