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New brass question


foxpig

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+1 on Onehole's general comments. I would not fire tis rifle again until some basics are clear.

After some 44 posts,it seems we don't know whether it's a tight neck ?

Your comment about bullets not falling easily through the fired cases is concerning-normally firing allows the neck to expand,limited by the chamber neck-of course-and the tension holding the bullet in is removed,and the bullet is pushed out.So after firing bullets should encounter but little resistence from the fired case neck,and should slip into the case quite/very readily.

Yours do not in this rifle....I presume they do in the virgin brass.

 

It has always seemed clear that something was happening between first firing (presumed no chambering issues,stiff bolts etc) giving excellent grouping,and the second firing of that brass,reloaded,which gave bullet scattering (tho' no signs of pressure,stiff bolt,extraction-at least,not reported anyhow.) No third firing done.

The logic has to be something has happened to this brass-and that can only be something that was done in firing it (unlikely with safe load) or therefore much more likely ,in the reloading.This was done using the same components,equipment and seatng depth...so the suspicion falls on the dies or bushing used.

 

Are you ABSOLUTELY sure you have the correct bushing (size,make,location in the die) ? Though very unusual,its just possible the bushing isn't quite to spec...(but not by a couple of thou.in the wrong direction).

It is also extremely unlikely there is a fault in several boxes of Lapua (and it's virgin firing is excellent).

 

This has been-remains -a puzzler-but the issues about what neck is it,and bullets not slipping into unfired cases suggest you need to check these issues. Forget Audette-it was always a very long shot,and only if the brass was of suspect manufacture (note: just firing 5 in any one condition would have been an inadequate sample-hundreds of shots seem to have been fired-surely it would be worth at least ten to have some confidence either way,and test each idea reasonably?

 

Priority has to be to clarify what neck you have,and what your reloading-rather your "resizing/necking/bumping " is doing to your brass.

 

g

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This is where I struggle. I'm not the brightest spark.

How do I measure the chamber neck to know if my brass is a tight one.

Yes the bullet drops into Virgin brass but of course only after expand iron .

I think I'll have to get the smithy involved . I haven't bothered him about it yet as I didn't want to pee him off.

I want him to build me a 6.5x47 soon.

As always thanks for your help but I think it's time someone who knows what there doing has a look

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I,ve deliberately stayed out of this post because you haven,t contacted me. I,m assuming this is the rifle I built you some time back ?

 

I have detailed records of your barrel, chamber and work done. I also have the fired brass from it when it was tested.

 

I tested your rifle with brass which had been necked up to .284 and fired four times in a .284. I didn't have any 6.5 x 284 brass to test yours with, so necked the .284 brass back down and body sized it too.

 

The neck bush is a .291

 

The rifle shot perfectly satisfactorily with a cobbled together load as shown in the precision rifleman's showcase. It simply needed a load working up.

 

As I recall, I set the headspace at 0.002" as its a hunting rifle. That is well within spec as a no go gauge fails at 0.004" It passed proof test which include headspace checks.

 

The runout in the rear of the chamber was documented at 0.0002" [ thats two tenths of a thou ] and again, is more than acceptable in any chamber [ no chamber is perfect, despite what people say/think ]

 

The fired brass shows NO growth at the web from sized to fired, again a perfect indicator that the chamber is as concentric as possible.

 

The reamer is a bog standard SAAMI spec 6.5 x 284 which has cut around a dozen chambers. Not worn, and in perfect condition. It is NOT a tight or fitted neck. I don't use them in any chambering.

 

Thats all the doubts about my work put to rest.

 

Right, for some help.

 

I would put money on your neck tension being too tight. Check your bush diameter. Load a bullet into your case and then measure the neck with the bullet in situ. If, say it measures .293, then you want a bush at .292 [ redding instructions ] personally, I like to go 0.002" under, so would plump for a .291

 

Virgin brass is giving astounding groups from such a lightweight barrel. Something in your loading set up is wrong. The chamber is perfect [or as near as humanly possible ] so its all it can be.

 

Pressure signs on fire formed brass are not at all unusual. Think about it. The virgin firing is in brass that is actually UNDER SAAMI spec....it has to be to fit every chamber, and there is a lot of "give" on first firing. The brass is a far better chamber fit when fire formed.Drop the load, in decreasing increments...the pressure will stop showing, and you will hit another accuracy node somewhere else.

 

If you want to borrow my Redding competition die set, to try with your brass, you have only to ask. ;)

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20160107_173718.jpg

Dave there was never even the slightest Dout about your work.i new it was something simple . All my other rifle's I have down and sorted. This one was a puzzler though.

As you can see my bush is 291.

I will work another load with 140 s anyway and take the lowest node.

And try a second firing hoping for the best.

If this is the case and the load I've been using is 2 hot. Does that mean I have 350 once fired 6.5x284 cases that are shagged?

Thanks for your help bud

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The cases will be fine Dave, providing the primer pockets aren,t sloppy. Have you checked them?

 

I perhaps haven,t explained myself properly. I didn,t think for one minute you were upset with the work....I,m sure you would have rung if so. Equally so, I was delighted with your kind texts saying how pleased you were with the gun. :)

 

Posts such as this alway end up with "experts" doubting the chamber, Smith, etc etc when the first port of call should be the gunsmith.

 

A good example being a Tight neck.

 

If I send a gun to the proof house with a tight neck....and don't tell them....there will only be one outcome. A Farking big bang. A good example of " expert" internet opinion.

 

Shout up if you want to borrow the dies. I also have a concentricity gauge you are welcome to try too.

 

All my redding dies in all calibres produce loaded rounds with between 0.001" and 0.002" runout. Guess what ? they shoot very accurately indeed.

 

That kinda makes a mockery of internet "wisdom" on chambers in particular.

 

Its something simple...trust me.

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What sort of die is that Dave ? A Wilson ?

 

Something I,ve never used so could,t comment, but its defiantly worth trying another.

 

If you want to send up a 100 once fired , I will neck size 50 , and neck/body size the other 50 for you, on my dies.

 

My Redding dies/methods have always worked for me. I,m firm believer in keeping things simple. I full length size every cartridge for my own use these days. That puts an identical cartridge into the gun every time. It does away with any doubts about barrels, chambers, etc etc.

 

Shout up. I don't like to see a customer struggle.

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Failure of the bullet to fall through a fired case-neck is NOT invariably a sign of a tight-neck chamber, or of any chamber, or even brass problem. Many cartridges with perfectly acceptable loads, especially those that run somewhat under maximum pressures, produce a relatively tight fired case-bullet fit. As an example, my 308 Win FTR rifles are all chambered with a 'minimum SAAMI' reamer which, if memory serves right is a 0.344" neck. My standard match load uses Lapua Palma brass with a light clean-up turn reducing walls to 0.145- 0.147" depending on the original brass thickness. That gives a loaded round neck O/D of ~0.338 as most match 30-cal bullets mike out at around 0.3083" slightly above the nominal diameter. That's a total clearance of 6 thou', or 3 at any single point of the neck circumference.

 

Some of my match load combinations see the fired brass unable to hold the bullet, on others it's 'a bit tight'. On load development workups, many cases won't let the bullet drop in thanks to a combination of below full pressures and the rate / characteristics of powder ignition and burn. I still have a large cache of 1980s 160gn all-up weight Norma 308 brass that runs down at 13 thou' and some of which when batched only a little above 12 thou', same with current Winchester out of the packet at 0.0135". These cases are running at 10 to 12 thou' overall clearance - and despite what some pundits tell you can provide outstanding groups - but I'll still find some load combinations that won't produce fired brass where the bullet drops through the neck. Yes, a 'tight' fired case neck might be a symptom of a problem, a common one from the 'bad old days' being untrimmed over-long for chamber case-necks, but more often than not there is nothing at all to worry about.

 

(Many American FTR shooters are now specifying below SAAMI 308 Win chamber necks, 0.342" and even 0.340", for no-turn use with Winchester brass or light turn Lapua. We don't encourage that in the UK and national league competitors could be DQ'd if a SAAMI spec inert round won't chamber - the FTR version of the NRA Rule 150.)

 

So far as neck tension goes, I prefer to use a bushing one thou' on the tight side followed by a separate expand operation using a mandrel. I've found the Sinclair E-series mandrels designed for case-neck expansion prior to neck-turning suit my loading techniques perfectly and they provide more constant subjective seating tension than bushing sizing alone. You need an expander die to hold the (interchangeable) mandrel, and it does add an onerous extra step as inside neck lubing is needed with ordinary steel mandrels. Some people are now producing carbide expand mandrels as well as the smaller dia. 'turn' versions, but they're £50 a throw.

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That's a proper smithy right there. Cheers dave. Yes it's a wilson die

I was told they are pretty much the best. And as I've said before they work a treat in my other guns.

However I'm seriously starting to think about getting into full length.

I will start again with 140 amax. If it shoots aswell with the 140 s as it does with the 123 s then it won't take long to find a node.

Without a Dout the most accurate rifle I've ever owned,seen , used hands down.

The offer of the brass sorting is lovely thanks dave. And I may take you up on that in the future. ( can't you do 350 !!!) Haha

My next post will be the conclusion and a sorted rifle I'm sure.

Cheers

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Just a thought. What sort of bushing are you using? I ask as I have read that with some bushings if you use them the wrong way up or down as it was you end up with more neck tension than desired. That they have a slight taper and are not paralell. Not sure if it was LE Wilson bushes or the Redding ones. May be worth a check, size one and measure neck and then flip the bush and repeat.

Just a long shot.....

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Just got here. Sorry if this is behind the curve but...

 

Get some QC into the reloading process

 

Borrow a concentricity gauge and measure the crap out of the rounds at each stage. Ditto OAL to the ogive. If that is consistent and to tight tolerance then the problem is elsewhere. Assuming everything is hunky dory then at least you have eliminated the reloading stage. Although there is enough evidence to suggest that is where it lies i.e. builder gets good accuracy, so do you with virgin brass.

 

Get data, prove your assumptions are correct and narrow in on the issue

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  • 1 month later...

Ok so just to finish off the thread for anyone who's intrested.

Dave was bang on with his prediction.

Currently on 3rd firing and groups are as good if not better than before.

Load development with the 140 amax took about half hour . Then an hour playing with oal . A total of 25 rounds and problem was solved.

Like to thank gbal and dave for there help and advice.

The rifle is currently getting a new stock and scope so ill post pics of groups after that.

Cheers

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