FL sizing problem

[JDBenelliM1]

Bought myself a nice new redding die set with the intention of FL sizing after every firing.

 

Used the FL die and loaded exactly the same charge,OAL etc as before.

 

Took 5 rounds of my old neck sized only rounds along for comparison.

 

The FL sized rounds are hard to extract. Bolt lift is easy until the last 4mm of lift which is hard and then I had to hit the bolt with the palm of my hand to get it to release rearward.

 

I tried the neck sized rounds after this and they were fine,no hard lift and extracted easily.

 

Anyone got any thoughts on what could be happening?

 

Brass is once fired PPU

 

Thanks

 

JD

[bradders]

I'd say the brass is stretching in length with the body being sized (squeezed) and the shoulder isn't getting bumped back

Try new brass

[Andrew]

Were the neck sized rounds from the PPU brass as well? Did you have problems chambering the FL sized cases?? Is your shell holder Redding as well??~Andrew

[Chris-NZ]

Andrews questions will tell the story.

If the FL'd ones chambered easily, the difficult primary extraction suggests pressure. What do the primers look like?

[JDBenelliM1]

All the brass is PPU. Only had one firing from new with no issues before. No problems chambering the FL cases. I currently use a Lee press with the Lee shell holder. The primers looked fine on first glance. I'll have a closer look this morning. Everything is equal and the same, the only difference is one is neck sized the other FL so I'm guessing if pressure is the issue it's down to less case capacity? I've had loads that were 0.8gr higher and not had any pressure signs but accuracy wasn't as good so dropped back to this load. This is in .308

[stephentri]

After full length sizing did you trim them to length?

[JDBenelliM1]

Cases are 2.009"

[gbal]

Cases are 2.009"

OK-short if anything.

So does that suggest it's non bumped shoulders?

 

Note-the dies are not just neck versus full length.They can also interact with shell holders,sometimes-hence suggestion to try a redding shell holder for redding dies,if you can borrow one first.

 

One advantage of the upmarket dies is that shoulder bumping can be adjusted....Redding should alllow that.

It is a little odd that FL doesn't seem to have,but necking was OK...(though in different dies..) but from what you describe ,the tightness is marginal-though needs fixing...it's also unusual to need a bump after a couple of firings,but pressure can change that too...though you see no signs,either.

Again,if possible try shoulder bump,gently-in someone's bump die,maybe-though it's obviously best to get your Redding set up ..set up!

 

gbal

[stephentri]

Have you measured from shoulder to base on both the full length sized and on the neck sized to see if there's a difference

[JDBenelliM1]

I've checked the cases and two of the three I shot are flattened. I quickly loaded three with 2.5gr less powder and they still had a slightly hard lift at the top but extracted fine with no primer flattening. It seems odd that FL sizing alone would cause such a rise in pressure.

 

The FL cases have visiblby rounder shoulders than the neck sized cases. I'll post some pictunes later. Having not FL sized before I'm unsure what a bumped shoulder should look like, as in very sharp or rounded, as it is now

 

The NS and the FL cases have only had 1 previous firing so I wouldn't expect to have big differences in shoulder to Base measurement. Only assuming this so please advise if wrong.

 

I can't believe I would need to reduce the load by 3gr just because I'm FL sizing so I'm starting to think it's a brass issue.

[gbal]

JD,you are quite right-FL or Neck resizing should not have any effect on powder capacity-one thing as yet unrevealed though is whether you have a standard SAAMI chamber (probable) or just [posssibly a custom cut/possibly tight neck/otherwise non standard one (unlikely,but we should eliminate that explicitly)-then we know the chamber/case tightness is down to case size,and that should be fixable.YOu won't be able to see a very small need for shoulder bumping-or be able to measure it accurately...the 'shoulder' isn't a very precise location.

 

Anothe possibility is that every manufactured bit has to have some tolerance (+/_) in the specification-not much,but can't be zero-manufactured nominally the same cartridges can have vey small differences,and chambers havee to cope.Sometimes a chamber at the very tightest spec,and brass at the very 'latgest' spec meet up,and can be sticky-though unusual,and resizing should fix-unless perchance the die is at the extreme tolerance too.....all unlikely,but then your 'problem' is not that frequent either-unless it's that a shoulder bump is needed....sooner or later most repeated reloads need it-and some dies do it-if loads are anywhere near max repeatedly....or of course,over max.

Good that a light reload has helped-suggests it's a brass expansion issue,but ypu should not need to reduce load-if the load is sub max,as per manual.and maybe .2 g,nothing like 2.5 grains....

gbal

[stephentri]

Have you set up the full length die correct as per instructions that came with it.

[JDBenelliM1]

Have you set up the full length die correct as per instructions that came with it.

Yes I think so. Ram at full up position then screw die until it touches, lower ram and give 1/8th extra in. Same as my neck die. My Lee press doesn't cam over which I why I'm also wanting to upgrade but I am sure the case holder makes good contact with the die ensuring the case has fully entered.

[JDBenelliM1]

Don't think the rifle has a special chamber. I bought it as it is and and I've not had any issues before. The brass would be SAAMI spec when new and the FL should just be resetting it back to this.

[gbal]

Any hint of a faint ring around the web area of the FL sized case ? I've had that with FL small base dies,trying to do what should not be done-resize brass from a different chamber......

 

I usually back off the die by 1/8 maybe 1/4 turn turn or so-so that when raised the ram barely kisses the resizer die.....but there may be less flex in my presses-shell holders can differ a little too-

-and I prefer to use Wilson neck/seater dies anyhow (though I don't think there really is much in it with premium screw in diesin a rigid press--and cases will need regular full length resizing anyhow....well,in theory....

 

gbal

[JDBenelliM1]

Any hint of a faint ring around the web area of the FL sized case ? I've had that with FL small base dies,trying to do what should not be done-resize brass from a different chamber......

 

I usually back off the die by 1/8 maybe 1/4 turn turn or so-so that when raised the ram barely kisses the resizer die.....but there may be less flex in my presses-shell holders can differ a little too-

-and I prefer to use Wilson neck/seater dies anyhow (though I don't think there really is much in it with premium screw in diesin a rigid press--and cases will need regular full length resizing anyhow....well,in theory....

 

gbal

Yes there is a ring at the web area, faint but definitely there. Its around 4mm up the case from the rim. I'm uploading a photo as we speak.

 

If this is the issue is the advice on backing off the die the solution?

[JDBenelliM1]

Any hint of a faint ring around the web area of the FL sized case ? I've had that with FL small base dies,trying to do what should not be done-resize brass from a different chamber......

 

I usually back off the die by 1/8 maybe 1/4 turn turn or so-so that when raised the ram barely kisses the resizer die.....but there may be less flex in my presses-shell holders can differ a little too-

-and I prefer to use Wilson neck/seater dies anyhow (though I don't think there really is much in it with premium screw in diesin a rigid press--and cases will need regular full length resizing anyhow....well,in theory....

 

gbal

Yes there is a ring at the web area, faint but definitely there. Its around 4mm up the case from the rim.

 

If this is the issue is the advice on backing off the die the solution?

 

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[JDBenelliM1]

here is the area where the ring is

 

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[Brillo]

Ah, the ring on the web area is the give-away. I had the same problem at one time.

The solution is to turn the die down another quarter of a turn, not back off. Your Redding press will have an over-cam operation.

To check this put the ram to it's limit, screw the die down to touch the shell holder, back off the ram and screw down the die half a turn.

Now take any old case, lub it as usual and push the ram up to the the near limit where it feels like won't go any further. If it's in the optimum position the bottom of the ram will have a couple of millimetres left to travel.

You'll now find you can push this further and the overcam will operate to a complete stop. This wil ensure the case is fully sized and the shoulder bumped correctly.

If it's really to hard just back off the die a smiggin. If it's too easy turn the due down a tad mor.

[JDBenelliM1]

Ah, the ring on the web area is the give-away. I had the same problem at one time.

The solution is to turn the die down another quarter of a turn, not back off. Your Redding press will have an over-cam operation.

To check this put the ram to it's limit, screw the die down to touch the shell holder, back off the ram and screw down the die half a turn.

Now take any old case, lub it as usual and push the ram up to the the near limit where it feels like won't go any further. If it's in the optimum position the bottom of the ram will have a couple of millimetres left to travel.

You'll now find you can push this further and the overcam will operate to a complete stop. This wil ensure the case is fully sized and the shoulder bumped correctly.

If it's really to hard just back off the die a smiggin. If it's too easy turn the due down a tad mor.

 

I havent bought a redding press yet but its on my list. currently using a Lee press which doesn't over cam so this may be an issue I cant resolve without upgrading. Im assuming the overcam function will put far more pressure on than I can without it? I do currently ensure the case has fully entered the die

[stephentri]

Your lee press is fine for full length resizing just make sure your die is screwed in deep enough and when sized the shell holder contacts the die this returns the brass to factory size.

[JDBenelliM1]

Still not sure on the best way to proceed. I'm thinking about loading 3 rounds with the die backed off and another three making sure the case is fully inserted (although I'm fairly confident the previous ones were) and see what happens.

 

For reference I'm using 43.5gr N140 under 155 SMK. producing 2835fps which was worked up safely showing no pressure signs.

 

I'm beginning to think it's the brass struggling to be re sized in some way creating a sticking point, but would this also explain the flattened primer? The cases enter the die fine without a noticeable hard point during the process suggesting it's being re-sized properly. Brand new brass shoots fine so if the cases are being properly re-sized to saami dimensions I would expect no issues.

 

I'm tempted to back to neck sizing only!

[stephentri]

If you have a head space gauge measure a new un fired cass then measure a cass that you have full length resized both should be the same if your sized cass is bigger then your die is not set up right.

[gbal]

Flattened primers and somewhat stiff bolt lift are fairly classic pressure signs-though velocity at 155/2835 is only on the verge of warm,perhaps- but in your chamber? Is the MV reliable....many chronos drift a bit...

load a few at Vihtavuori max less .4 or so, and see if they resize ok....and compare this to your 43.5 load-just reduce that,really...which may implicate or rule out pressure factors...

 

Presumably the brass is very lightly lubed before FL resizing?

 

Meanwhile,you could try resizing with slightly backed off screw ins for you FL die-and check whether the empty case then chambers/extracts OK (then you won't risk stuck loaded case/waste time loading stiff cases). This might/not focus the problem on the dies.

No joy with trying a redding shell holder-or any alternate one?

 

At least,as you say ,you can neck size and shoot on meanwhile-and try a reduced powder load-it won't make much difference ballistically,and might eliminate that possibility....though it's an unlikely one,as neck resizing seems to work....

gbal

[stephentri]

Measure case capacity with water in a neck sized case then in a full length resized case what's the difference? Let us know