Thread: Substituting projectiles

Originally Posted by JohnDuxbury

Piplstrelle, have you not heard of neck sizing with a full length die before? Its very simple to do and works perfectly.

Sorry, I wasn't ignoring you .

I get the concept . Whenever I've set a f/l die for bump sizing , when I got close to the shoulders the cases started to lengthen . I'm gonna take a guess and say to just neck size you wouldn't be sizing to the neck shoulder juncture , so perhaps only sizing 90% of the neck .

I'll be honest , totally slipped my mind regarding the 7.62 NATO being loaded to lower pressure. My over cautious nature would still have me doing some sort of development though . But , that's me .

Originally Posted by PipIstrelle

Sorry, I wasn't ignoring you .

I get the concept . Whenever I've set a f/l die for bump sizing , when I got close to the shoulders the cases started to lengthen . I'm gonna take a guess and say to just neck size you wouldn't be sizing to the neck shoulder juncture , so perhaps only sizing 90% of the neck .

I'll be honest , totally slipped my mind regarding the 7.62 NATO being loaded to lower pressure. My over cautious nature would still have me doing some sort of development though . But , that's me .

sorry that just doesnt make any sence at all.....
by patrial length resizing your cases arent growing in length,they are DELIBERATELY being left slightly longer/closer to the length the chamber of your rifle left them...same as neck sizing and WHY people necksize.... how can an action of squishing something down make it grow longer upwards??? other than possibly a tiny bit longer in neck itself which is what measuring case and trimming is for.....
if you really want to see partial length resizing for what it is...try a 7.62x39mm die wit ha .308 expander ball...most sets come with both sizes. we used to get a mini shoulder 70-80% of the way down the neck,where die stopped.

Originally Posted by Micky Duck

sorry that just doesnt make any sence at all.....
by patrial length resizing your cases arent growing in length,they are DELIBERATELY being left slightly longer/closer to the length the chamber of your rifle left them...same as neck sizing and WHY people necksize.... how can an action of squishing something down make it grow longer upwards??? other than possibly a tiny bit longer in neck itself which is what measuring case and trimming is for.....
if you really want to see partial length resizing for what it is...try a 7.62x39mm die wit ha .308 expander ball...most sets come with both sizes. we used to get a mini shoulder 70-80% of the way down the neck,where die stopped.

It makes absolute sense .

A full length die sizes in the order of , outside neck diameter, body /web , shoulder then inside neck diameter. If the die squeezes the body before the shoulder engages the case will grow in length. Similar to squeezing a balloon. It's quite a common phenomena and quite possibly effects some dies more than others , both my 243 and 223 hornady dies will do this my 6.5 Creedmoor, Forster bump die won't , probably because it's not designed to body size .
Just a quick example , I use Redding competition shellholders, I use them because it's easier to achieve consistent sizing . Sizing fired 243 cases and using the +0.010" shellholder the cases grew by 0.001 to 0.002 " , using the +0.008" the shoulder would remain pretty much as were and the +0.006" shellholder gave a consistent shoulder set back of 1 to 2 thou" . All measurable and the cases sized with the +0.010" were difficult to chamber . The growth occurs in the head to shoulder measurement.
I anneal, so none of the case growth can be attributed to spring back .
I'm really surprised you haven’t come across this , it seems to be a recurring question on The Stalking Directory forum . Sometimes it can be attributable to the dies or shellholder, generally it appears to be poor die set up .

It was proposed that case length may grow just by neck sizing, or by neck sizing using a full length die and in a way that was so significant that it may make a case over length in one neck sizing operation and potentialy be dangerous when swapping projectiles on military ammunition.

However, I can reliably report that neck sizing does not significantly increase case length like full length sizing may; certainly not enough to make a military case over length in the operation that we are discussing here. If it does, you are not neck sizing. In practice, it's not an issue. (And if it was, we can just trim them right? We are disassembling ammunition and reassembling it with a different bullet, we can do what we want. )

Originally Posted by PipIstrelle

It makes absolute sense .

A full length die sizes in the order of , outside neck diameter, body /web , shoulder then inside neck diameter. If the die squeezes the body before the shoulder engages the case will grow in length. Similar to squeezing a balloon. It's quite a common phenomena and quite possibly effects some dies more than others , both my 243 and 223 hornady dies will do this my 6.5 Creedmoor, Forster bump die won't , probably because it's not designed to body size .
Just a quick example , I use Redding competition shellholders, I use them because it's easier to achieve consistent sizing . Sizing fired 243 cases and using the +0.010" shellholder the cases grew by 0.001 to 0.002 " , using the +0.008" the shoulder would remain pretty much as were and the +0.006" shellholder gave a consistent shoulder set back of 1 to 2 thou" . All measurable and the cases sized with the +0.010" were difficult to chamber . The growth occurs in the head to shoulder measurement.
I anneal, so none of the case growth can be attributed to spring back .
I'm really surprised you haven’t come across this , it seems to be a recurring question on The Stalking Directory forum . Sometimes it can be attributable to the dies or shellholder, generally it appears to be poor die set up .

forth line.....other than tiny bit of length at neck...yes I understand the balloon concept..... but your not doing F all squeazing here are you...... thats the whole point of doing it that way,to leave case as close to chamber size as possible..to do less work to brass,to make it last longer and be better fit for the chamber it came out of.


and you dont come across something if you dont look for it...like poor velocity in a very accurate and great killing load..no chronograph = no problem

there is a very old saying in back country... a dead possum in the water tank isnt a problem untill you tell someone.

Originally Posted by Micky Duck

forth line.....other than tiny bit of length at neck...yes I understand the balloon concept..... but your not doing F all squeazing here are you...... thats the whole point of doing it that way,to leave case as close to chamber size as possible..to do less work to brass,to make it last longer and be better fit for the chamber it came out of.


and you dont come across something if you dont look for it...like poor velocity in a very accurate and great killing load..no chronograph = no problem

there is a very old saying in back country... a dead possum in the water tank isnt a problem untill you tell someone.

This isn't something I made up ,I don't require validation from a forum . I made the measurements at the time purely by chance as I was setting up my f/l die , which as it happened mirrored something I'd been told . Looking for it or not , it was measurable . I'm sure others have come across this and wondered why brass is suddenly a little tight to chamber.
Why would you think there's no squeezing on the case body as its sizing . The body will blow out during firing or do you think the chamber of your rifle remains steadfast resisting 55k psi of pressure without flexing and the case is a perfect fit ?
I'm not sure , but this appears to be angering you and that's unintended . It's just a forum and a discussion , its a difference of opinion, nothing more .
By the way love the analogy.

In the interest of politeness , I may restart this discussion on a fresh thread. Apologies to the OP for hijacking the thread .

Originally Posted by knightshade

Hi guys I am relatively new to reloading centrefire rifle rounds and I was contemplating pulling projectiles from F4 7.62 ball ammo and replacing it with 150 gr SSTs and it would be great to get your input as to the suitability of this task

Cheers Kylie

Would you share your results and process ?