Please may I reintroduce myself

[Campbell]

Make sure to use the K&M expanders. Their neck turn tool pilots are a bit larger than other brands.

Yes, I bought the dedicated .3065 KM expander mandrel. I have only used the K&M neck turning mandrel for neck turning.

Cam

 

[Campbell]

I have a problem/question that I have for months being try to find the answer to.

My reloading regime includes measuring and batching my bullets' ogive to base. My cases are annealed after every cleaning following shooting.

The tools I use: My press is a Rock Chucker (so probably isn't the best for feeling during seating?) My cases are f/l resized using a Redding die (with .337 bushing) Then, if necessary, are trimmed to a .0005 tolerance. They are then chamfered using a 15 degree, old rotary file, in reverse (this to me gives a very uniform and gentle chamfer) I use a K&M expander mandrel (.3065) I seat my bullets (HBC 155gr) using a Redding Competition S-line seating die. I have even purchased the Redding VLD seating stem which I have polished internally using rubbing compound with a wooden dowel whilst being rotated at 2000 rpm in a pillar drill. I have even polished the ends of the spring in order to allow consistent pressure whilst under compression during the seating.

My problem is that despite all of the above-mentioned, the ogive to catridge base measurement I get can vary by as much as .005! Why?

Many thanks in advance

 

[Campbell]

Best wishes on your recovery. What neck clearance problem are you having?

I am not sure sure what you mean by neck clearance, sorry.

Many thankks for you question.

Cam

 

[RegionRat]

My problem is that despite all of the above-mentioned, the ogive to catridge base measurement I get can vary by as much as .005! Why?

When you gage the bullets alone, you are being carful with your instruments in order to make the measurements the same. If you pushed real hard on a sample and took a number, then went real gentle on the same one, would you expect the same value?

When you assemble ammo you get friction forces in the neck. There is dispersion in that friction. Now imagine if you knew the hi-lo value of that friction force and you applied that spread of force to your gage in the concept above? You would expect at least that much spread in the results.

So, the spread in seating depths is caused by the dispersion in the fiction force, which causes the press and dies and bullets/brass to flex and deflect, and the seating stem to push each bullet a little differently the same way you would see it in taking your caliper readings with high force one time and gently the next.

Some of this dispersion is the variation of the contacts at the anvils or seating stem, some of it is the caliper or press deflections.

Not easy to describe in words and I am no poet, sorry. I will try.

The more consistent the brass prep, with more consistent seating force (friction), using the stiffest tooling, and those numbers go down. Be careful with brass cleaning and neck debur because those two issues add to any sizing and annealing issues you have in terms of causing seating depth variations.

A Wilson seater bottoms out on the tooling which is essentially a very rigid column of steel and the seating force variation is practically negated in terms of tool or linkage deflection. A Rock Chucker that is not bottomed out on the die, will deflect differently with bullet seating friction, so the seating method you use can also contribute to variations with tooling deflection.

A press has clearance in the linkages which must me loaded up to "stiffen". If those forces are variable, then the deflections are variable. Bottoming out on the tooling can reduce or eliminate those variations that originate from the press linkages.

So to reduce those variations we have to manage the brass prep and the neck friction, and select tooling methods that also reduce or eliminate additional deflections.

Hope that my writing isn't clouding the concepts. I am dyslexic and had editors at work that cleaned up my drafts. As a retiree, you get what you get.... YMMV

 

[Coyotefurharvester]

I am not sure sure what you mean by neck clearance, sorry.

Many thankks for you question.

Cam

You wrote about starting to neck turn brass, wondering why? Do you have a chamber that is tight(undersized) or custom neck diameter?

 

[searcher]

Simply put - turning the necks (need only skim to remove 90% clean metal on the thinnest pieces) will make your cases provide more consistent neck tension. That is not to say guys can't get by without improving their brass and still do well, but consistency is the name of the game and everything you can do to make each piece of brass the same as the other will benefit you. There are lots of reason people don't turn necks (who are serious target shooters). There are those shooters who are good enough that they don't need the slight improvement it offers to beat those competitors they shoot with. Then there are those who never mastered the art of turning and load development enough to see the improvement. Some don't even have a chrono to see the difference in velocity. And some don't because someone else simply tells then they don't need to. I'd not want to argue those reasons - but a proper neck turn will make your cases more uniform. I get about 40 reloads on my target rifles. I turn the necks twice- sometimes three times over the life of the brass. It takes me about an hour to do 100 pieces. In return, I get 1,500 to 2,000 shots for that hour of time. I know from my chrono and group improvement that it helps me (and I use Lapua brass). After tens of thousands of rounds downrange and many thousands shot over a chrono doing comparative testing, I'm in the camp that it is worthwhile. I'm not listening to any "expert", as I have formed my own opinion based on my findings. I'm not better than all the guys I have shot with - so I want any edge that is reasonably at hand. You already have the tool - so it makes perfect sense to do it yourself. I always see guys switching up equipment like multi-thousand dollar scopes because some guy says it's the cats meow. Never helped them a bit. And they are the same ones who bag on brass prep as "not necessary". You don't need to turn necks to shoot awesome groups. But turning will usually improve them to a degree you can see the difference.

 

[Campbell]

When you gage the bullets alone, you are being carful with your instruments in order to make the measurements the same. If you pushed real hard on a sample and took a number, then went real gentle on the same one, would you expect the same value?

When you assemble ammo you get friction forces in the neck. There is dispersion in that friction. Now imagine if you knew the hi-lo value of that friction force and you applied that spread of force to your gage in the concept above? You would expect at least that much spread in the results.

So, the spread in seating depths is caused by the dispersion in the fiction force, which causes the press and dies and bullets/brass to flex and deflect, and the seating stem to push each bullet a little differently the same way you would see it in taking your caliper readings with high force one time and gently the next.

Some of this dispersion is the variation of the contacts at the anvils or seating stem, some of it is the caliper or press deflections.

Not easy to describe in words and I am no poet, sorry. I will try.

The more consistent the brass prep, with more consistent seating force (friction), using the stiffest tooling, and those numbers go down. Be careful with brass cleaning and neck debur because those two issues add to any sizing and annealing issues you have in terms of causing seating depth variations.

A Wilson seater bottoms out on the tooling which is essentially a very rigid column of steel and the seating force variation is practically negated in terms of tool or linkage deflection. A Rock Chucker that is not bottomed out on the die, will deflect differently with bullet seating friction, so the seating method you use can also contribute to variations with tooling deflection.

A press has clearance in the linkages which must me loaded up to "stiffen". If those forces are variable, then the deflections are variable. Bottoming out on the tooling can reduce or eliminate those variations that originate from the press linkages.

So to reduce those variations we have to manage the brass prep and the neck friction, and select tooling methods that also reduce or eliminate additional deflections.

Hope that my writing isn't clouding the concepts. I am dyslexic and had editors at work that cleaned up my drafts. As a retiree, you get what you get.... YMMV

A superb post!

Many sincere thanks

I may come back to you with further questions about you post, if I may?

Cam

 

[Campbell]

Simply put - turning the necks (need only skim to remove 90% clean metal on the thinnest pieces) will make your cases provide more consistent neck tension. That is not to say guys can't get by without improving their brass and still do well, but consistency is the name of the game and everything you can do to make each piece of brass the same as the other will benefit you. There are lots of reason people don't turn necks (who are serious target shooters). There are those shooters who are good enough that they don't need the slight improvement it offers to beat those competitors they shoot with. Then there are those who never mastered the art of turning and load development enough to see the improvement. Some don't even have a chrono to see the difference in velocity. And some don't because someone else simply tells then they don't need to. I'd not want to argue those reasons - but a proper neck turn will make your cases more uniform. I get about 40 reloads on my target rifles. I turn the necks twice- sometimes three times over the life of the brass. It takes me about an hour to do 100 pieces. In return, I get 1,500 to 2,000 shots for that hour of time. I know from my chrono and group improvement that it helps me (and I use Lapua brass). After tens of thousands of rounds downrange and many thousands shot over a chrono doing comparative testing, I'm in the camp that it is worthwhile. I'm not listening to any "expert", as I have formed my own opinion based on my findings. I'm not better than all the guys I have shot with - so I want any edge that is reasonably at hand. You already have the tool - so it makes perfect sense to do it yourself. I always see guys switching up equipment like multi-thousand dollar scopes because some guy says it's the cats meow. Never helped them a bit. And they are the same ones who bag on brass prep as "not necessary". You don't need to turn necks to shoot awesome groups. But turning will usually improve them to a degree you can see the difference.

Please forgive my question, but surely one needs to remove the thickest parts of the exterior of the neck?

 

[Campbell]

You wrote about starting to neck turn brass, wondering why? Do you have a chamber that is tight(undersized) or custom neck diameter?

I am re-interested in neck turning because I am experiencing differing ogive to cartridge base measurements and I have been alerted/advised that this matter could be due to differing neck tensions. I shoot with some very accomplished "Limey"shooters and I listen to what they say. Every day in precision target shooting is a school day?

Many sincere thanks for your input!

Campbell (Cam)

 

[searcher]

Please forgive my question, but surely one needs to remove the thickest parts of the exterior of the neck?

Yes, if you only take off the thickest parts, that will make them better than they were, but going a bit further (to near-clean or clean metal) just makes them that much more uniform.

 

[Campbell]

Yes, if you only take off the thickest parts, that will make them better than they were, but going a bit further (to near-clean or clean metal) just makes them that much more uniform.

Many thanks for this!

Campbell (Cam)

 

[jimmymac]

You shouldn't have to jump through a bunch of hoops to get consistent bullet seating. Good results are easily achieved with a simple arbor press and Wilson seater. The simplest solution is often the best.