248 Win Case sizing conundrum

[Brillo]

This one is weird. I just can't get my head around what is happening here.

 

I have a .284 win which I bought of a guy on here and I'm really happy with the rifle. It came with some ammo with sized up 6.5x284 Lapua brass.

Having shot some rounds I then made some new rounds by neck sizing the fired cases. Obvious thing to do nes pas?

When I was seating the bullets some were very tight in the Wilson seating die and one round was so tight it took some effort to get it out.

Off I go to the range today and I shoot the remainder of the original rounds and then the new ones. These new ones wouldn't chamber - none of them. Odd or what?

I tried to chamber the fired cases and they went in OK.

I decided I had no option but to pull the heads of my newly made rounds and body size the cases. This I did and they chambered OK. When I tried to load the cases from the rounds I successfully fired earlier they wouldn't chamber either. They had increased in size since firing!!!!

 

What is happening here? If I have to body size after neck sizing I might as well just full length size each time.

[1967spud]

ring me mark

 

it does sound like to me that you have a slight over size chamber but i may be wrong

[Brillo]

ring me mark

 

it does sound like to me that you have a slight over size chamber but i may be wrong

Will do Mark. All the fired cases re-chambered OK on the range but they wouldn't 3 hours later..................

[The Gun Pimp]

Why wouldn't you full-length size every time? If you want to 'run your gun' slick - full-length size - it doesn't cost anything!

[gbal]

 

As I read this ,you have not fired a round you loaded-though the rounds in the fired cases you body sized chamber OK? When you fire them,let's hope they rechamber and reload OK,but it may well be that full length resize is needed , at least that's relatively easy,as Vince says-I would not worry too much about a little extra working of this brass-maybe it needs it!

Have you asked the previous owner/reloader if he had any quirks like this ? The brass is reformed,rather than 284win,so that might just be a clue.If you could get some virgin 284 and load,that might tell us something,esp if it doesn't work.

A just fired case rechambering on the range,but not 3 hours later is a conundrum,as you say-you'd assume it would be cooler,and contract a smidgin,if anything. Again it was reloaded by the previous owner.Are you using his dies etc,as set up by him,or different dies?

Let's hope that FL resizing gets you shooting OK. And new brass works as it should.

Gbal

[That bald headed Geordie]

As Gun Pimp says, full length resize, but also after f/l resizing insert the case into the chamber to see if it goes in ok.

If not, then it could be that you might need to trim the case lengths. Just a suggestion!

[Brillo]

Thanks all for the guidance. I always used to FL size but then went to neck sizing because so many good shooters recommended it, so going back to full length sizing ain't a problem except I have the dies for neck sizing.

To recap; the cases I shot were new cases resized from 6.5x284 Lapua. They chambered OK but the same cases would not chamber 3 hours later. Nothing had been done to the rifle in the mean time except bring it home.

[gbal]

Thanks all for the guidance. I always used to FL size but then went to neck sizing because so many good shooters recommended it, so going back to full length sizing ain't a problem except I have the dies for neck sizing.

To recap; the cases I shot were new cases resized from 6.5x284 Lapua. They chambered OK but the same cases would not chamber 3 hours later. Nothing had been done to the rifle in the mean time except bring it home.

The curious case of the fired cartridge.

" But it didn't!" cried Watson

"That is what is curious",remarked Holmes

 

So you got some previous owner home loaded ammo made from necked up 6.5x47 Lapua, with the rifle,which chambered and fired ok,and also rechambered OK immediately after firing,but then these cases would not chamber when you got home 3 hours later,with nothing else done to rifle or cases?

Ergo,something happened to the cases when they were fired in that chamber to make them too big on some measurement to later

fit that same chamber,after a 3 hour delay,though they did rechamber immediatelyy after firing.Very odd.Neck stretching for them all on exactly that firing seems precluded,as they did rechamber after firing.

SO, do they now chamber when Full Length resized(?);and reloaded(?),and after fing again(?)-perhaps you don't know yet...

Do you have the same neck bushings,if any,as previous loader?

229 B Baker Street awaits more data..!!

 

Gbal

[Swamp Donkey]

Sounds silly, I know, I know, but,

You say some of the bullets were very hard to seat, have you actually measured the bullets to ensure that they are what it says on the tin, and not oversize, thus making it hard to seat as they are expanding the neck to an extent that it has 'gone up a cal'

Also, how hot was the chamber when firing ? Yes the brass should shrink as it cools, but so will the chamber, which is less 'elastic' than brass

 

Pete

[oaken]

+1 my first thought was are you using the right bullets? Easy mistake to make. To some extent they will size the brass as you seat them. New brass is fairly elastic so may shrink back small enough to chamber once the bullet has been extracted?

[garyw]

Mark-i have a 284 fl die if you need one-R.C.B.S.

[Brillo]

Mark-i have a 284 fl die if you need one-R.C.B.S.

I might well take you up on that Gary. Will contact you after next experiment after I've had another chat with Holmes and Dr Watson

[Brillo]

Here's the latest on this problem. I spoke to the seller yesterday at Bisley and he has only ever loaded new cases (the rifle had fired less than 200 rounds when I bought it) so he could not shed any light on why the cases should apparently increase in size.

I loaded some rounds from the 'once fired' cases having full body sized them. I shot those rounds at Bisley yesterday (I was shooting with the Dorset Riflemen) and the rounds chambered ok. The difference this time from the first shooting session mentioned in my original post is that the fired cases would not chamber again immediately after firing the round. Now this is very odd. If the case would not go back in, why was it not too tight to extract?

Does this help anyone identify the cause of the problem.

 

My concern now is that I may now get cases that won't extract and if this happens every shot what would be the reason for that and what would be the fix (if there is one)?

[gbal]

Here's the latest on this problem. I spoke to the seller yesterday at Bisley and he has only ever loaded new cases (the rifle had fired less than 200 rounds when I bought it) so he could not shed any light on why the cases should apparently increase in size.

I loaded some rounds from the 'once fired' cases having full body sized them. I shot those rounds at Bisley yesterday (I was shooting with the Dorset Riflemen) and the rounds chambered ok. The difference this time from the first shooting session mentioned in my original post is that the fired cases would not chamber again immediately after firing the round. Now this is very odd. If the case would not go back in, why was it not too tight to extract?

Does this help anyone identify the cause of the problem.

 

My concern now is that I may now get cases that won't extract and if this happens every shot what would be the reason for that and what would be the fix (if there is one)?

 

"Curiouser and Curiouser!" cried Alice (in Wonderland)

 

Do these ((once fired/FL sized/reloaded and fired/extracted Ok/but then would not immediately rechamber cases )) chamber OK

some time after firing (3 hours was the original time delay,though it's not critical..)?

 

Gbal

[Brillo]

No is the simple answer gbal.

I've measured the cases and there is no change in OAL and the fired case is ever so slightly bigger in dia at the shoulder only ( 0.0005"), so that tells me that the chamber is not oversized.

Bear in mind that the FL sizing was done with a body die and then neck sized 2/3 down the neck, so there was, and is, no difference between the neck diameters at the shoulder of the loaded rounds and the fired rounds.

Even if the chamber was oversized, once the case was fire formed it should re-chamber OK shouldn't it?

[The Gun Pimp]

If I got a new custom rifle - which was supposed to be accurate - the first thing I would do is treat it to some brand-new brass. Sadly, when you buy secondhand you just don't know the history of the brass and, if it's been used in another rifle for example, or fired many times, then you are asking for problems.

 

Start again with new brass Mark - then tell us your problem.

 

Of course, 284 brass is formed by necking-up 6.5-284 brass. No problem - except one - you may end up with a small radius at the neck/shoulder junction, whereas your chamber will have a sharp angle at this point. Thus, it's best to run the cases through a FULL LENGTH body-die. Then, you may end up with the 'dreaded doughnut' on the inside of the neck with some cases. If you don't remove the doughnut (Spud will sell you a tool but a suitably sized drill will do the job) your rounds will become difficult to chamber - as your seated bullet will expand the case at this point - causing difficult chambering. Pressure - and thus accuracy - will be erratic.

 

I realise that this may not be your problem Mark but please - buy some new brass!

[1967spud]

Sure will Vince got brass here as well mark whe n youre ready

[gbal]

 

As first thoughts on this, it would be good to try some virgin brass-284 win-to see if there are these issues-or whether they come from the (Lapua) brass reforming processes etc.

Gbal

[Brillo]

If I got a new custom rifle - which was supposed to be accurate - the first thing I would do is treat it to some brand-new brass. Sadly, when you buy secondhand you just don't know the history of the brass and, if it's been used in another rifle for example, or fired many times, then you are asking for problems.

 

Start again with new brass Mark - then tell us your problem.

 

Of course, 284 brass is formed by necking-up 6.5-284 brass. No problem - except one - you may end up with a small radius at the neck/shoulder junction, whereas your chamber will have a sharp angle at this point. Thus, it's best to run the cases through a FULL LENGTH body-die. Then, you may end up with the 'dreaded doughnut' on the inside of the neck with some cases. If you don't remove the doughnut (Spud will sell you a tool but a suitably sized drill will do the job) your rounds will become difficult to chamber - as your seated bullet will expand the case at this point - causing difficult chambering. Pressure - and thus accuracy - will be erratic.

 

I realise that this may not be your problem Mark but please - buy some new brass!

Good points. I hadn't thought about the provenance of the brass. I do have some brand new 6.5x284 brass.

Do I neck up with an 7mm expander die first and then run through with full length sizer die or can it be be done in one go with a FL die?

 

Mark - do you have all of this and the doughnut thingy Vince refers to?

[1967spud]

Neck up with expander then run it through fl die

 

 

I have all bits here off when you ring mark

[Brillo]

Great. I'll buzz you tomorrow.

[Grouse]

Old thread, but what happened in the end????

[Brillo]

I had the chamber re-reamed.

[The Gun Pimp]

I had the chamber re-reamed.

Wow - to what end?

[Brillo]

I must admit I'd forgotten the interest in this problem and, as such, omitted to update everyone.

I took the rifle to a gunsmith near me and, to cut a long story short, it turned out I had a 'lobed'' i.e. non-concentric chamber. I understand that this can happen when the reamer chatters.

 

We determined this by marking a fired case and rotated it 1/8 turn each time I chambered it. At one point it chambered ok and the next wouldn't.

 

The barrel was set back and re-reamed but the gun smith could only go so far otherwise the proof marks would have been removed and so would need re-proofing.

 

This solved the problem albeit would sometimes be a bit tight to fit but by then I'd got into the routine of full length sizing anyway.