Reloading without neck sizing

I came across a description the other day of chamber reamer dimensions at the neck ground to allow fired cases to be reloaded without any sizing whatsoever, something along these lines: the chamber is cut tight enough at the neck - 3/4 to 1 thou over the loaded round diameter - so only elastic expansion of the brass occurs on firing. The brass then springs back perhaps 1.5 thou restoring 1/2- 3/4 thou neck tension for the next reload cycle without any neck sizing. In this way the cases can be reloaded repeatedly without ever needing to neck size. Obviously only suitable when chamber and ammunition cleanliness can be absolutely assured to maintain such small clearances so not suitable for my purposes but an interesting concept. Has anyone tried or heard of this approach please?

Heard of target shooters doing something similar.



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They used that technique in the "houston warehouse"

Works well until your brass thins at the neck due to galvanic corrosion and wear

Way too much trouble for way too small of a gain

I had a 7RUM chambered by Greg Duley using his reamer. I couldn't push a projectile back in to a fired case. Not sure the exact dimensions of the neck.

Yep, I did this a few years ago when I first started using Lapua .243 cases in my tight neck chambered .260.

On the recommendation from Walt Berger at Berger bullets, I now have a bit more clearance through the neck.

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*That* only gives you 0.0005 clearance and most of us feel this is not enough. If you reduce wall thickness *for an increase in clearance in the neck* in my opinion you will end up with better accuracy and if you feel neck tension is not enough get a smaller sizing bushing. I think you will have a more trouble free operation this way.

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I've got one rifle chambered like this. It is OK but it is crucial to be aware of any changes in the neck and neck area of the chamber. And it does involve some very careful turning of the necks of the cases to ensure they are all exactly the same thickness.

a) Try putting a new projectile into a fired case and see how well it stays in place....f all chance.
b) that sounds really dangerous to me unless the brass neck has been carefully and precisely sized and most ammo ie non-target type will not have been worked on that carefully.
c) if nothing else for accuracy you want consistent neck tension every time IMHO.

This is not something that I would consider acceptable for anything that isnt a careful single shot feed ie out hunting as the projectile can get knocked back.

Now I would certainly say my impression is for target work you want as low as tension as you can get ie about 1thou, hence when/if I full resize my brass to bump the shoulder back etc I then neck re-size which is slacker than a full die on my 303 anyway.

I had a 'no turn' tolerance put in my chamber and I'm now just trying a no neck sizing method to see how long I can keep the light and consistent bullet seating going. On the 3rd firing now and only 3 or 4 had developed a slightly tighter feel. Never been shooting tighter groups. 3rd cycle for me was the first time the brass needed to be bumped at all

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Originally Posted by Dead is better

I had a 'no turn' tolerance put in my chamber and I'm now just trying a no neck sizing method to see how long I can keep the light and consistent bullet seating going. On the 3rd firing now and only 3 or 4 had developed a slightly tighter feel. Never been shooting tighter groups. 3rd cycle for me was the first time the brass needed to be bumped at all

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Tight groups are always interesting, but I don't understand your set-up from your post. Chamber neck dimensions for 'no-turn' are usually around 0.004" more in diameter than across the neck of loaded brass, with significant expansion on firing that would have to be taken back down with sizing. The no neck sizing method requires very careful neck turning to get the clearance just so-so, and constant monitoring of the neck thickness from then on. Did you perhaps mean 'no neck size' tolerance ? What do you attribute the better groups to... what I mean is have you got a theory as to why minimum clearance necks are reducing groups ?

Even if it's only elastic expansion in diameter, surely the 60,000 psi will lengthen it with each firing?

Probly work for a few firings tho

Chris

True, that is what I read, peak pressures have to be dropped down to around 50kPSI for no sizing to be required at all, but once that point is found brass life becomes a non-issue. Contrary to my previous post, at the lower pressures the comment was also made that necks don't tend to thicken but it is carbon build-up around necks and chamber at the neck that is the thing to watch.

Dead is better, what peak pressure do you think you are running to give the small amount of stretching you've noted ?

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Originally Posted by 7mmsaum

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..Works well until your brass thins at the neck due to galvanic corrosion ...

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Can you explain that a bit please. I thought galv corrosion needed a moist environment?

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Originally Posted by Puffin

True, that is what I read, peak pressures have to be dropped down to around 50kPSI for no sizing to be required at all, but once that point is found brass life becomes a non-issue. Contrary to my previous post, at the lower pressures the comment was also made that necks don't tend to thicken but it is carbon build-up around necks and chamber at the neck that is the thing to watch.

Dead is better, what peak pressure do you think you are running to give the small amount of stretching you've noted ?

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Sorry for the delayed response. I've had a play on QL lately so I believe my peak pressure to be 48780 for my swede. I did have to trim the necks on the 4th firing but with annealing I'm still yet to size the necks. I have just put them all through the body die so they're snug instead of FL + neck sizing which I believe introduced too much runout over time.

Yeah not getting galvanic corrosion in the neck. Or brass wear. Surely a tight neck etc would mean less brass stretch? Explain ?

Well I guess I'm trying a few things. I did go to the trouble of making a wet tumbler and they've become all the rage. But I heard a little theory that the carbon coating on the inside can be rather consistent and may assist/insulate during firing.... I had no idea so I'm just bucking the shiney brass trend. I am using a non amonia based polish to clean the necks, and I use a nylon bore brush to keep the necks consistantly filthy on the insides haha. I can't recall exactly what I specified but the neck was set to be in between a 'turn' and 'no turn'. When I measure a fired neck it says .296" i think and there's no change once I load a round (which I seat the shank all the way in). I'll check that again just to be sure but my battery in my calipers has died. My lazy approach happened because that fella "froggy" reckoned he was pulling 'bug sized groups' with a similar reloading technique. My main change is that I stopped using lube in the necks as they 'feel' exactly the same during seating. Some say lube can effect the powder and others balk at graphite going down the barrel do I figured I'd try letting the existing carbon stay with a minor clean. I do get 3 out 100 that feel a bit tighter so I just mark them as foulers.

The last set of lapua brass lasted about 10 cyles before finally refusing to chamber. No split necks or loose primer pockets. Lapua is worth every cent

There, all my hobo reloading secrets are out haha