Time between sizing and seating; Does it have an effect?

[dmoran]

Loading at the range in the shade, no matter the ambient temperature, then moving that loaded brass into direct sunlight, which is much warmer, is going to cause a change in that brass. We quickly realize how comforting moving from direct sunlight to a shady area can be. Ten or fifteen minutes in the sun is going to affect that brass.

Have you tested this, or is it your theorem?
Would be great to see your test results (targets and Mv) if you have tested it !.!.!
Thanks - - Donovan

 

[Webster]

Loading at the range in the shade, no matter the ambient temperature, then moving that loaded brass into direct sunlight, which is much warmer, is going to cause a change in that brass. We quickly realize how comforting moving from direct sunlight to a shady area can be. Ten or fifteen minutes in the sun is going to affect that brass.

You don't know anything about metallurgy.

 

[JRS]

Have you tested this, or is it your theorem?
Would be great to see your test results (targets and Mv) if you have tested it !.!.!
Thanks - - Donovan

Not a theory, Donovan. My old neighbor, the late John Adams (a lifelong loading and shooting experimenter), proved it to be a fact.

 

[JRS]

You don't know anything about metallurgy.

Do rifle barrels, scopes, and actions expand/contract and move with temperature changes?

Stop slamming that metallurgy book on the desk…. use your head

 

[dmoran]

Not a theory, Donovan. My old neighbor, the late John Adams (a lifelong loading and shooting experimenter), proved it to be a fact.

Guess I don't see the relevance to the effects on case necks. For reloading in the shade, or in an air-conditioned room, then out into the sun is some what the norm for me that I have done a lot of over the years (and many others as well). I have also remained in side or under a covering and shot also, and not seen gain or loss to either accuracy or Mv that I could attribute to case necks being effected like your claim.
Each to our own I guess....
Donovan

 

[JRS]

Guess I don't see the relevance to the effects on case necks. For reloading in the shade, or in an air-conditioned room, then out into the sun is some what the norm for me that I have done a lot of over the years (and many others as well). I have also remained in side or under a covering and shot also, and not seen gain or loss to either accuracy or Mv that I could attribute to case necks being effected like your claim.
Each to our own I guess....
Donovan

I made no claim as to the effects of MV/accuracy Donovan. I simply stated the brass moves with temperature changes, especially from heat in direct sunlight.

 

[dmoran]

I made no claim as to the effects of MV/accuracy Donovan. I simply stated the brass moves with temperature changes, especially from heat in direct sunlight.

And is why I wrote: "Guess I don't see the relevance...."

 

[Webster]

Loading at the range in the shade, no matter the ambient temperature, then moving that loaded brass into direct sunlight, which is much warmer, is going to cause a change in that brass. We quickly realize how comforting moving from direct sunlight to a shady area can be. Ten or fifteen minutes in the sun is going to affect that brass.

If shooting results change with temperature don't you think it's most likely the powder or primer getting warmer and not the brass changing some infinitely small dimension due to temperature expansion or contraction?

 

[JRS]

If shooting results change with temperature don't you think it's most likely the powder or primer getting warmer and not the brass changing some infinitely small dimension due to temperature expansion or contraction?

All of the above have to be taken into consideration.

 

[savagedasher]

My guess the expansion rate on metals would be the softer or less weight would expand l more then heavy or denser Aluminum has a large expansion rate then steel . Larry

 

[Webster]

My guess the expansion rate on metals would be the softer or less weight would expand l more then heavy or denser Aluminum has a large expansion rate then steel . Larry

A one inch long piece of copper (not brass) raised 20 degrees F would expand 0.00026" in length. A quarter inch long piece of brass would expand 0.000065".

 

[JRS]

A one inch long piece of copper (not brass) raised 20 degrees F would expand 0.00026" in length. A quarter inch long piece of brass would expand 0.000065".

OK. Cartridge brass is made up primarily of copper. Copper expands, when heated, at a rate about 40 percent higher than steel. So…. your point is what Try another google search

 

[dmoran]

A one inch long piece of copper (not brass) raised 20 degrees F would expand 0.00026" in length. A quarter inch long piece of brass would expand 0.000065". Good info - Thank You

OK. Cartridge brass is made up primarily of copper. Copper expands, when heated, at a rate about 40 percent higher than steel. So…. your point is what Try another google search

I found @Webster's expansion input very interesting and appropriate to the replies.
It also tells me, mathematically Larry's and your input have very little relevance to case necks.
Also get from it how much expansion a bullet jacket could be subjected to, both in bore and in flight.
Donovan

 

[johara1]

I like a minimum of a week of "rest" between sizing and seating. If you brush the necks right before powder filling, that "increased" seating force goes away.

Tom

I have found this to be true also, Drop the powder the day before. .... Jim

 

[rifleman700]

Not a theory, Donovan. My old neighbor, the late John Adams (a lifelong loading and shooting experimenter), proved it to be a fact.

Post his testing as I would like to read it.

 

[rifleman700]

I have found this to be true also, Drop the powder the day before. .... Jim

I have never even considered this concept. I am anxious to give it a try.

 

[Webster]

I found @Webster's expansion input very interesting and appropriate to the replies.
It also tells me, mathematically Larry's and your input have very little relevance to case necks.
Also get from it how much expansion a bullet jacket could be subjected to, both in bore and in flight.
Donovan

Thanks for understanding. I get insulted and complemented at the same time.

 

[Webster]

OK. Cartridge brass is made up primarily of copper. Copper expands, when heated, at a rate about 40 percent higher than steel. So…. your point is what Try another google search

Your 40% difference is not correct The coefficient of expansion for steel is .000012 and cartridge brass is .0000111. For all practical purposes the same. All this was in regards to does neck tension change with time or temperature. Again for the second time COPPER.ORG the copper experts say stress in cartridge brass relaxes with time it doesn’t increase.

 

[fgregorio]

I would definitely like to see that.

So this is an account of what I did as a first off to the cases as to expand the rim of the neck (.308W brass- Palma rifle).
1- Wipe the ouside of the cases with a methilated spirits soaked rag taking very careful note to not to disturb in any way the carbon fouling inside the necks.
2- Full length trim the cases to 1.9985" using a Lee deluxe trim, using the hand crank option. I tried the electrical drill option and found it to be not as good to square the neck with the case head base. Check for squareness using a caliper and rolling the cases longways on the jaw. If one side of the neck catches- not squared.
3- Anneal.
4- Size using a Lee Collet die.
5- Expand the neck rim using a Lee Universal Expander die. To setup:
Put a case on the shellholder. Bring the ram up. Screw the die in until it makes very firm contact with the shellholder and screw it in another half turn. With firm contact with the ram up, tighten the die lock ring.
Still with a case in, wind down the top knob of the die until the knob contacts the case mouth rim expander. Get an untouched sized case, put a projectile on it, just resting on top, and measure its length with a caliper and bullet comparitor and then also measure the case mouth rim width- record values. Put the case back on the shellholder, turn the die knob one eighth of a turn, and bring the ram up. Measure the case again. It read then 7 thou in and a thou and a half wider on the rim. The contact between the bearing surface and case mouth became smoother. I knew I was close. Gave another eigth of a turn for a quarter turn total. Measure. 15 thou in and 3 thou in width on the rim. Perfect.
6- Dust the inside of the case mouths with HBN.
7- Seat projectiles using a Hydro bullet seater and Wilson Micrometer Seating die. I recall that the first lot of40 sat with a maximum spread of less than 2 psi between them for a 20psi to a 22psi range. Average bullet runout came down to less than a thou.

From then I didn't see the need to full length trim. Only wipe, anneal, size, expand, lube, seat. Results stayed the same.
Every so often I measure a few cases with the caliper (full length and for squareness). If at some stage I feel that they need trimming to reset. I'll do it.
Keeping in mind: brass flows at different rates around the neck. One side of the neck can flow out one thou while the opposite side of the rim may not flow in a measurable amount. Checking the case mouths for squareness with a caliper helps me to see when to trim to keep the runout down.

 

[Mulligan]

Tag