bump Dies??????????????

[craigyboy]

I have been thinking about getting one of these lately Bump Die, do you guys think they are a good idea? I think it would be a good job as you could just set it to bump the shoulder back .003 or so on once fired cases which should have expanded out to fill the chamber and you would end up with perfect headspace and without using the neck sizer you would be cutting down the working of your brass and also your brass would be left very well fitted to the chamber in all ways and possiblly improve accuracy, please correct me if I have got it wrong. I have a real notion of keeping my brass as tight a fit in my chamber as possible and this looks like it would help greatly.

[foxing2night]

graigyboy,

Not wanting to teach anyone to suck eggs???? but two things!!! three thuo bump is to much, you only need to bump the shoulder about 1 thou back if that?? and only when the cases get a bit sticky after a few firings,,,,

 

also you will still have to use a neck sizer to resize your cases to the correct neck tension????

 

you are on the right track as this is better than full lenth resizing all the time as this does work your brass a lot???

 

if you want more info i would be glad to help??????

 

all the best f2n

[craigyboy]

If it wasnt too much trouble foxing2night I would gladly accept some help, I am still new to reloading and trying to work out whats best for me.

 

I thought that the neck sizing die pushed the shoulder back aswell as setting correct neck tension, but after seeing these bump dies, I assume that the neck sizer die does just that, size the neck and nothing else. When I first set up my neck sizeing die it was denting the shoulder in the case so I had to back it off until it stopped denting the shoulder, so I just assumed that this die was also pushing the shoulder back. Any light shed on this is much appreciated. basically all I want to do is get a die that will be set up to keep my headspace correct as I want my brass to fit my chamber perfect and obviously full length resizing will not do this, I will just measure everthing off a once fired case and set the die to duplicate this.

[Vermincinerator]

Craigy,

The bump die is designed to push back the shoulder when chambering becomes difficult, ie closing the bolt takes alot more effort then usual.

Untill you start experienceing this condition you dont need a bump die.

I will expand on what f2n said by bringing to your attention that shoulder bumping is not something to be undertaken by the inexperienced and in no way should it be used as a regular reloading procedure.

Like f2t explained .003" is far to much even a thou could be regarded as too much, once your case is formed to your chamber you want to keep it that way or as near as possible.

Continuous use of a bump die WILL lead to premature case head failure, for example, each time you bump back the shoulder by .003", the case head web will expand by the same upon firing.

This procedure needs only to be undertaken to ease the closure of the bolt and only again when bolt closing becomes hard again.

If you do think you need one there are two types on the market, the Redding version called the "Body Die" which sizes the body and knocks back the shoulder:

 

http://www.redding-reloading.com/pages/bodydies.html

 

Also the new Forster which uses bushings to size only the neck and knock back the shoulder:

 

http://www.forsterproducts.com/Pages/precision_dies.htm

 

Ian

[foxing2night]

graig,

can you tell us some more about your reloading set up???ie, what dies you are using??? this is important as there are a lot of dies on the market and a few of them work in differant ways??

 

ie, full lenth dies

 

neck sizing dies

 

arbour press dies

 

also there is a proper way to set your dies up ready for reloading????, with out seeing what you are doing and going by what you have said,, you have not got the dies set up right and that is why you are pushing the shoulder back????

 

if you can give me some info as to what you are doing i will help as much as i can???

all the best f2n

p.s it is not rocket science,, but it does have to be right???? for your own safety,s sake

[craigyboy]

I am using an RCBS single stage press, redding dies, I have a full length sizer and a neck sizer but i have stayed away from the FL sizer and am just using a neck sizer, initially I got the neck sizer set up wrong but after it dented one case I realised that it was pushing the shoulder back too far so I Crudely measured the length from the case head to the shoulder of the case and set the neck sizer so it didnt move this (I know there are more accurate tools to measure this but it was all I had too hand) I havent had any problems with my loads yet so I musnt be that far away I just wasnt sure if I was doing it right and if these "bump dies" were a better job. Thanks.

[foxing2night]

graig,

firstly lets talk about bumping the shoulders back??

, this is only done if your cases get a bit sticky!! this you can feel when you chamber a round!!!!

ie. your normal load all of a sudden gets a bit hard when the bolt is closed???, now if you take one of these rounds out of the gun you will see that right on the apex of the shoulder it will be shining all the way round??? this is due to the case being to long and gualing inside the chamber!!! ie very tight fit in the length!!!!,

 

this situation is were you would use either a bumping die or a full lenth die????

 

now what i do when i get some sticky cases, i fire them and keep them to one side and then when i get home i will chamber an empty case, you will feel the bolt is a little bit hard to close??, now take it out and you should see it shining around the shoulder

 

this is when i get my shoulder bumping dia out and put it in a normal press?? put the ram all the way to the top and screw the dia down untill it meets the ram, then back the die off until there is a little gap,,,,,, with the rifle to hand bump a case and try it in the rifle turning the dia down a little bit at a time untill it chambers properly,,, you will feel the bolt get easier to close and the case should now be the right length for the chamber!!!!! a lot of people take the firing spring and firing pin out of the bolt so that they have more feel for the job????? but i don,t.

craig, i can not tell you how much to turn the die up or down as you will have to play about until you get it right your self????, one thing that i will say is that i had a 223 a few years ago and i only ever used a neck die and i never had a sticky case in that rifle??,

 

craig one of the most important things that i was told a long time ago was that if you only rezise the first three sixteenths of the case neck then the back part of the neck is just under the size of the chamber, so in theory the bullet is held in the rifle chamber by the back part of the neck and the front is sized enough to hold the bullet

 

I hope that i have not blown your mined????? it is difficult to under stand when it is writen out ????

 

craig if you get stuck??? i will try and get some photo,s to help you out????

 

all the best from wales f2n

[craigyboy]

Thanks f2n, I have got it sussed now, basically when they start to chamber tight get the bump die out and bit by bit bump them back until they are just about chambering without any resitance, I doubt ill need to bump them back for a few firings yet, but its nice too know the right way about it, much appreciated.

[Vermincinerator]

Craigy,

When i was shooting Benchrest i got 22 reloads out of my "Match Set" of cases before i needed to bump the shoulders and i was running "Hot", 3 grains over max.

The reason we wanted to bump back the shoulders is because we wanted to extract the last bit of life out of our meticulously prepared cases and hold on to possible match winning consistancy.

In my experience necks would give out before the shoulder would need bumping, i never used a bump die, i just prepped a new set of cases as soon as the first neck split appeared.

If closing your bolt is beginning to get heavy after only a few reloads, then you seriously need to look at the pressure of your loads rather then thinking about getting a bump die.

 

Ian.

[Redfox]

I agree with both of you .003" is way too much an as Ian points out the web area has to extend each time to make up the distance, it quickly thins out and splits exactly where you dont want it to happen ( near your noddle).

Proper neck sizing works very nicely and I too get many reloads with out bolt closure problems, the neck going first usually.

 

 

So listen to these lads and keep your money in your pocket until you can get the benefit of competition dies and spend on them.

redfox