Sizing methodology help.

[zanemoseley]

I'm still new to precision reloading and have a Savage 12 benchrest in 6br with I'm sure not the tightest chamber ever. I also have a set of Redding competition dies that has a micrometer bushing neck die and a shoulder bump die.

I've been watching some YouTube videos and see people downing the old neck size only method in favor of a FL size with .002-.003 of shoulder bump. I'm curious what the opinions are on this. Is the ideal setup going with a FL bushing micrometer sizing die then seating with a Wilson die and an arbor press?

With my dies assuming I keep them what is my best option? Should I neck size then bump the shoulder each time .002"-.003".

Thanks in advance.

 

[dmoran]

@zanemoseley -
Think there is some confusion. Bare these things in mind:
- If your "full length resizing" your sizing the case neck and body with a F/L die.
- If your "neck sizing only" your only sizing the neck with a Neck die, and not sizing the case body at all.
- If sizing the case body and the case neck in 2 separate steps, your either using a Body die or using a F/L bushing die with the bushing removed as a body die, to size the case body and in a separate step a neck die for the neck.
- Then there is also neck bump dies, and also partial neck sizing.

Donovan

 

[LHSmith]

I don't believe there is such a thing as a "FL bushing micrometer sizing die". Remove all doubts about chancing onto a off the shelf die that will "fit" YOUR chamber, and send Whidden 3 fired cases from your chamber and have a FL die made. I prefer bushing style dies.For your rifle I would bump only 0.001" to 0.002". Yes, I favor Wilson In-line seaters, but having Whidden also make a seater would a good choice also.

 

[BoydAllen]

Before you change anything make sure that you have a problem. Are you setting up your body die using some sort of gauge? What sort of runout do your fully sized cases have? If your results with your current setup are good, why would you need to change? What you refer to as a shoulder bump die is most likely a body die. Body dies do everything that a FL die does except size the neck. My usual problem with neck dies is that they do not align the case body with the case neck during sizing, BUT if your Redding neck die has a sliding sleeve, like the competition seater than that is not an issue. Bottom line you may be just fine with what you have...at least as far as sizing goes.

 

[zanemoseley]

Before you change anything make sure that you have a problem. Are you setting up your body die using some sort of gauge? What sort of runout do your fully sized cases have? If your results with your current setup are good, why would you need to change? What you refer to as a shoulder bump die is most likely a body die. Body dies do everything that a FL die does except size the neck. My usual problem with neck dies is that they do not align the case body with the case neck during sizing, BUT if your Redding neck die has a sliding sleeve, like the competition seater than that is not an issue. Bottom line you may be just fine with what you have...at least as far as sizing goes.

I've basically just fired all my virgin lapua brass in the rifle so just trying to setup my dies and process as best as possible. I need to buy a set of Hornady headspace comparators to check shoulder bump. I don't have a run out gauge yet, also on my want to buy list.

I checked my dies and you are correct what I was calling a shoulder bump die is called a "6mm BR Rem body X5", I have no idea what the "X5" means. The neck die does have a sliding sleeve as well as a micrometer adjustment for setting up a partial length neck resize.

 

[jimbires]

if your virgin brass is only 1 time fired it is probably not fully expanded yet . I'd neck size only another time or two until the brass starts to get tight to chamber , then you can set up your dies for correct shoulder bump .

 

[fguffey]

I have no idea what the "X5" means.

I was told it is possible to bump the shoulder back, being the only reloader that understands it is impossible to move the shoulder back and or bump the shoulder back I choose to ignore the advise. I am the only reloader that is not confused by the term 'bump', RCBS in their first set of instructions claimed the cam over press was a bump press, they also said if the press does not cam over it is not a bump press. So, the first thing I did when changing presses was to determine how much cam over the press had. When I checked the Rock Chucker I found the press was a non-cam over press, a feature that comes in handy when the Piggy Back 1 & 11 are added.

X5, reloaders are suppose to know what the other meant even when one of them is just making this stuff up. X5. The story goes the case must be fired 5 times before the case fits the chamber, after 5 firings the case must be full length sized to start over and I have always asked how is that possible?: I can not start over with a case that has been fired 5 times because we all should know the case is work hardened.

And then there is that part about head space, when you refer to head space are you asking/talking about the length of the chamber from the shoulder/datum to the bolt face or the length of the case from the shoulder/datum to the head of the case?

F. Guffey

 

[jepp2]

With my dies assuming I keep them what is my best option? Should I neck size then bump the shoulder each time .002"-.003".

jimbires is right, that your brass isn't fully formed to your chamber yet.

What is your best option? Depends on what you want. The benefit of the Redding comp neck sizing die, is that you can size only a portion of the case neck. So if that is what you want to do most of the time, it should work well for you. BUT, you will find you have more case neck runout than other sizing methods can result in. When I use a Redding bushing neck sizing die with Redding bushings, I get .003-.005" neck runout. When I use Whidden bushings in the Redding dies, I get about half that much. And that is both the S die and the Comp die.

If I body size the case and use a Lee Collet die, I get less than 0.001" neck runout. Mostly I use Redding FL sizing dies, that I hone the die neck to give me less than 0.001" expansion when the carbide expander comes back through the case neck. I consistently get less than 0.001" case neck runout with this setup. But I also lube the inside of my case necks and set my expander high, so it passes through the case neck just as the neck leaves the neck sizing portion of the FL die.

Get the Hornady comparator set, or some other reference (Wilson case gage) so you can set your die for the correct shoulder movement. I keep a set of fired brass in 0.001" increments to find the chamber length in my rifles. I record that and know what I need to size to.

 

['Freak]

Until the case has been a couple or four times fire formed, do body size but do so with the body die backed out far enough, at least 1/8th of a turn = ~ .009”, that it’ll not touch the case shoulder. If you body size first then that ought to size the case body to best fit the sliding case neck centering sleeve of the Comp. Bushing Neck Size die.

 

[M-61]

I'm still new to precision reloading

How does your response in any way help with the OP's opening sentence?:

being the only reloader that understands it is impossible to move the shoulder back and or bump the shoulder back

 

[M-61]

Before you change anything make sure that you have a problem.

OP: This would be step #1 for sure.

 

[M-61]

I am the only reloader that is not confused by the term 'bump',

If the above is indeed true, why not 'un-confuse' the rest of the reloading world?

 

[dmoran]

I was told it is possible to bump the shoulder back, being the only reloader that understands it is impossible to move the shoulder back and or bump the shoulder back I choose to ignore the advise. I am the only reloader that is not confused by the term 'bump'......

 

[Webster]

If the above is indeed true, why not 'un-confuse' the rest of the reloading world?

FGUFFEY: "being the only reloader that understands "

The aliens have arrived. They speak an unknown language.

 

[mikecr]

W/resp to your chamber(always) it's possible to use separate, or combined dies, for any sizing desired (or needed). A shoulder bump die can be just that, or it can be a full body die. It can be a body die that does not bump shoulders(ring die, or custom). Most FL-bushing dies are really body-bushing dies (a combination), and not FL dies at all.
I size each area separately myself.

For partial neck sizing I use Wilson inline with shims to adjust sizing length. I like the idea behind the Redding competition micrometer adjustable bushing neck die (no shims needed). https://www.midwayusa.com/product/1012454527/redding-competition-bushing-neck-sizer-die
Would like to put that micrometer on a custom body-bushing, or bump-bushing die & see how well it works.
I expand necks with Sinclair's mandrel system.

'Best' will always be an abstract, as your best may not be mine.
Just too many local differences to declare one approach as best across a community.

 

[Richard Coody]

I'm still new to precision reloading and have a Savage 12 benchrest in 6br with I'm sure not the tightest chamber ever. I also have a set of Redding competition dies that has a micrometer bushing neck die and a shoulder bump die.

I've been watching some YouTube videos and see people downing the old neck size only method in favor of a FL size with .002-.003 of shoulder bump. I'm curious what the opinions are on this. Is the ideal setup going with a FL bushing micrometer sizing die then seating with a Wilson die and an arbor press?

With my dies assuming I keep them what is my best option? Should I neck size then bump the shoulder each time .002"-.003".

Thanks in advance.

i have a savage target action rifle chambered in 6BR. i shoot groups like this.
what i recommend is to minimally resize your brass with no shoulder bump until the shoulder measurement stabilizes. usually that will happen by the third firing. that means the case is fully fireformed to your chamber. all your fired cases will measure the same. at this point take 3 fired and not resized cases and send them to harrell's. they will select one of their full length bushing dies that most closely matches your chamber. much less expensive than custom dies. i think it is around $60. that is what i used for that target.

 

[powderbrake]

I use your same dies on my 6BR prairie dog gun. I neck size only, so I don't have to worry about the chamber size or "shoulder setback" or dimensions on the case or chamber. It is very accurate.

I suggest you neck size with the dies you have, and only use the body die when you get difficulty chambering a case.

If you want to set your body die accurately, I suggest the Wheeler method of gradually sizing the case until the bolt handle just drops without resistance. (with firing pin & spring & ejector removed). Measure this with a Hornady case comparator and record that dimension.

Then gradually seat a bullet in a sized case until the bolt handle just drops without resistance to find the touch point. Measure the bullet position with a Hornady comparator and record that dimension as the "touch point".

If you want to full length size with a bushing die, then send 3 fired cases to Herrells and get their die, which is superb. I use this type of die on my 6ppc benchrest gun, adjusting with the Whidden method.

While some resistance while chambering a neck sized only case is to be expected, it is not important on a hunting gun. On a benchrest gun, to prevent movement of the gun when chambering, the full length resized case is preferred. If you are just getting started in benchrest, there are a lot of other things to worry about besides gun movement when chambering.

 

[M-61]

(with firing pin & spring & ejector removed)

I remove the extractor, spring and detent ball. I recommend extra detent balls on hand. I bought a bag of 50 (cheap) on Amazon either 1/8th" or 3.5mm. Can't remember which. I go thru maybe 4 balls until I get it. The others that go flying I have never found. Maybe they stay in orbit. That of course is done in a plastic bag which helps but no 1st time win for me.
I have nothing to add to powerbrake or Richard Coody above posts as I do the roughly the same. Also not bumping anything unless I experience hard bolt closure which one must differentiate from a bullet jamming.

 

[LHSmith]

I use your same dies on my 6BR prairie dog gun. I neck size only, so I don't have to worry about the chamber size or "shoulder setback" or dimensions on the case or chamber. It is very accurate.

I suggest you neck size with the dies you have, and only use the body die when you get difficulty chambering a case.

If you want to set your body die accurately, I suggest the Wheeler method of gradually sizing the case until the bolt handle just drops without resistance. (with firing pin & spring & ejector removed). Measure this with a Hornady case comparator and record that dimension.

Then gradually seat a bullet in a sized case until the bolt handle just drops without resistance to find the touch point. Measure the bullet position with a Hornady comparator and record that dimension as the "touch point".

If you want to full length size with a bushing die, then send 3 fired cases to Herrells and get their die, which is superb. I use this type of die on my 6ppc benchrest gun, adjusting with the Whidden method.

While some resistance while chambering a neck sized only case is to be expected, it is not important on a hunting gun. On a benchrest gun, to prevent movement of the gun when chambering, the full length resized case is preferred. If you are just getting started in benchrest, there are a lot of other things to worry about besides gun movement when chambering.

Yes, you can do it that way, but 1/ every cycle the brass goes through will have different dimensions - not very conducive to (ultimate) accuracy 2/ you will virtually eliminate the upper load window because it would force you to bump every cycle 3/ while waiting to body size until you "get difficulty chambering" you are undoubtedly stressing your bolt lugs leading to galling( perhaps eventually causing premature wear to the cocking cam). Try and check proper sizing by cycling sized brass through the action using the bolt drop method with galled lugs......not going to give repetitive results.

 

[dmoran]

Feel the need to add a couple more reasons to @LHSmith good reply ^^^:
4- case dimensional inconsistent creates pressure indifference in combustion, hence increased velocity spread (ES), from the indifference in pressures it takes to adhere the cases to the chamber walls.
5- case contact with the chamber walls increases pressure. From no resistance in bolt closer to having resistance on closer, I have seen +3000-psi spreads on pressure traces that accounted for +30-fps in velocity spread.
6- case dimensional inconsistency directly reflect on capacity variation as well.
Donovan