Bumped shoulder too far??

[Catch-22]

Some help / advice would be appreciated please.

Ive been reloading for many years and feel confident with my process. I always anneal (AMP), partial FL size (Whidden die just to point of brass chambering with little/no resistance on bolt close), expand necks with a mandrel and trim (Henderson) after each firing.

Recently, I’ve had a few (10 or so) of my 6.5x47 brass be too tight to chamber. This brass (400 odd) is on its 7th firing.

Removing my firing pin/spring and ejector, I tried the 10x pieces of tight brass in my chamber and found the bolt wouldn’t close.

I went back to my FL die and screwed it in just a tad more and after doing this a few times, checking bolt close each time, I found a point where the brass would chamber but the shoulder looked like this.

I don’t think I’ve over full length sized it, the shell holder is barely touching the bottom of the FL die, so I’m still only partially FL sizing it.

But I’ve never had a shoulder like this before. I assume it’s still ok to shoot and the shoulder will blow out again to my chamber, it’s just been FL sized more than I’m used too. It actually looks a bit like a ‘roll crimp’ on the shoulder. Is that normal if bumping just a bit more?

But i think it looks a littler weird, normally the shoulder is nice and sharp per the chamber. This looks more rounded to me. Neck doesn’t appear to have been pushed into shoulder and there is no lip/ridge to speak of on the shoulder, all nice and smooth.

Thoughts?

Thanks in advance.

[Catch-22]

And just to say there are no dents or divots in the brass, that’s just reflections on the photo from my shiny, clean brass. 😋

[Popsbengo]

It would seem to me that each increment of bumping has had the effect of turning the shoulder without reshaping the taper and work hardened the shoulder area.

If it was my brass I'd be inclined to anneal and fire form it back to the correct shape,  I can't see a hazard from doing that.

Maybe your annealing process isn't actually doing enough to de-stress the brass at the shoulder and it's become work hardened so springing back?

[Catch-22]

Thanks Pops.

i use the AMP Aztec mode, which analyses the brass and sets the correct heat/time for a perfect anneal. I’d be surprised if the brass was work hardened or not annealed enough.

But I’ll do as you suggest, I’ll anneal again prior to loading and fire forming again.

I’ll keep an eye on it and see I have any issues after fire forming and with subsequent reloads.

Cheers

[No i deer]

Not with the 6.5x47 but my saum..

Some of my cases are not bumping enough by 1 fow..

Makes for a snug fit..

The rest bump fine..

If I adjust the die it will bump the longer cases but it will also bump the shorter ones..

Some competition shell holders would sort it if I was that bothered about it..

Load and fire your brass and they'll fire form fine

[No i deer]

Mine are aztec annealed aswell

[Big Al]

Cases swell in diameter as well as length and if your die isnt sizing enough towards the web it will eventually become a problem. Have you measured your web area at the .200" mark from the bottom?

If your die isnt sizing the .200" mark enough then screwing it down further may eventually size that part of the case but at the detriment of the shoulder, I would take a look there. 

If the .200" area is too fat for your chamber it will make the bolt feel like cases are too long.

[furrybean]

^^^ He knows

[No i deer]

I don't think anybody makes a small based die for a 6.5x47..

You could try a body die..

It may size half a fow smaller at the 200 mark

[furrybean]

Whidden would

[Scotch_egg]

You can use a .308 small base die for 6.5X47

 

i have a barrel done by Callum Ferguson. It’s min spec and won’t chamber cases that have been once fired in another chamber. .308 small base die sorts it. 

[No i deer]

Interesting...

I thought the 308 was a slightly bigger case..

Thanks Dave.

That should solve his problem

[No i deer]

Furry bean had a small base die for sell not long ago on here

[Catch-22]

6 hours ago, Big Al said:

Cases swell in diameter as well as length and if your die isnt sizing enough towards the web it will eventually become a problem. Have you measured your web area at the .200" mark from the bottom?

If your die isnt sizing the .200" mark enough then screwing it down further may eventually size that part of the case but at the detriment of the shoulder, I would take a look there. 

If the .200" area is too fat for your chamber it will make the bolt feel like cases are too long.

Hi Al,

Many thanks for the suggestion to check the .200” line. Measuring all cases (post the extra FL sizing I did, which now makes the cases chamber), all measured right on 0.470”.

So brass looks to be in spec and after sizing is chambering correctly, it just looks like it’s mildly curling the shoulder a tad. But maybe that’s all ok?!?

Ive done as Pop suggested and I’ve annealed the brass again, now will load up and shoot them and see what happens.

Cheers

[Popsbengo]

7 hours ago, Big Al said:

Cases swell in diameter as well as length and if your die isnt sizing enough towards the web it will eventually become a problem. Have you measured your web area at the .200" mark from the bottom?

If your die isnt sizing the .200" mark enough then screwing it down further may eventually size that part of the case but at the detriment of the shoulder, I would take a look there. 

If the .200" area is too fat for your chamber it will make the bolt feel like cases are too long.

I had this with .338 cases and followed your advice to make a tool to measure precisely up from the head.  Small base die sorted it.

[Catch-22]

Or perhaps I’ve reached the point where Al notes, that I’ve managed to get the die to size enough of the .200” line correctly, BUT it is now just over sizing the shoulder, hence the rolling.

So maybe I do need a small base die then?

Do you FL size with the small base die every time then?

Does it effectively replace my Whidden 6.5x47 FL die? Or do I first FL with the small base die, then FL again with my 6.5x47 die to size the neck and shoulder?

Thanks

[No i deer]

I sbd my 284 brass everytime after having a problem after firing...

It's works like a dream..

[Catch-22]

3 minutes ago, No i deer said:

I sbd my 284 brass everytime after having a problem after firing...

It's works like a dream..

Thanks. Do you have a .284 sbd, or do you use a dedicated sbd and then afterwards use a regular 284w FL die?

Trying to understand if you just always only ever use the sbd or you need to use it in conjunction with your regular FL die as well?

cheers

[Big Al]

4 hours ago, Catch-22 said:

Hi Al,

Many thanks for the suggestion to check the .200” line. Measuring all cases (post the extra FL sizing I did, which now makes the cases chamber), all measured right on 0.470”.

So brass looks to be in spec and after sizing is chambering correctly, it just looks like it’s mildly curling the shoulder a tad. But maybe that’s all ok?!?

Ive done as Pop suggested and I’ve annealed the brass again, now will load up and shoot them and see what happens.

Cheers

Keeping on top of your brass sizing in terms of measurements for me is something best done at the start of a new brass cycle, because you are using fresh undersize factory brass you can see what your brass measures after its first firing, this will be a decent gauge of your chamber.

From first firing Im looking for my FL resizing to bump shoulder length by 0.002" and keep the 0.200" mark at a similar 0.002" reduction, usually my 47 cases would measure 0.469", this is the same for many other calibers including the 6BR its variants and Creedmoor's

The problem we all have is occasionally someone uses a reamer ground to minimum spec (often referred to as match spec) and they also cut a good chamber to the reamer size which has no slop in it, as a result many off the shelf FL dies cant satisfactorily control the 0.200" area because the reamer they were made with was bigger. It would actually be better if the chamber had been a little oversize as it would give the brass a chance to be better controlled. On the other hand you also get sloppy big dies from time to time that arent tight enough to control things as you would want to. Tolerances within SAAMI and CIP spec mean a chamber could be cut tight and a die cut slack, if you end up with these two extremes you have trouble sizing brass well.

If you can use a .308 body die and get your 0.200" area down to 0.469" you shouldn't have any problems.

Something to watch out for is when you start squeezing the 0.200" area your shoulder bump measurement might grow, think about squeezing a balloon at the bottom, it grows at the top as a result as the material displaced has to go somewhere. If the die isnt controlling both bump and 0.200" area together you can end up going around in circles in terms of tight fitting cases.

[furrybean]

Also this this a tunable step in load dev

[No i deer]

I have a 284 win small base die..

Running the brass through does make them about 1 fow longer at the shoulder.

Measure them before sb dying them.

The sbd is set up to bump the shoulder about 1 fow and the fl bushing die is set to bump it a further 1.5 to 2 fow.

To be honest I've not checked it after the fl bushing sizing to see if the 200 point had grown..

The cases chamber and extract like a dream

[Popsbengo]

what's 'fow'  ?

[Big Al]

17 minutes ago, Popsbengo said:

what's 'fow'  ?

0.001"

[No i deer]

1 hour ago, Big Al said:

0.001"

That's correct Al..

Keep writing 1 thousandth is irritating 🤣.

1 fow 👍

1 mower is 1 moa 🤣.

Zomerset lingo

[Catch-22]

1 hour ago, No i deer said:

I have a 284 win small base die..

Running the brass through does make them about 1 fow longer at the shoulder.

Measure them before sb dying them.

The sbd is set up to bump the shoulder about 1 fow and the fl bushing die is set to bump it a further 1.5 to 2 fow.

To be honest I've not checked it after the fl bushing sizing to see if the 200 point had grown..

The cases chamber and extract like a dream

Thanks, that’s helpful.

So, you first measure them at the .200” line. If too fat, you run them through your sbd (to tackle the .200” line on the body) AND then also your FL die to bump the shoulders. So sbd THEN your regular FL die?

But if your measurement of the .200” line isn’t too fat, I assume you just run it through your FL die until after a few more firings, you need to run it in your sbd AND then your FL die again.

Sorry, just trying to nail down best practice as I’ve never needed an and before.

And I take on board Al’s comments about using the sbd die but then the shoulder will grow. And if FL sizing after the and, then the .200” line may grow again…so that chicken and egg…size one bit and the other bit grows, and vice versa. One to just keep an eye on.