Shoulder bumping

[brown dog]

That's all I have to say about this thread.

All of you should buy each other a drink after lockdown.

 

[terryh]

😂👏

[No i deer]

Dont forget the sour grapes 😁

[Popsbengo]

😁

[No i deer]

You gotta know your onions 😁

[Big Al]

22 hours ago, Ronin said:

Al you still haven’t answered the question 

How much will the shoulder be moved if you use a FL size die to reduce the case body diameter by .001” if the die is touching the shoulder (standard CIP 6.5x47 lapua case ) 

I’m not referring to using a small base body die where the shoulder is not interfered with.

 

Simple question - what’s the answer ?

 

On 4/25/2020 at 6:33 PM, Big Al said:

 Did you read everything that was written thoroughly enough and understand it before you entered this discussion? 

With respect it doesn't seem so to to me, it seems like you booled in to slap me down for suggesting measuring cases at .200" was either a bad idea or at best pointless because we couldn't do anything about it, now your struggling to dig yourself out of the hole you have made for yourself.

I said earlier I was done but to be honest your making it so easy for me to look good that I might as well continue since its lockdown and it will most likely bring me some extra work.

You seem fixated on a particular scenario and its stopping you seeing the bigger picture. Nobody in this discussion said anything to suggest resizing at .200" was more important than headspace and that it should be pursued above all other things, especially safety. 

Dies are often sloppy mass produced things, other times they can be very tight, especially if the rifle has a sloppy chamber. Even a custom barrel is no guarantee of avoiding a sloppy chamber either through some builders being ignorant to what reamers should be doing or by polishing marked chambers to clean them up instead of re-cutting them. Rifle chambers are probably as bad in terms of size relative to spec as dies so getting good brass fit isn't always easy and many people are just in the dark as to know where the problems lie.

The scenario you are hanging on to above is only one scenario and in that case maybe the reloader might not get his body resized safely by 0.001" if his shoulder is already heavily touching the bottom of the die and the fit is good with both shoulder angles at exactly the same angle. As you suggest he might end up pushing his shoulder way back and risk case head separation due to excessive headspace. But that is only one of many scenarios so should we avoid doing anything for fear of one such scenario?

In one of many other different scenarios Ive also seen what can happen when you reach the point where effective sizing happens at the .200" mark and shoulder bump length actually grows!

Think of the brass like a balloon, you squeeze the bottom, what happens to the top? it grows! So how can that be if it was already touching at the shoulder you might ask? The answer is tolerances in reamer making for both dies and chambers. Let me explain even though it pisses me off to teach you stuff you should really know since you come across as all knowing.

Take a typical chamber reamer and measure the shoulder angle using some proper measuring gear like I have access to and you will see its rarely 30 degrees if that is the spec, or 23 or 40 or whatever its meant to be. Ive seen reamer shoulder angles out by one degree quite often and 30 minutes is nothing. I even had a UK reamer maker supply me with a 22/250 reamer where the shoulder was ground wrong by 2 degrees and I sent it back. He initially denied there could be anything wrong with his first class product but once enlightened he acknowledged the mistake and gave me a refund, I would never buy from him again as the man is a fool. The more you look at reamers the more you realise many of them are shite, thankfully my current supplier makes them bang on the money every time, he has the measuring capabilities to check and the machinery to hold the right tolerances.

OK, back to the case that grew in shoulder bump length when it was squeezed at the bottom, this was clearly as a result of the chamber shoulder angle and the die shoulder angle being quite different. Take a scenario where there is a discrepancy on tolerance of 30 minutes in opposing directions between the reamer that cut the chamber and the different reamer that cut the die. Overall you have an angle discrepancy of 1 degree, thats plenty of room for additional brass movement in an upward direction when pushed hard enough. It would happen with even less never mind 1 degree as many should bump gauges only pick up on a sharp single datum surface that can easily be moved in this example. It doesnt go downwards because the web is too thick and strong to accept whats being forced around, instead it goes upwards as the route of least resistance and Ive seen shoulder bump length grow by as much as 0.003" before when the .200" mark is resized a couple of thou. All this by simple observation and measurement and no daft forces applied with the press.

So where does all this bring us?

Well, it shows some people just how closely I look at the work I do and it shows that you dont look at things with the same level of detail or distrust in the tooling you are given as I do. To be fair though I doubt you would ever question that your reamers weren't what they should be because your experience in engineering is tinkering in your shed in the garden shed, mine was once at the sharp end where we checked everything as mistakes could be extremely costly.

Checking our fired brass and taking measurements (which was what this discussion was about) does no harm, I just tried to offer an insight into it from my perspective and people seem grateful for that. The more someone knows by measuring the more they can improve their reloading, the more chance they can see if the sizing die they have is actually a good match for the chamber they have and in many cases then can them improve the die themselves or give it to someone who can improve it for them or buy another in the hope its a better fit.

Whats the problem with all that I wonder?

Come on Ronin, your just not seeing this all at, the answer to your question lies in the answer I already gave you. Are you not seeing or or are you choosing to ignore it?

Heres a simplified version for you.

There isn't a simple answer to your question, it depends entirely on the shape/size of the particular rifle chamber which in turn has dictated the exact shape/size of the brass that you now say needs to be resized .001". Then the same applies to the FL sizing die you have, different internal die shapes and sizes will have different effects on different pieces of brass, the permutations are endless hense my original point that close measuring reveals answers.

If you think I haven't covered this comprehensively enough why dont you put provide us with the answer to you question, I assume you know?

 

[Big Al]

Interesting observation I made last night about moderators piling in en masse to back each other up, give it enough time and it always happens. 

[Big Al]

Now Ive said it twice already but this time it really is 'over and out' from me on this thread, there is nothing more I feel I can contribute that is useful.

Information has been exchanged, people are old enough to read it and make their own calls on what is useful to them and what isn't.

Happy Lockdown everyone 😘

[brown dog]

4 hours ago, Big Al said:

Interesting observation I made last night about moderators piling in en masse to back each other up, give it enough time and it always happens. 

Al,

I don't see a moderator pile-on.  

I see you and Ronin having a 'thing' and me passing comment on the childish binary absolutism of some internet discussions/arguments ..

...Such as the boorish gain-saying pedantry, passive aggression and mild ad hominems (the latter two being rather more a feature of your posts) in this thread.

The way it's played out is, frankly, beneath both of you.  

It's just lockdown.

Give up caffeine and drink more gin.

 Both of you.

😊

[No i deer]

I chipped in to put some humour into the thread as i could see it taking a sudden turn for the worst and it's not worth falling out over.!!

There's more serious matters going on around us to argue about 1 thousanths of an inch 😁

Atb NID

[No i deer]

5 hours ago, brown dog said:

Al,

I don't see a moderator pile-on.  

I see you and Ronin having a 'thing' and me passing comment on the childish binary absolutism of some internet discussions/arguments ..

...Such as the boorish gain-saying pedantry, passive aggression and mild ad hominems (the latter two being rather more a feature of your posts) in this thread.

The way it's played out is, frankly, beneath both of you.  

It's just lockdown.

Give up caffeine and drink more gin.

 Both of you.

😊

You've swallowed a dictionary again BD 🤣😂

[miki]

9 minutes ago, No i deer said:

You've swallowed a dictionary again BD 🤣😂

It'll pass ..... 🤣

[No i deer]

He's like Stephen Fry on steroids when it gets going 🤣😂

[terryh]

You want to shoot with him on a range 😯😂 (yes I know BD, I walked you off the target by error! 🤭)

[brown dog]

1 hour ago, No i deer said:

You've swallowed a dictionary again BD 🤣😂

😂

[brown dog]

1 hour ago, terryh said:

You want to shoot with him on a range 😯😂 (yes I know BD, I walked you off the target by error! 🤭)

Still not over it!😂

[VarmLR]

Lockdown has had odd effects on people, that's for sure.   We can all get a little frustrated and polarised but it's worth remembering that for the most part, UKV seems more like a family with shared interest and it's really not worth any of us falling out over such trivial matters when BD has it right here...two technical sides to the argument and the truth, as with so many things, may be part way between.  There's a lot of invaluable experience and knowledge on here folks and for the most part it's shared with generosity and real zest for the sport.

As for BD....ingesting Lexicons must surely mean his local supermarket has run out of bread again?