G
Guest
Guest
buckeyesguy5XSergeant
Rating: 3.2/5 this site
361 posts this site
Lake City LR brass sizing
12/27/2016
I just acquired some LC lr brass and am attempting to fl size it. My question, is this stuff always so damn hard to size? I've used regular LC, wcc, and fgmm in the past and nothing has even been comparable to this shit. Is this normal?
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/27/2016 Last edited 12/27/2016 by bigedp51
Lake City brass is harder than commercial brass and thicker in the base.
If it was fired in a M14 the chamber is .002 larger in diameter, meaning the case expanded more.
So yes it is harder to size the first time and you "might" need a small base die for the first sizing.
The first time you size the brass with a standard die pause at the top of the ram stroke for 4 to 5 seconds.
Pausing greatly reduces brass spring back, now see if the sized case fit in the chamber.
If not size again pausing a second time at the top of the ram stroke and check to see if the case chambers freely.
If not you need a small base die to bring the case back to minimum SAAMI dimensions.
NOTE, chambers and resizing dies vary in diameter and I have a standard Lee .223 FL die that reduces the case diameter more than my RCBS 223 small base die. But most times the standard FL die should do the job without the need of a small base die. But you never know until you size a few cases "AND" you may have mixed brass fired in different type rifles.
Rate now:
buckeyesguy5XSergeant
Rating: 3.2/5 this site
361 posts this site
Re: Lake City LR brass sizing
12/28/2016
I realize LC brass is harder and it depends on the chamber it was fired in, but it's like this shit was linked up for a 240! I got through some last night but I just couldn't believe how difficult they were goin. Lube em up like it was prom night was about the only thing that helped.
Rate now:
samnevXFirst Sergeant
Rating: 3.4/5 this site
3639 posts this site
Re: Lake City LR brass sizing
12/28/2016
Yes they are harder to resize. I bought 500 unprocessed pieces of LC brass. The first time I resized them was on an with RCBS Rock Chucker press using RCBS regular 308 dies with the Dillon trimmer attached. After finishing I had a blister on the palm of my hand. First time in 40 years of reloading that happened to me.
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
If you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
Rate now:
samnevXFirst Sergeant
Rating: 3.4/5 this site
3639 posts this site
Re: Lake City LR brass sizing
12/28/2016
I've never had that problem before with any other GI brass i've resized including LC brass i've used before. This new lot of LC brass was the first LC brass I bought in over 15 years. Perhaps all were fired in an M240 but I miked them before I resized them and the heads seemed no larger than brass I had fired in my other 308 weapons. But thanks for the tip.
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
Another cause of the hard sizing could be the pressure the cases were subjected to.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016
But It may have been shot from a machine gun to use up existing stocks of older ammo.
I sized some MG brass not long ago but it was wet tumbled first and sized with Hornady Unique case lube applied by hand and it was not that difficult to size. Maybe the clean cases make a difference and I wet tumble all my once fired military cases first before sizing to keep from embedding dirt and grit inside the die.
Bottom line, in my opinion wet tumbling or even tumbling with walnut media would make sizing less difficult because the outside of the case is scrubbed clean.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
I have 2 Redding body dies and I was not aware they were any different than a standard die minus sizing the neck. They are simply the equivalent of a full length die with a bored out neck
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
(so what we live in a plus and minus manufacturing world)
And a Redding body die is designed to size the body and bump the shoulder back for people who neck size only when the cases become tight in their chambers.
Now what good would a body die be to someone with a snug or smaller diameter custom chamber if the die did not reduce the case diameter enough???????
If anything Redding dies have tighter plus and minus manufacturing tolerances than the average die.
Bottom line, a redding body die is "NOT" going to make sizing machine gun brass easier.
If the OP wants to check his resized cases then I would recommend the JP Enterprize case gauge cut with a chamber finish reamer.
Meaning this gauge also checks case body diameter.
[h=1][/h] [h=1][/h]
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
Yes they will.
You are unaware Redding also makes a small base body die that sizes the shoulder area the same as a regular fl die and the bottom area .002" tighter.
In any event, the regular 308 body die will make sizing easier. For one, you are not sizing the neck. Second, it sizes less.
Rate now:
FLIGHT762
XGunny Sergeant
Rating: 3.1/5 this site
940 posts this site
Re: Lake City LR brass sizing
12/28/2016
I have a Redding small base body die in 308 Winchester. It in fact, does size the case head area smaller than a regular body die.
I had a SSG 69 that had such a tight chamber, cases fired in other rifles would not chamber in the SSG 69. The issue was the sizing of the case body in the web area. Other dies, including a RCBS small base die wouldn't do it. The only die that successfully sized the case web down far enough was the Redding Small Base Body Die so I could reload fired cases from other rifles in that SSG 69. It worked perfectly.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
No shit, I wonder why they call them small base dies?????????
And don't argue with me, you will just "die" tired and loose the argument anyway.
Who do you think your trying to bullshit, a body die is "NOT" larger in diameter and is the same size as a standard sizing die.
Now go ahead and ask me how I know this................................
Rate now:
padom
XFirst Sergeant
Rating: 3.8/5 this site
3050 posts this site
Re: Lake City LR brass sizing
12/28/2016
Ive never needed anything outside of a Forster FL sizing die to size LC brass or any other brass. I own them all, name the brand but the Forster works the best.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
[h=1]The Way of the Sizing Die[/h]
One of the questions we are asked a lot is “what is the best sizing die that I can use for my brass and rifle?” Today, we’ll address some of the ways the various sizers are used, so you can make the best decision for your rifle. In this article we’ll cover the conventional Full Length Sizing Die, Small Base Full Length Sizing Die, Body Die, Bushing Style Full Length Sizing Die, “Bump” Die, and Neck Sizing Dies.
We’ll start with what is referred to as a "conventional" full length sizing die. It sizes the body of the case, resizes the neck, and if we set it up following the die manufacturer’s instructions, push the shoulder to an industry standard setting that will work in factory chambered guns.
The "small base" full length sizing die comes down farther onto the case body and sizes it to a slightly smaller diameter. This die is generally used in rifles with actions that have less camming power during the opening and closing operation. This would be for semi-auto, pump, and lever action rifles since they simply do not have the camming power of a manually operated bolt action rifle.
The body die is, in essence, a conventional full length sizing die that works as if it were cut off at the shoulder/neck junction. It will full length size the body of the case and push, or “bump”, the shoulder to the location that we adjust it for. This is used is you want to keep the full length sizing operation separate from the neck sizing operation.
Several die manufacturers make full length and neck sizers that are machined to accept die bushings that let us vary the amount of tension we can apply to the neck for bullet seating purposes. It can also be used to compensate for varying neck wall thicknesses, such as if you outside turn your case necks to a thinner wall thickness.
What is referred to as a “bump” die is an interesting blend of the best of the full length and neck sizing dies in one operation. This type of die was previously only available through the services of a custom gunsmith or specialty houses like Neil Jones Custom Products and JLC Precision. Thanks to the folks at Forster Products, we finally have the first commercially available bump die. This die is called the Forster Precision Plus Bushing Bump Die. It’s available for 20 different cartridges, so the choices are limited to the more popular cartridges. This die will bump the shoulder to the location that you adjust it for, but it will not size the body of the case. It uses bushings for neck sizing, allowing you to vary the neck tension as well, and it will then decap the spent primers. Since this type of die does not size the body of the case, it is recommended that the brass be used in the same rifle that it was originally fired in, since it may not fit another rifle chambered for the same cartridge.
The last die we’ll discuss is the neck sizing die. Sometimes, a rifle will indicate during the load testing phases that it prefers to have the neck sized, but not the body of the case. The only drawback to this type of sizing is that at some point, you will eventually need to do a full length size operation on the case when you start running into bolt lift issues.
One of the questions that folks often ask is if they can adjust the full length die back to act as a neck die. The short, honest answer to this one is "no". What will happen, in most instances, is that when we adjust the full length sizing die to size maybe only half of the neck, we are still squeezing the body of the case. This does displace some of the brass, and the only direction that it can go is forward. This will also carry the shoulder forward and may prevent the case from chambering, since it will force the case to stretch and brass will flow toward the path of least resistance - the case mouth. However, you can adjust the die so it will only put a minimal bump on the shoulder to support it and prevent the shoulder from flowing forward. This is something that some of the best bench rest shooters have been doing, and it’s been proven to actually improve case life, while making sure the case fits your chamber precisely!
To do this, you will need several once fired cases from your rifle, a Sinclair Comparator/Bump Gage Body (09-1000), and the proper case shoulder Sinclair Bump Gage Insert (09-10230) for the cartridge that you are working with. Let’s use .223 Remington as an example. If we measure the cases with the Sinclair Comparator/Bump Gage and arrive at a reference measurement of 3.500” on a bolt action rifle, we would want to set up the full length, or bump die, to push or “bump”, the shoulder back .001” to .002” of an inch. This would give us a sized case dimension of 3.499” to 3.498”. If this is for your AR-15, we would then want to see a measurement anywhere from 3.497” to 3.496” (.003” to .004” of “bump”).
Bench rest shooters have found that sizing cases this way lets them chamber rounds cleanly, minimizing how much the rifle is disturbed in the sand bags, while it also controls how much the case flows forward. This minimal sizing extends brass life and works the case as if we were neck sizing only! It reduces the amount of work hardening the case will go through. It’s the preferred method that most of us on the Sinclair Tech Staff use for our personal rifles.
As you can see, there are many ways that you can use the available sizing dies for the best use in sizing brass for use in your rifle. Please don’t hesitate to contact any of us on the Sinclair Tech Staff if you have any additional questions.
Cordially,
Bob Blaine
Sinclair Reloading Tech.
NRA Certified Reloading Instructor & RSO
Sinclair International, Inc.
sinclairintl.com/GunTech/The-Way-of-the-Sizing-Die/detail.htm?lid=16039
Rating: 3.2/5 this site
361 posts this site
Lake City LR brass sizing
12/27/2016
I just acquired some LC lr brass and am attempting to fl size it. My question, is this stuff always so damn hard to size? I've used regular LC, wcc, and fgmm in the past and nothing has even been comparable to this shit. Is this normal?
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/27/2016 Last edited 12/27/2016 by bigedp51
Lake City brass is harder than commercial brass and thicker in the base.
If it was fired in a M14 the chamber is .002 larger in diameter, meaning the case expanded more.
So yes it is harder to size the first time and you "might" need a small base die for the first sizing.
The first time you size the brass with a standard die pause at the top of the ram stroke for 4 to 5 seconds.
Pausing greatly reduces brass spring back, now see if the sized case fit in the chamber.
If not size again pausing a second time at the top of the ram stroke and check to see if the case chambers freely.
If not you need a small base die to bring the case back to minimum SAAMI dimensions.
NOTE, chambers and resizing dies vary in diameter and I have a standard Lee .223 FL die that reduces the case diameter more than my RCBS 223 small base die. But most times the standard FL die should do the job without the need of a small base die. But you never know until you size a few cases "AND" you may have mixed brass fired in different type rifles.
Rate now:
buckeyesguy5XSergeant
Rating: 3.2/5 this site
361 posts this site
Re: Lake City LR brass sizing
12/28/2016
I realize LC brass is harder and it depends on the chamber it was fired in, but it's like this shit was linked up for a 240! I got through some last night but I just couldn't believe how difficult they were goin. Lube em up like it was prom night was about the only thing that helped.
Rate now:
samnevXFirst Sergeant
Rating: 3.4/5 this site
3639 posts this site
Re: Lake City LR brass sizing
12/28/2016
Yes they are harder to resize. I bought 500 unprocessed pieces of LC brass. The first time I resized them was on an with RCBS Rock Chucker press using RCBS regular 308 dies with the Dillon trimmer attached. After finishing I had a blister on the palm of my hand. First time in 40 years of reloading that happened to me.
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
If you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
Rate now:
samnevXFirst Sergeant
Rating: 3.4/5 this site
3639 posts this site
Re: Lake City LR brass sizing
12/28/2016
I've never had that problem before with any other GI brass i've resized including LC brass i've used before. This new lot of LC brass was the first LC brass I bought in over 15 years. Perhaps all were fired in an M240 but I miked them before I resized them and the heads seemed no larger than brass I had fired in my other 308 weapons. But thanks for the tip.
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
Another cause of the hard sizing could be the pressure the cases were subjected to.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016
buckeyesguy5 wrote:
I just acquired some LC lr brass and am attempting to fl size it. My question, is this stuff always so damn hard to size? I've used regular LC, wcc, and fgmm in the past and nothing has even been comparable to this shit. Is this normal?
Standard Lake City 7.62 would be machine gun brass "but" you have lr or "Long Range" brass that should have been fired from a M14 type sniper rifle or the M24.I just acquired some LC lr brass and am attempting to fl size it. My question, is this stuff always so damn hard to size? I've used regular LC, wcc, and fgmm in the past and nothing has even been comparable to this shit. Is this normal?
But It may have been shot from a machine gun to use up existing stocks of older ammo.
I sized some MG brass not long ago but it was wet tumbled first and sized with Hornady Unique case lube applied by hand and it was not that difficult to size. Maybe the clean cases make a difference and I wet tumble all my once fired military cases first before sizing to keep from embedding dirt and grit inside the die.
Bottom line, in my opinion wet tumbling or even tumbling with walnut media would make sizing less difficult because the outside of the case is scrubbed clean.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
spawnof918v wrote:
If you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
spawnof918vIf you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
I have 2 Redding body dies and I was not aware they were any different than a standard die minus sizing the neck. They are simply the equivalent of a full length die with a bored out neck
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
bigedp51 wrote:
I have 2 Redding body dies and I was not aware they were any different than a standard die minus sizing the neck.
Well, they are different. They size the body a lot less in the shoulder area. I don't have a RCBS 308 die anymore but my Lee is .003" tighter.spawnof918v wrote:
If you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
spawnof918vIf you want to reduce sizing effort you have to use a die that sizes less than a standard FL die. The die you want is the Redding body die. Size in the body die first, then in your FL die and things will go much easier.
I understand that Dillon 308 dies are carbide. Maybe that's another option cuz a lubed case through carbide is like a hot knife through butter. That may save you time if you don't want to size in multiple steps.
I have 2 Redding body dies and I was not aware they were any different than a standard die minus sizing the neck.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
spawnof918v wrote:
Well, they are different. They size the body a lot less in the shoulder area. I don't have a RCBS 308 die anymore but my Lee is .003" tighter.
And I have a standard Lee .223 full length die that will size the case diameter smaller than my RCBS .223/5.56 small base die.(so what we live in a plus and minus manufacturing world)
And a Redding body die is designed to size the body and bump the shoulder back for people who neck size only when the cases become tight in their chambers.
Now what good would a body die be to someone with a snug or smaller diameter custom chamber if the die did not reduce the case diameter enough???????
If anything Redding dies have tighter plus and minus manufacturing tolerances than the average die.
Bottom line, a redding body die is "NOT" going to make sizing machine gun brass easier.
If the OP wants to check his resized cases then I would recommend the JP Enterprize case gauge cut with a chamber finish reamer.
Meaning this gauge also checks case body diameter.
[h=1][/h] [h=1][/h]
Rate now:
spawnof918vXFirst Sergeant
Rating: 2.6/5 this site
3755 posts this site
Re: Lake City LR brass sizing
12/28/2016
Yes they will.
You are unaware Redding also makes a small base body die that sizes the shoulder area the same as a regular fl die and the bottom area .002" tighter.
In any event, the regular 308 body die will make sizing easier. For one, you are not sizing the neck. Second, it sizes less.
Rate now:
FLIGHT762
XGunny Sergeant
Rating: 3.1/5 this site
940 posts this site
Re: Lake City LR brass sizing
12/28/2016
I have a Redding small base body die in 308 Winchester. It in fact, does size the case head area smaller than a regular body die.
I had a SSG 69 that had such a tight chamber, cases fired in other rifles would not chamber in the SSG 69. The issue was the sizing of the case body in the web area. Other dies, including a RCBS small base die wouldn't do it. The only die that successfully sized the case web down far enough was the Redding Small Base Body Die so I could reload fired cases from other rifles in that SSG 69. It worked perfectly.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
spawnof918v wrote:
Yes they will.
You are unaware Redding also makes a small base body die that sizes the shoulder area the same as a regular fl die and the bottom area .002" tighter.
In any event, the regular 308 body die will make sizing easier. For one, you are not sizing the neck. Second, it sizes less.
Dear Spawn of the DeadYes they will.
You are unaware Redding also makes a small base body die that sizes the shoulder area the same as a regular fl die and the bottom area .002" tighter.
In any event, the regular 308 body die will make sizing easier. For one, you are not sizing the neck. Second, it sizes less.
No shit, I wonder why they call them small base dies?????????
And don't argue with me, you will just "die" tired and loose the argument anyway.
Who do you think your trying to bullshit, a body die is "NOT" larger in diameter and is the same size as a standard sizing die.
Now go ahead and ask me how I know this................................
Rate now:
padom
XFirst Sergeant
Rating: 3.8/5 this site
3050 posts this site
Re: Lake City LR brass sizing
12/28/2016
Ive never needed anything outside of a Forster FL sizing die to size LC brass or any other brass. I own them all, name the brand but the Forster works the best.
Rate now:
bigedp51XGunny Sergeant
Rating: 2.9/5 this site
769 posts this site
Re: Lake City LR brass sizing
12/28/2016 Last edited 12/28/2016 by bigedp51
[h=1]The Way of the Sizing Die[/h]
One of the questions we are asked a lot is “what is the best sizing die that I can use for my brass and rifle?” Today, we’ll address some of the ways the various sizers are used, so you can make the best decision for your rifle. In this article we’ll cover the conventional Full Length Sizing Die, Small Base Full Length Sizing Die, Body Die, Bushing Style Full Length Sizing Die, “Bump” Die, and Neck Sizing Dies.
We’ll start with what is referred to as a "conventional" full length sizing die. It sizes the body of the case, resizes the neck, and if we set it up following the die manufacturer’s instructions, push the shoulder to an industry standard setting that will work in factory chambered guns.
The "small base" full length sizing die comes down farther onto the case body and sizes it to a slightly smaller diameter. This die is generally used in rifles with actions that have less camming power during the opening and closing operation. This would be for semi-auto, pump, and lever action rifles since they simply do not have the camming power of a manually operated bolt action rifle.
The body die is, in essence, a conventional full length sizing die that works as if it were cut off at the shoulder/neck junction. It will full length size the body of the case and push, or “bump”, the shoulder to the location that we adjust it for. This is used is you want to keep the full length sizing operation separate from the neck sizing operation.
Several die manufacturers make full length and neck sizers that are machined to accept die bushings that let us vary the amount of tension we can apply to the neck for bullet seating purposes. It can also be used to compensate for varying neck wall thicknesses, such as if you outside turn your case necks to a thinner wall thickness.
What is referred to as a “bump” die is an interesting blend of the best of the full length and neck sizing dies in one operation. This type of die was previously only available through the services of a custom gunsmith or specialty houses like Neil Jones Custom Products and JLC Precision. Thanks to the folks at Forster Products, we finally have the first commercially available bump die. This die is called the Forster Precision Plus Bushing Bump Die. It’s available for 20 different cartridges, so the choices are limited to the more popular cartridges. This die will bump the shoulder to the location that you adjust it for, but it will not size the body of the case. It uses bushings for neck sizing, allowing you to vary the neck tension as well, and it will then decap the spent primers. Since this type of die does not size the body of the case, it is recommended that the brass be used in the same rifle that it was originally fired in, since it may not fit another rifle chambered for the same cartridge.
The last die we’ll discuss is the neck sizing die. Sometimes, a rifle will indicate during the load testing phases that it prefers to have the neck sized, but not the body of the case. The only drawback to this type of sizing is that at some point, you will eventually need to do a full length size operation on the case when you start running into bolt lift issues.
One of the questions that folks often ask is if they can adjust the full length die back to act as a neck die. The short, honest answer to this one is "no". What will happen, in most instances, is that when we adjust the full length sizing die to size maybe only half of the neck, we are still squeezing the body of the case. This does displace some of the brass, and the only direction that it can go is forward. This will also carry the shoulder forward and may prevent the case from chambering, since it will force the case to stretch and brass will flow toward the path of least resistance - the case mouth. However, you can adjust the die so it will only put a minimal bump on the shoulder to support it and prevent the shoulder from flowing forward. This is something that some of the best bench rest shooters have been doing, and it’s been proven to actually improve case life, while making sure the case fits your chamber precisely!
To do this, you will need several once fired cases from your rifle, a Sinclair Comparator/Bump Gage Body (09-1000), and the proper case shoulder Sinclair Bump Gage Insert (09-10230) for the cartridge that you are working with. Let’s use .223 Remington as an example. If we measure the cases with the Sinclair Comparator/Bump Gage and arrive at a reference measurement of 3.500” on a bolt action rifle, we would want to set up the full length, or bump die, to push or “bump”, the shoulder back .001” to .002” of an inch. This would give us a sized case dimension of 3.499” to 3.498”. If this is for your AR-15, we would then want to see a measurement anywhere from 3.497” to 3.496” (.003” to .004” of “bump”).
Bench rest shooters have found that sizing cases this way lets them chamber rounds cleanly, minimizing how much the rifle is disturbed in the sand bags, while it also controls how much the case flows forward. This minimal sizing extends brass life and works the case as if we were neck sizing only! It reduces the amount of work hardening the case will go through. It’s the preferred method that most of us on the Sinclair Tech Staff use for our personal rifles.
As you can see, there are many ways that you can use the available sizing dies for the best use in sizing brass for use in your rifle. Please don’t hesitate to contact any of us on the Sinclair Tech Staff if you have any additional questions.
Cordially,
Bob Blaine
Sinclair Reloading Tech.
NRA Certified Reloading Instructor & RSO
Sinclair International, Inc.
sinclairintl.com/GunTech/The-Way-of-the-Sizing-Die/detail.htm?lid=16039
