I was always under the impression the number should face upward if they were on the side they should be readable not upside down
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Neck Bushing Sizes
- Thread starter Allen Kitts
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bigedp51
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If the bushing numbers are facing up they can cause the bushing to tilt when upward pressure is applied by the case neck. Meaning the numbers are stamped and may have raised edges and the bushing may not lay flat.
Tech Line & Tips (FAQs)
Concentricity & Bushing Dies
www.redding-reloading.com
From tests we have conducted, we have learned that selecting the correct bushing is the most important factor in producing sized case necks that have good concentricity with the case body. Our tests showed that case neck concentricity is directly proportional to bushing size. In other words, as you size case necks with progressively smaller bushings, the concentricity gets progressively worse.
Our current recommendation, is to select a bushing that is .001 to .002" smaller than the loaded cartridge neck diameter. For example, if the neck diameter of your loaded cartridges is .248", start with a .247 or .246" bushing. We've had to change our initial recommendation, because some of cartridge cases manufactured today have neck walls near the minimum SAAMI thickness. When using brass which is at the thinner end of the SAAMI spec. we have found the bushing which is .001" smaller will provide the best result.
To create precision reloads, you must start with cases of good quality. They should all be from the same manufacturer and lot number. A good measure of case quality is how uniform the neck wall thickness is. Cases with uniform neck wall thickness, will be of uniform thickness all the way to the base. This is important for accuracy, as the cases will expand uniformly upon firing, and contract uniformly when sized. Neck turning helps, but it's only a partial cure, as you can't turn the case wall all the way to the base. The Redding Case Neck Gauge is the preferred instrument for checking neck wall thickness and uniformity. Also note that the concentricity of a fired case only indicates how concentric your firearm's chamber is. It provides you with little or no information on the quality of the cases you're using.
Other factors that can improve concentricity:
Tech Line & Tips (FAQs)
Concentricity & Bushing Dies
Concentricity & Bushing Dies - Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment
Reloading equipment for rifles, handguns, pistols, revolvers, custom dies, bullet casting equipment, powder measuring and weighing equipment, bullet seating dies
From tests we have conducted, we have learned that selecting the correct bushing is the most important factor in producing sized case necks that have good concentricity with the case body. Our tests showed that case neck concentricity is directly proportional to bushing size. In other words, as you size case necks with progressively smaller bushings, the concentricity gets progressively worse.
Our current recommendation, is to select a bushing that is .001 to .002" smaller than the loaded cartridge neck diameter. For example, if the neck diameter of your loaded cartridges is .248", start with a .247 or .246" bushing. We've had to change our initial recommendation, because some of cartridge cases manufactured today have neck walls near the minimum SAAMI thickness. When using brass which is at the thinner end of the SAAMI spec. we have found the bushing which is .001" smaller will provide the best result.
To create precision reloads, you must start with cases of good quality. They should all be from the same manufacturer and lot number. A good measure of case quality is how uniform the neck wall thickness is. Cases with uniform neck wall thickness, will be of uniform thickness all the way to the base. This is important for accuracy, as the cases will expand uniformly upon firing, and contract uniformly when sized. Neck turning helps, but it's only a partial cure, as you can't turn the case wall all the way to the base. The Redding Case Neck Gauge is the preferred instrument for checking neck wall thickness and uniformity. Also note that the concentricity of a fired case only indicates how concentric your firearm's chamber is. It provides you with little or no information on the quality of the cases you're using.
Other factors that can improve concentricity:
- Lube case necks, even with TiN coated bushings.
- Partial size case necks. Sizing 1/2 or 3/4 of the neck seems to be the most popular.
- Try flipping the bushing over. We like to install them with the letters down to start with.
- Trim cases mouths square so they will enter the bushing straight. Don't forget to chamfer the case mouth, inside and out. This is very important as it eases the entry of the case mouth into the bushing, and the bullet into the case mouth.
- Anneal case necks. Cases that have been fired many times work harden and this causes excessive spring-back of the case necks.
Mikecr
Well-Known Member
Redding is most correct on the topic.
They are a bit weak in this: "When using brass which is at the thinner end of the SAAMI spec. we have found the bushing which is .001" smaller will provide the best result."
Necks come in a wide band of thicknesses, and whether 8thou thick or 18thou, the 1thou interference represents max needed. So Redding bushings are selected to get that -regardless of brass thickness.
The reason their math doesn't always work out, leading to a band .001-.002 recommended, is because of chamber neck clearances. Higher neck clearances cause larger fired necks, leading to greater downsizing requirement to achieve 1thou interference. But that doesn't mean using a smaller bushing,, it means using a larger bushing. This, because with greater downsizing the brass is rolling at larger angles.
With that, bushing selection is often trial & error of recommended band.
Example:
Loaded neck diameter of .248
Chamber neck at .250
Fired necks will hit the .250 chamber neck plus a tiny chamber expansion and spring back to ~.2495. This in a general sense, because neck diameter and hardness affect it a bit.
You want .001 interference after sizing(unloaded necks of .247). Will a .247 bushing sizing down from .2495 actually leave necks at .247? NO. The necks will release from the bushing springing back outward to .2475. You end up with 1/2thou interference.
You'll need a bushing ~.002 smaller than loaded necks, .246, from which necks will spring back to .2465, or 1.5thou interference. And 1.5thou interference is better to desired than 0.5thou interference, so the better bushing selection is .002 under loaded neck (in this case).
But this is considered by some as a 'tight neck' chamber, offering only 2thou clearance.
Example 2:
Loaded neck diameter of .248
Chamber neck at .254
Fired necks come out ~.2535
Desired sized neck OD again at .247
Sizing down .2535 with a .247 bushing is >5thou difference. That level of sizing ANGLE changes the result, actually causing necks to release at ~.2465, or 1.5thou interference from .248.
Not bad, so Redding's recommended .001 under loaded works out.
A 246 bushing (.002 under loaded) would be too much.
IMO, it's a greater trend in CLEARANCES that Redding recommendations are following.
You can always purchase both 1thou and 2thou under bushings, and try them both for your final selection choice.
They are a bit weak in this: "When using brass which is at the thinner end of the SAAMI spec. we have found the bushing which is .001" smaller will provide the best result."
Necks come in a wide band of thicknesses, and whether 8thou thick or 18thou, the 1thou interference represents max needed. So Redding bushings are selected to get that -regardless of brass thickness.
The reason their math doesn't always work out, leading to a band .001-.002 recommended, is because of chamber neck clearances. Higher neck clearances cause larger fired necks, leading to greater downsizing requirement to achieve 1thou interference. But that doesn't mean using a smaller bushing,, it means using a larger bushing. This, because with greater downsizing the brass is rolling at larger angles.
With that, bushing selection is often trial & error of recommended band.
Example:
Loaded neck diameter of .248
Chamber neck at .250
Fired necks will hit the .250 chamber neck plus a tiny chamber expansion and spring back to ~.2495. This in a general sense, because neck diameter and hardness affect it a bit.
You want .001 interference after sizing(unloaded necks of .247). Will a .247 bushing sizing down from .2495 actually leave necks at .247? NO. The necks will release from the bushing springing back outward to .2475. You end up with 1/2thou interference.
You'll need a bushing ~.002 smaller than loaded necks, .246, from which necks will spring back to .2465, or 1.5thou interference. And 1.5thou interference is better to desired than 0.5thou interference, so the better bushing selection is .002 under loaded neck (in this case).
But this is considered by some as a 'tight neck' chamber, offering only 2thou clearance.
Example 2:
Loaded neck diameter of .248
Chamber neck at .254
Fired necks come out ~.2535
Desired sized neck OD again at .247
Sizing down .2535 with a .247 bushing is >5thou difference. That level of sizing ANGLE changes the result, actually causing necks to release at ~.2465, or 1.5thou interference from .248.
Not bad, so Redding's recommended .001 under loaded works out.
A 246 bushing (.002 under loaded) would be too much.
IMO, it's a greater trend in CLEARANCES that Redding recommendations are following.
You can always purchase both 1thou and 2thou under bushings, and try them both for your final selection choice.
bigedp51
Well-Known Member
- Joined
- Dec 10, 2010
- Messages
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Size your cases with the numbers up and then down and see if your neck runout increases. Meaning you are checking to see if the numbers up are causing the bushing to tilt
Blackhawk
Well-Known Member
Well stated!
Without checking the sizing bushings ID with a pin gage set , I gather that said bushing is tapered slightly larger on the non numbered side to allow ( I assume ) for an easier case extraction while still retaining the cases shoulder integrity from your Fl resizing die.If the bushing numbers are facing up they can cause the bushing to tilt when upward pressure is applied by the case neck. Meaning the numbers are stamped and may have raised edges and the bushing may not lay flat.
Tech Line & Tips (FAQs)
Concentricity & Bushing Dies
Concentricity & Bushing Dies - Redding Reloading Equipment: reloading equipment for rifles, handguns, pistols, revolvers and SAECO bullet casting equipment
Reloading equipment for rifles, handguns, pistols, revolvers, custom dies, bullet casting equipment, powder measuring and weighing equipment, bullet seating dies
From tests we have conducted, we have learned that selecting the correct bushing is the most important factor in producing sized case necks that have good concentricity with the case body. Our tests showed that case neck concentricity is directly proportional to bushing size. In other words, as you size case necks with progressively smaller bushings, the concentricity gets progressively worse.
Our current recommendation, is to select a bushing that is .001 to .002" smaller than the loaded cartridge neck diameter. For example, if the neck diameter of your loaded cartridges is .248", start with a .247 or .246" bushing. We've had to change our initial recommendation, because some of cartridge cases manufactured today have neck walls near the minimum SAAMI thickness. When using brass which is at the thinner end of the SAAMI spec. we have found the bushing which is .001" smaller will provide the best result.
To create precision reloads, you must start with cases of good quality. They should all be from the same manufacturer and lot number. A good measure of case quality is how uniform the neck wall thickness is. Cases with uniform neck wall thickness, will be of uniform thickness all the way to the base. This is important for accuracy, as the cases will expand uniformly upon firing, and contract uniformly when sized. Neck turning helps, but it's only a partial cure, as you can't turn the case wall all the way to the base. The Redding Case Neck Gauge is the preferred instrument for checking neck wall thickness and uniformity. Also note that the concentricity of a fired case only indicates how concentric your firearm's chamber is. It provides you with little or no information on the quality of the cases you're using.
Other factors that can improve concentricity:
- Lube case necks, even with TiN coated bushings.
- Partial size case necks. Sizing 1/2 or 3/4 of the neck seems to be the most popular.
- Try flipping the bushing over. We like to install them with the letters down to start with.
- Trim cases mouths square so they will enter the bushing straight. Don't forget to chamfer the case mouth, inside and out. This is very important as it eases the entry of the case mouth into the bushing, and the bullet into the case mouth.
- Anneal case necks. Cases that have been fired many times work harden and this causes excessive spring-back of the case necks.
This is in accordance with all manufactures regardless of brand instructions of making certain that your bushings are inserted with the numbered side facing up when viewed from the top of the die
A fact I am certain that you are cognizant of.
I'm positive that you have a reason for the inversion of your sizing bushing.
Could you please expand on your reasoning, as I for am very curious.
Thank you for your response !
After further reading of your post I now understand your wisdom as well as your logic !
Last edited:
bigedp51
Well-Known Member
- Joined
- Dec 10, 2010
- Messages
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The instructions that come with the Redding bushing dies do not tell you which way to place the bushing in the die. This tells me the Redding bushings do not have a tapered inside diameter. The online Redding bushing die FAQ tells you to start with the numbers facing down. And this is also the advice given in reloading forums by reloaders with Redding dies.
My Forster bushing bump dies tell you to place the bushing in the die with the tapered side down. And I assume this is because the tapered end has a larger and polished inside radius.
Blackhawk
Well-Known Member
I stand corrected sir and Thank You .
I must state in my defense that my Horandy Match Grade Dies state that the bushing number must / should be inserted with the number side upright, and I incorrectly assumed that neck sizing bushings from all manufacturers are seated in this manner.
Now I recall that different die manufacturers use different neck sizing bushings that are proprietary and can not be interchanged with other manufacturer's dies.
To that end each manufacturer has their own recommended method for insertion of their neck sizing bushings.
This is clearly a case of open mouth and insert foot!
I stand corrected and apologize for my error !
Thank You again for your pointing it out to me.
Varmint Hunter
Well-Known Member
For what Redding charges for a bushing, especially the Ti bushings, you should not have to orient them in any special way. I always inserted the bushings so that I could easily see the stamping but now flip them over to eliminate the 1 in a million chance that it will make a difference. Most of us aren't shooting 1,000 BR so I'm skeptical as to who may actually benefit from the "stamp-side-down" orientation.
Has anyone actually tested this orientation issue to determine if there is a measurable difference?
Has anyone actually tested this orientation issue to determine if there is a measurable difference?
It's all about a runout issue. When you stamp something what happens?
A ridge gets made around the letters so when you size the case and the bushing was to come up hard on the stem against the ridges on the lettering it can tilt causing runout that's why they want letters down. If you insist on letters up then by all means run your letters up.
A ridge gets made around the letters so when you size the case and the bushing was to come up hard on the stem against the ridges on the lettering it can tilt causing runout that's why they want letters down. If you insist on letters up then by all means run your letters up.
