All this talk about inner diameter, expander plugs, outer diameter...
I decided to write a brief article for THR based on my personal experiences.
Happy Turkey Day (in advance).
Loading Accurate Bottlenecked Rifle Ammunition
(Easily)
Reloading / handloading is a hobby / activity which can be rewarding on a number of levels. The reasons reloaders cite as justification for their hobby varies widely (and is often used in combination). Among these:
1. You can save money
2. You can shoot more for the same money
3. You are in “control” of how your loads are assembled, and the quality thereof
4. You can experiment with loads, to determine what your firearm likes to “eat”
5. You can load more accurate ammunition than factory ammo
And so on…
The key component focused on in this article is #5, accuracy, and how to obtain more refined accuracy specifically on bottlenecked rifle cartridges.
But first .. some layman physics on interior ballistics.
When a primer is struck by a firing pin and the ignition process begins, several key things happen inside the chamber of your firearm on a timescale measured in nanoseconds. First, the anvil crushes the primary explosive in the primer cup, detonating it. This sends a powerful, hot flash through the flash hole in the bottom of the centerfire cartridge. This flash ignites the powder, which begins burning with increasing velocity as pressure and heat build within the chamber. The bullet (projectile) begins to move forward, engaging the lands of the rifling in the barrel, travels down the barrel, and out the muzzle.
As a hand loader, you are in direct control of the above process. Everything which transpires from the time the primer cup is hit, until the bullet leaves the muzzle of your firearm, is a direct result of the method and manner in which you construct your rounds – component selection, bullet weight, powder charge, how you prepare your brass – it all factors in to that small segment of time spanning from the striking of the primer until the exit of the projectile from the firearm.
Preparation:
Start with properly cleaned and inspected brass.
Trim all brass to the trim-to length specified for that caliber. (This is important as one of the steps below will rely on the casing length being precise).
Primer ignition is where it all begins, so we’ll start at initiation and move forward from there.
Initiation:
To ensure every primer sends the same amount of “flash” through the flash hole, we will first uniform the primer pocket, flash hole, and remove any burrs on the inside of the flash hole. These burrs are caused by flash holes being created via a “punch” during manufacturing. (Some premium brass has the holes drilled, and the deburring step can be skipped for such brass).
Military brass should be reamed prior to uniforming the primer pockets step.
Uniforming primer pocket.
The primer pocket can be uniformed via readily available tools. Note, these tools are substantially different from similar looking tools that are designed to clean carbon out of the primer pocket! Primer uniforming tools have cutters which are designed to trim the bottom of primer pockets to a uniform length, so that all primers sit at precisely the same depth. Some of these come with (or can be accessorized with) power-drill compatible inserts, which makes the process go much faster.
Holding the shell casing in one hand (leather gloves help grip), insert the cutter in to the primer pocket and turn at low RPM. Very little material will be removed during this, however, the primer pocket uniformer bits are small, so insert / remove the cutter 2-3 times to keep the cutters from becoming clogged with brass. Each time you’ll notice fewer shavings coming out. Examine the brass when finished – you’ll notice a “flat ring” has been cut in the bottom of the pocket. Now your primer will seat straight and true, and all to the same depth.
Uniforming flash hole / deburring flash hole
This step can be skipped on drilled premium brass. Punched bulk factory brass will have a burr on the inside of the casing. This can lead to uneven ignition of the powder.
As an aside note, even if you skip this step, always inspect the interior of every case you reload. In one instance during this step, I found a large amount of spooled brass shavings the factory missed during Q&A that filled up a substantial portion of the casing. A cursory exterior inspection would not have caught this! Over 50 grains of brass material was pulled out of that casing with a dental pick. This would have resulted in a SEVERELY overpressured round if loaded the same as all other cartridges, and perhaps would have resulted in a dreaded KABOOM.
In two other cases, I found brass which was NOT punched from the factory. There WAS NO FLASH HOLE. In several other cases over the years, I have found noticeably TOO LARGE of flash holes (as in nearly the diameter of the primer itself).
To uniform the flash hole AND de-burr the interior side of the flash hole, use an appropriate hand tool (many are on the market). Be careful of your adjustment to the length of this tool! Many of these tools have a drill-bit looking end that begins to taper outwards after .1” or so. If you have your tool adjusted TOO LONG you will remove TOO MUCH material from the interior side of flash hole, making it too thin. You may potentially blow it out during firing (making the brass unusable for reloads).
This is why earlier on, I said “trim to the trim to length” before starting this step – as these tools index off of the case mouth!
More case prep tips – this time with the neck.
Since you’ve uniformed the ignition end, let’s talk about the business end.
In my own (thorough) testing, I have found that neck tension is the single most influential factor in accuracy. Your mileage may vary, but of every “control vs. x” test I’ve conducted at the range, highly uniformed neck tension universally created smaller groups compared to control loads where neck tension was NOT monitored.
You have a couple of choices here – the not-so-time-consuming-way, or the very-time-consuming-way.
Method #1: Direct measure.
The easier of the two is to sort brass by neck thickness. The easiest way to do THAT is to measure the outer diameter of LOADED ROUNDS with a good old fashioned dial micrometer. (Don’t use calipers unless that’s all you have – unless you hold them perfectly perpendicular to the surface you won’t get reliable results).
Why loaded rounds? Because you can easily, and rapidly discern neck thickness from this measurement.
Take the outer diameter you measure. Subtract the diameter of the bullet. Divide by two. There’s your neck wall thickness. Group these in to lots to the nearest .00025 (yes that’s a very small number but capable on dial micrometers).
Choosing collets bushings for a neck sizing die as follows (examples infers .308 as a point of reference.)
Example #1: Outer diameter of loaded round = .3385, inner diameter (bullet diameter) is .308, case wall thickness = .3385-.308=.0305, neck wall thickness is .0305/2= 0.01525. After this round is fired, you would use a .336 bushing to size the inner diameter to .002 under the bullet diameter.
Example #2: Outer diameter of loaded round = .336, inner diameter (bullet diameter) is 0.308, case wall thickness = 0.336-0.308=0.028, neck wall thickness is 0.028/2= 0.01400. After this round is fired, you would use a .334 bushing to size the inner diameter to .002 under the bullet diameter.
See the pattern? My teachers in school taught me to show my math, but there's a trick here. You reload using a bushing that is .002 under the measured outer diameter of the neck of a loaded round.
The downside to this method is you have to separate your brass in to LOTS and reload using the appropriate bushing for that lot.
Enter neck turning. Takes extra time up front but saves you the hassle of keeping separate lots, as well as cuts down on the bushings you have to buy.
Method #2 – neck turning.
Take a random lot of brass (25 or 50), measure the outer diameter. (Fill-down formulas in an Excel or Calc spreadsheet help the math along - you can just enter each measurement that way and end up with a column that shows neck thickness.)
Empty brass that is sized uniformly is fine – the expander die will ensure each inner diameter is the same, so only the outer diameter will vary case to case. Record the measurement of each, and find your standard deviation, or just the average neck diameter if you don’t know what standard deviation is or how to calculate it.
Neck turn using a handheld neck turner to .0005 less than the diameter of your determined standard deviation or average, (adjust the neck sizer in .00025 since you're doing two "sides"). You don't want to make your case necks super thin, as they'll not only be weaker and prone to splitting, but they'll get overworked expanding to your chamber and back again each iteration of firing/sizing. If there's some uncut brass showing when you're done, that's fine. Under the massive pressures of shooting a round, the bras will flow and it WILL even itself out, and the difference it causes in subsequent neck thickness will be negligible.
There’s power adapters to make this easier – those let you chuck your brass in to a handheld drill - but make sure you hand-hold your neck sizing tool and let it “float” (wobble). You’ll rarely get a case perfectly straight in a power tool holder, but the tool will still cut uniformly if you allow it to float in your hand some.
Those blessed with a lathe in the garage can properly align each shell casing with a high degree of precision and turn it perfectly uniform, but this is not an essential requirement to get highly accurate ammunition. Hand held trimmers are perfectly capable of getting a high degree of concentricity in their cuts.
Now that all brass has a uniform neck diameter, you may use a SINGLE bushing that will give you .002 of neck tension after each firing – no need to keep your brass sorted by neck thickness! (So you spend extra time up front to relieve yourself of some paperwork and clutter later. All brass of each generation can go in the same "bin".)
(Note: The above steps can also be set to .001 neck tension if you want, for additional accuracy, BUT keep in mind this is ultra-light and should only be done for ammo intended for use with single shot, hand-fed, bolt action rifles. If ammo will be in a magazine when fired or chambered from a magazine, .002 is much safer. If it’s a semiauto, .003 is safer, or you can do .002 with a crimp on cannelured bullets)
WHY is neck tension so important, and why should I care??
The process of physics that begins, when your bullet starts to move is a nonlinear differential equation. Your neck tension determines WHEN your bullet starts to move and how FAST your bullet starts to move. That means (in Laymens terms) that initial “bump” sets the rate at which everything else happens until your projectile leaves the barrel. Velocity will be affected - for better or worse is irrelevant – inconsistent muzzle velocity is bad for precision shooting!
Why? Because everything which happens AFTER the bullet leaves the barrel is functioning on a six-axis complex series of additional nonlinear differential equations. Wind, gravity, air resistance, all affect trajectory. While the RATE of gravity doesn’t change, a slower moving bullet will be affected MORE before it strikes the target than a faster moving bullet because it spends more TIME in the air. Likewise, air resistance slows bullets down increasingly fast as the bullets slow down (inertia is lost). (Faster moving bullets take more air resistance to slow down, in other words.)
So inconsistency in exit velocity plays a major factor in how everything in the real world impacts your trajectory. You want as consistent of an exit velocity as possible for maximum accuracy.
Since powder ignition, powder weight consistency, and bullet seating tension are the prime (only) contributors to the initial impulse of a projectile, they are the parts to pay most attention to.
Anal Rententive Stuff Which May Or May Not Matter (splitting hairs).
The above assumes you are shooting the same make (and preferably same lot) of brass. If you are pulling from different manufacturers or a random assortment of once fired you got off GunBroker or some surplus site, you will definitely want to sort brass by manufacturer so that you have “similar” wall thicknesses. (This is, of course, leading to a quick discussion about case VOLUME.)
I’ve measured lots of brand new, virgin, unfired factory brass with neck thicknesses of +/- .002”! That’s a HUGE difference in the amount of material in the overall case! Since the outside of the cases are all sized the same (whether from full length sizing or being fireformed in your barrel), the differences in wall thickness directly correspond to CASE VOLUME.
Case volume affects the rate at which your powder burn accelerates – since volume affects the reciprocal pressure in the chamber, smaller volumes will increase the burn rate. Depending on the powder and length of barrel, this may increase or decrease the speed of the projectile as it exits the firearm.
Different lots of power and primers should likewise never be mixed within the same batch of fully-prepped ammunition.
Experimenting with bullet seating depth can also have large implications on accuracy. Normally seated bullets have to jump a “gap” before they fully engage the rifling. During this time it is possible for them to skew – enter slightly sideways, or to jump with an inconsistent force. If your bullets are all seated the same exact depth, you won’t typically suffer velocity issues, but reducing the “gap” the bullets must jump can have profound impacts on accuracy. We’re splitting hairs here, because by “profound” I’m talking about .1 MOA or less, but we’re talking about accurate ammo, so that IS a profound difference to some people.
Finally, some rifles like some powder, bullet, and powder weight (charge) combinations better than others. Some rifles like moderate powder charges, some are more accurate towards the bleeding edge of the MAX scale. This is up to you to determine through trial and error, and accurate record keeping.
A word about powder.
You can get “acceptable” accuracy out of volume-dumped powder. For most cartridges, +/- .1 or .2 grains isn’t going to ruin your 100 yard groups. If you are loading towards the “MAX” end of the scale, you’ll want to weigh your charges for safety, NEVER volume-dump “max” loads.
If you are loading for the highest degree of accuracy, you’ll want to weigh ALL of your charges to at LEAST +/- 0.1 gr. Some of the more competitive long range shooters will use expensive scales to measure to 0.01 grains.
Always calibrate your scale before beginning; even high-tech electrogadgets will vary their zero point with humidity and temperature. Be mindful of air currents, heater ducts, and so on. If you “heat” your realoading room (common for basement / garage setups), give the equipment and room time to “come to temp” before starting, as increasing temperature CAN affect your zero point if you “heat as you go.” The net effect of this is it can cause loaded rounds to have progressively more or less powder as the room and equipment come up to temp.
This post reflects my opinions and experiences only, your mileage may vary.
I tried to abstain from posting specific brand recommendations as I’m not a paid spokesperson and it’s not my job to advertise specific brands. This being said, I’ve used ALL brands at one time or another and I’m not overly partial to any specific one.
I will mention I DO lean towards Redding or Forster on neck sizers and seating dies, and RW Hart makes a solid and reliable neck turner.
I decided to write a brief article for THR based on my personal experiences.
Happy Turkey Day (in advance).
Loading Accurate Bottlenecked Rifle Ammunition
(Easily)
Reloading / handloading is a hobby / activity which can be rewarding on a number of levels. The reasons reloaders cite as justification for their hobby varies widely (and is often used in combination). Among these:
1. You can save money
2. You can shoot more for the same money
3. You are in “control” of how your loads are assembled, and the quality thereof
4. You can experiment with loads, to determine what your firearm likes to “eat”
5. You can load more accurate ammunition than factory ammo
And so on…
The key component focused on in this article is #5, accuracy, and how to obtain more refined accuracy specifically on bottlenecked rifle cartridges.
But first .. some layman physics on interior ballistics.
When a primer is struck by a firing pin and the ignition process begins, several key things happen inside the chamber of your firearm on a timescale measured in nanoseconds. First, the anvil crushes the primary explosive in the primer cup, detonating it. This sends a powerful, hot flash through the flash hole in the bottom of the centerfire cartridge. This flash ignites the powder, which begins burning with increasing velocity as pressure and heat build within the chamber. The bullet (projectile) begins to move forward, engaging the lands of the rifling in the barrel, travels down the barrel, and out the muzzle.
As a hand loader, you are in direct control of the above process. Everything which transpires from the time the primer cup is hit, until the bullet leaves the muzzle of your firearm, is a direct result of the method and manner in which you construct your rounds – component selection, bullet weight, powder charge, how you prepare your brass – it all factors in to that small segment of time spanning from the striking of the primer until the exit of the projectile from the firearm.
Preparation:
Start with properly cleaned and inspected brass.
Trim all brass to the trim-to length specified for that caliber. (This is important as one of the steps below will rely on the casing length being precise).
Primer ignition is where it all begins, so we’ll start at initiation and move forward from there.
Initiation:
To ensure every primer sends the same amount of “flash” through the flash hole, we will first uniform the primer pocket, flash hole, and remove any burrs on the inside of the flash hole. These burrs are caused by flash holes being created via a “punch” during manufacturing. (Some premium brass has the holes drilled, and the deburring step can be skipped for such brass).
Military brass should be reamed prior to uniforming the primer pockets step.
Uniforming primer pocket.
The primer pocket can be uniformed via readily available tools. Note, these tools are substantially different from similar looking tools that are designed to clean carbon out of the primer pocket! Primer uniforming tools have cutters which are designed to trim the bottom of primer pockets to a uniform length, so that all primers sit at precisely the same depth. Some of these come with (or can be accessorized with) power-drill compatible inserts, which makes the process go much faster.
Holding the shell casing in one hand (leather gloves help grip), insert the cutter in to the primer pocket and turn at low RPM. Very little material will be removed during this, however, the primer pocket uniformer bits are small, so insert / remove the cutter 2-3 times to keep the cutters from becoming clogged with brass. Each time you’ll notice fewer shavings coming out. Examine the brass when finished – you’ll notice a “flat ring” has been cut in the bottom of the pocket. Now your primer will seat straight and true, and all to the same depth.
Uniforming flash hole / deburring flash hole
This step can be skipped on drilled premium brass. Punched bulk factory brass will have a burr on the inside of the casing. This can lead to uneven ignition of the powder.
As an aside note, even if you skip this step, always inspect the interior of every case you reload. In one instance during this step, I found a large amount of spooled brass shavings the factory missed during Q&A that filled up a substantial portion of the casing. A cursory exterior inspection would not have caught this! Over 50 grains of brass material was pulled out of that casing with a dental pick. This would have resulted in a SEVERELY overpressured round if loaded the same as all other cartridges, and perhaps would have resulted in a dreaded KABOOM.
In two other cases, I found brass which was NOT punched from the factory. There WAS NO FLASH HOLE. In several other cases over the years, I have found noticeably TOO LARGE of flash holes (as in nearly the diameter of the primer itself).
To uniform the flash hole AND de-burr the interior side of the flash hole, use an appropriate hand tool (many are on the market). Be careful of your adjustment to the length of this tool! Many of these tools have a drill-bit looking end that begins to taper outwards after .1” or so. If you have your tool adjusted TOO LONG you will remove TOO MUCH material from the interior side of flash hole, making it too thin. You may potentially blow it out during firing (making the brass unusable for reloads).
This is why earlier on, I said “trim to the trim to length” before starting this step – as these tools index off of the case mouth!
More case prep tips – this time with the neck.
Since you’ve uniformed the ignition end, let’s talk about the business end.
In my own (thorough) testing, I have found that neck tension is the single most influential factor in accuracy. Your mileage may vary, but of every “control vs. x” test I’ve conducted at the range, highly uniformed neck tension universally created smaller groups compared to control loads where neck tension was NOT monitored.
You have a couple of choices here – the not-so-time-consuming-way, or the very-time-consuming-way.
Method #1: Direct measure.
The easier of the two is to sort brass by neck thickness. The easiest way to do THAT is to measure the outer diameter of LOADED ROUNDS with a good old fashioned dial micrometer. (Don’t use calipers unless that’s all you have – unless you hold them perfectly perpendicular to the surface you won’t get reliable results).
Why loaded rounds? Because you can easily, and rapidly discern neck thickness from this measurement.
Take the outer diameter you measure. Subtract the diameter of the bullet. Divide by two. There’s your neck wall thickness. Group these in to lots to the nearest .00025 (yes that’s a very small number but capable on dial micrometers).
Choosing collets bushings for a neck sizing die as follows (examples infers .308 as a point of reference.)
Example #1: Outer diameter of loaded round = .3385, inner diameter (bullet diameter) is .308, case wall thickness = .3385-.308=.0305, neck wall thickness is .0305/2= 0.01525. After this round is fired, you would use a .336 bushing to size the inner diameter to .002 under the bullet diameter.
Example #2: Outer diameter of loaded round = .336, inner diameter (bullet diameter) is 0.308, case wall thickness = 0.336-0.308=0.028, neck wall thickness is 0.028/2= 0.01400. After this round is fired, you would use a .334 bushing to size the inner diameter to .002 under the bullet diameter.
See the pattern? My teachers in school taught me to show my math, but there's a trick here. You reload using a bushing that is .002 under the measured outer diameter of the neck of a loaded round.
The downside to this method is you have to separate your brass in to LOTS and reload using the appropriate bushing for that lot.
Enter neck turning. Takes extra time up front but saves you the hassle of keeping separate lots, as well as cuts down on the bushings you have to buy.
Method #2 – neck turning.
Take a random lot of brass (25 or 50), measure the outer diameter. (Fill-down formulas in an Excel or Calc spreadsheet help the math along - you can just enter each measurement that way and end up with a column that shows neck thickness.)
Empty brass that is sized uniformly is fine – the expander die will ensure each inner diameter is the same, so only the outer diameter will vary case to case. Record the measurement of each, and find your standard deviation, or just the average neck diameter if you don’t know what standard deviation is or how to calculate it.
Neck turn using a handheld neck turner to .0005 less than the diameter of your determined standard deviation or average, (adjust the neck sizer in .00025 since you're doing two "sides"). You don't want to make your case necks super thin, as they'll not only be weaker and prone to splitting, but they'll get overworked expanding to your chamber and back again each iteration of firing/sizing. If there's some uncut brass showing when you're done, that's fine. Under the massive pressures of shooting a round, the bras will flow and it WILL even itself out, and the difference it causes in subsequent neck thickness will be negligible.
There’s power adapters to make this easier – those let you chuck your brass in to a handheld drill - but make sure you hand-hold your neck sizing tool and let it “float” (wobble). You’ll rarely get a case perfectly straight in a power tool holder, but the tool will still cut uniformly if you allow it to float in your hand some.
Those blessed with a lathe in the garage can properly align each shell casing with a high degree of precision and turn it perfectly uniform, but this is not an essential requirement to get highly accurate ammunition. Hand held trimmers are perfectly capable of getting a high degree of concentricity in their cuts.
Now that all brass has a uniform neck diameter, you may use a SINGLE bushing that will give you .002 of neck tension after each firing – no need to keep your brass sorted by neck thickness! (So you spend extra time up front to relieve yourself of some paperwork and clutter later. All brass of each generation can go in the same "bin".)
(Note: The above steps can also be set to .001 neck tension if you want, for additional accuracy, BUT keep in mind this is ultra-light and should only be done for ammo intended for use with single shot, hand-fed, bolt action rifles. If ammo will be in a magazine when fired or chambered from a magazine, .002 is much safer. If it’s a semiauto, .003 is safer, or you can do .002 with a crimp on cannelured bullets)
WHY is neck tension so important, and why should I care??
The process of physics that begins, when your bullet starts to move is a nonlinear differential equation. Your neck tension determines WHEN your bullet starts to move and how FAST your bullet starts to move. That means (in Laymens terms) that initial “bump” sets the rate at which everything else happens until your projectile leaves the barrel. Velocity will be affected - for better or worse is irrelevant – inconsistent muzzle velocity is bad for precision shooting!
Why? Because everything which happens AFTER the bullet leaves the barrel is functioning on a six-axis complex series of additional nonlinear differential equations. Wind, gravity, air resistance, all affect trajectory. While the RATE of gravity doesn’t change, a slower moving bullet will be affected MORE before it strikes the target than a faster moving bullet because it spends more TIME in the air. Likewise, air resistance slows bullets down increasingly fast as the bullets slow down (inertia is lost). (Faster moving bullets take more air resistance to slow down, in other words.)
So inconsistency in exit velocity plays a major factor in how everything in the real world impacts your trajectory. You want as consistent of an exit velocity as possible for maximum accuracy.
Since powder ignition, powder weight consistency, and bullet seating tension are the prime (only) contributors to the initial impulse of a projectile, they are the parts to pay most attention to.
Anal Rententive Stuff Which May Or May Not Matter (splitting hairs).
The above assumes you are shooting the same make (and preferably same lot) of brass. If you are pulling from different manufacturers or a random assortment of once fired you got off GunBroker or some surplus site, you will definitely want to sort brass by manufacturer so that you have “similar” wall thicknesses. (This is, of course, leading to a quick discussion about case VOLUME.)
I’ve measured lots of brand new, virgin, unfired factory brass with neck thicknesses of +/- .002”! That’s a HUGE difference in the amount of material in the overall case! Since the outside of the cases are all sized the same (whether from full length sizing or being fireformed in your barrel), the differences in wall thickness directly correspond to CASE VOLUME.
Case volume affects the rate at which your powder burn accelerates – since volume affects the reciprocal pressure in the chamber, smaller volumes will increase the burn rate. Depending on the powder and length of barrel, this may increase or decrease the speed of the projectile as it exits the firearm.
Different lots of power and primers should likewise never be mixed within the same batch of fully-prepped ammunition.
Experimenting with bullet seating depth can also have large implications on accuracy. Normally seated bullets have to jump a “gap” before they fully engage the rifling. During this time it is possible for them to skew – enter slightly sideways, or to jump with an inconsistent force. If your bullets are all seated the same exact depth, you won’t typically suffer velocity issues, but reducing the “gap” the bullets must jump can have profound impacts on accuracy. We’re splitting hairs here, because by “profound” I’m talking about .1 MOA or less, but we’re talking about accurate ammo, so that IS a profound difference to some people.
Finally, some rifles like some powder, bullet, and powder weight (charge) combinations better than others. Some rifles like moderate powder charges, some are more accurate towards the bleeding edge of the MAX scale. This is up to you to determine through trial and error, and accurate record keeping.
A word about powder.
You can get “acceptable” accuracy out of volume-dumped powder. For most cartridges, +/- .1 or .2 grains isn’t going to ruin your 100 yard groups. If you are loading towards the “MAX” end of the scale, you’ll want to weigh your charges for safety, NEVER volume-dump “max” loads.
If you are loading for the highest degree of accuracy, you’ll want to weigh ALL of your charges to at LEAST +/- 0.1 gr. Some of the more competitive long range shooters will use expensive scales to measure to 0.01 grains.
Always calibrate your scale before beginning; even high-tech electrogadgets will vary their zero point with humidity and temperature. Be mindful of air currents, heater ducts, and so on. If you “heat” your realoading room (common for basement / garage setups), give the equipment and room time to “come to temp” before starting, as increasing temperature CAN affect your zero point if you “heat as you go.” The net effect of this is it can cause loaded rounds to have progressively more or less powder as the room and equipment come up to temp.
This post reflects my opinions and experiences only, your mileage may vary.
I tried to abstain from posting specific brand recommendations as I’m not a paid spokesperson and it’s not my job to advertise specific brands. This being said, I’ve used ALL brands at one time or another and I’m not overly partial to any specific one.
I will mention I DO lean towards Redding or Forster on neck sizers and seating dies, and RW Hart makes a solid and reliable neck turner.
