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Round 3 National League - Diggle


Ronin

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It was a great weekend and we all had a good laugh even though the weather turned nasty. Fantastic performances from Ricky, Adam and Ste in F/TR and great to see them up there with the Top F-Open scores. Well done Des,Ian and David. A very hard but enjoyable shoot and like you said Dave, it's great to see new faces and see them all doing well.

Thanks to Vince and Les for putting on a great weekend.

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Tomorrow, I will measure and experiment with those cartridges and report back.

 

1. Measurement.

As mentioned, I've measured the cases now and it is a bit puzzling.

Before removing the heads, I checked the OAL - it was fine, and they all fell in and out of my Wilson seater.

Then I used an RCBS Precision Mic to check the cases and instead of finding them a bit long as expected - actually they were either the same or even slightly shorter.

So, that would suggest the only thing left is spring-back.

 

2. Experiment

So, to test that theory, I set back 2 of them using the Redding body die just as it was set up, and set back the other 3 with the die set up a little tighter in.

If there is any spring-back variation overnight it may show up in how they chamber - that will be tomorrow's instalment.

 

Cheers,

Des.

 

 

 

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I give up!

I've tried everything and still they defiantly refuse to fit.

1.Put them through two body does, standard and small base.

2. Resized the necks.

3. Put them through a full-length sizer - still no joy!!! :(

 

I then thought, well it must be the case length, one did seem distinctly longer, but another, shorter one still didn't fit.

One thing I noticed, the rims were rather tight in the shell-holder.

 

So, I'm totally stumped - I shall put them aside and show them to Callum the next time I'm up at his place, hopefully he can figure it out.

 

Cheers

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Have they been fired in another chamber ? Like a looser chamber at the web or

If the rims are tight they could be buckled from not running enough lube when sizing you end up bending the rim wich will alter case headspace

Try bumping them right back about 7 thou if they go in then bin them - cases sound like their junk anyway

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Certainly odd.

 

 

Is there a discernible difference in the diameter of the case at the base above the rim??

 

I had trouble in Raton with a few cases that needed a small base body die to bump back into shape from over pressure loads...

 

Could be as Grant says the rim being deformed - is there any ejector plunger marks on the case base for example that would cause it to be difficult to slide into a shell holder?

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Have they been fired in another chamber ? Like a looser chamber at the web or

If the rims are tight they could be buckled from not running enough lube when sizing you end up bending the rim wich will alter case headspace

Try bumping them right back about 7 thou if they go in then bin them - cases sound like their junk anyway

 

They should not have been fired in another chamber, this is the new brass I got for Raton.

Should not...there is a danger I may have picked up a few odd ones from an earlier batch to use as blow-offs and then got them mixed in with the main new batch.- that might explain why every other case is OK, but these 5 are so different.

Anyway, I've just taken a look at my supplies and there's no need to be over-using the same cases, I'll get a new batch ready for Bisley at the end of the month, and not have to worry.

 

Thanks to all who've contributed, pm'ed and phoned - there's a wealth of info' out there!

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evening desmond

 

could you check to see if it's tight in terms of the outside edge of the rim sliding into the shell holder? if it is then the base of the case being tight in the shell holder is a classic sign of over expansion of the case head due to your loads/rounds being over pressure. you'd possibly also have loose primer pockets, but not always.

 

if it's not tight on the edges, then maybe the rims are buckled like grant suggests. try placing the bases of the cases on a flat surface and look to see if they sit happily or if they are rocking or you can see daylight underneath them.....

 

keep us informed of progress.

 

derek

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Evening Roderick,

 

You may be onto something - I normally have an RCBS shell-holder in my press, it accepted all the cases without any problem.

Just out of curiosity, I swapped it for a Redding shell-holder - guess what? 4 of the 5 cases were very tight indeed.

It would seem therefore that not all shell-holders are equal.

My current load of 65.5grs is not particularly hot, but before settling on it, I tested loads going a good deal higher - possibly those loads stretched the caseheads of a few cases, which was not revealed by the more 'generous' RCBS shell-holder.

 

Cheers.

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Des, did you use these rounds at the short range Diggle shoot? I lost 15 cases in exactly the same way as you have and they wouldn't fit the shell holder, I must admit that I haven't tried to chamber them since, when I screw that barrel back on I will try to remember to chamber them.

 

The reason I ask was it the short range shoot is that I know I suffered from water in the chamber causing high pressure, I wasn't the only one either,

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Des, did you use these rounds at the short range Diggle shoot? I lost 15 cases in exactly the same way as you have and they wouldn't fit the shell holder, I must admit that I haven't tried to chamber them since, when I screw that barrel back on I will try to remember to chamber them.

 

The reason I ask was it the short range shoot is that I know I suffered from water in the chamber causing high pressure, I wasn't the only one either,

 

 

Hi Des /Ian i ahve suffered exactly the same with 32/100 of my shehane rounds from the rain after the short range day . ive put it down to chamber pressure increasing with ingression of water in to the chamber apon firing. after careful measuring my case heads have expanded 2 thou and are also tight fitting in to a lee no 2 shell holder so much so that i have tried re full ength sizing them with a no 5 shell holder with no success end result 32 knackered cases

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Des, did you use these rounds at the short range Diggle shoot? I lost 15 cases in exactly the same way as you have and they wouldn't fit the shell holder, I must admit that I haven't tried to chamber them since, when I screw that barrel back on I will try to remember to chamber them.

 

The reason I ask was it the short range shoot is that I know I suffered from water in the chamber causing high pressure, I wasn't the only one either,

 

No Ian,

At the short range match I was using a shehene that was past its 'use by' date - another lesson learned the hard way.

Though, its nice to know I'm not alone in suffering the same expanded casehead problem.

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No Ian,

At the short range match I was using a shehene that was past its 'use by' date - another lesson learned the hard way.

Though, its nice to know I'm not alone in suffering the same expanded casehead problem.

 

Ah yes, I remember the conversation now.

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Des

 

Quite a few of my cases from Raton are extremely tight in the Shell holder,and some do not even fit,I have come to the conclusion that these were some that were used for load development at the Cooper range and were the top end of the load which I back off, (not enough as we all know)

 

I have scrapped all my Raton brass, 400 inside neck turned cases by Al Warner, .

 

Also I had to junk Shehane cases due to water ingress at the a Short range Diggle, (same as Ian and Spud) around 20 cases that will not fit the shell holder! bloody annoying.

 

G

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I have scrapped all my Raton brass, 400 inside neck turned cases by Al Warner, .

 

Also I had to junk Shehane cases due to water ingress at the a Short range Diggle, (same as Ian and Spud) around 20 cases that will not fit the shell holder! bloody annoying.

 

G

 

 

That had to hurt Gary.

 

 

All my Raton brass scrapped too, though not made by Al, I spent considerable time on them..

 

The Cooper test range was certainly was hard on cases

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Also I had to junk Shehane cases due to water ingress at the a Short range Diggle, (same as Ian and Spud) around 20 cases that will not fit the shell holder! bloody annoying.

G

I wonder will FTR have any problems after the soaking at Diggle?

It really indicates especially in F open we should not shoot in heavy rain on safety grounds?

Cheers

Dave

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I wonder will FTR have any problems after the soaking at Diggle?

It really indicates especially in F open we should not shoot in heavy rain on safety grounds?

Cheers

Dave

ill second that

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I wonder will FTR have any problems after the soaking at Diggle?

It really indicates especially in F open we should not shoot in heavy rain on safety grounds?

Cheers

Dave

 

i'm not sure the biggest safety concern lies with f-open.....

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someone please correct me if i'm wrong here, but it's my understanding that putting rounds into a wet chamber doesn't increase chamber pressure drastically. what it does do is stop the case from gripping the side of the chambers effectively. approximately half the pressure is absorbed by this process. wet chamber walls means that more of the pressure is used to force the case head back against the bolt face, thus increasing bolt thrust. thereby the increased pressure on the case head is causing it to expand giving everyone their problems with the shell holders / chambering rounds where this has happened.

 

whilst it's not ideal to increase bolt thrust, it's not going to be as much force as a case head separation for example and most actions will cope with this. so, to be avoided i'd say but not massively unsafe. other people may have a different view on this and i'm open to having my mind changed here.

 

i'd be more concerned lying down beside someone loosing primer pockets on a .308 palma case on it's first firing.....

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Nowler, while you're correct on increasing bolt-thrust through less case-chamber grip, there is more at play here. The amount of moisture that was getting into people's rifles, likewise some relays on Round 1 at Diggle in March went way beyond a little damping of the chamber. I believe that water ultimately gets into the barrel ahead of the case body and that's when the big problems start. Water is incompressible, so any that gets between the outside of the case-neck walls and the neck section of the chamber will likely create the same condition as using an oversize round in tight-neck chamber. As water moves further ahead into the back end of the rifled area, it will act as a barrier between bullet and bore also massively increasing pressures.

 

How would it get that far forward? First the wind direction and strength in the March round was almost optimal for blowing raindrops (and snowflakes too as we got that as well) into a right-hand action's loading port. But likely most moisture is carried into the chamber by cartridges that have got a bit wet in the transfer between box and rifle and the moisture levels in the chamber build up. Also, the act of chambering successive rounds will help move any moisture in the rear of the chamber forward to the neck / throat / bore area.

 

In this scenario, if the major factor is water between the case-neck and chamber, F/O rifles are FAR more likely to suffer massive over-pressures than F/TR as nearly every Open competitor has a custom chamber and runs with relatively small clearances, where (in the UK at any rate, not USA from quotes I see by their F/TR competitors on the AccurateShooter Forum) F/TR rifles normally run with minimum SAAMI dimension chamber dimensions and even with non turned Lapua brass, clearances are at least 50% greater than in most F/O set-ups. I got hammered by a snowstorm at the end of the sole 20-round match we managed on Day One of the March round and blew the primers on the last two shots (6.5X47L and not a tight-neck chamber with slightly turned brass increasing clearances further). It was difficult to tell what it did to the point of impact bearing in mind that I could hardly see anything to aim at, nor could I see the shot marker, only the much larger score paddle on the bottom of the frame. If I had been only half way through the match in this condition, I'd have either retired or asked the RO to consider a halt or abandoning the match. It's neither fun nor sensible to continue in these conditions.

 

The fact that it was the very strong 6.5X47L case with small primers that blew them doesn't suggest to me that F/TR competitors using 'Palma' brass are at any greater risk than F/O shooters with WSMs / 284s with LR primers. In fact, I've seen such conditions three times now since I started shooting the GB League, the first time being the teams matches in 'The Europeans' at Bisley four or five years back which had to be abandoned on safety grounds after a spate of blown primers. In each and every case, it is F/O competitors who subsequently admitted to dangerous over-pressure problems. (In the aforementioned teams matches, F/TR shooters were complaining of changed elevations and hard bolt lifts and just before everything was shut down I was employed trying to dry out the chamber on Russell Simmonds' F/TR rifle as the team captain had rotated him off the firing line temporarily after around seven or eight score shots. But nobody down our end of the line blew a single primer while the problem had become endemic futher up the firing line amongst the F/O teams.)

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all fair points laurie, and i can't argue with them. i'd forgotten how wet it can get at diggle... i hadn't considered the primer size comparisons either....

 

cheers

 

d

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it was beyond wet i hate to admit that it was the first time in over 40 years of one type or shooting or another i wanted to pack up and go home. ill remember that relay we shared Laurie as long as i live,

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